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YANG Xiaoli, LI Li, YANG Jingjuan, TIAN Yang, BAI Zhongbin
2024,40(3):1-8, DOI: 10.13982/j.mfst.1673-9078.2024.3.0448
Abstract:
The ameliorating effects of Moringa oleifera seed protein hydrolysate (MSPH) on intestinal mucositis in mice were investigated. Moringa oleifera seed protein was extracted, enzymolized, and freeze-dried to obtain MSPH. Male BALB/c mice were randomly divided into the blank control (Con) group, the model (Mod) group, and the MSPH treatment group with six mice in each group. 5-fluorouracil (5-FU) was intraperitoneally injected to induce intestinal mucositis in mice, and MSPH (800 mg/kg•BW) was administered orally for intervention. The weights of the mice were recorded daily. The intestinal histopathology was observed using HE staining, and the villus height/crypt depth was calculated. The concentrations of INF-γ, SIgA, ROS, G-CSF, ET, and D-LA in serum and those of IL-1β, IL-6, MDA, MPO, and TNF-α in the small intestine were determined using enzyme-linked immunosorbent assay. The mRNA expressions of ZO-1 and occluding in the small intestine were determined using real-time fluorescence quantitative polymerase chain reaction. Compared to the mice in the Mod group, the body masses of those in the MSPH group significantly increased (P=0.001 1) in the later stage of the experiment, while their spleen and thymus indices increased by 16.22% and 34.69%, respectively. The villus height/crypt depth increased by 25.88% in the MSPH group. The INF-γ, ROS, G-CSF, ET, and D-LA contents decreased by 16.85%, 17.50%, 14.22%, 8.28%, and 9.27%, respectively, while the SIgA content increased by 23.07% in the MSPH group compared to that in the Mod group. The contents of IL-1β, IL-6, MDA, MPO, and TNF-α decreased by 9.72%, 11.23%, 9.74%, 7.29%, and 5.17%, respectively, while mRNA expressions of ZO-1 and occludin in intestinal tissues increased by 121.64% and 29.35%, respectively, in the MSPH group. Thus, 5-FU-induced intestinal mucositis in mice can be ameliorated by MSPH intervention owing to reduction in inflammation, oxidative stress and intestinal permeability.
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2024,40(3):9-17, DOI: 10.13982/j.mfst.1673-9078.2024.3.0355
Abstract:
To determine the effects and mechanism of Angelica sinensis volatile oil (ASVO) on depressive behavior, chronic unpredictable mild stress (CUMS)-induced depression mouse models were established. Mice were divided into normal, model, low-dose, medium-dose, and high-dose ASVO (15, 30, and 60 mg/kg, respectively), and fluoxetine hydrochloride (2.1 mg/kg) groups. After four weeks of intervention, the number of central zone crossing, central zone activity duration, and sucrose preference were increased (P<0.01) while the tail suspension time was reduced (P<0.05, P<0.01) in all ASVO groups compared with those in the model group. The pathological changes in the hippocampal CA1 region were alleviated, and the contents of serum interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) decreased (P<0.01) while that of IL-10 increased (P<0.01). Despite no significant changes in the dopamine (DA) content and neurotrophin-3 (NT-3) expression in the brain tissue of mice in the low-dose ASVO group (P>0.05), the contents of DA, norepinephrine (NE), and 5-hydroxytryptamine (5-HT) and the expression of nerve growth factor (NGF), NT-3, and brain-derived neurotrophic factor (BDNF) increased in the other groups (P<0.05, P<0.01). These results indicate that ASVO can improve CUMS-induced depressive behavior in mice, which is related to the inhibition of neuroinflammation, upregulation of monoamine neurotransmitter contents, and promotion of neurotrophic factor expression.
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JIAO Xinxin, XU Min, WU Hua, LIU Zixuan, XIAO Junsong
2024,40(3):18-27, DOI: 10.13982/j.mfst.1673-9078.2024.3.0353
Abstract:
The ameliorative effects of carnosic acid (CA) on dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) in mice were assessed. Ulcerative colitis was induced by the oral administration of 3% DSS via distilled drinking water for seven days. A total of 60 mice were randomly divided into five groups: blank control (CK), DSS model (DSS), low-dose carnosic acid (CAL), high-dose carnosic acid (CAH), and mesalazine (PC). The ameliorative effects of CA were evaluated based on body weight, disease activity index (DAI) score, colonic histopathology, and changes in intestinal permeability. To investigate the possible mechanism of CA, the activities of myeloperoxidase (MPO) and superoxide dismutase (SOD), the level of malondialdehyde (MDA), the expression level of tight junction proteins, including ZO-1 and occludin, and the changes in intestinal flora in mice were examined. When the CA and DSS groups were compared, CA intervention was found to reduce weight loss and the DAI score and ameliorate the pathological damage in colonic tissues in UC mice. The MPO activity was also found to significantly decrease in the CA groups. The MDA content in the colon tissue was reduced by 13.75% and 70%, respectively (P<0.05), while the SOD activity increased by 6.12- and 9.62-fold, respectively (P<0.05), in the CAL and CAH groups. Notably, the intestinal permeability was significantly reduced, and the expression levels of ZO-1 and occludin were restored. Gavage of 50 mg/kg CA enhanced the abundance ratios of Firmicutes and Bacteroides and restored the decrease in the abundance of beneficial bacteria, such as Akkermansia, caused by DSS. The relative abundance of detrimental bacteria, such as Alistipes, was also reduced. Overall, CA may mitigate UC by lowering the levels of oxidative stress, protecting the intestinal barrier, and regulating the composition of the intestinal microbial community.
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CHEN Lihua, CHEN Shaohua, RONG Yuzhi, FENG Shengbao, ZHANG Yeting, ZHONG Yanwei, JIANG Jinjin
2024,40(3):28-38, DOI: 10.13982/j.mfst.1673-9078.2024.3.0330
Abstract:
To illustrate the high-value utilization of highland barley brewer’s spent grains, the process used to prepare its protease hydrolysate was optimized based on protein extraction from highland barley brewer’s spent grains using the DPPH free radical scavenging rate and reducing power as indicators. Thereafter, the in vitro antioxidant activity and cytoprotective effects of the hydrolysates were examined. The soluble and white highland barley brewer’s spent grains were found to be rich in protein, with protein contents of 31.46 g/100 g and 18.47 g/100 g, respectively. Using the ultrasound/cellulase-assisted alkali extraction and acid precipitation method, the protein extraction rates from the soluble and white highland barley brewer’s spent grains were 76.10% (m/m) and 29.88%, respectively. Alkaline protease was found to be most suitable for enzymatic hydrolysis of the proteins of soluble highland barley brewer’s grains. The optimal enzymatic hydrolysis conditions were as follows: solid to liquid ratio, 1:60 (m/V); ultrasonic treatment time, 15 min; enzyme dosage, 3.7% (m/m); and enzymatic hydrolysis time, 3.5 h. Under these conditions, the DPPH free radical scavenging rate of the protease hydrolysate of soluble highland barley brewer’s spent grains reached 95.02%. Different concentrations of the protease hydrolysate of soluble highland barley brewer’s spent grains did not exhibit negative effects on HepG2 cell viability. In addition, as the concentration of the protease hydrolysate of soluble highland barley brewer’s spent grains increased, ROS in cells damaged by H2O2 gradually decreased. In fact, 5.0 mg/mL (m/V) of the protease hydrolysate reduced ROS in damaged cells by approximately 50%. In addition to serving as a reference, this study provides a theoretical basis for preparing the protease hydrolysate of soluble highland barley brewer’s spent grains and illustrates its high-value utilization in healthy food and cosmetics.
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LI Shuchan, CHEN Yang, LI Yaqi, ZENG Wenshen, ZHAO Wenjun, LIANG Hongbo, LI Pan, DU Bing
2024,40(3):39-47, DOI: 10.13982/j.mfst.1673-9078.2024.3.0414
Abstract:
The in vitro antioxidant activity of fermented qushi decoction (FQD) was evaluated based on the free radical scavenging capacity. The results showed that the total antioxidant capacity of the high-dose FQD group was significantly higher than that of the unfermented qushi decoction (QD) group. In particular, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging rates and the total antioxidant capacity significantly increased by 24.38%, 11.98%, and 11.76%, respectively, in the high-dose FQD group. FQD showed no significant effects on the total egg production of Caenorhabditis elegans. However, the average lifespan of C. elegans increased by 8.02% to 26.36% after FQD intervention. Under heat stress and oxidative stress conditions, the maximum survival time of C. elegans was extended by 25% and 16.67% in the FQD groups, respectively. In addition, the antioxidant enzyme activity of C. elegans was significantly enhanced (P<0.05) and the level of lipofuscin accumulation was reduced after FQD intervention. In conclusion, FQD provides anti-aging effects on C. elegans by increasing the in vitro antioxidant capacity, prolonging the lifespan of C. elegans, enhancing stress resistance, and improving the antioxidant enzyme activity. This study tentatively indicates that FQD has anti-aging effects, and the findings provide a theoretical basis for the development and utilization of related nutraceuticals.
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DING Ping, YE Zhiming, LIU Bing, ZHANG Luyong
2024,40(3):48-55, DOI: 10.13982/j.mfst.1673-9078.2024.3.0400
Abstract:
The protective effects of protocatechualdehyde (PCA) on hearts of mice with diabetic cardiomyopathy (DCM) and its possible molecular mechanism were investigated. After the successful construction of DCM mouse models, PCA intervention was made. The heart-to-body mass ratio of mice and the cardiac function were determined. The expression levels of pro-inflammatory factors, troponin I, lactate dehydrogenase (LDH), and creatine kinase (CK) in the myocardial tissues were also determined. Hematoxylin and eosin (HE) staining and Masson staining methods were used to observe the morphological changes of the myocardial tissues. The expressions of nod-like receptor protein 3 (NLRP3) in the myocardial tissue and myocardial cells were detected, and the effects of PCA on the survival rate of myocardial cells were evaluated. The results showed that the heart-to-body mass ratio, ejection fraction, and fractional shortening increase by 5.42 mg/g, 54.91%, and 28.07%, respectively, after PCA intervention. At the same time, serum LDH, CK, and troponin I concentrations decrease to 538.51 U/L, 885.93 U/L, and 221.87 pg/mL, respectively. The levels of tumor necrosis factor-α, interleukin1β, and interleukin-6 also decreased (P<0.05). PCA also inhibited myocardial cytotoxicity and activation of NLRP3 inflammasome induced by high glucose concentrations. PCA can protect the myocardium of DCM mice. Inhibition of the activation of NLRP3 inflammasome may be the way to cardiac improvement.
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WANG Huanran, ZHU Yilong, SUN Ping
2024,40(3):56-64, DOI: 10.13982/j.mfst.1673-9078.2024.3.0365
Abstract:
The physicochemical properties of Tuber panzhihuanense polysaccharides (TPP) and their protective effects on liver oxidative damage in exercise-fatigue mice were explored. U ltrasound assisted hot water extraction was adopted to extract the crude polysaccharides from T. panzhihuanense, while column chromatography was applied to separate and purify them and determine their molecular weights and monosaccharide compositions. Exercise-fatigue mouse models were constructed. Relevant biochemical indicators were measured to explore the protective effects of TPP on the livers of exercise-fatigue mice. The results showed that TPP-A and TPP-B were obtained after separation and purification of TPP. The molecular weight of TPP-A equals 23.74 ku, and it is composed of mannose and glucose. The molecular weight of TPP-B is 46.81 ku, and it consists of mannose, glucose, and glucuronic acid. Comparison of the TPP treatment group and the excessive exercise model group (E-CK) showed that TPP significantly reduced inflammatory factors in mice liver cells, the levels of glutamate-pyruvate transaminase and glutamic oxaloacetic transaminase in serum, and the contents of reactive oxygen species (SOD) and malondialdehyde in liver tissues (P<0.05), but significantly increased the activity of antioxidant enzymes in liver tissues. In the low-, medium-, and high-dose TPP groups, the SOD activity increased by 18.15%, 39.73%, and 59.06%, respectively (P<0.05), whereas CAT activity increased by 49.91%, 86.40%, and 127.80%, respectively (P<0.05). Furthermore, GSH activity increased by 16.00%, 24.01%, and 38.87% in the low-, medium-, and high-dose TPP groups, respectively (P<0.05). The results showed that TPP enhances the activity of antioxidant enzymes in mouse liver tissues, and that its protective effects on liver injury in fatigue mice may be related to the reduction in the level of oxidative stress in cells.
