Volume 38,Issue 3,2022 Table of Contents

1 Antioxidant and Hypoglycemic Activity of Polysaccharide from Panzhihua Black Truffle

WEI Xinyue , CHEN Kebao , GUAN Tongwei

2022, 38(3):1-7. DOI: 10.13982/j.mfst.1673-9078.2022.3.0785

[Abstract](547) [HTML](280) [PDF 3.36 M](690)

Abstract:
Polysaccharides, the main component present in truffle, exhibit diverse biological properties, including antioxidant, anti-tumor, and hypoglycemic activity. Polysaccharide activity is closely related to its structure; however, reports on related structures and biological activity of polysaccharide components in Panzhihua black truffle remain scarce. Herein, the polysaccharide from Panzhihua black truffle was isolated and purified using water extraction and Sephadex G-200. Additionally, its primary structure and in vitro antioxidant and hypoglycemic activity were analyzed. The molecular weight of the black truffle polysaccharide is 1.29×104 u, and it mainly consists of mannose, glucose, rhamnose, and galactose at a molar ratio of 2.89:1.81:0.34:0.50. Infrared spectrum analysis revealed that the polysaccharide was pyranoid with an α-glycosidic bond. In vitro experiments revealed that the polysaccharide exhibited specific DPPH and hydroxyl free radical scavenging effects, affording better scavenging ability against DPPH free radicals, with an IC50 value of 1.02 mg/mL. Meanwhile, the antioxidant activity increased with increasing polysaccharide concentration. In addition, in vitro hypoglycemia analysis indicated that the polysaccharide could significantly inhibit α-glucosidase and α-amylase activity, with IC50 values of 1.99 mg/mL and 3.30 mg/mL, respectively. This study provides a theoretical basis for the comprehensive development of black truffle polysaccharide.

2 Hypoglycemic and Lipid Lowering Effects of Potato Resistant Starch on Hyperlipidemia Rats

YUCHI Miao , WU Jianmei , GAO Lu , LIU Dengyu , QU LIN

2022, 38(3):8-14. DOI: 10.13982/j.mfst.1673-9078.2022.3.0640

[Abstract](263) [HTML](188) [PDF 933.66 K](482)

Abstract:
To explore the hypoglycemic and blood lipid-lowering effects of potato resistant starch on hyperlipidemia rats, 48 rats were randomly divided into a blank control group and a model control group according to their body weights. After 2 weeks of high-fat feeding, they were randomly divided into 5 groups according to the total cholesterol (TC) level: high-fat model group, positive control group, and potato resistant starch high-, medium-, and low-dose groups. After 6 weeks of intervention, the body weights, liver coefficients, blood lipid levels and other indicators of the rats in each group were measured, and the pathological tissue sections of their livers were examined. Results: Compared with the blank group, the body weight of the high-fat group increased by 2.21%, the heart weight, liver weight, liver coefficient, and periepididymal fat weight all increased by 23.70%, 85.84%, 63.88% and 23.74%, respectively; TC, TG, LDL-C and blood sugar levels increased; The high-fat model was successfully established. Compared with the high-fat group, the experimental group's body weight, liver weight, liver coefficient, and periepididymal fat weight decreased, with the largest reductions being 2.50%, 14.18%, 9.18%, and 19.46%, respectively; The levels of TC, TG, LDL-C, AI and blood sugar were significantly reduced, and the largest reductions were 29.84%, 49.33%, 59.21%, 43.89% and 11.33%, respectively, with no significant difference found in HDL-C. The results of HE staining experiments showed that compared with the high-fat group, the degrees of liver steatosis in the rats of the high- and medium-dose groups were significantly improved. The results showed that potato resistant starch can lower the blood sugar and blood lipid levels, and makes a positive contribution to the prevention and treatment of hyperlipidemia.

3 Regulatory Effect of Fermented Soybean Dietary Fiber on Gut Microbiota of Sows

GUO Yongjing , LIU Guo , FENG Konglong , SONG Mingyue , DAI Weijie , HUANG Zaocheng , CAO Yong

2022, 38(3):15-24. DOI: 10.13982/j.mfst.1673-9078.2022.3.0508

[Abstract](245) [HTML](194) [PDF 3.41 M](396)

