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Volume 37,Issue 7,2021 Table of Contents

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    • 1  Antihypertensive Effect of the ACE Inhibitory Peptides Derived from Bovine Casein in Rats
    LIU Fei ,  MIAO Jian-yin ,  YANG Yu-yu ,  HE Ze-qi ,  QIAO Zi-jiao ,  LIU Guo ,  DU Jie ,  NING De-shan ,  CAO Yong
    2021, 37(7):1-7. DOI: 10.13982/j.mfst.1673-9078.2021.7.1041
    [Abstract](427) [HTML](224) [PDF 437.32 K](812)
    Abstract:
    In order to investigate the blood pressure-lowering effect of angiotensin I-converting enzyme inhibitory peptides (ACEI) derived from bovine casein, spontaneously hypertensive rats (SHR) were used as the animal model. After 30 days of sample administration, the blood pressure, heart rate, serum and urine of rats were examined. Compared with the model control group, the systolic blood pressure and heart rate of the ACE inhibitory peptides high- and low-dose groups and the positive control group were 175, 175, and 172 mm Hg, respectively, with the differences being statistically significant (p<0.01); the concentration of calcitonin gene-related peptide (CGRP) in the ACE inhibitory peptides high-dose group increased to 10.09 pg/mL, with the change being statistically significant (p<0.05); the concentrations of total calcium (TCa), endothelin-1 (ET1), blood glucose (GLU), total cholesterol (CHOL), high density lipoprotein cholesterol (HDL-C) and blood uric acid (UA) in the ACE inhibitory peptides high-dose group decreased significantly (to 2.06 mmol/L, 8.69 pg/mL, 6.41 mmol/L, 1.13 mmol/L, 0.29 mmol/L and 108.20 μmol/L, respectively), with the changes being statistically significant (p<0.05). The results showed that under the experimental conditions, ACE inhibitory peptides not only relieved the fast heartbeat and lowered significantly blood pressure in rats, but also help to improve the serum biochemical indices and renal function indices of rats with renovascular hypertension while exhibiting a certain monitoring effect on the blood sugar, blood uric acid and cholesterol. ACE inhibitory peptides may lower blood pressure by increasing blood CGRP, inhibiting ETI, and lowering blood calcium level.
    2  Inhibition on Prion Replication by Ethanol Crude Extracts from Inonotus obliquus
    YANG Wei ,  CHEN Zhi-bao ,  CHEN Cao ,  WEI Yan-mei ,  XIA Ying ,  DAI Hao-fu
    2021, 37(7):8-13. DOI: 10.13982/j.mfst.1673-9078.2021.7.1126
    [Abstract](350) [HTML](210) [PDF 2.09 M](595)
    Abstract:
    To optimize the extraction process of the ethanol crude extracts from Inonotus obliquus and preliminarily study its effect on prion replication. The optimum extraction condition of ethanol crude extracts from Inonotus obliquus were employed by alcohol extraction and orthogonal test. To evaluate the cell safety of the ethanol crude extracts from Inonotus obliquus, CCK-8 kit was used to determine the safe concentration. According to the results of safety evaluation, Western blot was used to detect the effect of the ethanol crude extracts from Inonotus obliquus on prion replication. The antioxidant activity of ethanol crude extracts from Inonotus obliquus was studied by measuring hydrogen peroxide and antioxidant factors. The optimal extraction conditions were as follow: the ratio of solid to liquid was (Inonotus obliquus power: alcohol) 1:10 (g/mL), the volume fraction of ethanol was 75%, the extraction time was 2 h, the extraction temperature was 80 ℃. At this condition, the yield of ethanol crude extracts from Inonotus obliquus was 6.32%. The maximum safe concentration range of ethanol crude extracts from Inonotus obliquus was 6.25×10-4 mg/mL, Under this condition, after 24 h treatment, prion replication were inhibited by the ethanol crude extracts from Inonotus obliquus (p<0.01), which could reduce the content of H2O2 and increase the content of SOD and antioxidant factor GCLM、GCLC，and it was statistically significant. The results showed that ethanol crude extracts from Inonotus obliquus had an inhibitoryeffect on prion replication, which may be related to its antioxidant activity.
    3  The Purgative Effect of Complex Sugar Substitute and Its Regulation Effect on Intestinal Flora
    LI Guo-kun ,  DONG Jia-hua ,  XIAO Jian-hai ,  BAI Si-xiao ,  CHEN Xiao-yi ,  SU Li-jie
    2021, 37(7):14-22. DOI: 10.13982/j.mfst.1673-9078.2021.7.1067
    [Abstract](305) [HTML](290) [PDF 588.52 K](623)
    Abstract:
    The laxative effect and the regulation of intestinal flora of complex sugar substitutes were investigated by mice experiment and in vitro bacterial proliferation experiment in this study. To evaluate the laxative effect of compound substitute sugar, Balb/C mice were divided into blank control group, model group, positive control group, compound glucose-substituted G1 group (0.75 g/kg·BW), G2 group (1.5 g/kg·BW), G3 group (2.25 g/kg·BW), G4 group (3 g/kg·BW) and G5 group (3.75 g/kg·BW) to establish constipation model with loperamide, and phenolphthalein and five different concentrations of complex substitute sugars were used for intervention. The weight of mice before and after the experiment, the advance rate of ink, the time of the first black defecation, the number of defecation grains within 6 h and the weight of defecation were observed. The effect of compound sugars on the proliferation of intestinal flora in mice was explored through in vitro culture experiments. The results showed that five different doses of compound sugar substitute intervention group could promote the defecation of mice, among which the defecation effect of 3.75 g/kg·BW group was the most significant. Compared with the model group, the ink propulsion rate increased by 48.47%, the first black stool time decreased by 67.25 min, the number of defecation particles increased by 8.75 n in 6 h, and the fecal weight increased by 0.20 g in 6 h. The in vitro culture experiment showed that compound sugar at the concentration of 0.75 g/mL, 0.15 g/mL, 0.225 g/mL, 0.3 g/mL and 0.375 g/mL could promote the proliferation of Bifidobacterium and Lactobacillus and inhibit the proliferation of Enterobacter and Enterococcus. In the concentration from 0.075 g/mL to 0.375 g/mL, the higher the concentration of compound sugar, the more obvious the trend of promoting the proliferation of Bifidobacterium and Lactobacillus. Therefore, the compound sugar substitute in this study has a laxative effect and can regulate the intestinal flora.
    4  Antiallergic Activity and Mechanism of Ethanol Extract from Perilla Leaves
    XING Yu-bin ,  LIU Si-jia ,  XING Ping ,  CHEN Xiao-ping
    2021, 37(7):23-30. DOI: 10.13982/j.mfst.1673-9078.2021.7.1138
    [Abstract](244) [HTML](240) [PDF 630.99 K](670)
    Abstract:
    Objective: to investigate the anti allergic activity and mechanism of ethanol extract from Perilla frutescens leaves in vivo. Methods: passive skin anaphylaxis test was carried out in mice. The serum levels of immunoglobulin E, leukotriene B4 and platelet activating factor in mice were determined to explore the anti allergic effect and mechanism of perilla leaf ethanol extract on type I hypersensitivity. To explore the antiallergic effect of ethanol extract from Perilla frutescens leaves on type IV anaphylaxis, DNCB induced delayed type hypersensitivity test was carried out in mice. Results: In the passive skin anaphylaxis test of mice, compared with the model group, the high-dose ethanol extract of perilla leaves significantly reduced the itching times of mice (p<0.01), from 24.3 times to 15.8 times. The first itching time was significantly prolonged from 121.59 s to 231.90 s. The levels of IgE, PAF and LTB4 in serum of high dose group decreased by 30.92%, 15.5% and 22.45%, respectively; compared with the DNCB-induced delay model group, the high-dose ethanol extract of perilla leaves significantly reduced the ear swelling degree of mice on the 3rd and 6th days (p<0.05) hypersensitivity in mice, on the 9th day, the ear swelling was significantly reduced (p<0.01). The levels of IL-4, IFN-γ and TNF-α in high-dose group decreased by 19.14%, 32.52% and 16.61% respectively. In conclusion, the extract of Perilla frutescens has obvious anti allergic effect on type I and type IV allergy. Its anti allergic mechanism to type I allergy is related to preventing the release of bioactive substances and interfering with the production of arachidonic acid metabolites.
    5  The Dietary Fiber of Pomelo Fruitlets Improves Intestinal Health of Diabetic Mice
    HUANG Miao-ru ,  SONG Hai-feng ,  CHEN Zi-jun ,  HU Yue ,  LIN Qi-xin ,  ZHANG Huan-you ,  MA Lu-kai ,  LIU Hui-fan
    2021, 37(7):31-39. DOI: 10.13982/j.mfst.1673-9078.2021.7.1099
    [Abstract](246) [HTML](220) [PDF 3.07 M](762)
    Abstract:
    In order to investigate the effect of dietary fiber from pomelo fruitlets on intestinal health in mice, the mice were randomly divided into 6 groups, in accordance with the dose of 0.2 mL/10 g body weight for intragastric administration. After 4 weeks of gavage, the mouse feces and colon were collected, and the water content, pH value and short-chain fatty acid (SCFAs) content were measured; HE staining was used to observe the damage of colon tissue. The total DNA of the fecal bacteria of each group of mice was extracted by the kit, and the V4 region of the 16S rRNA gene was sequenced using high-throughput sequencing technology. Finally, the sequencing data were analyzed by bioinformatics methods, and the correlation between blood glucose related indicators and intestinal flora was analyzed in combination with previous studies. The results showed that the water content, SCAFs content in the colon and feces of diabetic mice were increased, and the pH level was decreased in the dietary fiber experimental group. The water content in colon and feces of TDF group was increased most significantly, by 8.04% and 21.36%, respectively. SCAFs content in colon and feces were significantly increased in TDF group, increasing by 475.19% (acetic acid) and 702.56% (butyric acid), respectively. Meanwhile, the intestinal mucosal damage caused by diabetes was relieved by the dietary fiber of pomelo fruitlets to some extent in the HE staining experiment Moreover, the growth of beneficial bacteria could be promoted and the proliferation of harmful microorganisms could be inhibited. The blood glucose level of mice was regulated by the dietary fiber, which may be related to the fermentation of probiotics and the production of short-chain fatty acids after entering the intestinal tract. It can be seen that the dietary fiber of pomelo fruitlets can maintain the integrity of intestinal mucosal barrier, regulate the structure of intestinal flora, and improve the intestinal health of mice.