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2024,40(3):65-73, DOI: 10.13982/j.mfst.1673-9078.2024.3.0350
Abstract:
Adenylate cyclase (AC) is essential for the enzymatic synthesis of cyclic adenosine monophosphate (cAMP). In fact, AC catalyzes the synthesis of cAMP and pyrophosphates (PPi) by adenosine triphosphate (ATP). In this study, Thermomonospora echinospora-derived AC (TeAC) was heterologously expressed in Escherichia coli. Following purification of the protein via affinity chromatography, its enzymatic properties were analyzed. Thereafter, the protein was utilized for the catalytic synthesis of cAMP. After inducing the expression of recombinant TeAC in E. coli at 16 ℃, TeAC was purified via affinity chromatography on a Ni column. Based on SDS-PAGE, the band of the protein of interest corresponded to 40 ku, which aligns with the expected protein size. The optimal temperature and pH of recombinant TeAC enzyme were 50 ℃ and 10.5, respectively. Enzyme kinetic analysis revealed Km, Vmax, and Kcat values of 115.1 mmol/L, 64.52 μmol/(mg•min), and 8.13 s-1, respectively, for enzymatic catalysis using the ATP substrate. After 11 h of the reaction catalyzed by TeAC, the yield of cAMP was 19.1 g/L. Overall, TeAC with efficient catalytic performance was successfully expressed, and its application in the catalytic synthesis of cAMP led to increased yield and production efficiency. This study lays the foundation for the enzymatic synthesis of cAMP.
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LIU Hao, CHEN Ye, ZENG Yingjie, CHEN Lianhong, LI Sining, WANG Mei, LI Yuanyuan, YANG Huirong
2024,40(3):74-82, DOI: 10.13982/j.mfst.1673-9078.2024.3.0416
Abstract:
Black highland barley is rich in a variety of nutrients and bioactive ingredients, and hence of important research significance and development value. This work investigated the fermentation characteristics of yeast in the wort having different proportions of black barley malt and barley malt (10:0, 8:2, 6:4, 4:6, 2:8, and 0:10 m/m; referred to as HA, HB, HC, HD, HE and HF, respectively) and the nutritional composition, quality, and sensory characteristics of the resulting beer. The results indicated that the addition of black barley malt significantly decreased the pH value, fermentability, and ethanol yield (P<0.05) thereby affecting yeast fermentation performance. An increase in the proportion of black barley malt resulted in an increase, in the β-glucan and anthocyanin contents, turbidity, and chroma of the resulting beer while the polyphenol content increased up to 105.31 mg/L in HB beer sample. The HE and HD beer samples exhibited high foaming ability , while the HB, HC, HD, and HE beer samples demonstrated good foam retention capacity. A total of 54 types of flavor substances were detected from the six beer samples. The addition of black barley malt caused a reduction in the type and concentration of alcohols while increasing the ester compounds. Around 32 esters were identified in the HB and HC beer samples. PCA analysis revealed significant differences in the flavor components of the different samples indicating that the addition of black barley malt could significantly improve the flavor composition of beer. The HB and HC beer samples obtained higher scores in sensory analysis. In summary, addition of black barley malt at 20% to 40% (m/m), resulted in beer with excellent quality, flavor, and sensory characteristics.
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SANG Wei, LI Guohua, ZHAO Xin, MA Yuzhe, QIAN Weisheng, LU Xi
2024,40(3):83-90, DOI: 10.13982/j.mfst.1673-9078.2024.3.0273
Abstract:
To screen for safe strains of Enterococcus faecalis, stool samples were collected from healthy 1-month-old infants and strains were cultured in MRS medium. A total of 64 E. faecalis strains were identified via 16S rRNA sequencing. Among them, 16 were selected for in vitro safety evaluation, and their hemolytic property, antibiotic sensitivity, and six virulence genes were determined. Based on the hemolysis results, the 16 strains of E. faecalis did not exhibit β-hemolysis. Further, the antibiotic sensitivity tests revealed that the strains were highly resistant to tetracycline (56.25%) and erythromycin (43.75%), followed by penicillin (37.50%) and ciprofloxacin (31.25%). No vancomycin- and teicoplanin-resistant strains were found. Eight relatively safe strains were identified based on the above experiments, and five virulence genes: ace, asal, efaA, cylA, and gelE, were subsequently determined, with ace+ efaA+ gelE+ as the dominant mode. Finally, four candidate strains of E. faecalis, namely LX29, LX31, LX41, and LX50, were acquired after comprehensive evaluation. Overall, our findings lay the foundation for subsequent functional research and product development.
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ZHANG Lin, XIA Chengcheng, WANG Wenyue, YU Fan, XIAO Ke, YI Chi, FAN Xin, ZHU Xiaoqing, XIAO Junfeng, LI Qin, WANG Chao, MU Yang, ZHOU Mengzhou
2024,40(3):91-101, DOI: 10.13982/j.mfst.1673-9078.2024.3.0322
Abstract:
Traditional solid-state fermented vinegar has superior flavor and quality due to its rich flora. As lactic acid bacteria are important functional microorganisms in solid-state vinegar fermentation, they are widely used in food-related and biological fields. However, lactic acid bacteria are stressed by high ethanol concentrations during vinegar fermentation. Therefore, how lactic acid bacteria survive at high ethanol concentrations should be explored. In this study, ethanol-tolerant Lactobacillus paracasei PC-5 and ethanol-intolerant Lactobacillus plantarum PR-7 were selected for comparison. Based on the biological indicators, the polysaccharide content and cell membrane permeability of PC-5 increased to 0.56% and 75%, respectively, and were significantly higher than those of PR-7 in an ethanol environment with a volume fraction of 8%. PC-5 outperformed PR-7 in terms of the activities of hexokinase (HK), 6-phosphofructokinase (PFK), and pyruvate kinase (PK) in the metabolic pathway, with activities increasing to 99.80, 2.78, and 3.43 U/mg, respectively. Finally, PC-5 was added to the vinegar at different fermentation stages to achieve mixed culture co-fermentation with yeast. Polyphenol production and total antioxidant capacity were found to increase by 32.14% and 55.56%, respectively, compared with those of single culture bacteria fermentation. Therefore, lactic acid bacteria had positive stimulation effects on vinegar fermentation. Such findings provide a good theoretical basis for the use of lactic acid bacteria in mixed culture fermentation of vinegar.
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DU Xiaoyi, YANG Jiguo, LUO Wenshan, XU Yujuan, YU Yuanshan, LI Lu
2024,40(3):102-112, DOI: 10.13982/j.mfst.1673-9078.2024.3.0375
Abstract:
Lactiplantibacillus plantarum was used to ferment the Sanhua plum juice. The optimal process for Sanhua plum juice fermented by L. plantarum was established by screening the protectant of probiotics and optimizing the fermentation process. On this basis, the fermented Sanhua plum juice was stored at 4 ℃ and 25 ℃ for storage experiments. Results showed that the optimal protectant of probiotics for the Sanhua plum juice fermented by L. plantarum was isomaltose, and its optimal addition amount was 0.50%. The optimal fermentation conditions were as follows: inoculation volume, 3%; fermentation temperature, 37 ℃; Rotation speed of fermentation, 200 r/min. Under these conditions, the number of viable L. plantarum in the fermented Sanhua plum juice could reach 108 CFU/mL, which was significantly higher than that in the fermented Sanhua plum juice before optimization. The number of viable L. plantarum in the fermented Sanhua plum juice stored at different temperatures was 107~108 CFU/mL, which met the requirements of probiotic fermented juice. During storage, L. plantarum could consume malic acid in fermented plum juice to some extent, and metabolize to produce lactic acid and acetic acid. After 28 days of storage at 4 ℃ , the content of soluble solids, content of total phenols, content of total flavonoids, content of total anthocyanins, ABTS+• clearance rates and FRAP of the fermented Sanhua plum juice decreased by 0.20 Brix°, 3.71%, 1.52%, 30.52%, 6.22%, and 0.08 g TE/L, respectively. However, the contents of soluble solids and active substances and antioxidant activity were all higher than those of the fermented Sanhua plum juice stored at 25 ℃. Therefore, in actual production, the Sanhua plum juice fermented by L. plantarum is more suitable for storage at 4 ℃. The results of this study provided a theoretical basis for industrial production and application of Sanhua plum juice fermented by L. plantarum.
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LIANG Wanshi, WU Jiamin, LIN Jiawei, CAO Kai, SONG Weitong, ZENG Xin'an, LIU Dongmei, HUANG Yanyan
2024,40(3):113-120, DOI: 10.13982/j.mfst.1673-9078.2024.3.0246
Abstract:
To investigate the structural characteristics of cpsB, a capsular polysaccharide synthesis protein prepared with the help of Lactiplantibacillus plantarum DMDL 9010, the physical and chemical properties, hydrophilic/hydrophobic properties, transmembrane structure, functional sites, phosphorylation sites, signal peptides, structural domains, conserved functional domains, sequence homology, and spatial structure of cpsB were studied and predicted by bioinformatics. The results showed that the relative molecular weight of cpsB was 2 920, the isoelectric point was 6.86, and the protein contains 191 amino acids. It was a hydrophobic protein with high stability. The transmembrane structure prediction demonstrated that it has no transmembrane structure and it is an intracellular protein. CpsB contains 15 phosphate sites. The amino acid sequence does not contain signal peptides, and the encoded proteins are all endocrine proteins. In conserved functional domain prediction, only one PHP domain was found in the gene, which might be involved in regulating the expression of the exopolysaccharide gene. In the secondary structure of cpsB, α-helix accounts for 51.14%, and there are no β-sheets and β-turn structures. The proportion of tertiary structures in cpsB was similar to that of secondary structures. In this study, the functional mechanisms of cpsB, a capsular polysaccharide synthesis protein produced using Lactiplantibacillus plantarum DMDL 9010, were studied in depth. The findings are important to understand its extracellular polysaccharide biosynthesis through genetic engineering.
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ZHAO Yujuan, LIU Caizi, GAO Yansong, ZHAO Zijian, GAO Lei, YANG Ge, WANG Chao, LI Shengyu
2024,40(3):121-130, DOI: 10.13982/j.mfst.1673-9078.2024.3.0401
Abstract:
In order to obtain the lactic acid bacteria strains suitable for the fermentation of Dongbei Suancai, the growth performance and fermentation characteristics of 10 lactic acid bacteria strains isolated from fermented vegetables were evaluated in this study. It was found that Lactiplantibacillus plantarum YJ132 and Leuconostoc mesenterides subsp. mesenterides UA107 exhibited significant fermentation potential: After 16 h of fermentation, the optical densities at 600 nm (OD600) of their fermentation broth increased to 1.707 and 1.672, respectively, whilst their pHs decreased to 3.93 and 3.88, respectively. After 24 h of fermentation, the titratable acidity (TA) reached 65.62 g/L and 63.21 g/L, respectively, and the degradation rate of nitrite reached 96.41% and 95.78%, respectively. Even after 24 h of cultivation in a 5% NaCl solution, the OD600 remained above 1.51. Overall evaluation of YJ132 and UA107 revealed their suitability as fermentation strains for Dongbei Suancai. Using YJ132 and UA107 for Suancai fermentation, the final product had a TA content of 35.96 g/L. The contents of reducing sugar and soluble protein decreased to 6.51 mg/g and 111.27 μg/g, respectively. The nitrite content was significantly reduced in the early stage of fermentation compared with the control group (P<0.01). The inoculated LAB inhibited the proliferation of harmful bacteria, such as Escherichia coli (P<0.01), and increased the microbial diversity in the Suancai with Lactobacillus being the dominant bacterial group during the middle and late fermentation stages. Accordingly, it is inferred that YJ132 and UA107 improve the quality of Suancai by regulating the microbial community. In summary, YJ132 and UA107 are excellent LAB strains that are suitable for the fermentation of Dongbei Suancai.