Abstract:
The regulatory effects of soy sauce residue-derived fermented soybean dietary fiber (FSDF) on gut microbiota and its short-chain fatty acid products in sows were investigated. The sows fed a feed containing 5% FSDF (a low-salt, low-oil, and odorless food-grade dietary fiber derived from soy sauce residues) were used as the experimental group (DF), and the blank control group (CK) was fed the normal feed (the same feed without FSDF). The feces samples of the two groups were collected, and 16S rDNA sequencing technology was used to examine the changes in the structure of sows’ intestinal flora. The contents of short-chain fatty acids in the feces were determined by gas chromatography-mass spectrometry (GC-MS). The Spearman correlation analysis was conducted to evaluate the correlation between gut microbiota at genus level and short-chain fatty acids. The results of the Welch's t-test showed that the abundance of slackia in the intestinal flora of DF group was significantly higher than that of CK group (p<0.05). LEfSe results showed that Clostridium IV and Deltaproteobacteri were the two differentially abundant species in DF group. After the feeding with FSDF, the contents of individual short-chain fatty acids in DF group increased to varying degrees, especially the butyric acid content significantly increased (p<0.05). The results indicated that addition of FSDF to the feed could changed the gut microbiota structure of sows, and promoted the enrichment of short-chain fatty acid-producing flora in the intestine, thereby increasing the contents of short-chain fatty acids in the intestine, especially butyric acid.

4 Effects of Pleurotus citrinipileatus Polysaccharides on the of Secretion Cytokines and Nitric Oxide Synthase (NOS) in An in Vitro Induced Inflammation Model

LUO Xiaoheng , ZHAO Zhekun , GAO Yi , ZHAO Shuang

2022, 38(3):25-32. DOI: 10.13982/j.mfst.1673-9078.2022.3.0521

[Abstract](213) [HTML](220) [PDF 913.52 K](479)

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Pleurotus citrinipileatus was used as the raw material, and crude polysaccharides were extracted by water extraction and alcohol precipitation from its fruiting bodies of. The Sevage method was used to remove proteins, and two components, PSI and PSII were obtained after purification by DEAE-Cellulose ion exchange and Superdex-75 gel chromatography. The in vitro inflammation model was established by lipopolysaccharide (LPS) stimulation. The optimal doses of the two polysaccharides were screened by the MTT method. The activity of nitric oxide synthase (NOS) was determined by the absorbance assay, and the levels of secreted cytokines, IL-1β, IL-6 and TNF-α, were determined by enzyme linked immunosorbent assay kits to evaluate the anti-inflammatory effect of the polysaccharides on RAW264.7 cells. The results showed that the cellular inflammation level reached the highest when the concentration of LPS was 5 μg/mL. On the basis of the cell model, the optimal dose of PSI and PSII were 500 μg/mL and 200 μg/mL, respectively. Compared with the LPS model group, the inhibition rates of PSI on NOS activity, IL-1β, IL-6 and TNF-α were 37.54%, 28.84%, 28.27% and 30.25%, respectively. The inhibitory rates of PSII on NOS activity, IL-1β, IL-6 and TNF-α were 51.24%, 37.56%, 31.35 % and 32.67%, respectively. The research confirmed that PSI and PSII had the alleviating effects on LPS-induced inflammatory cells, which were mainly manifested in inhibiting the level of secreted inflammatory cytokines, promoting cell proliferation, and reducing the phagocytic ability of macrophages. Compared with PSI, PSII had a greater inhibitory effect on the secretion levels of nitric oxide synthase (NOS) and cytokines, IL-1β, IL-6 and TNF-α, thereby exhibiting a better anti-inflammatory effect. Key words:

5 The Ameliorating Effect of Brassica napiformis Superfine Powder on Chronic Obstructive Pulmonary Disease in Mice

CHEN Linglin , ZHA Xueqiang , LI Qiangming , LUO Jianping , YANG Lei

2022, 38(3):33-40. DOI: 10.13982/j.mfst.1673-9078.2022.3.0628

[Abstract](177) [HTML](311) [PDF 2.76 M](382)

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The ameliorating effect of Brassica napiformis superfine powder (BUP) on the mice with chronic obstructive pulmonary disease (COPD) induced by intranasal instillation of lipopolysaccharide was investigated. The results showed that the active ingredients of BUP, such as soluble dietary fiber, polyphenols, flavonoids, glucosinolates and isothiocyanates, had higher dissolution rates (which are increased by 77.27%, 63.89%, 17.86%, 26.72% and 42.86% respectively) compared with the Brassica napiformis powder (BOP) that was prepared via crushing and passing through a 60-mesh sieve; BUP could ameliorate weight loss, emphysema and pulmonary fibrosis in COPD mice, increase the proportion of regulatory T cells in broncho alveolar lavage fluid (BALF) of COPD mice, reduced the proportion of macrophages, dendritic cells and neutrophils, and down-regulate the levels of IL-1β and IL-6 while up-regulating IL-10 level in the lung tissues of COPD mice. BUP could prevent from p65 entering the nucleus to promote the expression of inflammatory factors through inhibiting the phosphorylation of IκB and NF-κB p65 in lung tissues. At the same time, BUP could balance the level of reactive oxygen species in the BALF of COPD mice, improve the levels of oxidative stress-related factors, such as nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), and promote the expressions of Nrf2, heme oxygenase-1 (HO-1) and quinone oxidoreductase-1 (NQO-1) in the lung tissues of COPD mice. The research results showed that the ameliorating effect of BUP on COPD mice was greater than that of BOP, due to the higher dissolution rate of BUP’s active ingredients, and the underlying mechanism might be related to its anti-inflammatory and antioxidant effects. The experimental results provide a new reference for the development and utilization of Brassica napiformis.