    6  Enzymatic Synthesis of Different Chain Lengths of Coumarate and Capacity of Scavenging Radical
    YIN Xia ,  XIN Xuan ,  LI Xiao-feng
    2021, 37(7):40-45. DOI: 10.13982/j.mfst.1673-9078.2021.7.0217
    [Abstract](299) [HTML](203) [PDF 811.05 K](636)
    Abstract:
    Enzymatic transesterification is often used to improve the lipophilicity of phenolic acids. In this study, a series of new derivatives of p-coumaric acid were successfully synthesized in non-aqueous medium by introducing fatty acid chain into p-coumaric acid in the form of carboxyl group by enzymatic transesterification strategy. Under the optimal reaction conditions: the lipase NOV.435 of 40 mg/mL, the solvent of pyridine: cyclohexane of 1:9, the molar ratio of substrate of 1:10, temperature of 50 ℃, the rotation speed of 180 r/min, the conversion rate was reached to 98%. In addition, further study showed that the scavenging activity of p-Ca against DPPH radical (alcohol-soluble system) was 56.34% at 20 μM, and the scavenging activity against DPPH radical of lauryl coumarate, p-decyl coumarate, p-octyl coumarate, p-hexyl coumarate, p-butyl coumarate and TBHQ at the same concentration was 73.91%, 70.32%, 68.90%, 60.62%, 43.65% and 67.51%, respectively. Obviously, the scavenging activity of laurel ester against coumarate was higher than those of p-Ca and TBHQ. Conclusion: coumarate has good free radical scavenging ability by enzymatic synthesis of different chain lengths in non-aqueous phase. Therefore, the synthesized ester derivatives with different antioxidant activities will be expected to be used in different food, drug and cosmetic systems, and provide beneficial guidance for the synthesis of ester derivatives.
    7  Ethanolamine-based Deep Eutectic Solvent Pretreatment of Wheat Straw to Improve Its Polysaccharide Enzymatic Hydrolysis Efficiency
    DONG Yan-mei ,  HONG Yuan-fang ,  MA Yang-yang ,  AN Yan-xia
    2021, 37(7):46-56. DOI: 10.13982/j.mfst.1673-9078.2021.7.1180
    [Abstract](233) [HTML](293) [PDF 1.21 M](665)
    Abstract:
    In order to explore the mechanism of deep eutectic solvents (DESs) pretreatment of lignocellulosic biomass, seven DESs with choline chloride (ChCl) as hydrogen bond acceptor (HBA) and seven DESs with ethanolamine compounds as hydrogen bond donor (HBD) were employed to pretreat wheat straw. Their physical and chemical properties were measured, and the effects of different DES on the components and enzymatic hydrolysis efficiency of biomass were studied. The results indicated that the viscosity of DES was between 0.04~1.37 Pa·s, the conductivity was 0.29~3.57 ms/cm, and the pH of 5 mM DES was between 7.41~11.02 at 30 ℃; it was effective for lignin and xylan. The solubility of DES was as high as 425 mg/g and 523 mg/g at 90 ℃, and it was almost insoluble to cellulose. After these DES pretreatments, the enzymatic hydrolysis efficiency of polysaccharides in wheat straw was significantly improved, and the pretreatment effect depended on the pH value. Among them, [Choline chloride]: [ethylenediamine] was the most suitable solvent for pretreatment of wheat straw. After 4 h of pretreatment at 90 ℃, the removal rate of lignin was 83.14% and the yield of reducing sugar was 93.88%. A large amount of lignin and part of xylan were selectively removed from wheat straw without changing the crystal structure of cellulose, and the efficiency of subsequent enzymatic hydrolysis was significantly improved. It found that this type of DES is good for grass biomass and eucalyptus. After the pretreatment, the sugar yield was obviously improved (57.10~98.13%), but it was not effective for pine. This work would provide a theoretical basis for rational design novel DESs for biomass pretreatment.
    8  Comparison of Extraction Effect of Several DNA Extraction Methods in Tuna Products
    XU Wen-jie ,  XIONG Xiong ,  HUANG Man-hong ,  LI Yi ,  CAO Min ,  LU Li-xia ,  XIONG Xiao-hui
    2021, 37(7):57-65. DOI: 10.13982/j.mfst.1673-9078.2021.7.0894
    [Abstract](225) [HTML](260) [PDF 1000.52 K](569)
    Abstract:
    There are many types of tuna, shoddy and fake tuna products are found in the market from time to time. DNA-based detection technologies have been widely used in the detection of adulteration of tuna products. DNA extraction is crucial to the application of DNA detection technology. In this study, 28 deep-processed tuna products were used as the experimental samples. Three different DNA extraction methods (SDS method and two commercially available kits) were compared in terms of DNA quality, yield, PCR amplification and method operability. The results showed that all the three methods can be used for DNA extraction from most tuna products. Compared with the other two commercially available kits, the SDS method led to a lower DNA yield with a higher purity and a A260-to-A280 ratio (1.89), less salt residue, lower inhibition in real-time fluorescent quantitative PCR and relatively low cost, which meets the demand for adulteration detection of tuna products.
    9  A Strategy to Increase the Intracellular Overexpression of Recombinant Proteins by Expressing Pichia pastoris Translation-related Factors
    LIN Wen-yang ,  LIAO Xi-hao ,  CHEN Nan-zhu ,  HUANG Da-fu ,  CHEN Liang ,  ZHONG Bing-xu ,  LIANG Shu-li ,  LIN Ying
    2021, 37(7):66-73. DOI: 10.13982/j.mfst.1673-9078.2021.7.0494
    [Abstract](279) [HTML](197) [PDF 1.51 M](997)
    Abstract:
    This study was to screen the translation-related factors that promote the expression of recombinant proteins in Pichia pastoris, and amplify gene fragments of five types of translation-related factors (a total of 28) in Pichia pastoris (including ribosomal proteins, translation initiation factors, elongation factors, aa-tRNA synthetases, ribosome biogenesis factors, and ribosome-associated chaperones). These gene fragments were cloned into the pPICZA vector through homologous recombination. The recombinant vectors were further obtained and transformed into the Pichia pastoris GS115 strain with enhanced green fluorescent protein (eGFP) as the reporter protein. Then, the expression levels of 28 strains with overexpressed translation-related factors within 120 h were measured and calculated, to identify the key factors that could potentially promote the expression of the recombinant proteins in Pichia pastoris. Finally, the red fluorescent protein, monomeric red fluorescent protein (mRFP), was used as the reporter protein for verification. The results revealed that 6 translation-related factors (eIF4A, eEF1A, eEF3, Ded81, Bcy1, Ssb) that could improve the intracellular expression of recombinant proteins in Pichia pastoris, were screened in this study. Among them, the eGFP unit cell expression of eIF4A, eEF1A, eEF3, Ded81, Bcy1, Ssb increased by 18.40%, 18.80%, 29.50%, 28.45% and 21.60%, respectively, and the mRFP unit cell expression increased by 20%, 8.00, 19.00%, 5.40% and 15.40%, respectively. Bcy1 increased the biomass of eGFP-expressing strains by 20.00% and the biomass of mRFP-expressing strains by 30.90%. These results provide ideas for improving the expression of recombinant proteins in Pichia pastoris through the translation.
    10  Optimization of Pretreatment Process Before Fermentation to Reduce the Methanol Content in Hetian Dried Red Jujube Brandy
    LI Gui-lin ,  PENG Xin ,  LI Ze-han ,  SHAO Yong-ming ,  YANG Fan ,  LI Han-lun ,  YANG Xing-yuan
    2021, 37(7):74-82. DOI: 10.13982/j.mfst.1673-9078.2021.7.0953
    [Abstract](253) [HTML](230) [PDF 2.54 M](620)
    Abstract:
    In this study, dried red jujube fruits from the Hetian area of Xinjiang were used as the raw materials to brew brandy. The effects of different conditions of pretreatment prior to fermentation on the methanol content, alcohol content, higher alcohol and sensory score of jujube brandy were investigated. On the basis of single factor experiments, the methanol content was chosen as the response value, low amount of added methanol pectinase, enzymolysis temperature and boiling time, were selected for the three-factor three-level Box-Behnken test. The experiment data were analyzed using Design-Expert 11.0 software to obtain the optimal pretreatment conditions for reducing methanol content. The results showed that the optimal pretreatment process conditions for producing low-methanol dried red jujube brandy were: boiling immersion time, 11.00 min; amount of added methanol pectinase, 1.00 mL/kg; enzymolysis temperature, 46.00 ℃; enzymolysis time, 6.00 h. Under the conditions, the methanol content was 1.37 g/L (similar to the response surface minimum methanol prediction value: 1.39 g/L), alcohol content was 31.50% vol, and comprehensive sensory score was 94.63. Therefore, the Box-Behnken response surface method can be used to optimize the pretreatment process of dried red jujube brandy fermentation, to reduce the methanol content while improving the quality of brandy.
    11  Isolation, Structural Characterization and Antioxidant Activity of Brown Rice Bound Phenolics
    FENG Zhi-ying ,  ZHANG Ming-wei ,  ZHANG Rui-fen ,  LIU Lie ,  CHI Jian-wei ,  DONG Li-hong ,  JIA Xu-chao
    2021, 37(7):83-89. DOI: 10.13982/j.mfst.1673-9078.2021.7.0040
    [Abstract](415) [HTML](323) [PDF 461.82 K](649)
    Abstract:
    Brown rice bound phenolics were extracted by alkaline hydrolysis and separated by multiple chromatographic methods. Four monomers were obtained and their structures were identified by high performance liquid chromatography-tandem mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR). The isolated compounds were elucidated as 6-hydroxy-2-oxo-1,2,3,4-tetrahydroquinoline-4-carboxylic acid methyl ester (1), 4-carboxymethoxy-6-hydroxy-2-quinolone (2), 4-carboxyl-6-hydroxy-2-quinolone(3) and 2 - (5-hydroxy-2-oxoindole-3-yl) acetate methyl ester (4). Compound 1 was a new natural product and compound 2 was reported from brown rice for the first time. The contents of four monomers were determined by high performance liquid chromatography (HPLC) and the content of compound 1 was the highest (0.9 mg/g DW). Antioxidant activity of four compounds was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferric ion reducing antioxidant power (FRAP) assays and oxygen radical absorbance capacity (ORAC) methods, respectively. The strongest DPPH radical scavenging activity was compound 4, with the IC50 value being 72.19 μM. Compound 2 exhibited the highest FRAP reducing activity, which was 249.60 mmol FeE/mol. ORAC method showed that compounds 3 and 4 had the best antioxidant capacity, which were 2.87 and 2.69 μmol TE/μmol, respectively. These results will promote the cognition of brown rice bound phenolics. It can also provide scientific basis for the development and utilization of functional substances in brown rice.