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HU Dandan, CHEN Shanqiao, SUN Zhidong, WU Zufang
2024,40(3):131-141, DOI: 10.13982/j.mfst.1673-9078.2024.3.0177
Abstract:
To obtain high-quality fermented leaf mustard, the process of pickling and fermentation of leaf mustard was optimized and empirically studied by means of analytic hierarchy process and multi-factor analysis. The results showed that when Lactobacillus brevis L8, Lactobacillus plantarum L9, and Saccharomyces cerevisiae Y9 are jointly applied in fermentation, the optimal ratio equals 1:1:1. After the yellowing processing of fresh leaf mustard was optimized, a three-factor and three-level orthogonal test was carried out by modifying the amount of bacterial inoculation, the duration of yellowing, and the amount of salt added. The optimal fermentation process conditions for leaf mustard are as follows: a volume fraction of bacterial inoculation of 5%, a yellowing duration of 2 d, and a salt addition amount of 5%. Under these conditions, the total acid content was 0.85 g/100 g, and the amino acid nitrogen content was 0.203 g/100 g. The half-life of nitrite was 4.23 days, and the sensory score was 86.50 points. Overall, the quality is reasonably acceptable. This research has laid a technical foundation for further developing high-quality fermented vegetables.
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QIN Yin, XU Wenhui, WU Kai, MENG Pan, CAI Ju, LIN Changsong
2024,40(3):142-152, DOI: 10.13982/j.mfst.1673-9078.2024.3.0112
Abstract:
To compare the effects of different extraction methods on the physicochemical properties and biological activities of polysaccharides extracted from Polygonatum sibiricum, the rhizomes and roots of P. sibiricum were used as raw materials and PP was extracted using water extraction (WE), enzyme extraction (EE), and ultrasonic-assisted extraction (UE) methods. This study compared the yields, chemical compositions, oil-holding capacities, alcohol solubility, hygroscopicity, antioxidant activities, the α-glucosidase and α-amylase inhibitory activities, monosaccharide compositions, and molecular weights of PP extracted using different methods. The results showed that, compared with the other two extraction methods, EE gives a higher yield (8.11%), a higher total sugar content (52.79%), greater oil-holding capacity (5.67 g/g), higher hygroscopicity (25.28%), and a higher weight-average molecular weight (5.343 × 105 g/mol). The half-maximal inhibitory concentrations (IC50) of the three polysaccharides obtained against 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) were 0.41, 0.23, and 0.25 mg/mL, respectively. Meanwhile, the IC50 values against 2,2-diphenyl-1-picrylhydrazyl were 0.19, 0.16, and 0.18 mg/mL, respectively. The IC50 values against α-glucosidase were 2.14, 1.98, and 2.06 mg/mL, respectively, whereas those against α-amylase were 0.62, 0.41, and 0.58 mg/mL, respectively. All three polysaccharides are acidic polysaccharides, while the monosaccharides are mainly composed of glucose. Infrared spectroscopy indicated that all three polysaccharides have characteristic polysaccharide functional groups, and electron microscopy reveals different structural features. In short, different extraction methods have different effects on the physicochemical properties, biological activities, monosaccharide composition, and microstructure of polysaccharides of P. sibiricum. EE is an effective method to improve the physicochemical properties and biological activities of polysaccharides, and polysaccharides extracted from P. sibiricum have certain biological activities and development value.
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YANG Xilan, DONG Jieyi, LIU Jiayue, LIU Dongmei
2024,40(3):153-162, DOI: 10.13982/j.mfst.1673-9078.2024.3.0411
Abstract:
Roxburgh rose is rich in nutrients such as polysaccharides and vitamin C as well as superoxide dismutase (SOD), and has the potential to reduce the risk and incidence of chronic diseases. In this study, Lactobacillus delbrueckii DMLD-H1 (H1) and Streptococcus thermophilus DMST-H2 (H2) were selected as the fermentation starters. By optimizing the strain ratio, inoculation amount and the addition amount of Roxburgh rose juice, the optimal fermentation process for preparing Roxburgh rose yogurt was established. The physicochemical properties of the resulting Roxburgh rose yogurt were then compared with those of the yogurt produced using commercial strains. The results showed that the optimal fermentation conditions for Roxburgh rose yogurt were as follows: H1:H2=1:2; inoculation amount, 1.0×107 CFU/mL; Addition amount of Roxburgh rose juice, 0.06 g/mL. The pH value of the Roxburgh rose yogurt obtained under such conditions was 4.47, with its acidity being 76.78 °T, and the water-holding capacity being 32.94%. From such a yoghurt, 11 volatile substances were isolated, and the relative molecular masses of proteins were mainly in the range of 22~38 ku. The pH value of the yogurt decreased to 3.89 and the viable bacterial count was 1.1×108 CFU/mL after 4 weeks of post-acidification. After comparison with the commercial yogurt, it was found that the Roxburgh rose yogurt was able to inhibit yoghurt’s post-acidification, improve the water-holding capacity, and increase the casein protein content of the yogurt; However, the Roxburgh rose may affect the original flavour substances in the yogurt. The study provides a theoretical basis for the development of a new type of Roxburgh rose yogurt and a reference for the development of new functional yogurts.
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Effects of the Free Radicals in Cold Plasma Treatment on the Structure and Allergenicity of Glycinin
PENG Kaifeng, ZHOU Yingxue, LI Xiaojuan, LIU Zhiwei
2024,40(3):163-171, DOI: 10.13982/j.mfst.1673-9078.2024.3.0304
Abstract:
A comparative investigation was performed using oxidation systems comprising single active particles, namely •OH and H2O2, and free radical scavenging systems based on cold plasma (CP) (•OH scavenging: CP + tertiary butanol; H2O2 scavenging: CP+MnO2) to explore the specificity of different active particles in CP treatment (•OH and H2O2) on the structure and antigenicity of glycinin. The IgG/IgE binding abilities of glycinin were found to gradually decrease to 69.00% as the •OH concentration increased up to 20 mmol/L in the •OH oxidation system. In the CP + tertiary butanol oxidation system without •OH, the IgG/IgE binding abilities of glycinin increased from 59.45% (IgG) and 52.50% (IgE) with CP treatment (40 kV, 2 min) alone to 67.95% (IgG) (100 mmol/L tertiary butanol) and 73.77% (IgE) (300 mmol/L tertiary butanol), respectively. Similarly, the IgG /IgE binding abilities of glycinin decreased to 65.65% (IgG) and 30.84% (IgE) as the H2O2 concentration increased to 2.0 mmol/L in the H2O2 oxidation system. In the CP + MnO2 oxidation system without H2O2, the binding abilities of glycinin increased to 91.22% (IgG) and 73.90% (IgE) as the MnO2 concentration increased to 25 mmol/L. Structural analysis based on SDS-PAGE and fluorescence spectra indicate that the •OH-induced primary and tertiary structure changes of glycinin are directly related to the reduction of the antigenicity of glycinin. Meanwhile, only the tertiary structure of glycinin was modified by H2O2. Therefore, •OH and H2O2 are key active particles in CP treatment for the oxidative modification of protein structures and its related antigenicity elimination.
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JIAO Tingting, SHI Mengnan, LUO Hui, WANG Qinghua, WANG Baijuan, RUAN Dianrong, ZHOU Ling, XIONG Changyun
2024,40(3):172-181, DOI: 10.13982/j.mfst.1673-9078.2024.3.0432
Abstract:
In this study, 18 raw Pu-erh tea samples with storage times of 3 to 20 years were selected to investigate the changes in quality indicators of raw Pu-erh tea during storage through sensory evaluation and physicochemical composition analysis. The results showed that with increasing storage time, the color of raw Pu-erh tea gradually deepened, while the fresh aroma transformed into an aged fragrance. Simultaneously, the flavor changed from mellow and rich to mellow and neutral, and the color of the leaf bottom turned darker. The sensory quality was seen to improve after storage for 10 years and above, but began to decline after 18 years of storage. The water extract components, caffeine, GC, C, and CG showed irregular changes, while the concentration of gallic acid gradually increased. The contents of free amino acids, EGC, EC, EGCG, GCG, and ECG showed a decreasing trend with increasing storage time. Seventeen quality indicators were standardized and the samples were subjected to correlation analysis, principal component analysis, and cluster analysis that revealed significant correlations among the quality indicators. The tea samples could be divided into five categories by systematic clustering and could be clustered into one category every 3~4 years. In particular, category A had the highest composite score, followed by category D, while category E had the lowest score. Although the quality indicators show a decreasing trend with the increase in number of storage years, they remained stable during 3~4 years of storage. The results provide a basis for an in-depth study on the quality changes of raw Pu-erh tea during storage.
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HU Ao, GUO Bingbing, ZHANG Wei, WANG Lan, CHEN Sheng, SHI Liu, XIONG Guangquan, LI Wei
2024,40(3):182-190, DOI: 10.13982/j.mfst.1673-9078.2024.3.0362
Abstract:
In this study, the dorsal muscle of prefabricated Channa argus was used as the research object, and the changes in temperature distribution, degree of doneness, sensory score, texture and water molecule distribution in the muscle under microwave heating at 160, 320, 480, 640 or 800 W were analyzed. The microwave cooking process parameters of prefabricated fish fillets were optimized. The results showed that the fish flesh were fully done at 70~80 ℃ under the microwave power of 160, 320, 480, 640 or 800 W. Through the measurement of degree of doneness and sensory evaluation, the optimal cooking time at different microwave powers (from low to high) were at 8, 6, 4, 3 and 2 min, respectively, with the corresponding minimum shear force being 67.85, 51.9, 63.70, 71.39 and 66.44 g. With the steady increase of the sample surface’s temperature, muscle protein denatured, the ability of muscle to bind water decreased, the proportion of free water continued to increase, and the shear force of fish flesh overally increased first then decreased. Based on the results of doneness degree, sensory score, texture analysis and water molecule distribution, the microwave treatment at 640 W for 3 min made the fish flesh fully cooked, the shear force the highest, the tenderness of the fish flesh the most popular, and the sensory score the highest. Thereby being the most suitable microwave cooking parameters for prefabricated Channa argus fillets.
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ZHANG Huimin, XING Yan, QIU Runkang, ZHAGN Limei, NI He, ZHAO Lei
2024,40(3):191-199, DOI: 10.13982/j.mfst.1673-9078.2024.3.0324
Abstract:
To track the anti-inflammatory substances in purslane, the lipopolysaccharide-induced RAW264.7 macrophage inflammation model was established, which was guided by the tracer of active substances. The extraction, separation and structural identification of anti-inflammatory substances in purslane were performed by column chromatography (for extraction), silica gel column chromatography (for separation), and preparative high performance liquid chromatography and gas chromatography-mass spectrometry (for analyses). The results showed that the three crude extracts obtained from purslane through sequential extractions with petroleum ether-ethanol, anhydrous ethanol and pure water solvents reduced the secretion of nitric oxide (NO) in the cells to 33.13, 25.83 and 20.53 μmol/L, respectively, with the crude petroleum ether extract exhibiting the strongest inhibitory effect (P<0.05). The petroleum ether phase was further separated into four fractions, with the Fr.1, Fr.2 and Fr.3 fractions had stronger anti-inflammatory effects, though the Fr.1 and Fr.2 fractions contained potential toxic components. Therefore, the Fr.3 fraction was selected for further separation. The Fr.3 fraction was separated through a silica gel column to obtain three fractions. The Fr.3.1 subfraction exhibited the strongest inhibitory effect against the NO secretion (11.80 μmol/L). The Fr.3.1 subfraction was further purified by the preparative liquid chromatography and GC-MS analysis, and the main components of the Fr.3.1 subfraction were identified as stearic acid (47.09%), di(2-ethylhexyl)phthalate (13.21%) and other components. This study established a method for separating and purifying anti-inflammatory substances from purslane, and provides a theoretical reference for the development and utilization of purslane.