6 Nutritional Components Analysis and Evaluation of Anchovy (Engraulis encrasicholus)

LING Shengnan , LIU Teyuan , CHEN Xueye , WANG Hongli , WANG Xichang , SHI Wenzheng

2022, 38(3):41-48. DOI: 10.13982/j.mfst.1673-9078.2022.3.0706

[Abstract](384) [HTML](670) [PDF 472.25 K](970)

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In order to further understand the nutritional value of the anchovy and improve its added value, the contents of its main nutritional components, amino acids, fatty acids and mineral elements were hereby detected and analyzed, and its nutritional value was also evaluated. The results showed that the contents of moisture, crude protein, crude fat and ash in anchovy were 75.67%, 16.38%, 5.05%, and 2.31%, respectively. A total of 17 amino acids were detected in anchovy, and the proportions of essential amino acids to total amino acids (EAA/TAA) and essential amino acids to non-essential amino acids (EAA/NEAA) were 40.49% and 68.06%, respectively, which fully met the recommended standards of FAO/WHO (EAA/TAA at around 40%, EAA/NEAA >60%). 37 fatty acids were detected in anchovy, of which eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were 31.74%, and the n-3/ n-6 value (5.58) was much higher than the daily diet recommended by FAO/WHO (0.1~0.2). The highest major element of anchovy was Ca (744.23 mg/100 g) and the highest trace element was Fe (2.24 mg/100 g). To sum up, anchovy is a high protein and low-fat fish resource, with rich and balanced proportion of amino acids, fatty acids and mineral elements and high nutritional value. This study can provide a theoretical basis for processing, transportation and product development of anchovy.

7 Isolation and Identification of a Basophilic Bacterium BD from “Bursted” Pidan and De novo Sequencing Analysis of the Strain

ZHANG Hao , YANG Linjie , ZHANG Tengfei , SUN Jing , LIANG Zhenhua , PI Jinsong , DU Jinping

2022, 38(3):49-55. DOI: 10.13982/j.mfst.1673-9078.2022.3.0659

[Abstract](210) [HTML](274) [PDF 1.21 M](387)

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A Gram-negative bacterial strain named BD was isolated from the “bursted” Pidan by traditional microbial culture method. The strain was identified by morphological observation, biochemical analysis and 16S rDNA. The phylogenetic tree was also constructed. The growth performance, alkali resistance and the gas production capacity of the strain were investigated through bacteriological experiment. The whole genome of the strain was sequenced using De novo system and a draft map was obtained. The results showed that the physiological and biochemical characteristics of the strain were Vibrio genus, and the homology of 16S rDNA sequence with Vibrio metschnikovii reached 99.92%. This strain could grow in a high alkali (pH 12) environment, and the optimal growth temperature was 25~40 ℃. De nove sequencing of the strain showed that the genome size of the strain was 3.70 Mb, encoding 3381 genes in total. Functional annotation of protein-coding genes showed that the genome of this strain contained a large number of genes related to carbohydrate metabolism pathway and membrane transport function pathway. This study provides a theoretical basis for the development of the "burst" control scheme of Pidan processing, and provides a reference for the mining of functional genes related to the adaptation of microorganisms to high alkali and high lipid environment.

8 Formation of Viable but Non-culturable State of Cronobacter sakazakii during Milk Fermention

CAO Yifang , ZHOU Ailian , BAI Hong , YU Yigang , XIAO Xinglong

2022, 38(3):56-62. DOI: 10.13982/j.mfst.1673-9078.2022.3.0714

[Abstract](230) [HTML](296) [PDF 1.18 M](396)

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In this study, Lactobacillus bulgaricus, a commonly used milk starter, was selected for milk fermentation. The interactions between C. sakazakii and Lactobacillus bulgaricus and the survival of C. sakazakii were investigated during milk fermentation. Furthermore, 16s rDNA high-throughput sequencing technique and PMA-qPCR method were used to analyze whether C. sakazakii entered into the viable but non-culturable (VBNC) state during milk fermentation. The results showed that after 48 h-fermentation of L. bulgaricus in milk, the values of pH and acidity reached to 3.40 and 212.00, respectively. When C. sakazakii was inoculated in milk in the middle fermentation stage, the pH value and acidity value were 3.47 and 214.30 respectively. When C. sakazakii was inoculated in milk in the early fermentation stage, the values of pH and acidity were 3.50 and 193.30 respectively after 48 h fermentation; which had a greater adverse impact on the fermentation. The concentration of C. sakazakii stabilized at 9.08 lg(CFU/mL) after 48 hours of growth in milk, the growth of C. sakazakii could not be detected by plate counting in the later stage of fermentation whenever C. sakazakii was inoculated into the milk. However, the existence of viable C. sakazakii could be detected by 16s rDNA and PMA-qPCR technology, which indicated that C. sakazakii could be VBNC state during milk fermentation. The existence of VBNC state of C. sakazakii might lead to an underestimation of total viable pathogenic cells, thus causing potential health hazards of milk and dairy products.