    12  Functional Characteristics and Subunit Structure of Fresh Wheat Protein with Different Processing Methods Based on Principal Component Analysis
    WEN Qing-yu ,  ZHANG Kang-yi ,  YANG Shu-zhen ,  ZHU Jun-guo ,  WANG Yu-fei ,  LI Tian-yi
    2021, 37(7):90-100. DOI: 10.13982/j.mfst.1673-9078.2021.7.1103
    [Abstract](228) [HTML](192) [PDF 976.86 K](579)
    Abstract:
    Two kinds of heat-treated fresh wheat were used as raw materials, the proteins were extracted by alkaline extraction and acid precipitation in this paper, and their structure and functional properties were determined. At the same time, the functional characteristics of fresh wheat protein with different processing methods were comprehensively evaluated by mean of principal component analysis. The results showed that the subunit band with a molecular weight of 21.2 ku gradually disappeared in the cooked fresh wheat protein, while the same subunit band gradually appeared in the fried fresh wheat protein; the water holding capacity of the two kinds of heat-treated fresh wheat protein continuously increased with the extension of heat treatment time, whereas the changes of oil retention, emulsification, foaming, and solubility for the two kinds of heat-treated fresh wheat protein showed a trend of first increasing and then decreasing, the corresponding maximum values were 4.23 g/g, 4.30 m2/g, 44.67%, and 30.31%, respectively; the changes of emulsion stability showed opposite trend. According to the results of the principal component analysis of functional characteristics, the highest comprehensive scores of cooked and fried fresh wheat protein were 29.43% and 14.08%, respectively. It was concluded that the functional characteristics of cooked fresh wheat protein were better than those of fried fresh wheat protein. Moreover, the functional characteristics of fresh wheat protein were best at cooked time of 15 min. In a word, the functional properties of cooked fresh wheat protein were better than those of fried fresh wheat protein, which was suitable for the processing of fresh wheat. Furthermore, a certain theoretical basis was provided for the thermal processing of fresh wheat raw materials.
    13  Comparison of Different Chitosan-based Hydrogels in Microstructure and Controlled-releasing Property
    LIANG Gang-qiang ,  XIANG Tuo ,  LIANG Yan ,  SITU Wen-bei
    2021, 37(7):101-107. DOI: 10.13982/j.mfst.1673-9078.2021.7.1088
    [Abstract](284) [HTML](627) [PDF 2.34 M](1084)
    Abstract:
    In this paper, two different methods of ion cross-linking and sulfhydrylization were used to modify chitosan to prepare chitosan hydrogel with active protein. Through infrared spectroscopy, particle size/zeta potential analysis, transmission electron microscopy, scanning electron microscopy, and simulated digestion experiments, the microstructure and controlled release performance were discussed. The experimental results found that due to intermolecular hydrogen bonding, pH value, CS:TPP mass ratio, and BSA concentration had significant effects on the protein loading rate of cross-linked chitosan hydrogels, and the introduction of sulfhydryl groups made the sulfhydryl chitosan polymerized. Sugar hydrogel had a smaller particle size (average 409.61 nm) and a lower surface potential (average -0.67 mV) in an acidic environment. The changes in the microstructure of chitosan-based materials further affected the controlled release properties of their hydrogels. The simulated digestion experiment showed that the cross-linked chitosan hydrogel had a sudden release phenomenon in the simulated gastric juice. Before being transported to the colon, 44.76% of the active protein had been released, while the sulfhydryl chitosan hydrogel simulated the environment of the upper digestive tract. The medium release rate was slow, only 8.42% of the active protein was released. When it runs to the simulated colon, the release rate of the active protein gradually increases, showing a sustained release effect. About 30% of BSA is gradually released in the colon. Therefore, sulfhydryl chitosan-based hydrogels have better controlled release performance, which plays an important role in improving the bioavailability of active proteins.
    14  In Vitro Assessment of the Digestive Tolerance and Antioxidation of Juice from Physalis pubescens L. Fermented by Lactic Acid Bacteria
    JU Ge-jinyue ,  XU Hong-yu ,  WEN Jing ,  WU Ji-jun ,  YU Yuan-shan ,  LI Lu ,  TIAN Shu-yuan ,  WANG Jing-jing
    2021, 37(7):108-114. DOI: 10.13982/j.mfst.1673-9078.2021.7.1182
    [Abstract](271) [HTML](282) [PDF 2.97 M](669)
    Abstract:
    The simulated gastrointestinal digestion system in vitro was applied to evaluate the digestive tolerance of two strains of lactobacillus, polyphenol content and antioxidation of juice from Physalis pubescens L. fermented by two lactobacillus strains, Lactobacillus plantarum and Lactobacillus fermentans. The results showed that the total count of Lactobacillus plantarum and Lactobacillus fermentans were seperately 7.54 CFU/mL and 7.82 CFU/mL of juice following digestion for 10 h in simulated gastrointestinal systerm in vitro. The polyphenol content increased from 0.33±0.01 mg/mL and 0.40±0.03 mg/mL to 1.37±0.03 mg/mL and 1.30±0.01 mg/mL, respectively, in the fermented juice of Physalis pubescens L. before and after in vitro digestion. The polyphenol releasing level positively correlated with pH value of gastric juice. DPPH·, ABTS+· scavenging power and total reducing power (FRAP) increased by 4.92%, 23.80% and 41.32%, respectively, when the Lactobacillus plantarum fermented juice was digested for 2 h in simulated gastric systerm. While those of fermented by Lactobacillus plantarum increased by 4.98%, 15.55% and 17.72%, respectively. The results showed that Lactobacillus plantarum and Lactobacillus fermentum still had good activity after in vitro digestion, and the content of polyphenols and antioxidant activity in the juice were high.
    15  Changes in Content and Antioxidant Activity of Tea Polyphenols during in Vitro Simulated Gastrointestinal Digestion
    LI Yu-ren ,  WANG Rui ,  WANG Xu-jie ,  CHEN Chun-feng ,  YANG Hui ,  LUO Zhong-fang ,  YANG Xiao-ping
    2021, 37(7):115-120. DOI: 10.13982/j.mfst.1673-9078.2021.7.0025
    [Abstract](342) [HTML](361) [PDF 1.17 M](847)
    Abstract:
    The composition and antioxidant activity of tea polyphenols in vitro were evaluated using gastric intestinal digestion model. Their effect on the growth of intestinal bacteria was also investigated. Results showed that the degradability of tea polyphenols in simulated gastrointestinal digestion was more significant than that of after simulated gastric digestion. During the simulated gastric digestion, the content of tea polyphenols decreased by 12.00%, GCG decreased significantly by 32.50%, EGC increased by 13.80%. During the simulated gastrointestinal digestion, the content of tea polyphenols decreased significantly by 35.90%~46.10%, EGCG decreased significantly by 98.40%~98.70%, GC increased significantly by 97.00%~114.00%. The total antioxidant capacity, DPPH· radical scavenging capacity and ABTS+· radical scavenging capacity of tea polyphenols were significantly decreased after simulated gastrointestinal digestion (p<0.05). During the simulated gastrointestinal digestion, the antioxidant capacity was positively correlated with the content of tea polyphenols, except ABTS+· radical scavenging capacity. Effect of tea polyphenols on intestinal bacterial growth during the simulated gastrointestinal digestion was evaluated. Results showed that tea polyphenols significantly inhibited the growth of Escherichia coli and proliferated the growth of Lactobacillus acidophilus. After simulated gastrointestinal digestion, bacteriostatic effect of tea polyphenols on Escherichia coli enhanced, but had no significant effect on Lactobacillus acidophilus.
    16  The Basic Properties and Analysis of Nutritive Active Ingredients of Kadsura coccinea Fruit
    ZHANG Dian-dian ,  GAO Jia-dong ,  DAI Zhang-yan ,  ZHANG Wen-hu ,  ZHANG You-sheng ,  LIU Jun
    2021, 37(7):121-127. DOI: 10.13982/j.mfst.1673-9078.2021.7.1214
    [Abstract](211) [HTML](232) [PDF 415.08 K](499)
    Abstract:
    In this work, the basic properties, nutrient and active ingredients of fruit peel, pulp juice, seeds and core of Xianghei-0701 Kadsura coccinea fruit were investigated. The results showed that the peel was occupied the largest proportion (42.52%~47.75%) in the whole fruit, while pulp juice was followed and accounted for the proportion (35.23%~37.77%). The percentage of seed was the smallest proportion (7.65%~11.16%). However, the ash content (7.25%), protein content (11.24%) and fat content (22.20%) of seed were highest. In addition, many kinds of minerals, especially maganese and zinc, were found in seed. The content of unsaturated fatty acids in seeds was up to 74.78%, among which the content of C18:2 (linoleic acid) was up to 60.30%. The contents of free polyphenols (23.69 mg/g), binding phenols (6.90 mg/g), total polyphenols (30.59 mg/g) and total flavones (30.54 mg/g) were the highest in seeds. The research illustrated that Xianghei-0701 seeds were a healthy food raw material which should be paid special attention. The peel thickness was 1.11~2.59 mm. The alkaloid content (3.20 mg/g) and anthocyanin content (8.89 mg/g) of peel were high. Therefore, the peel could be used for developing function candied products. The fruit juice could be used for developing “special drinks”. The seeds could be developed in lipids and functional foods due to their high content of ash, protein, fat.