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ZHANG Yu, LI Jingyuan, LEI Qi, SUN Pengdong, DENG Yang
2024,40(3):200-208, DOI: 10.13982/j.mfst.1673-9078.2024.3.0163
Abstract:
γ-Aminobutyric acid (GABA) is an active substance with several physiological functions. Its content is generally low in grains, but GABA can be effectively enriched by stress treatments. In this study, the effects of combined treatments using citric acid and spermidine on the GABA content in buckwheat sprouts were studied, and the mechanism was preliminarily analyzed. Response surface optimization experiments showed that the combination of 2 mmol/L citric acid and 0.1 mmol/L spermidine was more conducive to the accumulation of GABA during buckwheat germination, and the GABA content could reach 12.23 mg/g, which was 1.11 and 1.27 times higher than that of single treatments with citric acid and spermidine, respectively. Simultaneously, the activities of glutamate decarboxylase (GAD), diamine oxidase (DAO) and polyamine oxidase (PAO) under combined treatments were investigated to analyze the reasons for the GABA content variations. The results indicated that the activities of the three key enzymes after treatments were 1204 nmol/(min.g), 18.92 U/g and 3.58 U/g, respectively, which were significantly higher than those of groups with no or single treatments. The results suggest that the combined treatment with citric acid and spermidine significantly increases the GABA content of buckwheat sprouts. This is related to the increase in the enzyme activities of GAD, DAO and PAO, which are the key enzymes in the GABA synthesis pathway, and the combined treatment exhibits a certain synergistic effect. This study provides ideas and theoretical basis for enriching GABA in grains.
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ZHENG Xiuyan, CHEN Xi, HE Yangbo, HUANG Lei
2024,40(3):209-218, DOI: 10.13982/j.mfst.1673-9078.2024.3.0289
Abstract:
Fresh Dictyophora rubrovalvata M.Zang was subjected to coal fire drying (CFD), air source heat pump drying (ASHPD), microwave vacuum drying combined with forced air drying (MVD+FAD), and vacuum freeze drying (VFD).The quality attributes of the dried samples, including appearance, color, nutritional composition, amino acid composition, texture properties, and microstructures, were compared. Based on the experimental results, VFD could maintain the stalk and skirt shape of D. rubrovalvata M.Zang to the maximum extent. The VFD-processed samples had the highest protein, crude fiber, and total acid contents, and their color was the closest to that of fresh products (ΔE=3.60). The stalk and skirt shape of D. rubrovalvata M.Zang prepared by ASHPD were also well maintained. In addition, the ASHPD-processed sample had the highest fat content and its protein content was preserved reasonably well after ASHPD. The sweetness/bitterness value of D. rubrovalvata M.Zang dried by different methods was ranked as follows: VFD (4.99%)>MVD+FAD (4.66%)>ASHPD (4.50%) >CFD (4.37%). The tissue structure of the VFD sample was brittle, and its internal binding force was smaller than that of the other samples. Notably, these properties are similar to those of fresh products. However, the dried products prepared using the other three drying methods had greater internal binding strengths and higher resistance to damage. As a result, more energy is needed for chewing before swallowing. The D. rubrovalvata M.Zang samples prepared by VFD and ASHPD had clearer cellular structures, with VFD enabling better preservation of the original cellular structure. The comprehensive evaluation results of the drying methods appeared in the following order: VFD>MVD+FAD>ASHPD>CFD. Overall, VFD is an ideal drying method; however, this method is associated with a higher cost than the other methods. Among the methods, ASHPD has a higher promotion value in practical production.
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LI Zhengwen, RUAN Zheng, LI Biansheng, LI Dandan, LI Laifeng, WU Wenjing
2024,40(3):219-228, DOI: 10.13982/j.mfst.1673-9078.2024.3.0320
Abstract:
Egg white has good foaming and gelling properties, thus plays an irreplaceable role in aerated foods. In order to study the physico-chemical properties of egg white foam gels in different states, egg white foams in different whipping states (whipping time: 0, 50, 70 or 90 s) were prepared at room temperature and a constant stirring rate (980 r/min). The physicochemical properties of the egg white foams were determined. Then, the egg white foams with different whipping times were heated for solidification to prepare egg white foam gels. The properties of the egg white foam gels were investigated through microscopic observation, color measurements, texture analysis and rheological analysis. The experimental results showed that at a constant stirring rate, the bubble state of the egg white foam changed with the whipping time. Prolonging the whipping time appropriately could benefit the formation of solid foam with low specific gravity (0.16~0.17), high foaming ability and foam stability. The egg white foam after being whipped for 70 s (foam in small hook-like shape, with a specific gravity of 0.165) had the highest stability. After being heated for solidification, the lightness of such an egg white foam gel (L*=90.28) increased significantly, whilst the hardness (27.69 g) and elasticity (0.78 mm) decreased significantly (P<0.05), exhibiting excellent gel properties. The results revealed that the rheological properties of egg white foam influenced significantly the properties of egg white foam and its gel, which provides a theoretical reference for the application of egg white foam in aerated foods.
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MA Feng, ZHANG Zhenyu, CHEN Qimiao, NIU Jiajia, CAO Yong, MIAO Jianyin
2024,40(3):229-238, DOI: 10.13982/j.mfst.1673-9078.2024.3.0438
Abstract:
The soluble dietary fibers (SDF) of pear pomace were prepared by enzymatic hydrolysis using cellulases, and the SDF yield was taken as the evaluation index to optimize the process conditions for the preparation of SDF by enzymatic hydrolysis through single factor experiments and response surface methodology. The physicochemical properties and functional characteristics of the pear pomace SDF were analyzed. The results showed the SDF extraction process to be optimized under the following conditions: an enzyme/substrate mass ratio of 1.1%, reaction time of 5.2 h, material-to-liquid ratio of 1:21, reaction temperature of 37 ℃, and a pH value of 4.5. The resulting experimental SDF yield equaled 6.29%, which was consistent with the theoretical value of 6.23%. The SDF showed improved water holding and swelling capacity compared to the original pear pomace. In addition, SDF could scavenge DPPH (IC50=0.494 mg/mL) and ABTS+ (IC50=0.429 mg/mL) free radicals, demonstrating good antioxidant activity. SDF showed better cholesterol adsorption performance in the intestine (4.81 mg/g), but the adsorption capacity for NO2- in the gastric environment (84.68%) was significantly higher than that in the intestinal environment (16.21%). The SDF of pear pomace seem to have good physical and chemical functional properties, and this study provides a theoretical basis for the high-value utilization of pear pomace.
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CAI Xuemei, YUE Yang, LIU Xin, ZHANG Jing, PENG Yiqin, YI Yuwen, QIAO Mingfeng
2024,40(3):239-246, DOI: 10.13982/j.mfst.1673-9078.2024.3.0412
Abstract:
In order to select the suitable cooking methods for Brassica rapa L. (BrL), this study analyzed the effects of five cooking methods (boiling, steaming, microwaving, pressure cooking, and frying) on the nutrient and free amino acids (FAA) contents, antioxidant activities, and flavor characteristics of BrL using a food calorimeter (Calory Answer), an amino acid autoanalyzer, and an E-tongue. The results showed that the total FAA content of fresh BrL is 261.06 mg/100 g, with sweet amino acids dominating. The total FAA contents of BrL increased by 90.50%, 59.74%, and 83.92% by steaming, microwaving, and frying, respectively. The proportion of bitter amino acids also increased. Boiling increased the proportions of sour and umami amino acids and reduced the proportion of bitter amino acids. Frying, microwaving, and pressure cooking significantly increased the caloric value and carbohydrate content of BrL, whereas steaming and frying significantly increased the polyphenol content and antioxidant activity of BrL (P<0.05). E-tongue can be used to effectively evaluate the flavor differences of BrL samples treated with different cooking methods. The flavor of boiled and steamed BrL is similar. The flavor of microwaved and pressure cooked BrL is also similar. The taste of fried Brl greatly varied from that of the other BrL samples. Comprehensive evaluation based on principal component analysis (PCA) suggested that the most suitable cooking method for BrL is steaming, followed by frying.
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TANG Mengting, LIAO Xiansheng, GU Mengya, LI Pengchun, HONG Yaping, XU Mengting, JIN Shan, YE Naixing, ZHANG Jianming
2024,40(3):247-258, DOI: 10.13982/j.mfst.1673-9078.2024.3.0452
Abstract:
To investigate the aroma differences of three types of tea dhools scented with osmanthus, headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), sensory evaluation, and odor activity values (OAV) were used to analyze the aromatic compounds of osmanthus black tea, osmanthus beauty tea, and osmanthus oolong tea. A total of 726 common aromatic compounds and 324 differential aromatic compounds were detected in the three types of osmanthus teas (P<0.05). Osmanthus tea is mainly composed of heterocyclic compounds, terpenoids, esters, hydrocarbons, and ketones, accounting for 78.73% of the total compounds. The key aromatic compounds (OAV>10) in osmanthus tea include furaneol, α-ionone, linalool, citral, hotrienol, and 1-dodecanol. The key aromatic compounds of osmanthus black tea were found to be linalool, β-myrcene, α-ionone, β-ionone, linalyl acetate, benzyl alcohol, and 1-dodecanol, whereas those of osmanthus beauty tea include phenylacetaldehyde, citral, hotrienol, linalool, terpinene, α-ionone, and β-ionone. Lastly, the key aroma components of osmanthus oolong tea were found to be α-ionone, indole, β-ionone, and 1-dodecenal. This study shows that osmanthus scenting can significantly improve the aroma of different tea dhools and give them a rich and long-lasting osmanthus fragrance. The quality of osmanthus black tea was observed to be the best.
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YU Henghe, MA Yifan, HAN Dong, HUANG Feng, LI Xia, GUO Debin, ZHANG Chunhui
2024,40(3):259-271, DOI: 10.13982/j.mfst.1673-9078.2024.3.0312
Abstract:
To construct the characteristic flavor fingerprints of soy-marinated duck neck, three commercially available soy-marinated duck necks (H brand, W brand and J brand) were analyzed by electronic nose, electronic tongue, gas chromatography-mass spectrometry (GC-MS), and high-performance liquid chromatography (HPLC), combined with odor activity value (OAV), taste activity value (TAV), and EUC (equivalent umami concentration). The results show that 44, 37 and 32 volatile flavor substances were identified in the W brand, J brand and H brand, respectively. Among them, compounds such as eugenol, linalool, ethyl cinnamate and anethole were identified as the common characteristic volatile flavor substances because of their high OAVs and special aromas, which contributed to sweet, fruity, and fat aromas of the three types of duck necks. The results of electronic nose showed that three kinds of duck necks differed in sulfur-containing compounds and nitrogen oxides; Glutamic acid, alanine acid, 5'-inosinic acid and 5'-guanylic acid were identified as the characteristic taste substances of soy-marinated duck necks owing to their TAVs higher than 1, which contributed significantly to umaminess and sweetness. In addition, the EUC value of H brand (4.41 g MSG/100 g) was significantly higher than those of the other two groups (P<0.05), indicating that the umaminess of H brand duck neck was better than J brand and W brand duck necks. This result is also consistent with the results of the electronic tongue test. This study provides a theoretical foundation for maintaining the characteristic flavor of soy-marinated duck neck and improving the flavor of the product.