9 Synergistic Inhibitory Activity of Momordica charantia Saponin and Whey Protein Hydrolysate on Dipeptidyl Peptidase-IV

YU Haikun , Rayhnigul , WU Shangyi , CHEN Jiali , XIA Kouna , LI Mohan , YUE Xiqing

2022, 38(3):63-73. DOI: 10.13982/j.mfst.1673-9078.2022.3.0664

[Abstract](166) [HTML](278) [PDF 6.32 M](444)

Abstract:
To evaluate the inhibitory activity of dipeptidyl peptidase-IV (DPP-IV) from natural animal products, Momordica saponins (MS), whey protein pepsin hydrolysates (WPPHs), and whey protein trypsin hydrolysates (WPTHs) were used as raw materials, and the hydrolysis conditions were optimized by single factor test and response surface analysis, and then MS and WPPHs and WPTH were compounded, combined with simulated in vitro digestion, the inhibitory activity of DPP-IV was explored. The results showed that MS, WPPHs and WPTHs had DPP-IV inhibitory activity. The optimal hydrolysis conditions were as follows: When the enzyme was added at 4% and the pH was 2.7 for 2 h, the highest DPP-IV inhibitory rate of WPPHs was 15.43%; The highest DPP-IV inhibition rate of WPTHs was 14.62% when the addition amount was 4% and pH 7.6 was enzymatically hydrolyzed for 4 h. MS and whey protein hydrolysate had a synergistic effect on inhibitory activity of DPP-IV. When the combined volume ratio of MS, WPPHs and WPTHs is 1:1, it is significantly higher than that of their accumulation alone (p<0.05). After gastric digestion, the DPP-IV inhibition rate of WPPHs decreased by 2.02%, and the DPP-IV inhibition rate of MS and WPTHs increased by 0.99% and 7.01%, respectively; after intestinal digestion, the DPP-IV inhibition rate of WPPHs increased by 2.23%, while the DPP-IV inhibition rate of MS and WPTHs decreased by 4.12% and 2.70%, respectively. The results provide basic data for the synergistic inhibitory activity of natural animal and plant products against dipeptidyl peptidase-IV, and provide a new direction for the development of hypoglycemic functional products.

10 Molecular Dynamics Simulation Combined with Thermal Stability Experiments to Analyze the Interaction Mechanism between Acetylglucosamine and Lipase

ZHENG Dunjin , SHEN Ruifeng , HE Kangping , LUO Jiawei , CHEN Yinxi , HUANG Jiahui , YU Jieting , ZHENG Shaopeng , GU Weiming , CAO Shilin

2022, 38(3):74-81. DOI: 10.13982/j.mfst.1673-9078.2022.3.0492

[Abstract](255) [HTML](320) [PDF 2.14 M](538)

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In this study, molecular dynamics simulation was used to examine the interaction between Candida Antarctica Lipase B (CaLB) and acetylglucosamine (GlcNAc), and demonstrate the protective effect of GlcNAc on CaLB through thermal stability experiments. The results show that at 323.15 K, the electrostatic potential energy of CaLB and GlcNAc as well as Lennard-Jones (L-J) decreased significantly in the first 20 ns simulation time. When the CaLB-250 mmol/L-GlcNAc model was at 0~100 ns, the electrostatic potential energy and LJ potential energy decreased by 3350 kJ/mol and 2791 kJ/mol, respectively, and the number of hydrogen bonds between them increased from 0 to about 115. The accessible area (SASA) of CaLB and GlcNAc is close to 50 nm2. The root mean square deviation (RMSD) and root mean square fluctuation (RMSF) data show that the RMSD of the Free-CaLB model at 323.15 K and 353.15 K were 0.2617 nm and 0.3473 nm, respectively, while the RMSF of the CaLB-GlcNAc model at different concentrations was smaller than that of Free-CaLB, and the fluctuation of the CaLB-GlcNAc assembly model region (Val 147-Leu 155) was significantly smaller than that of the Free-CaLB model, indicating that GlcNAc can weaken the toughness of Free-CaLB and maintain effectively the original structure of CaLB. Thermal stability experiments showed that: after Free-CaLB and CaLB-GlcNAc were treated at 60 ℃ for 2.0 h, the residual enzyme activity of Free-CaLB was only 22.26%, whilst the residual enzyme activity of CaLB-GlcNAc was 52.11%. In summary, the thermal stability of Free-CaLB can be improved by acetylglucosamine.