    17  Analysis of Flesh Browning, Expression Characteristics of Aquaporin Genes in ‘Yali’ Pear during Chilling Injury Induced by 1-MCP and MAP
    HE Jin-gang ,  FENG Yun-xiao ,  CHENG Yu-dou ,  WANG Shen ,  FU Ya-xiong ,  GUAN Jun-feng
    2021, 37(7):128-136. DOI: 10.13982/j.mfst.1673-9078.2021.7.1066
    [Abstract](268) [HTML](220) [PDF 2.36 M](679)
    Abstract:
    Fruit quality, flesh browning, expression characteristics of aquaporin genes in ‘Yali’ pear were analyzed during long-term cold storage. The ‘Yali’ fruit was treated with 1.0 μL/L of 1-methylcyclopropene (1-MCP), packaged with polyethylene film as modified atmosphere packaging (MAP), then was stored at 0 ℃ for 180 d and 20 ℃ for 7 d. During storage, fruit firmness, soluble solid contents (SSC) was analyzed, and gas (O2, CO2, ethylene) contents were measured; flesh browning rates, chlorogenic acid contents, polyphenol oxidase (PPO) and peroxidase (POD) activities in the flesh were measured. Expression characteristics of PbPIPs and PbTIPs were analyzed by Real-time PCR. The results showed that fruit firmness reduced and SSC increased during cold storage. The ethylene production in MAP was effectively restrained by 1-MCP treatment, and the peak ethylene content of 1-MCP+MAP-treated fruit was 17.30 μL/L. Fruit firmness was maintained by 1-MAP treatment and MAP respectively, whereas flesh browning was more serious. During long-term cold storage, the flesh browning rates and chlorogenic acid contents were higher in 1-MCP and MAP fruits, especially in 1-MCP+MAP treated fruit, the flesh browning rate was 25.78%. In addition, PPO and POD activities were high as well. During cold storage, the expression levels of PbPIP1;1 and PbTIP2;1 were down-regulated, while the expression levels of PbPIP1;4, PbPIP2;1, PbPIP2;2, PbPIP2;5 and PbTIP1;1 were up-regulated. The expressions of PbPIPs and PbTIPs tested were regulated by 1-MCP and 1-MCP+MAP. In conclusion, 1-MCP and MAP treatment could maintain fruit firmness and SSC in ‘Yali’ pear during long term storage, but caused serious flesh browning, which might be a consequence of high concentration CO2 and chilling injury. PbPIP2;1 and PbPIP2;5 participated the process of chilling injury, and could be regulated by low temperature and ethylene.
    18  Walnut Drying by Combined Drum Catalytic Infrared with a Variable Temperature and Hot Air
    QU Wen-juan ,  FAN Wei ,  CAO Fei-fan ,  MA Hai-le ,  SHI Jun-ling ,  PAN Zhong-li ,  JIANG Qun-hui
    2021, 37(7):137-147. DOI: 10.13982/j.mfst.1673-9078.2021.7.0162
    [Abstract](268) [HTML](255) [PDF 2.45 M](585)
    Abstract:
    In order to improve the drying efficiency of hard shell nuts, this work developed a new type of multi-unit drum-type catalytic infrared drying equipment with a variable temperature, and adopted a combined drying technology of drum catalytic infrared with a variable temperature and hot air. In this work, the walnut drying effect, energy consumption and kinetic process were studied. The results showed that the catalytic infrared temperature, radiation distance, and rotating speed of the drum all had significant effects on the drying performance. After 22.50 min of infrared radiation pre-drying under the optimal radiation temperature of 300+400 ℃, radiation distance of 30 cm and rotation speed of 25+35+35 Hz, and then 14 h of hot air drying under the temperature of 43 ℃ and speed of 3 m/s, the total drying time was 14.38 h. Compared with that of single hot air drying, the drying time was shortened by 28.10% and the energy consumption was saved 25.04%. The dried walnut shell had no brown spots, the shell opening rate was 0%, the L value was 54.24, the a value was 10.61, the b value was 19.89 and the color was bright red and yellow. In addition, the maximum drying rate (0.28 g/g·min) was significantly higher than that of the single hot air drying (0.11 g/g·min). Correspondingly, the Henderson-Pabis model established can well predict the changes of water content and drying rate of walnut in the drying process and the fitting effect was good with R2 of 0.99 and RMSE of 0.03. Therefore, the combined drying technology of drum catalytic infrared with a variable temperature and hot air is a kind of new type drying method with high efficiency and energy saving, suitable for drying nuts products.
    19  Evaluation of Sensory and Physico-Chemical Properties of Grey Jujube from Different Producing Regions
    SONG Ye ,  WANG Jian-zhong
    2021, 37(7):148-154. DOI: 10.13982/j.mfst.1673-9078.2021.7.1053
    [Abstract](252) [HTML](218) [PDF 868.00 K](704)
    Abstract:
    Taking grey jujubes from six main producing regions in China as the research objects, the fuzzy sensory evaluation method was used to conduct a comprehensive sensory evaluation on these grey jujubes, and the difference in structural parameters, color difference parameters, and physico-chemical and nutritional parameters among the jujubes were simultaneously analyzed. The results showed that the gray jujubes in Ruoqiang area of Xinjiang had the highest comprehensive sensory score (85.62), and those from the Xinzheng area of Henan had the lowest comprehensive sensory score (72.62), thus, the former was ranked higher than the latter in sensory evaluation. The variation of the red values, a values, of fruit peel was 21.78~24.63, while the variation of the yellow values, b values, of fruit flesh was 28.44-32.22. Among them, the peel of the grey jujubes from the Tumushuk region had the highest redness, and the flesh of the grey jujubes from the Hetian region had the highest yellowness. The texture data showed that the grey jujube in Aral and Ruoqiang regions were firmer, more compact and chewier, while the chewability and cohesiveness of the grey jujubes in Xinzheng region were relatively poor. The contents of total sugars, reducing sugars, total acids, vitamin C, total phenolics of the grey jujubes from all the regions were 76.47~84.95 g/100 g, 32.30~46.90 g/100 g, 4.28~5.34 g/kg, 15.56~30.12 mg/100 g, 1622.30~1756.00 mg/kg, respectively. The nutritional indices of the Xinjiang grey jujube were significantly higher than those of Henan Xinzheng. The correlation between sensory and physico-chemical results indicated that the difference in the a value of fruit peel could characterize the color quality of jujube fruit, and the texture parameters such as firmness and chewiness could be used to evaluate the tissue state of jujube fruit.
    20  Effect of Storage Modes on Crystallization Behavior and Macroscopic Properties of Fat Crystalline O/W Emulsion
    JIAO Wen-juan ,  LI Bing ,  LI Lin ,  ZAN Sheng-jie ,  SU Shuang ,  CHEN Zhi-yi ,  ZHANG Xia
    2021, 37(7):155-161. DOI: 10.13982/j.mfst.1673-9078.2021.7.0791
    [Abstract](321) [HTML](281) [PDF 872.29 K](573)
    Abstract:
    The crystallization behavior and macroscopic properties of emulsions under modes with a constant temperature (storage at 4 ℃, 25 ℃ or 37 ℃ for 6 h) and temperature fluctuation (storage at 37 ℃ for 1 h then 4 ℃ for 6 h) were investigated in this study. The results showed that under the constant temperature storage, the solid fat content (SFC) and fat crystal structure of the crystalline emulsions stored at different temperatures differed: SFC as 28.31%, 22.75% and 17.21%, respectively, at 4 ℃, 25 ℃ and 37 ℃; The β' form content (97.68%) of the emulsion stored at 4 ℃ was the highest with the fat crystal particles being relatively small; The β form content of the emulsion at 37 ℃ was the highest (61.65%) with the fat crystal particles being the largest. Under the storage with temperature fluctuation, the SFC value (28%) of the emulsion stored with fluctuation at 37 ℃~4 ℃was essentially the same as that at a constant-temperature of 4 ℃, although their fat crystal structures (fat crystal particle size and content of β form) were different. The apparent viscosity of the emulsion stored at a constant temperature of 25 ℃ was the highest, whilst that of the emulsion stored with fluctuation at 37 ℃~4 ℃ was the smallest. In summary, for the same storage time period, a storage at a lower temperature (4 ℃) tended to facilitate the formation of a crystalline emulsion with a higher SFC content and smaller fat crystal particles; A storage at a higher temperature allowed the formation of a crystalline emulsion with a lower SFC content and bigger fat crystal particles. Under the storage at a constant temperature, adjusting the storage temperature can construct a crystalline emulsions with different SFC values and fat crystal structures, and the storage under the combined constant-temperature and temperature fluctuation mode can allow the formation of crystalline emulsions with the same SFC but different fat crystal structures.
    21  Optimization of the Ratio of Low-Glycemic Quinoa Eight-Treasure Porridge and Determination of GI Value in Human Body
    LIANG Xia ,  ZHOU Bai-ling ,  WANG Hai-ping ,  TIAN Xiang
    2021, 37(7):162-168. DOI: 10.13982/j.mfst.1673-9078.2021.7.1065
    [Abstract](322) [HTML](574) [PDF 1.54 M](760)
    Abstract:
    The purpose of this research was to develop a kind of quinoa eight-treasure porridge with high nutrition (E/T≥0.40) and low glycemic index (GI≤55). Quinoa was used as the main raw material, which was mixed with other cereals and beans. Amino acid E/T nutrition mode, in vitro digestion test and sensory evaluation were used to guide the optimization of the raw material ratio. On this basis, GI value of the product was determined through a human trial. The optimal ratio of raw materials was obtained through the optimization experiments: the ratio of grains to beans was 35:65, with the ratio of quinoa, barley kernel and oat as 22:6.5:6.5 in grains, and the ratio of chickpea, peanut, mung bean, white kidney bean and adzuki bean as 15:15:12.5:12.5:10 in beans. Under these conditions, the GI value of the quinoa eight-treasure porridge was 48, which was a low-glycemic food and could stabilize blood sugar; The amino acid E/T was 0.41, which reached the level of E/T amino acid recommended by FAO/WHO (1973) (≥0.40, indicating high nutritional value); The eight-treasure porridge gained a sensory score of 82.0, and had rich flavor, bright color and good mouthfeel. The purpose of this research was to provide an experimental basis for the development of low-glycemic eight-treasure porridge products.