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WANG Lin, HAN Sensen, LI Cong, CAI Kezhou, ZHOU Hui, XU Baocai
2024,40(3):272-280, DOI: 10.13982/j.mfst.1673-9078.2024.3.0238
Abstract:
To explore the major flavor substances in beef soup and the flavor differences between different brands of beef soup, seven brands of beef soup were selected, and their flavor substances were determined using liquid chromatography, amino acid analyzers, and electronic tongues. Seventeen free amino acids and five flavor nucleotides were identified in seven brands of beef soup, with the main flavors being sourness, bitterness, saltiness, umami, Kokumi, and aftertaste. The contents of solids, salt, and water-soluble proteins in beef soup are influenced by the processing techniques, which in turn affects the flavor of the beef soup. The five main substances causing flavor differences are I, Glu, Ser, HX, and Phe, according to the partial least squares discriminant analysis (PLS-DA). Seventeen flavor substances affecting the texture of beef soup were determined by partial least squares regression (PLSR). The results provide a basis for further study on the directional regulation of the quality and flavor of beef soup.
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LIANG Ming, HU Junpeng, CHEN Rongqiao, XIAN Yanping, WU Yuluan, BAI Weidong, DAI Hang, HOU Xiangchang
2024,40(3):281-288, DOI: 10.13982/j.mfst.1673-9078.2024.3.0440
Abstract:
A modified “quick, easy, cheap, effective, rugged and safe” (QuEChERS)-gas chromatography-mass spectrometry (GC-MS) technique was adopted to determine 19 flavor esters in milk samples having different fat contents, and the relationship between flavor esters and fat content was investigated. The flavor esters were extracted with acetonitrile from the samples and purified using prostate specific antigen (PSA). Subsequently, the extract was filtered through a filter membrane and analyzed using GC-MS. The 19 flavor esters were separated using a DB-FFAP chromatographic column. They were then detected in the single ion monitoring (SIM) mode, and their contents were quantified using the external standard calibration method. The results showed good linear relationships for 19 flavor esters within the range of 5.0~500.0 μg/L, with their correlation coefficients (R2) being higher than 0.999. The average recoveries were in the range of 76.0%~109.2%, and the intra-day precision was 1.9%~8.5% (n=6). The limits of detection (LODs) and limits of quantification (LOQs) are 3.5~14.0 μg/kg and 10.0~40.0 μg/kg, respectively. Real-time sample detection revealed the contents of δ-decalactone, γ-dodecalactone, and δ-dodecalactone to be positively correlated with the fat content, and therefore were higher in whole milk followed by low-fat milk and by skimmed milk. In addition, flavors and fragrances may be added in some milk samples, resulting in significant increases in the contents of γ-nonalactone and γ-undelactone. The proposed method is rapid, simple, and accurate, with good reproducibility and can be used to determine 19 flavor esters in milk samples of different fat contents.
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XIE Yongheng, LU Shaohao, LIU Chongsheng, XU Liping, XU Gaoyan, WU Zhaoming, ZHANG Lina, ZHAO Zhenjie, GAO Yang
2024,40(3):289-300, DOI: 10.13982/j.mfst.1673-9078.2024.3.0046
Abstract:
In this study, gas chromatography-mass spectrometry/olfactometry (GC-MS-O) combined with odor activity value (OAV) was used to identify 9, 16, 12 and 10 key aroma compounds from Jiashi, Huanghe, Xizhoumi 25 and Xizhoumi 17, respectively. Among which, 7 aroma substances, such as ethyl acetate, butyl acetate and benzyl acetate, were the characteristic aroma substances of Chinese thick skinned muskmelon. Six sensory characteristics of melon, namely fruity, cucumber-like, sweet, greens, floral and musk-roasted aromas, were determined by quantitative descriptive analysis, and the corresponding sensory scores were given. Cluster heat map analysis was used to analyze the differences in the types and contents of key aroma substances in four kinds of melon. Partial Least Squares Regression (PLSR) was used to investigate the reasons behind the formation of sensory characteristics of melon aroma. The results showed that ethyl acetate was related to the musk-roasted sensory characteristics, 2-methylbutylacetate and butyl acetate were related to fruity sensory attribute. Benzyl acetate, 3-methylbutanal, (E,Z)-3, 6-nonene-1-ol, methyl thioacetate, (Z)-6-nonene-1-ol and ethyl 3-methylbutyrate were significantly correlated with the floral and cucumber-like sensory features of melon. This study provides a basis for improving the aroma of thick skinned muskmelon and establishing its sensory quality evaluation system.
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ZHANG Ying, WU Shi, GU Qihui, YE Qinghua, ZHANG Jumei, CHEN Moutong, WU Qingping
2024,40(3):301-308, DOI: 10.13982/j.mfst.1673-9078.2024.3.0439
Abstract:
Antiserum was prepared by immunizing SPF-grade Balb/C mice with the whole-cell protein of the highly virulent Listeria monocytogenes 819-2 strain. The extracellular proteome of the strain was analyzed using the immunoproteomics approach, to identify and obtain strong immunogenic proteins of L. monocytogenes as candidate antigens for specific antibody preparation. The whole-cell protein of the 819-2 strain was extracted using the ultrasonic method. The SPF-grade Balb/C mice were immunized four times using this protein extract to prepare antiserum, and the titer of the antiserum equaled 1:512 000 as measured using indirect ELISA. The extracellular protein of L. monocytogenes 819-2 strain was extracted using TCA precipitation with 10% (m/V) deoxycholate sodium (DOC). The spots for strong immunogenic proteins were identified with the help of immunoproteomics and LC-MS/MS. Two-dimensional electrophoresis results showed 85 protein spots and five strong immunogenic proteins, including P60, InlC, MltG, Enolase, and YxeA family protein, were successfully identified. The results provide a foundation for the preparation of specific antibodies based on highly immunogenic proteins for the enrichment and rapid detection of L. monocytogenes in food and food processing environments.
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WANG Wei, JIANG Feng, WU Wanqin, CHEN Ran, ZHU Xiaoling, LI Beibei
2024,40(3):309-318, DOI: 10.13982/j.mfst.1673-9078.2024.3.0269
Abstract:
Identification of pork with lymphoid tissues based on quantitative analysis of inflammation and immunity-related metabolites through ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was studied. Samples were extracted with 80% acetonitrile-water and degreased with n-hexane. The separation was carried out using a BEH C18 column (2.1 mm×100 mm, 1.7 μm), with 5 mmol/L ammonium acetate solution-acetonitrile as the mobile phase. Gradient elution was conducted for 25 min, and positive and negative ions were determined simultaneously. A quantitative method for 38 inflammation and immunity-related metabolites based on UPLC-MS/MS was established to quantitatively examine these metabolites in ordinary pork and pork with lymphoid tissues, and the identification model for the latter was constructed by chemometrics. The results reveal a good linear relationship between the target compounds in the concentration range of interest. The recoveries of low concentration spiked samples range from 50.3% to 118.8%, and the recoveries of high concentration spiked samples range from 57.0% to 127.0%, with RSDs below 20%. Based on the PCA and OPLS-DA models, the pork samples with lymphoid tissues and ordinary pork samples can be well identified, and the samples with lymphoid tissue proportions more than 20% can be distinguished from ordinary samples. The R2 and Q2 were 0.954 and 0.858, respectively, and the model showed no over-fitting and good prediction performance. The contents of inflammation and immunity-related metabolites combined with chemometrics can effectively distinguish pork samples with lymphoid tissues from ordinary pork samples, providing a reliable method for the identification of pork with lymphoid tissues.
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LI Xiaoling, WAN Yiwen, XIAO Wei, SUO Wenwen, YANG Xiao
2024,40(3):319-325, DOI: 10.13982/j.mfst.1673-9078.2024.3.0197
Abstract:
A method based on Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) dispersive solid-phase extraction coupled with high performance liquid chromatography tandem mass spectrometry was developed for the determination of pendimethalin in aquatic products. The samples were extracted with ethyl acetate containing 0.1% (V/V) formic acid, and the extracts were purified by dispersive solid-phase extraction with 0.6 g polystyrene-divinylbenzene (PS-DVB) and 0.2 g primary secondary amine (PSA) sorbents. The purified extracts were collected and concentrated at 40 ℃ to almost dry under nitrogen gas. The resulting extracts were re-dissolved in 1.0 mL of acetonitrile, filtered through microfiltration membrane (0.22 μm), and analyzed by high performance liquid chromatography-tandem mass spectrometry. The target compounds were separated on a Kinetex C18 column (100 mm×2.1 mm, 2.6 μm), and gradient elution was performed with acetonitrile and 0.1% (V/V) aqueous formic acid solution. Electrospray ion source (ESI) and selective reaction monitoring (SRM) were used for analysis, and the matrix-matched internal standard method was used for qualitative and quantitative determinations. The results showed that good linear relationship was in the range of 2~100 μg/L, with the correlation coefficient being 0.999 5. The limits of detection (LOD) and quantitation (LOQ) were 0.5 μg/kg and 1.0 μg/kg, respectively. The average recoveries of pendimethalin at three different spiking levels in a sample matrix carp, procambarus clarkiir or pelodiscus sinensis ranged from 78.9% to 110.6%, with RSDs ranging from 3.8% to 6.8% under. This method has the advantages of high speed, accuracy and sensitivity, and can meet the requirements for detecting pendimethalin residue in aquatic products from rice fields.
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LI Xin, SHEN Xiaojun, WANG Yuanyuan, LIU Rui, YAN Gang
2024,40(3):326-332, DOI: 10.13982/j.mfst.1673-9078.2024.3.0309
Abstract:
In order to achieve rapid detection of the catechin content in crude Pu-erh tea, high performance liquid chromatography (HPLC) was used to determine the contents of three catechin monomers, namely, epigallocatechin gallate (EGCG), epigallocatechin (EGC), and gallic acid (GA), in 50 crude Pu-erh tea samples, and the partial least squares models (PLS) were also established to predict the contents of these catechins by combining the near infrared spectra (NIRS) of the samples. The established models were then verified. The experimental results showed that the coefficient of determination (R2) values of the models for EGCG, EGC, and GA models were 99.99%, 99.99%, and 99.92%, respectively. The values of root mean square error of calibration (RMSEC) for EGCG, EGC, and GA were 0.17, 0.15, and 0.10, respectively, and the corresponding relative standard deviation (RSD) values were 0.19%, 0.27%, and 0.56%, respectively. The results of external validation indicated that the mean absolute errors between the predicted values and actual values of the three models for catechin monomer contents were 0.13, 0.12, and 0.07, respectively, and the mean relative errors were 0.17, 0.25, and 0.45, respectively. The experimental results show that the near infrared analysis model established in this study has high prediction accuracy and stability, and has potential application value in rapid detection of catechins in crude Pu-erh tea.
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GU Yanping, ZHANG Shufei, ZHANG Huiyun, ZHANG Zhanhui, SUN Haibin, LIU Huaitao, LIU Yanping, WANG Xiaonan, CHANG Hong, WANG Siwei
2024,40(3):333-341, DOI: 10.13982/j.mfst.1673-9078.2024.3.0168
Abstract:
In order to understand the status of Chinese maximum residue limits (MRLs) standard for the pesticides in litchi and longan, and ensure the development of national litchi and longan industry, the current status of the Chinese MRLs standard for pesticides in litchi and longan were analyzed in this article based on the “National food safety standard-maximum residue limits for pesticides in food” (GB 2763-2021), combined with the registration of pesticides on the litchi and longan in China. The MRLs, Acceptable Daily Intake (ADI) and corresponding standards for detection methods are listed according to the types of pesticides. Statistics showed that there were 133 MRLs in 125 types of pesticides related to litchi and longan in GB 2763-2021, among which 109 recommended MRLs have corresponding detection methods, and 33 valid MRLs that have been registered in China. Comparing to GB 2763-2019, 53 MRLs standards were newly added and the growth rate was up to 66.25%. Moreover, 3 standards on detection methods were newly added. However, according to the data from the monitoring of pesticide residues, standards on MRLs and detaction methods for litchi and longan still need to be supplemented, and the process for setting up standards on the MRLs and detection methods for litchi and longan needs to be speeded up.