11 Physicochemical Properties and Antioxidant Activities of the Polysaccharides from Chinese Water Chestnut Peels

ZENG Fanke , PAN Leiman , ZHANG Yi , LAI Furao , WU Hui , ZHANG Mengmeng

2022, 38(3):82-88. DOI: 10.13982/j.mfst.1673-9078.2022.3.0581

[Abstract](229) [HTML](490) [PDF 1.50 M](452)

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To explore the application potential of polysaccharides from the peels of Chinese water chestnut (Eleocharis dulcis) in the food field, X-ray diffraction spectroscopy, thermogravimetric analysis, Zeta potential analysis, ubbelohde viscosity measurement method, infrared spectroscopy were used to investigate the physical and chemical properties of purified polysaccharides, WVP-1and WVP-2, including crystallizability, stability and viscosity; the cell antioxidant assay and AAPH-induced erythrocyte hemolysis assay were used to evaluate the antioxidant activity of WVP-1 and WVP-2. The results showed that WVP-1 and WVP-2 had few crystalline regions and existed mainly in amorphous form; the glass transition temperatures of WVP-1 and WVP-2 were 61.30 and 69.50 ℃; their thermal decomposition temperatures were 290.50 and 308.50 ℃; the zeta potential values were 9.60 and -18.50 mV; the intrinsic viscosities were 5.33×10-3 and 3.80×10-2 mL/mg; the degree of esterification of the pectin polysaccharide, WVP-2 was 15.00%. In addition, in the concentration range of 62.5~1000 μg/mL, WVP-1 and WVP-2 could effectively inhibit the increase in the level of ROS induced by AAPH in HepG2 cells, and also protected effectively erythrocytes against AAPH attack and oxidative hemolysis. In summary, WVP-2 has better stability, viscosity and antioxidant activity than WVP-1, and WVP-2 is a pectin with low esterification degree, which can be used in the food field as a food additive and functional active ingredient.

12 Enhancing the Thermal Stability of Purple Cabbage Anthocyanins and Mechanisms of Co-pigmentation Using Five Polyphenolic Compounds

SUN Chenchen , GAO Qingchao , LI Yahui , ZHANG Zhiyong , WANG Shulin , LIANG Ying

2022, 38(3):89-96. DOI: 10.13982/j.mfst.1673-9078.2022.3.0744

[Abstract](292) [HTML](302) [PDF 754.88 K](440)

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Five polyphenolic compounds (catechin, gallic acid, vanillin, quercetin, and kaempferol) were selected as co-pigments of purple cabbage anthocyanins. Results indicated that the co-pigmentation effects of catechin and gallic acid strengthened with increased concentration; however, a slow increase rate was observed when the concentration reached 0.01 mol/L. The co-pigmentation effect of vanillin was strongest at 0.004 mol/L but declined when the concentration was further increased. Quercetin and kaempferol exhibited poor co-pigmentation effects and accelerated the degradation of purple cabbage anthocyanin when the concentration of 0.002 mol/L was reached. These results showed that catechin was the most effective co-pigment among the five polyphenolic compounds, followed by gallic acid. Moreover, the thermal stability of purple cabbage anthocyanin was increased significantly by catechin, gallic acid, and vanillin. Gallic acid showed the best enhancement effects on thermal stability, with the degradation rate decreasing from 34.02% to 22.88%, while quercetin and kaempferol had little effects on thermal stability. Thermodynamic analysis revealed that co-pigmentation of purple cabbage anthocyanin with catechin, gallic acid, and vanillin was a spontaneous exothermic process, which suggests that the co-pigmentation effects were caused by noncovalent bonding. Therefore, catechin, gallic acid, and vanillin can be used to enhance the thermal stability of purple cabbage anthocyanins during production, with catechin showing the most promising effect.

13 Synergistic Bactericidal Effect of the Combined Use of Ultrasound and Chlorogenic Acid against Aeromonas salmonicida Biofilms

SUN Jinyue , LIU Fang , WU Haihong , SUN Zhilan , SUN Yuancheng

2022, 38(3):97-104. DOI: 10.13982/j.mfst.1673-9078.2022.3.0777

[Abstract](181) [HTML](219) [PDF 1.10 M](421)