    22  Comparison of Three Kinds of Pretreatment on Quality of Freeze-Dried Apple Slices
    TANG Shi-sheng ,  MA Dao-kuan ,  LIU Jun ,  LU Su-shan ,  WU Yao-sen ,  XIAO Bo ,  GONG Li
    2021, 37(7):169-175. DOI: 10.13982/j.mfst.1673-9078.2021.7.1212
    [Abstract](304) [HTML](325) [PDF 1.29 M](1042)
    Abstract:
    In order to protect the color of apple during the processing of freeze-dried, four groups were designed according to different pretreatments: the control group, the blanching group, the color protection liquid soaking group, and the blanching-color protection liquid soaking composite color protection group. The vacuum freeze-drying was applied to produce freeze-dried apple slices, and then the water content, vitamin C content, titer acidity, rehydration ratio, texture, color difference, sensory evaluation, microstructure and other quality of each group of products were compared. The results showed that the moisture content, the vitamin C content, the titer, the rehydration ratio, the hardness, the brittleness, the brightness values and sensory evaluation in four freeze-dried apple slices ranged from 5.13% to 5.47%, 9.56 to 17.06 mg/100 g, 2.22 to 2.37 g/100 g, 5.15 to 3.49, 9715.67 to 9384.67 g, 1762.50 g to 1989.00 g, 77.73 to 84.04, 5.82 to 8.02, respectively. Vitamin C content of the CK group was significantly (p<0.05) higher than those of the other three groups. The rehydration ratio of the BCP group was significantly (p<0.05) higher than that of the CK group. The color protection effect of the BCP group was best, with the brightness value 84.04 and the overall score 8.02. The results of the microstructure showed that the cells were disorganized and the structure was loose and broken after the combined treatment of pretreatments and vacuum freeze-drying. In general, although the four groups of freeze-dried apple slices had differences in nutrient composition and sensory evaluation, they all retain the typical flavor of apples. The better freeze-dried slice quality was found in the BCP group. This study could provide the theoretical and technical guidance for the industrial production of freeze-dried apple slices.
    23  Ultrafine Grinding Improves the Dissolution Contends, Digestion and Absorption of Ca, Fe and Zn in Lentinula edodes Powders
    XUE Shu-jing ,  YE Jia-qi ,  YANG De ,  LU Qi ,  SHI De-fang ,  FAN Xiu-zhi ,  LI Lu
    2021, 37(7):176-183. DOI: 10.13982/j.mfst.1673-9078.2021.7.1120
    [Abstract](258) [HTML](288) [PDF 2.36 M](601)
    Abstract:
    The dissolution amounts of Ca, Fe and Zn in the cover powder and stalk powder of Lentinula edodes, the bioavailability based on in vitro digestion model and the partition coefficient based on n-octanol absorption model were evaluated, and compared with the corresponding coarse powder (all 60 mesh). The results showed that the water dissolution rates of Ca, Fe and Zn and the soluble Ca contents were increased in the ultrafine powers from Lentinus edodes caps and stems (p<0.05). The soluble Fe contents in the ultrafine stems powers and the soluble Zn contents in the ultrafine cap powders were significantly higher than those in the corresponding crude powders. The dissolution contents of polysaccharide and protein-bound Ca, Fe and Zn were improved to some extents. The order of accessibility of the three elements in gastric and gastrointestinal digestive fluids in vitro was Zn > Ca > Fe. The average accessibility of Zn in the ultrafine caps and stems powers was 80.38% and 86.77%, respectively, and that of Ca was 56.41% and 61.41%, respectively, while that of Fe was 13.46% and 22.17%, respectively. In comparison with crude powders, ultrafine grinding powders resulted in signi?cant higher Ca and Zn accessibility ,and higher partition coefficients were observed for Ca, Fe, Zn from ultrafine stem powders powers and Ca, Zn from ultrafine cap powders powers (p<0.05). The results could be the basis of product development of Lentinula edodes and Ca, Fe, Zn intakes.
    24  Comparative Comprehensive Quality Analysis of Rosa roxburghii Fruit from Different Regions in Guizhou Province
    YU Lu ,  ZHAO Zhi ,  ZHANG Wen-xin ,  REN Ting-yuan
    2021, 37(7):184-193. DOI: 10.13982/j.mfst.1673-9078.2021.7.0041
    [Abstract](240) [HTML](172) [PDF 481.70 K](755)
    Abstract:
    To identify superior Rosa roxburghii cultivars in Guizhou and provide a scientific basis for large-scale planting, cultivation, and processing of medicinal Rosa roxburghii products, this study examined Rosa roxburghii fruits from 22 regions of Guizhou by determining their basic nutritional content. Measured values include soluble solids, titratable acids, soluble proteins, vitamin C, and superoxide dismutase (SOD) activity. Overall quality of Rosa roxburghii fruit from different regions was analyzed and compared. Correlation analyses, principal component analyses, and cluster analyses were performed, and a scoring model was constructed to comprehensively evaluate Rosa roxburghii fruit quality. Significant differences were identified in the comprehensive quality indices of Rosa roxburghii fruits from different regions (p<0.05). In particular, vitamin C content varied greatly. Except for SOD activity index, a significant correlation was observed between all other indices (p<0.05). Soluble solid, total sugar, soluble protein, and vitamin C contents were the highest in fruit from the Renhuai region, whereas reducing sugar content and SOD activity were the highest in those from the Yinjiang region. Amino acid content was the highest in fruit grown in the Wangmo region. All comprehensive quality indices were relatively high in fruit from the Dejiang region. Three principal components (eigenvalue>1) were identified, and the cumulative variance contribution rate reached 75.162%. According to the comprehensive scoring model Fsynthesis=0.468F1+0.327F2+0.205F3, the Rosa roxburghii fruit-growing regions are ranked in descending order of overall fruit quality as follows: RH>YJ>DJ>WM>LD>ZA>DZ>PD>HZ>LD>CS>LL>DF>BJ>ZN>KL>FG>AS>MJ>SN>SC>LZ>PZ. When the Euclidean distance is 20, Rosa roxburghii fruits from different regions can be divided into three categories according to their overall quality, and the results of cluster analysis are basically consistent with those of principal component analysis. Rosa roxburghii fruits in Dejiang, Renhuai, Yinjiang, and Wangmo were found to be of better overall quality. Fruit quality is thus closely correlated with altitude. Therefore, good-quality Rosa roxburghii fruits from high-altitude regions should be considered for exploitation and utilization.
    25  Optimization of Fermentation Process of Hemp Seed Milk and Changes in Antioxidant Activity
    LAI Hui-min ,  WANG Shi-lian ,  RUAN Zheng ,  LI Bian-sheng
    2021, 37(7):194-202. DOI: 10.13982/j.mfst.1673-9078.2021.7.0974
    [Abstract](342) [HTML](205) [PDF 3.28 M](761)
    Abstract:
    The optimal production process and formula of hemp seed milk was determined through single factor and response surface experiments using the fuzzy comprehensive evaluation method, with cooked hemp seed milk as the raw material, the lactic acid bacteria mixture ratio, amount of added strain, fermentation temperature and fermentation time as the independent variables, as well as the number of viable bacteria, acidity and sensory score as the evaluation indicators. Experiments show that the fuzzy comprehensive evaluation value was the highest (0.927 points), with the number of viable bacteria, acidity and sensory score being 1.9×108 CFU/mL, 78 oT and 8.74 points, respectively, under the following conditions: ratio of Bulgarian lactobacillus: Thermophilic streptococcus: Lactobacillus casei: Streptococcus acidophilic, 2:2:1:1.78; inoculation quantity, 6.21%; fermentation temperature, 39.42 ℃; fermentation time, 7.12 h. After fermentation, the contents of total sugars and total solids in the hemp kernel milk were 69.29 mg/mL and 6.08±0.22 g/100 g, respectively, which were significantly lower than those before fermentation (p<0.05). The contents of total acids, total phenolics and total flavonoids were 7.99±0.34 mg/mL, 28.04±0.82 mg GAE/100 mL and 27.11±1.34 mg GAE/100 mL, respectively, which were significantly higher than those before fermentation (p<0.05). The antioxidant activity experiments showed that when the DPPH free radical scavenging rate and ABTS+ free radical scavenging rate were 50%, the concentrations of hemp seed milk after fermentation were 26.09 mg/mL and 7.22±0.13 mg/mL, respectively, which were equivalent to 0.25 mg/mL and 0.13 mg/mL tocopherol, and the antioxidant activity increased significantly (p<0.05).
    26  Effect of De-sugaring Treatment on Potato-wheat Mixed Flour Quality
    XIONG Tian ,  HE Jian-jun ,  CAI Fang ,  WANG Shao-hua ,  SHI Jian-bin ,  CAI Sha ,  SUI Yong ,  CHEN Xue-ling ,  FAN Chuan-hui ,  JIA Zhi-wen ,  MEI Xin
    2021, 37(7):203-212. DOI: 10.13982/j.mfst.1673-9078.2021.7.1028
    [Abstract](165) [HTML](186) [PDF 1.05 M](580)
    Abstract:
    This research was conducted to reduce the negative impact of the high sugar content of the whole potato flour (the resultant noodles are difficult to form, tend to break and lead to muddy soup) and ultimately improve the quality of the whole potato flour-wheat mixed flour, pure water and ethanol with different volume fractions (25%, 50% and 75%) were used to de-sugar the whole potato flour. The changes in soluble polysaccharides, protein content, color and odor index of the whole potato powder before and after de-sugaring were analyzed. The effects of different addition amounts (5%, 10%, 15%, 20%, 30%) of potato flour on the water holding capacity, oil holding capacity, light transmittance and thermal properties of the mixed flour produced by the unmodified or de-sugared potato flour and wheat were investigated. The results showed that pure water desugar efficiency was high with low protein loss, and there was no effect on the original flavor of potato. After pure water de-sugaring, the gelatinization temperature and enthalpy (ΔH) of the potato powder increased, the water holding capacity (WHC) decreased, the oil holding capacity (OHC) increased, and the light transmittance was improved. After pure water de-sugaring, the soluble sugar removal rate of the whole potato powder was 45.77%, the protein retention rate was 93.32%, the light transmittance was 96.09%, the water and oil retention were 4.67 g/g and 1.79 g/g, respectively. The starting temperature (To), peak temperature (Tp) and endpoint temperature (Tc) were 56.8 ℃, 65.0 ℃ and 65.6 ℃, respectively, and ΔH was 1.35 J/g. Compared with the mixed flour containing unmodified potato flour, the WHC of the mixed flour containing de-sugared potato powder pure water de-sugaring group was less affected by the proportion of the potato flour, with its processing characteristics such as OHC, light transmittance and thermal properties were also maintained within a relatively constant range, thereby being more suitable for processing and utilization.