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ZHANG Zhihao, SUN Liping, SHI Fengfeng, HUANG Jiaxing, WEI Xiaoping
2024,40(3):342-349, DOI: 10.13982/j.mfst.1673-9078.2024.3.0332
Abstract:
In this study, a highly efficient and accurate method was developed for identifying Guizhou characteristic blueberry honey (from honey bee Apis cerana) based on specific TaqMan probe of real-time fluorescent PCR. Blueberry honey samples (including Apis mellifera) were collected from the blueberry growing areas of Bai zhulin, Maka and Wukaping in Guizhou, meanwhilw, commercial local honey and Canadian blueberry honey were also purchased. Twenty-six blueberry samples at the same flowering stage were collected from the blueberry gardens and the areas around the bee farms in the Baizhulin region of Majiang Town, Guizhou Province. The trnL gene in the sampling plant genome were sequenced. A trnL gene-specific primer of blueberry was designed based on the multiple sequence alignments of trnL gene sequences in the plant genome. TaqMan probe was used for validation. The results showed that the TaqMan probe had high specificity, and the minimum concentration of DNA as low as 0.3 ng/μL can be detected was in blueberry sample using the established TaqMan probe real-time fluorescent PCR detection method. Such an established method was used to test the samples of 11 kinds of commercial honey and Guizhou blueberry honey. It was found that the Ct value of Guizhou blueberry honey was 24~26, the number of blueberry pollen was 800~1 700, and the Ct values of other honey samples were over 30, indicating that this method can effectively distinguish Guizhou blueberry honey from other honeys, thereby having a good application prospect.
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2024,40(3):350-360, DOI: 10.13982/j.mfst.1673-9078.2024.3.0024
Abstract:
Food Glycemic Index (GI) is an important index reflecting food digestion and absorption rates and postprandial glycemic response, which can accurately reflect the fluctuation of human blood glucose after food intake for a period of time. According to the value of GI, foods are generally divided into three categories: high GI food (GI>70), medium GI food (55
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2024,40(3):361-372, DOI: 10.13982/j.mfst.1673-9078.2024.3.0061
Abstract:
Fucoxanthin, a natural carotenoid with an antioxidant activity, is mainly from marine algae such as brown algae and microalgae (e.g. diatoms and chrysophyta). Fucoxanthin has great potential for market development, but its industrialization degree is relatively low. In view of this problem, this review firstly provides an overview of the physicochemical characteristics and functional properties (such as antioxidative, anti-tumor, anti-obesity and anti-inflammatory effects) of fucoxanthin. The research progress on the upstream development and downstream processing technologies for fucoxanthin production is comprehensively reviewed. The upstream development of fucoxanthin (biosynthetic pathway, screening of fucoxanthin for production, and culture methods and conditions), and downstream processing technologies (extraction and purification methods, steady-state preparation, and product manufacturing technology) are introduced in detail. The currently existing technical bottlenecks are pointed out and possible solutions are proposed. Finally, the application status of fucoxanthin in food, cosmetics, medicine is presented. This paper will provide reference value for future research on industrializable technologies of fucoxanthin.
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YU Xia, HU Jiafeng, HUANG Xiaodong, HU Xiaoqing
2024,40(3):373-378, DOI: 10.13982/j.mfst.1673-9078.2024.3.0087
Abstract:
Plants, especially medicinal plants, contain a variety of active substances such as polysaccharides, polypeptides, polyphenols, amino acids, etc., and the carbonaceous substances stored in plants account for 80% of those in all the organisms, which have a broad application prospect in cosmetics. However, the effective ingredients in natural plant materials are relatively low, and the traditional extraction processes are inefficient and even result in some toxic components with side-effects in the extracts, thereby affecting their applications in cosmetic raw materials. These problems can be solved by microbial fermentation of plant raw materials or their extracts, by which the release of active substances is promoted, these active substances are enriched or transformed into new active substances, their efficacies can be enhanced and expanded, and toxic side effects are reduced. Plant active substances derived from fermentation have multiple functions such as antibacterial, whitening, antioxidative, anti-inflammatory, and collagen regeneration-promoting effects, which lead to broad application prospects in the cosmetics products.
Volume 40,2024 Issue 3
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Effect of salidroside and its aglycone tyrosol on life span of C. elegans
huang zhongxing, Bisheng Zheng, Yuanyuan Wang, Yuanyuan Wang
Abstract:
Abstract: Rhodiola extract has biological activities such as anticancer, antidepressant, and longevity. Salidroside (Sal) and its aglycone tyrosol (Tyr) are the two main active monomers of Rhodiola rosea L., which has potential anti-aging activity. Caenorhabditis elegans (C. elegans) were used as an aging model to study the potential anti-aging activities of Sal and Tyr. Our results showed that the lifespan of C. elegans were effectively prolonged by Sal and Tyr. The lifespan of C. elegans were extended by 13.91 and 15.19% by high doses of Sal (200 μmol/L) and Tyr (100 μmol/L), respectively. Both Sal and Tyr could improve motility, stress resistance and antioxidant stress ability. After the treatment of C. elegans with high concentration of Sal and Tyr, ROS levels were decreased by 27.63% and 18.39%, MDA levels were decreased by 71.81% and 64.64%, CAT enzyme activity was increased by 2.17 times and 3.02 times, and SOD activity was increased by 3.03 times and 1.76 times, respectively. RT-qPCR experiments showed that daf-2 and age-1 genes were down-regulated and daf-16, jnk-1 and skn-1 genes were up-regulated by Sal and Tyr. The transcription factors DAF-16 and SKN-1 are induced into the nucleus by Sal and Tyr to achieve anti-aging effects .In summary, Sal and Tyr can show anti-aging activities by regulating reoxidation-reduction balance and regulating the expression of anti-aging and anti-oxidation-related genes in nematodes. Therefore, Sal and Tyr are good choices for the development of dietary supplements to delay aging.
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Investigating of The Anti-fatigue Mechanism of Earthworm Based on UHPLC-Q-TOF-MS/MS and Network Pharmacology
孟璇, 王梦娇, 赵天旸, 张国忠, 赵德龙, 何希宏, 赵化冰, 贾立明, 贾京华, 张黎明
Abstract:
The anti-fatigue mechanism of the active ingredients of earthworm was investigated based on ultra performance liquid chromatography-quadrupole-time of flight mass spectrometry/mass spectrometry (UHPLC-Q-TOF-MS/MS) analysis and network pharmacology. UHPLC-Q-TOF-MS/MS was used to obtain the information of the chemical constituents of earthworm, and the targets of constituent action, fatigue and anti-fatigue gene targets were collected to take the intersection, and gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses were performed. KEGG Mapper was utilized to elucidate the anti-fatigue mechanism initially, and animal experiments were designed to verify the anti-fatigue efficacy of earthworm. Network analysis showed that the anti-fatigue effects of Dillon were mainly focused on the positive regulation of phosphorylation, the NF-kappa B (NF-κB) signaling pathway, Serotonergic synapse, the JAK-STAT pathway and the arginine and proline metabolism pathway. The results of animal experiments showed that, compared with the control group, the experimental time of weight-bearing swimming in mice in the earthworm extract group was prolonged from 9.78 min to 34.07 min (P<0.001), which was more significant in the middle-dose group, the content of hepatic glycogen was significantly elevated, which was 2591.21 mg/g in the high-dose group (P<0.001), and the content of urea nitrogen and blood lactic acid in the high-dose group were reduced to 3.65 nmol/L and 182.21 nmol/L, respectively (P<0.01). In conclusion, the anti-fatigue effect of earthworm was exerted through the synergistic effect of multi-components, multi-targets and multi-pathways, which provides new ideas and methods for the subsequent research on anti-fatigue mechanisms.
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Preparation and Oxidative Stability of Walnut Oil Microcapsules
Abstract:
In this study, walnut oil microcapsules were prepared by using spray drying technology to solidify β-cyclodextrin and soy protein isolate as wall materials. Encapsulation efficiency was the chosen evaluation index，and determination of the optimal experimental range was accomplished through single-factor experiments on core-to-wall ratio, solid content concentration, ultrasonic power, and time. Following this, response surface experiments were conducted to find the best preparation process by establishing a quadratic regression equation model between the four factors mentioned above and the encapsulation efficiency. Results indicated that the highest encapsulation efficiency reached 73.02%, under conditions of 430W ultrasound power, 1:3 core-wall ratio, and 12.5 wt.% solid concentration. Additionally, physicochemical properties of the walnut oil microcapsules were determined, and they exhibited excellent solubility (86.01%). The contact angle was 41.11°, which indicated that it had good fluidity. The particle size distribution was uniform, concentrated around about 3 μm. At the same time, it had good thermal stability, and had a stable structure below 264 ℃. Oxidative stability experiments showed that the shelf-life of walnut oil microcapsules at room temperature (25 ℃) was 174 d, which was significantly higher than that of 75 d for unencapsulated walnut oil. Hence, walnut oil microcapsules prepared under the optimal conditions in this study exhibited excellent solubility and stability, thereby expanding the application scope of walnut oil in food processing.
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Extraction of Polysaccharides from Grifola Frondosa by Deep Eutectic Solvents and Analysis of Their Antioxidant Activities
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In order to realize the efficient utilization of G. Frondosa Polysaccharide (GFP), novel Deep Eutectic Solvents (DESs) were used to extract GFP. The extraction conditions were optimized and the antioxidant activities of the GFP were investigated. From eight DESs, DES-2 (choline chloride-ethylene glycol) was screened as the most efficient one for extracting polysaccharides from the fruiting bodies of G. frondosa. On the basis of single factor experiment, the orthogonal experiment was designed to optimize the extraction conditions of GFP. The optimal extraction condition was determined as DES-2 water content of 10%, DES-2 molar ratio of 1:1, liquid-solid ratio of 80 mL/g, extraction temperature of 60 °C, and extraction time of 40 min. Under this condition, the extraction yield of GFP was 30.25%, which was 2.23 times that of traditional hot water extraction. The results of antioxidant studies indicated that W-GFP extracted by hot water had EC50 values of 0.11 mg/mL, 0.45 mg/mL and 0.26 mg/mL in the DPPH, ABTS and ·OH radical scavenging tests, respectively, while D-GFP extracted by eutectic solvents had corresponding EC50 values of 0.11 mg/mL, 0.56 mg/mL and 0.23 mg/mL. Therefore, this study suggested that extraction of GFP by DES had the advantages of green and high yields and the obtained GFP exhibited good antioxidant activities, which provides theoretical basis for the development and utilization of GFP functional foods.