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The bactericidal effect of ultrasound (US) combined with chlorogenic acid (CA) on Aeromonas salmonicida biofilms was investigated, and the mechanism underlying the combined bactericidal effect was explored. A. salmonicida biofilms were treated with US, chlorogenic acid (0.5%, 1%, 2% CA), or US combined with chlorogenic acid (US plus 0.5% CA, US plus 1% CA, US plus 2% CA). Results showed that treatment with US combined with 1% CA for 60 min reduced the formation of A. salmonicida biofilms by approximately 8 logCFU/mL, similar to that in treatment using 2% CA alone. Analysis of the extracellular polysaccharide content revealed that the concentrations of soluble and insoluble polysaccharides in A. salmonicida biofilms were reduced to 13.01 and 16.52 μg/mL, respectively, after treatment with US combed with 1% CA. Analysis of extracellular contents using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) revealed that the combined treatment resulted to a significant disintegration of the spatial structures of biofilms. Subsequently, membrane permeability of the bacterial cells in the biofilms sharply increased, resulting in significantly higher extracellular nucleic acid and ATP concentrations than the control group (p<0.05). Moreover, combined treatment significantly lowered the activity of respiratory chain dehydrogenase (RCD) within the bacterial cells (p<0.05). These results suggest that the combined use of US and CA exerted synergistic bactericidal effects on biofilms by reducing extracellular polysaccharide content and intracellular enzymatic activity of biofilms and disrupting the bacterial cell integrity.

14 Advantages of Spray Liquid Nitrogen Quick Freezing and Gradient Thawing for Quality Preservation of Litchi

WU Weijun , CHENG Lina , XU Yujuan , YU Yuanshan , ZOU Bo , LI Jun , XIAO Gengsheng

2022, 38(3):105-114. DOI: 10.13982/j.mfst.1673-9078.2022.3.0474

[Abstract](422) [HTML](310) [PDF 2.53 M](632)

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In order to explore the freeze-thaw characteristics of litchi and determine its suitable freeze-thaw method, the effects of spray liquid nitrogen quick freezing (-40 ℃/-60 ℃/-80 ℃/-100 ℃) and gradient thawing (-20 ℃/0 ℃/5 ℃/4 ℃/25 ℃) on the freeze-thaw characteristics and quality of litchi were investigated. The obtained results were compared with those of conventional freezer freezing, immersion freezing and ambient temperature thawing. The results show that in the range of -20 ℃~-100 ℃, the lower the temperature, the shorter the time required to pass through the zone of maximum ice crystal formation, and the better the protective effect on frozen litchi. The combination of spray liquid nitrogen quick freezing at -100 ℃ and a gradient thawing process (-20 ℃~-5 ℃~4 ℃~25 ℃) preserved over 85.00% of nutrients and bioactive substances of fresh litchi (polyphenol content, soluble sugar content, Vc content were 3.92 mg/g, 150.69 mg/g, 2.15 mg/g, respectively). This combined treatment caused only 5.05% of water loss and 57.00% of hardness retention rate, and maintained quite well the integrity of cell structures, which suppressed the flow of free water from the vacuoles towards the intercellular spaces between cells and in the cell walls. In summary, spray liquid nitrogen quick freezing combined with gradient thawing is a suitable freeze-thaw method for litchi, which can maintain its quality. The results of this study provide valuable support for the industrial storage and processing of litchi.

15 Isolation and Identification of Beef-derived Pseudomonas and Comparison of Their Decay-causing Ability

ZHANG Ruoyu , LUO Xin , ZHU Lixian , LIU Yunge , CHEN Xue , HAO Jiangang , HUANG Xin , ZHANG Yimin

2022, 38(3):115-124. DOI: 10.13982/j.mfst.1673-9078.2022.3.0523

[Abstract](193) [HTML](282) [PDF 886.65 K](510)

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In order to explore the decay-causing abilities of beef-derived Pseudomonas strains with varying protease activities and lipase activities towards chilled beef, seven Pseudomonas strains with greatly different enzyme-producing abilities were screened based on enzymatic activities. The isolated strains included three strains of Pseudomonas fluorescens (PP3413、PP754、PL1415), one strain of P. putida (P011), one strain of P. poae (PL347), one strain of P. salomonii (PP1438), and one strain of Pseudomonas libanensis (PL1459). Then, the stains were used to re-contaminate the surface of sterile chilled fresh beef. At the end of storage (8 d), the number of Pseudomonas and TVB-N values for the samples inoculated with Pseudomonas fluorescens (PP3413, PP754 and PL1415) were relatively high (8.97~9.65 log CFU/g, and 20.35~25.02 mg/100 g, respectively). However, the number of Pseudomonas and TVB-N values of the beef samples inoculated with PL347 (which had the highest lipase activity) were 6.25 log CFU/g and 13.95 mg/100 g, respectively, which were significantly lower than those of other treatment groups (p<0.05). In addition, the TVB-N values of the samples contaminated by the strains with stronger protease-producing abilities, PP754 (25.02 mg/100 g) and PP3413 (22.06 mg/100 g) were higher than those of the strains with stronger lipase-producing abilities, PL1459 (21.80 mg/100 g) and PL1415 (20.35 mg/100 g). In summary, P. fluorescens had relatively high enzymes-producing ability and decay-causing ability, with the strains with stronger protease-producing abilities likely having higher decay-causing abilities towards beef than those with stronger lipase-producing abilities. However, the specific relationship between the decay-causing ability of Pseudomonas towards chilled fresh beef and its enzyme-producing ability needs to be further confirmed.