    27  Characteristic and Mechanism of Methylene Blue Adsorption by Pepper Stem Biochar
    LIU Jian-zhuo ,  ZHANG Zhen-yan ,  LI Lin-zhou ,  FENG Jian-cheng ,  LI Ji-hui ,  ZHANG Rong-hu
    2021, 37(7):213-220. DOI: 10.13982/j.mfst.1673-9078.2021.7.1160
    [Abstract](281) [HTML](272) [PDF 1.43 M](644)
    Abstract:
    In this study, pepper stem, one of wastes from preliminary processing of pepper, was used as raw material to produce pepper stem biochar (PB-200) by pyrolysis in a nitrogen atmosphere under 200 ℃. Adsorption characteristics of PB-200 on methylene blue (MB) was researched by batch adsorption experiment under different pH, adsorption time, temperature and initial concentration conditions; and it was characterized by scanning electron microscopy (SEM), surface area and porosity analyzer, particle size analyzer, zeta potential analyzer, Fourier-transform infrared (FT-IR) spectrometer, elemental analyzer, etc to investigate the mechanism of the biochar adsorption. The results showed that PB-200 resulted in good adsorption performance at pH=3~11, and as the pH increased from 3 to 11, the adsorption of PB-200 increased from 72.34 to 144.91 mg/g. The kinetic studies showed that the experimental data was fitted by the pseudo second-order model well (R2≥0.99); and the isothermal adsorption process of MB can be better described by the Langmuir adsorption isotherms model than the Freundlich model (R2≥0.99). The adsorption capacity of MB was up to 115.08 mg/g under the condition of an initial MB concentration of 100 mg/L when the biochar (20 mg) was mixed with MB solution (40 mL, pH 7.0) for 24 h at 25 ℃. It can be seen that PB-200 is an efficient adsorbent for removing MB in wastewater. Compared with pepper stems, the average particle size and pore size of PB-200 were reduced from 334.58 μm and 20.30 nm to 233.81 μm and 16.95 nm, respectively, and the specific surface area was increased from 0.70 m2/g to 0.96 m2/g; rich pore structure and oxygen-containing functional groups were demonstrated by the SEM, FT-IR and elemental analysis. The physical properties of PB-200 were significantly improved compared with Pepper stem; the adsorption of MB was chemisorption (electrostatic adsorption and and monalayer adsorption). PB-200 is an efficient adsorbent for removing methylene blue.
    28  Extraction and Antioxidant Activity Analysis of Melanoidins from the Sesame Residue of Pure Sesame Oil
    MAO Zhao-jie ,  LIN Bing-jie ,  YU Yuan ,  WANG Xia ,  XIAN Li ,  ZHANG Yu ,  YANG Zhong-xin ,  ZHANG Feng-xiang
    2021, 37(7):221-227. DOI: 10.13982/j.mfst.1673-9078.2021.7.0206
    [Abstract](244) [HTML](207) [PDF 1.69 M](701)
    Abstract:
    Sesame seed residue was used as raw material. The melanoidins were extracted from sesame dregs by different solutions assisted with ultrasonic extraction. The taste and structure of melanoidins were evaluated by electronic tongue, Fourier transform infrared, respectively. The antioxidant activities of sesame residue melanodins were also analyzed. The results showed that the melanoidin content of the sample extracted by pH 10.0 alkali solution was the highest, followed by 60% ethanol solution. The extraction by alcohol had a stronger bitter taste. The protein content of extraction by pH 10.0 alkali and the total sugar content of extraction by 60% alcohol were higher than that of other solutions, which content were 47.58% and 25.18%, respectively. Sesame residue melanin was mainly protein binding type. Bitterness was the most prominent taste of sesame residue melanodins, the highest bitter value was 7.28±0.03, followed by umami. With the increase of melanoidins concentration, their antioxidant abilities also increased. The extraction by water had the best ·OH scavenging effect, which has reached 56.52%. The DPPH· scavenging rate of extraction by 60% alcohol at the concentration of 1 mg/mL was 95%. There were heteroaromatic rings such as aromatic amines and furans in sesame residue melanodins. This work showed that melanoidins of sesame residue will be suitable to be extracted by pH 10 alkali and 60% alcohol solution and has good antioxidant activity. It will provide theoretical basis for the exploration of melanoidins and the utilization of sesame residue.
    29  Detection and Comparison of Volatiles in Fruit from Three Different Kinds of Loofah
    LI Jun-xing ,  WU Hai-bin ,  LUO Jian-ning ,  CHEN Jun-qiu ,  ZHAO Gang-jun ,  LIU Xiao-xi ,  ZHENG Xiao-ming ,  GONG Hao
    2021, 37(7):228-237. DOI: 10.13982/j.mfst.1673-9078.2021.7.0020
    [Abstract](218) [HTML](224) [PDF 26.34 M](806)
    Abstract:
    To fully identify the volatile compounds of loofah fruit aroma, and understand the variation features in different types of loofah, head space solid-phase micro-extraction (HS-SPME) combined with gas chromatography (GC)-mass spectrometry (MS) was used to analyze the volatile profiles of three kinds of loofah (SG, DR and YL). A total of 55 volatiles were identified in three kinds of materials, in which 15 kinds of hydrocarbon compounds were identified and showed the most species. The 43, 52 and 47 volatiles were detected in the YL, DR and SG, respectively, in which benzaldehyde, nonanal and linalool with the highest relative content, respectively. The principal component analysis and hierarchical cluster analysis based on the 55 compounds were used. It indicated that SG was clearly distinguished from DR and YL, and the volatiles in DR and YL were similar. These results was consistent with the biological classification of three types of resources. The 30 distinct volatiles (p<0.05) were detected in two groups of three types of loofah through one-factor ANOVA. The 20 variant volatiles were displayed the higher contents compared to these of DR and YL. Hexanal and (E)-2-Hexenal were mainly related to the green aroma characteristics, while benzeneacetaldehyde might result in the sweet aroma in DR. The results of this work will provide the reference for the research of flavor traits and quality breeding of loofah.
    30  Analysis of the Characteristic Volatile Flavor Components of Preserved Lao-Xiang-Huang of Chaozhou
    LIN Liang-jing ,  CAI Hui-tian ,  BAO Han ,  HUANG Xue-ying ,  CHEN Xi ,  GAO Xiang-yang
    2021, 37(7):238-249. DOI: 10.13982/j.mfst.1673-9078.2021.7.0929
    [Abstract](324) [HTML](266) [PDF 1.75 M](945)
    Abstract:
    In this study, the volatile flavor components of different brands of preserved Lao-Xiang-Huang from the Chaoshan area were analyzed based on gas chromatography-ion mobility spectrometry GC-IMS. A total of 9 types and 70 species were detected, including 8 esters (6%~12%), 14 aldehydes (10%~14%), 12 alcohols (13%~17%), 3 ketones (3%~5%), 23 terpenoids (49%~72%), 6 acids (1%~2%), 3 furans (2%~3%), 1 thiazole (0.4%~0.5%) and 1 pyrazine (0.6%~0.6%). Through the calculation and analysis of relative activity value (ROAV), the key volatile flavor contributors of (ROAV>1) were obtained, including geraniol, citronellol, linalool, 1,8-cineole-M, 1,8-cineole-D, myrcene-M, methional, 3-methylbutanal, 3-methylbutanol, propanal, methyl 2-methylbutanoate, 1-phenylethanol and nonanal. Among them, methional contributed the most to the flavor of the preserved Lao-Xiang-Huang. Principal component analysis (PCA) can effectively distinguish the samples of different brands. Partial least squares discriminant analysis (PLS-DA) combined with one-way ANOVA was used to screen 15 marker volatile compounds (VIP>1). GC-IMS can distinguish different brands of preserved Lao-Xiang-Huang, and allow rapid analysis of the differences in volatile compounds, thereby providing a reference for qualitative and quantitative research on the characteristic flavor components of preserved Lao-Xiang-Huang.
    31  Analysis of Volatile Components in Flowers and Leaves of Camellia luteoflora Y.K.Li
    JIN Tang ,  DAI Yu-xuan ,  WANG Dong ,  XU Hai-xia ,  WANG Li
    2021, 37(7):250-258. DOI: 10.13982/j.mfst.1673-9078.2021.7.0011
    [Abstract](324) [HTML](212) [PDF 1.35 M](732)
    Abstract:
    The volatile components of Camellia luteoflora Y.K.Li were detected by GC-MS. The differences in volatile composition of Camellia luteoflora Y.K.Li from organs by different extraction methods were compared. The essential oil of C. luteoflora was extracted by ultrasonic-assisted extraction (UAE) and head space solid-phase micro-extractions (HS-SPME), respectively. Their components were analyzed by gas chromatography-mass spectrometry (GC-MS), and further identified by NIST08.LIB standard mass spectrometry library. The peak area normalization method was used to quantitatively analyze these compounds. A total of 137 volatile components were detected in flowers and leaves, and 121 were identified. The 74 compounds were identified in flowers, including 15 terpenoids, 1 steroids, 11 aromatic compounds and 46 aliphatic compounds. The content of linalool (16.71%) was the highest. The 72 compounds were identified in leaves, including 23 terpenoids, 2 steroids, 14 aromatic compounds and 33 aliphatic compounds. Trans-2-hexenal (20.63%) had the highest content. There were 25 compounds both in flowers and leaves, including linalool, trans-2-hexenal and hexanal, which accounted for 44.82% of flowers and 47.69% of leaves, respectively. In this work, a variety of volatile components with pharmacological activities and attracting insect pests were identified in C. luteoflora, which laid a foundation for understanding the volatile components of C. luteoflora and provided a theoretical basis for pests control and relative product development and utilization.