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Improvement of Interfacial Properties of Rice Glutelin via Complexing with Pectin and the Storage Stability of Pickering Emulsion
Zhang Jiayu, Zhou Jisong, Fu Qingxuan, Huang Guiying, Hou Wenfu, Peng Dengfeng, Jin Weiping
Abstract:
Rice glutelin (RG) is a commonly used food emulsifier. However, RG is easy to aggregate into hydrophobic particles with large size at the neutral pH, resulting in poor stability and weak interfacial activity. In this work, RG was modified by pectin through electrostatic complexing, and the effects of the RG-to-pectin ratio on the particle size, contact angle, interfacial adsorption property and interfacial film structure were explored. On this basis, these composite particles were utilized as interfacial stabilizers to fabricate the Pickering emulsions, and their particle size distributions, microstructures, rheological properties, and storage stabilities were investigated. Results showed that when the mass ratio of RG to pectin was 1:1, the average particle size of the composite particle was 675.4±24 nm, the contact angle was 64.23±2.5°, the oil-water interfacial tension was reduced from 36.55±0.055 mN/m to 13.00±0.29 mN/m, and the interfacial film was mainly dominated by elasticity with an elastic modulus of 46.07±0.55 mN/m. The Pickering emulsion covered by this composite particle possessed the smallest particle size (d4,3 ~ 31.1±0.047 μm) as well as the highest apparent viscosity and storage modulus. Therefore, complexing with pectin could significantly reduce the size of RG and give it appropriate surface hydrophilicity, thereby improving its abilities to reduce interfacial tension and increase the viscoelastic properties of the interfacial film, which was conducive to prepare stable Pickering emulsion. This study provides a new strategy for expanding the application of RG in food emulsion systems.
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Study on the Active Constituents of Dendrobium officinale by Microbial Fermentation
Abstract:
Dendrobium officinale is a plant with medicinal and edible homology, ranking first among the "Nine Great Fairy Grasses in China". To investigate the changes in active ingredients of Dendrobium officinale during microbial transformation. Select the most suitable strain for fermentation using Dendrobium officinale as the fermentation substrate to ferment Dendrobium officinale, based on a single factor experiment, the comprehensive score changes of the polysaccharide, flavones and total phenolics were used as evaluation indicators, using orthogonal experiments to optimize the optimal fermentation process, and measure the antioxidant capacity of Dendrobium officinale after fermentation. Using Dendrobium officinale as the fermentation substrate, the most suitable strain is Aspergillus niger. The optimal fermentation process is as follows: the ratio of material to liquid is 1:3, the initial pH is 8, the inoculation amount is 10%, the fermentation temperature is 34 ℃, the fermentation time is 9 days, and the validation test results show that the polysaccharide content is 72.65 mg?g-1, the flavonoid content is 6.67 mg?g-1, the polyphenol content is 11.32 mg?g-1, and the comprehensive score Pi is 0.9455. Using Vitamin C as a control, the DPPH free radical scavenging ability IC50 of fermented Dendrobium officinale was 0.672 mg?g-1, ABTS free radical scavenging ability IC50 was 0.408 mg?g-1, and reducing ability IC50 was 16.498 mg?g-1. The screened strains can better dissolve the active substances in Dendrobium officinale, and use microorganisms to ferment, which can reduce the molecular weight of polysaccharides in Dendrobium officinale and increase the absorption of polysaccharides by the human body; It can also increase the extraction amount of phenolic substances, optimize the fermentation process, increase the antioxidant capacity of Dendrobium officinale, and achieve the goal of economy, safety, and efficiency, greatly improving the application value of Dendrobium officinale.
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Advances in Carbon Based Nanocomposites as Electrocatalysts for Nitrite Detection
Abstract:
Nitrite is one of the most commonly used food additives, which imparts better flavour, texture and aroma to foods, preserves the reddish-pink colour of meat and prevents the risk of bacterial contamination of cured meat. However, the misuse and potential toxicity of nitrite pose a great threat to human health, so it is particularly important to develop effective and reliable methods for the detection of nitrite. Carbon-based nanocomposites have shown great potential in the field of electrochemical sensors due to their many excellent properties. In this paper, the mechanism of electrochemical detection of nitrite by carbon matrix nanocomposites is introduced, followed by an overview of the research results of carbon matrix nanocomposites as electrocatalysts in nitrite sensing and detection in different dimensions, and the problems and challenges of electrochemical sensors of carbon matrix nanocomposites in nitrite analysis and detection are proposed, and finally, the future development trend of the materials is outlooked.
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Determination of Six Disinfectants Residues in Goat Milk Powder by Prime HLB SPE Purification Combined with HPLC-MS/MS
deng hang, zhang ke xin, chen shao qin, wu she lian, chen si yu, huang xiao ning
Abstract:
In this study, a method was developed for the determination of six Dodecyl dimethyl benzyl ammonium chloride, Tetradecyl dimethyl benzyl ammonium chloride, Benzyl dimethyl hexadecyl ammonium chloride, Dodecyl trimethyl ammonium bromide, Didecyl dimethyl ammonium chloride and Tetra butyl ammonium hydrogen sulfate in goat milk using HPLC-MS/MS. The sample was dissolved in hot water and extracted by ultrasonication followed by protein precipitation with acetonitrile. Sodium chloride was used to separate the water and organic phases. Purification was performed using a Prime HLB SPE column before separation on a Hypersil GOLD C18 chromatographic column (100 mm×2.1 mm, 2.1μm). Detection was carried out using electrospray ionization (ESI+) in multi-reaction monitoring (SRM) mode. Quantification of non-skimmed and skimmed goat milk powder samples utilized an external standard method specific to each blanked matrix type. The results demonstrated excellent linearity (correlation coefficients > 0.999) within the concentration range of 0.01-5.0 μg/L for all six disinfectants, with detection limits (S/N≥3) and quantitation limits (S/N≥10) determined as 0.05 μg/kg and 0.10 μg/kg respectively. Using goat milk powder as a sample, the spiked recovery rate ranged from 97.07% to 105.6%, with relative standard deviations (RSD, n=6) ranging from 0.987% to 4.576%. This method fulfills the detection requirements for six types of disinfectant residues in goat milk powder.
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Construction of New Cell Scaffold Based on 3D Printing and Its Application in Cell Cultured Meat
Abstract:
3D printing technology, as an emerging manufacturing process, can rapidly generate artificial tissue structures resembling natural tissues through layer-by-layer deposition. However, there is scarce reporting and urgent development of 3D printing scaffolds for constructing cell-cultured meat. Therefore, there is an urgent need for the development of edible material-based scaffolds, and issues such as the plasticity and efficiency of the scaffold need further optimization. In this study, 3D printing ink was developed using edible protein materials and scaffolds were prepared. The 3D printing performance and parameters were first analyzed and optimized. Further, the mechanical stability of the scaffold was studied based on water absorption and degradation rate. Finally, the biological compatibility of the scaffold and its interaction with cells were elucidated through cell proliferation culture, live/dead cell staining, and omics analysis. The results show that scaffolds prepared with an extrusion speed of 4.00 mm3/s combined with a printing speed of 6.00 mm/s exhibit significantly higher uniformity, plasticity, and accuracy in comparison to other combination groups. Regarding cross-linking time, the scaffold with a 10-minute cross-linking time demonstrates significantly higher biological compatibility than other groups, along with better mechanical stability and support. Furthermore, scaffolds with a 10-minute cross-linking time exhibit significantly better cell adhesion, proliferation, and migration capabilities than other groups. The cell proliferation curve further reveals the excellent performance of the scaffold in cell culture. The study clarified the interaction between scaffolds and cells and provided new methods and ideas for cell cultured meat production.
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Effect of Sodium Alginate Addition on the Functional Properties of Rice Bran Protein
肖志刚, 高岩, 毕崇慧, 周廉瞬, 元沅, 段玉敏, 王鹏
Abstract:
This paper aimed to study the effect of different sodium alginate additional amounts (0%, 15%, 30%, 45%, 60%, 75%, 90%) on the physicochemical properties (emulsification, emulsification stability, foaming ability, foaming stability, particle size, Zeta potential) and structural characteristics (endogenous fluorescence, surface hydrophobicity, free sulfinyl group, disulfide bond, Fourier transform infrared spectroscopy) of rice bran protein. The results showed that the emulsification, foaming, and foaming stability of rice bran protein were increased by 40%, 18%, and 9%, respectively, and the emulsification stability was increased by more than 20 times when the additional amount of sodium alginate was 45%, as well as the particle size of the complex was the smallest and the charge was the largest. With the increase in the additional amounts of sodium alginate, the endogenous fluorescence intensity of rice bran protein decreased and redshifted, the surface hydrophobicity and the content of free sulfhydryl group increased and the content of disulfide bond decreased. Furthermore, the results of Fourier transform infrared spectroscopy confirmed that sodium alginate could change the secondary structure of rice bran protein. The results of this study are intended to provide a theoretical basis for the further application of rice bran protein-sodium alginate complexes.
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Preparation and Performance Evaluation of Arginine Microcapsule Powder Dried by Double Shearing Emulsification and spray Drying
Abstract:
Arginine is widely utilized as a component or nutritional additive in the pharmaceutical, medical food, and feed industries. In this paper, arginine microencapsulated lotion was formed by double shearing and double emulsification, and a solid microcapsule was prepared by spray drying. The morphology, physicochemical properties, and digestion characteristics of arginine microcapsules were systematically analyzed through a series of characterization and detection methods such as optical microscopy, electron microscopy, mass spectrometry imaging, electronic nose, electronic tongue, thermogravimetric analysis, and in vitro simulated digestion. The storage stability was investigated through a series of stability tests. The results showed that the double shear emulsification could form a stable W/O/W arginine microcapsule lotion. The microcapsule prepared by spray drying was round and spherical, with an average particle size of 41.36 μm, and the loading amount of arginine was 12.16 wt.%, which was mainly distributed inside the capsule, and the embedding rate was 95.51%; The outer water-soluble wall material exhibited good masking effects on the ammoniacal odor and bitterness of arginine. Additionally, it demonstrated a higher propensity for disintegration during the 30-minute simulated gastric juice digestion, resulting in a sustained release rate of 93.14% for arginine; Moreover, arginine microcapsules had good stability, with an arginine retention rate of 93.82% after 90 days of storage at room temperature. This study may provide a theoretical basis for the commercial application of arginine microcapsules in practice.
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Cherry juice freeze-dried powder alleviates hyperuricemic renal injury by regulating uric acid transporter
Abstract:
Abstract: The hyperuricemia (HUA) mouse model established by intraperitoneal injection of potassium oxonate for 7 days. HUA were intervened by cherry juice freeze-dried powder (CJP), benzbromarone and allopurinol. The serum uric acid (UA), creatinine (Cr), and blood urea nitrogen (BUN) were detected by the kits. The pathological changes of liver and kidney were investigated by hematoxylin-eosin (HE) staining. Western blot and immunohistochemistry were used to detect the expression level of uric acid transporter in mouse kidney. To explore the effect of CJP alleviates hyperuricemic renal injury by regulating uric acid transporter. The UA level in the high-dose group of CJP decreased from 191.99 μmol/L to 113.12 μmol/L (P<0.01), but it was still 25% higher than the normal level, while the Cr level decreased from 16.09 μmol/L to 7.40 μmol/L (P<0.01), and the BUN level decreased from 8.24 mmol/L to 4.73 mmol/L (P<0.01). These two indicators have reached the normal level. Renal tissue injury improved significantly. The protein expression levels of uric acid reabsorption protein urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) were down-regulate, while the protein expression levels of uric acid secretion proteins ATP-Binding Cassette Superfamily G Member 2 (ABCG2) , Anion Transporter 1 (OAT1), and Anion Transporter 3 (OAT3) were up-regulate by CJP in HUA mice kidney. HUA induced kidney damage relieved by CJP, and CJP had no obvious toxicity to the liver. Therefore, CJP alleviates hyperuricemic renal injury by regulating uric acid transporter. This study can provide scientific basis for cherry to develop healthy products for preventing and treating hyperuricemic renal injury.