16 Establishment of Three-dimensional Heat Transfer Model for Catalytic Infrared Tomato Peeling and Calculation of Equipment Energy Consumption

LIU Ying , QU Wenjuan , YANG Siyu , MA Haile , PAN Zhongli , JIANG Qunhui

2022, 38(3):125-134. DOI: 10.13982/j.mfst.1673-9078.2022.3.0751

[Abstract](236) [HTML](241) [PDF 2.32 M](464)

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To improve the processing performance of infrared dry peeling of tomatoes, a three-dimensional heat transfer model for infrared radiant heating was established. This model was used to predict the temperatures for different positions on the surface of and inside the tomato during infrared peeling, and the fitting effect was verified by comparing predicted values of temperature with the measured values. Furthermore, the energy consumption of two different infrared equipment was calculated, compared, and analyzed to select the ideal infrared equipment. The gas-roller conveying catalytic infrared equipment could rapidly heat the tomato skin (the highest surface temperature was 60.32 ℃) with a more uniform surface temperature distribution (the maximum temperature difference was approximately 6.44 ℃) when compared with the static catalytic infrared equipment. The increase in internal temperature was minimal (the highest internal temperature was 49.10 ℃), and the internal temperature distribution was relatively uniform (the maximum temperature difference was approximately 18.25 ℃). The predicted values of the model fitted well with the measured values (R2≥0.93), and the estimated standard error EESE value was low (0.13~10.80 ℃). These findings indicated that the three-dimensional heat transfer model showed a good fitting effect, reflecting the temperature distribution on the surface of andinside the tomato under different infrared equipment. Moreover, the gas-roller conveying catalytic infrared equipment was superior to the static catalytic infrared equipment, given the higher efficiency and energy-saving afforded by reducing the processing time by 16.60% and saving 34.80% of energy consumption. This method could have broad application prospects and industrial value in the field of fruit and vegetable peeling.

17 Physico-chemical Characteristics Improvement and Scenting Process Optimization of Jasmine Broken Green Tea

YE Fei , GUI Anhui , LIU Panpan , WANG Shengpeng , HU Shanbin , LEI Dayan , HAN Hanshan , YANG Qiguo , GAO Shiwei , ZHENG Pengcheng

2022, 38(3):135-142. DOI: 10.13982/j.mfst.1673-9078.2022.3.0670

[Abstract](259) [HTML](243) [PDF 635.34 K](460)

Abstract:
In order to improve the jasmine broken green tea quality, four different scenting processes and the sensory qualities, chemical components, aroma and cost of jasmine broken green tea were compared in present paper. Results indicated that the sensory scores were signific antly enhanced from 1.92 to 4.25 points with the number of scenting flowers increasing and flower extraction process adding, the lightness of tea and brew also improved from 4.05% to 5.20%, but the color of tea and infused tea become red (p<0.01); the catechin astringent index decreased from 2.35% to 8.87% (p<0.01). The 20 characteristic aroma components were revealed and identified by the headspace solidphase microextraction (HS-SPME) combined with gas chromatography mass spectrometry olfactometry (GC-MS-O) analysis, such as methyl benzoate, linalool, benzyl acetate and methyl salicylate, those aroma intensity was larger than 3. Overall, the quality of jasmine broken green tea produced by one scenting and final scenting process meets the requirements of commodities, and the cost is relatively low, which could be used for broken green tea production.

18 Comparative Analysis of the Effects of Different Moisture Contents on the Quality of Self-heating Grilled Trichiurus haumela

CHANG Lili , WANG Ailin , LIU Zhiyu , SHI Wengang , JIANG Pengfei , LIANG Pengcheng , ZHOU Tiancheng , SUN Chenglong , TANG Yue

2022, 38(3):143-151. DOI: 10.13982/j.mfst.1673-9078.2022.3.0598

[Abstract](246) [HTML](280) [PDF 2.22 M](461)