    32  Analysis and Comparison of Volatile Components in Purple rice Sweet Wine with Different Sterilization Treatments by Electronic Nose and Headspace Gas Chromatography-ion Mobility Spectrometry
    PENG Xu-yi ,  ZHENG Jing-shao ,  LIU Yu-hang ,  XU Lin-huan ,  KUANG Wei-yang ,  HUANG Wei
    2021, 37(7):259-268. DOI: 10.13982/j.mfst.1673-9078.2021.7.1091
    [Abstract](208) [HTML](243) [PDF 966.38 K](683)
    Abstract:
    In order to select a more suitable sterilization method and maintain the original flavor of purple rice sweet wine as much as possible, this article used electronic nose, headspace gas chromatography-ion mobility spectroscopy (HS-GC-IMS) to analyze and compare the volatile components of four groups of samples of heat sterilization, irradiation sterilization, ultra-high pressure sterilization and unsterilized control. The results of electronic nose test showed that the discrimination between the samples was good, and the differences of volatile components were mainly caused by nitrogen oxides, alcohols and aldehydes and ketones, methyls, sulfides. HS-GC-IMS detection and identification found that the 4 groups of samples shared 42 substances in 7 categories of alcohols, esters, aldehydes, ketones, acids, olefins and alkanes. The relative content of alcohols was the highest (62.03%~65.73%), followed by esters (12.70%~13.93%) and ketones (9.36%~11.59%), the sterilization method had a great influence on the relative content of each component. The relative odor activity value (ROAV) showed that there were 11 key flavor compounds in the samples, mainly including ethyl 2-methylbutyrate (69.39~100), acetaldehyde (38.61~42.05), ethyl isovalerate (18.16~27.23), isoamyl alcohol (9.91~18.08), butyraldehyde (14.13~18.06), ethyl isobutyrate (8.22~12.18). Both linear discriminant analysis and nearest neighbor algorithm analysis showed that the volatile components of ultra-high pressure and unsterilized samples were the most similar, followed by irradiation and heat sterilization samples, indicating that ultra-high pressure sterilization had the least effect on the aroma of samples, which was the best sterilization method for purple rice wine. The results of this study provide reference value for the selection of sterilization methods for sweet fermented rice.
    33  Evaluation of Different Rounds of Moutai-flavor Baijiu Based on Principal Component Analysis
    TANG Wei-chuan ,  KONG Xiang-kai ,  WANG Ting ,  QIU Sheng-qiang ,  ZHAO Jin-song ,  QIAN Yu ,  YUN Ling
    2021, 37(7):269-277. DOI: 10.13982/j.mfst.1673-9078.2021.7.1107
    [Abstract](341) [HTML](577) [PDF 2.34 M](808)
    Abstract:
    In order to evaluate and differentiate different rounds of Moutai-flavor Baijiu, the flavor substances from seven rounds of Moutai-flavor Baijiu in the same cellar as the object were detected by gas chromatography and analyzed by principal component analysis. The results showed that the total acid content in crude spirits decreased with the increase of the number of rounds. The total acid content in the first round was the highest, reaching 2.94 g/L, and then decreased all the time, finally reaching the minimum value of 1.51 g/L in the sixth and seventh rounds. The total ester content first increased and then decreased, starting from 3.57 g/L, and the total ester content in the third round reached the highest value of 5.14 g/L, then declined to 3.10 g/L. The content of acetic acid, n-propanol, ethyl acetate, ethyl lactate, acetaldehyde, acetal and other compounds was relatively high in the crude spirits. The contents of acetic acid, ethyl acetate and n-propanol in the first and second crude spirits were extremely high, they accounted for 14.77%~15.55%, 14.16%~22.90% and 37.78%~37.98% respectively. The results of principal component analysis showed that the cumulative contribution rate of the first three principal components could reach 89.3%, and each round of Baijiu could be effectively distinguished on the scatter chart of comprehensive score. The first round of Baijiu alone occupied the first quadrant, the second round of Baijiu was located near the negative axis of X axis, the third to fifth rounds of Baijiu were concentrated, located below X axis and near Y axis, and the sixth and seventh rounds were concentrated near the positive axis of X axis. The comprehensive score of each round of Baijiu was: 4>5>3>7>6>1>2. To sum up, the difference of flavor substances combined with principal component analysis could accurately and quickly distinguish and evaluate the crude spirits of different rounds of Moutai-flavor Baijiu, which could provide theoretical support for the crude spirits' hooking and rating.
    34  Comparison of Functionality and Aroma Components of Mulberry Wine Fermented by Different Methods
    WANG Sha ,  LU Hong-mei ,  CHEN Li ,  MOU Can-can ,  WU Zhen ,  LI Rong-yuan
    2021, 37(7):278-285. DOI: 10.13982/j.mfst.1673-9078.2021.7.1197
    [Abstract](266) [HTML](261) [PDF 1.32 M](733)
    Abstract:
    Dashi mulberries in Kaiyang county, Guizhou province was used as raw materials. The effects of batch fermentation, fed-batch fermentation, and batch fermentation with residues on the functional components and aroma components of mulberry wine were studied. The results showed that: the highest content of functional ingredients (resveratrol 0.19 mg/100 mL, polyphenols 2020.89 mg/L, flavonoids 310.56 mg/L, total anthocyanins 97.25 mg/L) were found in batch fermentation with residues for mulberry wine. The solid phase microextraction combined with gas chromatography-mass spectrometry technology (SPME/GC-MS) was used to detect the aroma components of mulberry wine in batch fermentation, fed-batch fermentation, and batch fermentation with residues, and there were 133, 142, and 146 aroma components of mulberry wine, respectively. The batch fermented mulberry fruit wine with residue had the most variety of aroma components, including 9 alkanes (1.43%), 16 alcohols (29.70%), 57 esters (56.20%), and 27 aldehydes and ketones (4.64%), 11 kinds of acids (3.62%), 10 kinds of benzene and phenols (0.68%), 4 kinds of olefins (0.70%), 12 kinds of other substances (1.35%). The significant correlation was found between 20 kinds of main aroma components and typical of mulberry wine. Fermentation with residues in batches was not only beneficial to increase the content of functional components of mulberry wine, but also increase the diversity of mulberry wine flavor substances.
    35  Reduction of Hydroxymethylfurfural (HMF) via Three Additives in Model Reaction System
    OU Juan-ying ,  JIANG Kai-yu ,  GAO Yu-yue ,  ZHANG Yan-jie ,  HUANG Cai-huan
    2021, 37(7):286-293. DOI: 10.13982/j.mfst.1673-9078.2021.7.1200
    [Abstract](227) [HTML](319) [PDF 585.87 K](694)
    Abstract:
    Sodium bicarbonate, ammonium bicarbonate, table salt, potassium aluminium sulphate, and ammonium aluminium sulphate were used to investigate their effect on hydroxymethylfurfural (HMF) formation in four model reaction systems based on HMF formation pathways. Results indicated that in the Maillard reaction (glucose-glycine) and fructose-heating models, HMF content decreased significantly and their values were 5.01, 3.02 mg/L and 3.30, 17.52 mg/L with addition of 2.00 mg/mL sodium bicarbonate and ammonium bicarbonate, respectively. However, in the Maillard reaction, glucoses- fructose- and sucrose-heating models, HMF content were 80.53, 13.02, 265.02 and 310.11 mg/L after 0.60 mg/mL potassium aluminium sulphate treatment, respectively. Compared to control, there was 620.26-fold increase in HMF content. In biscuits, HMF content could be also decrease by sodium bicarbonate, ammonium bicarbonate, and table salt and the maximum reduction was 35.34%. The potassium aluminium sulphate and ammonium aluminium sulphate could remarkedly increase HMF formation, although sodium bicarbonate, ammonium bicarbonate, and table salt were presented. When added with 1.00 g/80.00 g flour, potassium aluminium sulphate and ammonium aluminium sulphate could induce the 62.41% and 55.64% increase of HMF content, respectively. Since the dietary HMF can be transformed to carcinogen 5-sulfooxymethylfurfural in body, the finding of the present research could support the national regulation for limiting use of potassium aluminium sulphate and ammonium aluminium sulphate as the raising agents in bakery foods.
    36  Correlation between Texture-Analyzer Parameters and Physical Properties Measurement of Peanut
    TANG Peng-yu ,  MENG Fan-bo ,  HUANG Dao-mei ,  ZHENG Xiu-yan ,  LIN Mao
    2021, 37(7):294-301. DOI: 10.13982/j.mfst.1673-9078.2021.7.1105
    [Abstract](252) [HTML](266) [PDF 1.28 M](599)
    Abstract:
    In order to clarify the correlation between texture parameters and physical properties of peanut, two peanut varieties with apparent differences were selected as samples in this study. The influence of the texture-analyzer parameters on the physical properties of peanut samples was investigated by regulating the critical control points of the texture. The results showed that inappropriate texture-analyzer parameters could significantly affect the physical properties of peanut samples and reduce the accuracy of test results. For example, the compression shape variable had a significant influence on the hardness, elasticity, cohesion, chewiness and other texture properties of peanut. However, the compression shape variable had a small influence when it was between 35% and 50%. The detection speed had a significant negative correlation with the brittleness of peanut samples. The brittleness detection results were relatively stable when the test speed was 40 mm/min. The stability of shear force results would be seriously affected by the higher shear rate, which resulted in an increase in systematic errors. Therefore, the better stable shear force data could be obtained when the controlled shear rate was less than 60 mm/min. The results of physical properties were different between the different types of peanuts. The systematic errors could be reduced by using suitable determination parameters and the physical property differences between samples were better represented. As a result, when the physical properties of peanut samples were determined, the stable data could be obtained by selecting parameters of compression deformation ratio 35%~50%, test speed 40 mm/min and the shear rate of no more than 60 mm/min, which had little effect on the physical determination of peanut.