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Optimization of Plant-based Chicken Steak Formulation Based on Clean Label and Protein Nutritional Evaluation
Jiang Yuhan, Zhang Zhenwei, Yu Jie, Zhu Meilin, Zhang Chunrong, Jia Lirong
Abstract:
In this study, the reduction of excipients and food additives was investigated on the basis of the existing plant-based chicken steak formula of the manufacturer to achieve label cleanliness. In this study, the effects of different additives of L-cysteine, flaxseed gum, konjac gum, egg white powder, inulin, and TGase on the texture and sensory quality of the product were investigated by using texture meter measurements and sensory evaluation. And a clean-label based formulation was formed as follows (mass fractions): 12.26% of soybean pullulan protein, 7.36% of peanut pullulan protein, 53.96% of water, 14.72% of soybean oil, 3.68% of soybean isolate protein powder, 3.07% of gluten powder, 0.1% of L-cysteine, 0.49% of TGase (liquid), 4.37% of compound seasoning, 0.74% of salt, and 1.47% of white sugar. In this study, the protein nutritional value of plant-based chicken steak of the above formulation was compared with that of chicken steak. The protein digestibility of the plant-based chicken steak was 37.56%, which was close to that of the chicken steak (protein digestibility of 41.85%); its ratio of essential amino acid content to total amino acid content (EAA/TAA) was 0.41, and the ratio of essential amino acids to non-essential amino acids (EAA/NEAA) was 0.71, which were all in line with the standards set by FAO/WHO; its amino acid score (AAS) was 1.71 and the chemical score (CS) was 1.26.Therefore, the plant-based chicken steak produced by the above formulation is a high quality source of protein. Based on the analysis of the above indicators, four excipients and additives (flaxseed gum, konjac gum, egg white powder, and inulin) were removed from the original formulations with quality assurance, and a reliable basis for label cleanliness and protein nutrient evaluation of plant-based meat products was provided by this study.
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Efficient Secretion and Expression of Human Lactoferrin in Pichia Pastoris
Abstract:
Human lactoferrin has many biological activities such as antimicrobial activity, anti-inflammation, anti-tumor and participating in immune regulation. It has broad application prospects in food, cosmetics and feed additives. The cost of extracting lactoferrin from emulsion is high, which restricts the large-scale production and application of lactoferrin. It is expected to solve this problem by constructing a high-yield cell factory to obtain rhLf. In this study, the promoter and signal peptide in the gene expression element were optimized. The total protein in the supernatant of the human lactoferrin expression strain was increased from 215.00 mg/L to 849.52 mg/L by nearly three times through optimization of expression elements. Furthermore, the production of rhLf was increased by overexpressing the secretion-promoting protein factors related to the rhLf production and secretion pathway and regulating the cellular stress response. By overexpressing Yap1and Msn2, which balances the redox state of yeast cells under production pressure, the total protein in the supernatant of human lactoferrin expression strain was increased from 849.52 mg/L to 1055.68 mg/L. Finally, the target protein was semi-quantified, which was increased from 34.82 mg/L to 197.30 mg/L by nearly 4.8 times. This study greatly improved the protein production capacity of human lactoferrin expression strains through a variety of combination strategies and provided guidance for efficient secretory expression of Pichia pastoris.
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Experimental comparison of industrial Wolfberry vacuum drying at room temperature
zongxuewen, songzengquan, 刘登科, 杨勇, 叶凡, 庞盈
Abstract:
In order to improve the quality and efficiency of single mass drying of Wolfberry, an air source heat pump vacuum drying system was designed and manufactured to meet 1125kg Wolfberry fresh fruit. On the basis of no-load capacity test, the drying efficiency of Wolfberry was studied by side pumping, end pumping and so on. The experimental results showed that the vacuum capacity and heating capacity of the equipment met the design requirements. During the drying process, the pressure in the drying oven decreased exponentially, and the water loss rate of Wolfberry decreased gradually with the drying time. The side-pumping vacuum mode had a good dehumidification effect, which can reduce the humidity in the box to below 45%RH within 50 minutes and maintain a low humidity environment throughout the drying process. Correspondingly, it had shorter drying time (18.6h) and dehumidification per unit energy consumption (0.53(kg*h/Kw)). Lower drying temperature can reduce the formation of Wolfberry bubble wolfberry and improve the proportion of high-quality dried fruit. The results of this study laid a foundation for the development of 4-ton vacuum drying system of Wolfberry at room temperature, and had reference value for the development of vacuum drying system of fruits, vegetables, Chinese herbs and the quality optimization of vacuum drying of Wolfberry.
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Bioactive Substances, Antioxidant Activities and Anti-inflammatory Activities of 9 Kinds of Berries in Northeast China
Abstract:
In order to promote the development and utilization of berry-related functional products in Northeast China, the contents of total phenols, total flavonoids and total anthocyanins in 9 kinds of berries widely cultivated and common in Northeast China were determined and analyzed. The types and contents of phenolic monomers in berries were determined by high performance liquid chromatography. Antioxidant activity and anti-inflammatory activity of berries were evaluated by measuring DPPH· scavenging ability, ABTS+? scavenging ability, hyaluronidase inhibiting ability and albumin denaturation inhibiting ability, and correlation analysis was conducted. The results showed that the contents of total phenols, total flavonoids and total anthocyanins in blue honeysuckle and lingonberry were higher, which were 2.83 and 2.42 g (GAE) /100g DW, 0.99 and 2.09 g (Rutin) /100g DW, 104.33 and 414.73 mg/100g DW, respectively. And they had strong antioxidant and anti-inflammatory activities. The correlation results showed that the total phenolic content contributed the most to the antioxidant and anti-inflammatory activities of the berries. 19 monomer phenols were identified and quantified in 9 berries. Chlorogenic acid, cryptochlorogenic acid, arbutin and baicalein were all detected in berries. Chlorogenic acid and cryptochlorogenic acid were the main phenolic monomers in most berries. Among them, the monomer phenol species in lingonberry and the monomer phenol content in blue honeysuckle were the highest. The experiment provided a theoretical basis for the comprehensive utilization of berries in Northeast China.
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Preparation and Characterization of Debranched Short Straight-Chain Starch-Based Complex Particles Encapsulated with an Emulsion System of Flavonoids from Angelica Keiskei Koidz
LI Hua, 吴金鸿, BAI Xue, ZHAO Zhirui, ZENG Jihao, SHENG Yi, LIU Jianhua, CHEN Yuzhu
Abstract:
In this paper, zein and pectin were modified by adding debranched short straight-chain starch (DBS), and the effects of different DBS additions on the structure and emulsification of the ternary complex particle were investigated. In addition, the ternary complex particles were also characterized by the Fourier infrared spectroscopy, high-performance gel exclusion chromatography with the refractive index detector, and so on. Subsequently, the preparation parameters of the Pickering emulsion embedded with the flavonoids extracted from the Angelica keiskei Koidz. were optimized using an orthogonal experimental design, aiming to develop a delivery system of the flavonoids for enhancing their bioavailability. Results showed that adding DBS effectively improved the amphiphilicity of zein and pectin, and formed a kind of ternary complex particles with the smallest particle size (592.6 nm) and the lower Zeta potential (– 45.8 mV). Moreover, the ternary complex particles formed a tightly stacked network structure when the addition amount of DBS was 0.4 g and the mass ratio of DBS, zein, and pectin was 0.16:1:1. And flavonoids extracted from the Angelica Keiskei Koidz. can be protected to tolerate the digestive environment of the oral and stomach, and the bioavailability can be improved up to 49.35%. This study provides a theoretical reference for the development of short straight-chain starch-based Pickering emulsions, their application in delivery systems, and the improvement of the bioavailability of flavonoids.
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The Inhibitory Effect of Tea Tree Essential Oil on Listeria Monocytogenes and Its Application in Refrigerated Fresh Pork
Wang Qingyao, Xiao Xinglong, Liu Yuanyuan, Lin Yihan, Zhang Yan
Abstract:
The inhibitory effect of tea tree essential oil on Listeria monocytogenes and its application in the preservation of refrigerated fresh pork were investigated in this study. The minimum inhibitory concentration (MIC) of tea tree essential oil on Listeria monocytogenes was determined, the bacterial growth curve and the changes in cell ultrastructure were observed. The impact of tea tree essential oil treatment on the total bacterial count, total volatile basic nitrogen content, thiobarbituric acid reactive substances content, pH, color, and texture changes during the refrigeration of pork were analyzed. The results showed that the MIC of tea tree essential oil against Listeria monocytogenes was 4.0 mg/mL, all different treatment groups with tea tree essential oil demonstrated a significant inhibitory effect on Listeria monocytogenes. Tea tree essential oil damaged the structural integrity of both the cell membrane and the cell wall of Listeria monocytogenes, causing release of internal cellular contents and ultimately the demise of the bacteria. Additionally, in contrast to the control group, the total number of colonies in MIC, 2MIC and 4MIC tea tree essential oil treatment groups decreased by 1.18, 1.37 and 1.56 log CFU/g, respectively, and the values of TVB-N and TBARS did not exceed the maximum threshold during storage (0～12 days), tea tree essential oil effectively inhibited the growth of microorganisms in pork, delayed the degradation of nitrogenous compounds, fat oxidation, color changes, and maintained the quality. The results showed that tea tree essential oil could inhibit the growth of Listeria monocytogenes and extend the shelf life of chilled pork for about 3 days, and can be used as a fresh-keeping agent for chilled pork.
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Characterization of Low Concentration-sensitivity Porcine Plasma Protein-Xanthan Acid-induced Cold Gel
Abstract:
Protein-polysaccharide complex hydrogels play an important role in maintaining food texture. In this paper, gluconolactone (GDL) was used as acidifier to regulate the pH value of porcine plasma protein (PPP) -Xanthan gum (XG) complex solution to 3.5, so as to form a stable PPP-XG composite gel. The results of texture, rheology and electron microscope analysis showed that PPP and XG with low concentration could form typical gels with dense network structure. Potential and interaction force proved that non-covalent interaction occurred between PPP and XG, electrostatic and hydrogen bond as the main driving force. At a certain polysaccharide concentration, the gel had the highest hardness at a protein to polysaccharide ratio of 1:1. At other concentrations, the gel hardness showed a decreasing trend. The concentration of XG could promote the hardness of gel. When the XG concentration was 0.3%, the mixed solution had a suitable viscosity and hardness, and the maximum hardness was 250.02g at 0.3%PPP, while the lowest holding power was 53.96%, the highest syneresis value was 9.77%, the energy storage modulus and intermolecular force were the strongest, and the gel structure was dense. The swelling properties of the composite gel showed that the water absorption capacity of the composite gel at pH value 7.4 was significantly better than that at pH value 2.0 (P < 0.05). The results indicated that the composite gel could improve the textural properties of food, and could be used as a delivery carrier of potential heat-sensitive ingredients, providing a reference for food processing.
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Dynamic Changes in Aroma Components During the Processing of Rucheng Baimao (Camellia pubescens) Black Tea
Abstract:
To investigate the dynamic changes in the aroma components of Rucheng Baimao (Camellia pubescens) black tea, HS-SPME-GC-MS technology was used to detect the volatile components in the fresh leaves (XY), withering (WD), rolling (RN), fermentation (FJ), and drying (GZ) stages of Rucheng Baimao (Camellia pubescens) black tea. The results showed that a total of 129 volatile components were detected, including 30 alcohols, 10 aldehydes, 35 esters, 5 ketones, 30 alkanes, 10 olefins, and 9 other types. Among them, alcohols, esters, and alkanes were the main categories of volatile components in the processing, and the relative content of alcohols and esters was much higher than that of other volatile components types. Based on multivariate statistical analysis and rOAV value calculation, linalool, phenylethanol, geraniol, 2-phenylacetaldehyde, and β-ionone is an important contributor to the aroma and quality of Rucheng Baimao (Camellia pubescens) black tea, providing floral and sweet characteristics for Rucheng Baimao (Camellia pubescens) black tea. The metabolic pathways mainly involved in the biosynthesis of volatile terpenoids are the MVA and MEP pathways, phenylalanine metabolism pathways, and carotenoid degradation pathways. This study can provide a certain reference for the regulation of aroma and quality of Rucheng Baimao tea and black tea.
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