    37  A SERS Rapid Detecting Method for New Coccine Based on the Analytic Hierarchy Process and Technique for Order Preference by Similarity to Ideal Solution
    LIU Zhi-peng ,  WEI Qing-yi ,  WU Lei-lei ,  PU Hong-bin
    2021, 37(7):302-309. DOI: 10.13982/j.mfst.1673-9078.2021.7.0566
    [Abstract](345) [HTML](181) [PDF 1.18 M](635)
    Abstract:
    Rapid detection methods play a critical role in on-site detection, rapid screening and government supervision in the field of food safety. However, there is a lack of performance evaluation means in current rapid food detection methods, thus, it is urgent to establish a multi-index comprehensive evaluation method. In this study, a functional surface-enhanced Raman scattering (SERS) sensor based on Au/UiO-66(NH2) material was constructed to achieve SERS rapid detection of food colourants. Under the optimal conditions, the intensity of the characteristic Raman peak of new coccine at 1137 cm-1 had a good linear relationship in the concentration range of 1.0~50 mg/L, with R2 as 0.9684 and the detection limit as low as 0.40 mg/L. The Analytic Hierarchy Process (AHP) combined with Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was used to evaluate three detection schemes for new coccine, including rapid detection with SERS sensor, rapid detection box of synthetic colourants and high performance liquid chromatography (HPLC). On the basis of 18 indicators selected from four aspects (adaptability, operability, economy and technology) of the detection methods, the indicator weight was determined by AHP, and then the comprehensive evaluation values of the three detection methods for new coccine (0.66, 0.31 and 0.58, respectively) were calculated through combining with TOPSIS . The results showed that the functional SERS rapid detection method for colourants based on Au/UiO-66 (NH2) material can replace the rapid detection box of synthetic colourants and HPLC method. The SERS detection method in this study provides a new option for rapid screening of illegal added colourants in food.
    38  Determination of Several Procyanidins in Litchi Pericarp by HPLC with Pass-through Extraction
    QIN Guo-xin ,  LI Hui-ling ,  HE Jie ,  ZHOU Qi-feng ,  LAO Shui-bing ,  YAN Fei-yan ,  WANG Jing ,  JIN Mao-jun ,  CHENG Liang ,  WEI Yu-ning ,  WANG Hai-jun ,  CHEN Yong-xian
    2021, 37(7):310-314. DOI: 10.13982/j.mfst.1673-9078.2021.7.0950
    [Abstract](248) [HTML](187) [PDF 511.59 K](566)
    Abstract:
    A method was established in this study for determining the contents of catechin (C)，epicatechin (EC)，gallic acid (GA)，procyanidin B2 (PCB2)，procyanidin B4 (PCB4) and procyanidin A2 (PCA2) in litchi pericarp. The samples were extracted with 85% aqueous ethanolic solution and purified by Oasis PRiME HLB solid-phase extraction column, and analyzed by HPLC. The chromatographic column was thermo Syncronis C18 (250×4.6 mm, 5 μm), with methanol and 1 % glacial acetic acid as the mobile phase in gradient elution at a flow rate of 1.0 mL/min, column temperature at 35 ℃ and detection wavelength at 280 nm. The separation was carried out using consisting of. In the range of 0.5~100 mg/L, the concentrations of catechin, epicatechin, gallic acid, procyanidin B2, procyanidin B4 and procyanidin A2 had a good linear relationship with the peak areas with coefficients all higher than 0.9998. The average spiking recovery rates were 83.00%~102.00%, with relative standard deviations (RSD) between 0.48% and 0.83 %. The limits of detection (LOD, S/N=3) were 0.52, 0.55, 0.35, 0.45, 0.95 and 0.65 mg/kg, and the limits of quantification (LOQ, S/N=10) were 1.26, 1.64, 0.95, 1.35, 2.80 and 1.45 mg/kg for catechin, epicatechin, gallic acid, procyanidin B2, procyanidin B4 and procyanidin A2, respectively. This method is simple, rapid, accurate, reproducible, and can be used for the simultaneous quantitative determination of catechin, epicatechin, gallic acid, procyanidin B2, procyanidin B4 and procyanidin A2 in litchi pericarp.
    39  Python/RGB Color Data Analysis Platform for Rapid Detection of Reducing Sugar Concentration
    CHEN Hui ,  HAO Jin-heng ,  YUAN Zhi-tao ,  LUO Jia-wei ,  CHEN Yin-xi ,  ZHENG Shao-peng ,  LI Pei-yu ,  LYU Yong-si ,  LIANG Shi-hao ,  LAI Lin-hao ,  CAO Shi-lin
    2021, 37(7):315-320. DOI: 10.13982/j.mfst.1673-9078.2021.7.0898
    [Abstract](305) [HTML](195) [PDF 646.21 K](621)
    Abstract:
    A new method for determining reducing sugar concentration through food biochemical experiments using python was investigated in this study. Reducing sugar-containing samples were diluted to different concentrations and placed on the 96-well plates, before being scanned by the scanner to obtain the color images in tiff. The RGB color data of the samples were collected by the RGB analysis module of the online analysis platform developed by our research group. By investigating the conditions such as the sampling size and optimal image resolution, a rapid detection method for reducing sugar in food based on RGB color system was established. For glucose detection, the fitting coefficient was higher than 0.98 when the concentration of glucose remained the same with the sample size as 100 μL and the image resolution as 1200 dpi. The accuracy of the relationship between RGB color data and the concentration of reducing sugar was higher, and the result was similar to the that obtained by spectrophotometry, but this method is more convenient and faster and allowed multi-channel processing. At the same time, through measuring the content of reducing sugar in the real sample and comparing with the results obtained by spectrophotometry, the reliability and feasibility of using Python/RGB color data analysis platform to determine quickly the concentration of reducing sugar in food were verified.
    40  Rapid Detection of Terbutaline Sulfate in “Lean Meat Powder” Based on SERS
    LI Zhi-cheng ,  ZHENG Xiao-dong ,  LIU Xue-mei ,  YAN Xin-huan ,  CAO Ning ,  ZHOU Da-sen ,  SONG Ye
    2021, 37(7):321-326. DOI: 10.13982/j.mfst.1673-9078.2021.7.1021
    [Abstract](229) [HTML](210) [PDF 825.34 K](701)
    Abstract:
    A method for rapid detection of terbutaline sulfate by surface enhanced Raman spectroscopy (SERS) was developed. Firstly, the surface-enhanced active substrate was prepared, and the enhancer was characterized by electron microscopy and UV-Vis absorption spectroscopy. The experimental results showed that the prepared silver sol exhibited the greatest enhancing effect on the Raman signal information of terbutaline sulfate, thus, the silver sol was selected as the surface enhancer. A portable Raman spectrometer was used to detect terbutaline sulfate in water and urine. The Raman signals at 800 cm-1, 1050 cm-1, 1330 cm-1 and 1450 cm-1 were identified as the Raman characteristic peaks of terbutaline sulfate. A good linear relationship between the signal intensity of surface enhanced Raman spectrum and the concentration of terbutaline sulfate in the range of 1~10 mg/L was obtained through further experiments. The correlation coefficient R2 was 0.9718, with the detection limit as 0.5 mg/L and the detection time as 60 s. The recoveries of the blank samples were 84.9%, 91.6% and 89.1% in the three-levels standard spike-and-recovery experiments. These results were in good agreement with those of comparative experiments by high performance liquid chromatography-based traditional large-scale analysis instrument methods. The results of this research showed that the method is advantageous as it is fast, accurate, non-destructive and easy to operate, which laid a good foundation for the supervision of “lean meat powder”.
    41  Progress in the Study of H and J Aggregates of Astaxanthin
    ZHAO Ying-yuan ,  WANG Zhao-xuan ,  XUE Wen-jie ,  SHU Ao ,  WANG Gao-wei ,  ZHANG Sheng-meng ,  JIA Hui-hui ,  LI Rui-fang
    2021, 37(7):327-334. DOI: 10.13982/j.mfst.1673-9078.2021.7.1129
    [Abstract](366) [HTML](814) [PDF 2.08 M](1219)
    Abstract:
    Astaxanthin is a natural terpene unsaturated compound, which has two β-ionone ring and eleven conjugated double bonds in the molecular structure. As the only one carotenoid that can pass through the blood-brain barrier, astaxanthin has numerous biological activities beneficial for human health. In recent years, astaxanthin has attracted much attention in the fields of food, medicine, biology and cosmetics due to its excellent antioxidant properties. As a naturally occurring carotenoid, astaxanthin can be spontaneously aggregated in the hydrated organic solvent, thus presenting different forms of existence, such as yellow H aggregates, orange M monomer, and pink-purple J aggregates, and different kinds of carotenoid aggregates could make a big difference in color, structure, optical property, biological activity, and so on. This article mainly focuses on the formation mechanism of aggregates, influence factors, detection methods (ultraviolet-visible spectroscopy, transmission electron microscope, circular dichroism, Raman spectroscopy, fluorescence spectroscopy, molecular simulation method, etc.) and the application prospect of astaxanthin aggregates in recent ten years, in order to lay a foundation for future astaxanthin aggregates physiological activity and application research.
    42  Progress in Rapid Detection of Heavy Metal Contamination in Food Based on Functional Nucleic Acid
    DENG Sha ,  DONG Yi ,  REN Yao ,  DENG Rui-jie ,  HE Qiang
    2021, 37(7):335-343. DOI: 10.13982/j.mfst.1673-9078.2021.7.1056
    [Abstract](198) [HTML](239) [PDF 1.48 M](674)
    Abstract:
    Food safety is closely related to human health. Heavy metal pollution has become a prominent problem in the field of food safety. In order to ensure food safety, it is extremely important to develop a fast, cheap and popular method for detecting heavy metal pollution in food. In recent years, biosensing and analysis technologies based on functional nucleic acids have attracted widespread attention. Functional nucleic acids such as ribozymes and nucleic acid aptamers as a new type of biological recognition molecules can realize the specific recognition of metal ions, and have the potential to be used for constructing a highly sensitive and selective analysis and detection platform for heavy metals in food. This article reviews the progress of applying functional nucleic acids in the detection of polluted heavy metals such as lead ion (Pb2+), mercury ion (Hg2+) and cadmium ion (Cd2+), with the focus on the fluorescent sensor and colorimetric sensor constructed by functional nucleic acid(s) as well as the nucleic acid nanosensor constructed by the composite of functional nucleic acid(s) and nanoparticles. In addition, considering the broad scope and large number of samples involved in the detection of heavy metal ions in food, this article highlights a detection platform integrating functional nucleic acids with microfluidic technology and portable detection equipment to provide ideas for on-site analysis of food heavy metal contamination.
    Journal introduce

    Editor in chief：李琳

    Inauguration：现代食品科技

    International standard number：ISSN 1673-9078

    Unified domestic issue：CN 44-1620/TS

    Domestic postal code：46-349

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