Abstract:
To solve the problem of declining quality of self-heating fish products after sterilization and reheating, this study used Trichiurus haumela as the raw material. And a colorimete, texture analyzer, scanning electron microscope (SEM) and Raman spectrometer were used to compare the color, texture and sensory quality of Trichiurus haumela after being grilled to different moisture contents (70%, 60%, 50% and 40%), sterilized and self-heated, to determine the optimal moisture content of self-heating grilled fish fillet. After the fish filets were grilled at 140 ℃, 160 ℃, 180 ℃ and 200 ℃ to the optimal moisture content, the color, texture, sensory score, microstructure and protein denaturation degree were compared. Then, the optimal grilling conditions of self-heating grilled fish filets were obtained. The results showed that with the decrease of moisture content, the value of L* and whiteness decreased from 64.65 and 60.74 to 42.23 and 35.82, respectively, and the values of a* and b* increased from -0.59 and 17.05 to 12.23 and 24.69, respectively. When the moisture content was 40%, the hardness, adhesiveness and chewiness of the samples were 4.27 times, 5.53 times and 5.89 times that with a moisture content of 70%. Sensory evaluation indicated that the fish fillet had the highest sensory scores for all the quality attributes when the sample was grilled to have a moisture content of 70%. The self-heating grilled fish fillets had a smaller muscle fiber diameter, tender flesh, stable protein structure and higher sensory quality when the fish was grilled 140 ℃ to make its water content reach 70% (that is, 140 ℃ for 24 min and 3 s). The muscle fiber diameter was finer, the meat was tenderer, and it had a stable protein structure and better sensory quality than other samples in this optimal condition. The results of this study could provide a theoretical basis for improving the quality of self-heating grilled fish products.

19 Procyanidins Regulatethe Multi-scale Structures and in Vitro Digestibility of Rice Starch during Fermentation

TU Yuan , LI Xiaoxi , LU Ping , CHEN Ling , LI Lin

2022, 38(3):152-158. DOI: 10.13982/j.mfst.1673-9078.2022.3.0251

[Abstract](220) [HTML](342) [PDF 1.89 M](394)

Abstract:
To regulate the digestibility of fermented rice products, the effects of procyanidins on digestibility and multi-scale structures of rice starch during fermentation were systematically examined by small-angle X-ray scattering, gel penetration chromatography and in vitro simulated digestion. Research results showed that the digestive resistance of rice starch granules increased due to the interactions between the procyanidin and starch molecules during the fermentation process. The resistant starch (RS) content reached 66.85% when the amount of added procyanidins was 8%. During the synergistic fermentation by procyanidins and microbes, procyanidin inhibited the activities of microbial extracellular enzymes and reduced the degrees of starch degradation and disorder of aggregated structure. The procyanidins and starch molecules formed starch-procyanidin-starch complexes, which increased the thickness of the semi-crystalline layer in starch semi-crystalline layered structure, decreased the thickness of the amorphous layer, and raised the degree of compactness of aggregated structures and the proportion of short-range ordered structures on the surface. The starch-procyanidin-starch complexes also allowed the release of procyanidins and inhibition of amylase activity during digestion, which ultimately significantly decreased the digestibility of rice starch. The research results provide a basis for regulating the digestibility of fermented rice products.

20 Comparative Analysis of Antioxidant Activity of Five Kinds of Soy Sauces

FENG Tuo , SHAN Pei , SHENG Mingjian , WANG Zejian , WANG Bo , ZHANG Zhihong , GAO Xianli

2022, 38(3):159-167. DOI: 10.13982/j.mfst.1673-9078.2022.3.0721

[Abstract](275) [HTML](358) [PDF 403.30 K](309)

Abstract:
Total phenol, total flavonoid, dark color substance, amino acid nitrogen, salt-free solid, reducing sugar, total sugar, total acid, and free amino acid contents in a black soybean sauce and four other kinds of soy sauces were compared. In addition, DPPH and ABTS radical scavenging activity, reducing power, and metal ion-chelating activity of the selected soy sauces were comparatively analyzed. Correlation, cluster, and principal component analyses were performed to elucidate the internal relationship between antioxidant substances and antioxidant activity in the five soy sauces. The contents of six active ingredients, except for amino acid nitrogen, salt-free solid, and free amino acids, were significantly higher in the black soybean sauce than in the other four kinds of soy sauce (p<0.05). Furthermore, except for metal ion chelation, the antioxidant activity was significantly higher in the black soybean sauce than in the other four soy sauces (p<0.05). Correlation analysis showed that total phenols, total flavonoids, and dark color substances were the main components responsible for the significant difference in antioxidant activity among the five soy sauces. Cluster and principal component analyses indicated that the comprehensive quality of the black soybean sauce was significantly higher than that of the other four kinds of soy sauce. The findings provide supportive data and a scientific basis for further research on the antioxidant activity of black soybean sauce and will help consumers select an appropriate soy sauce.

21 Effect of Microwave Drying Process on the Color, Texture, and Sensory Quality of Persimmon Slices

WEI Zhenzhen , DUAN Zhenhua , TANG Xiaoxian , QIN Yanting , ZHOU Siyun , DUAN Weiwen , LIU Yan

2022, 38(3):168-175. DOI: 10.13982/j.mfst.1673-9078.2022.3.0620

[Abstract](287) [HTML](295) [PDF 624.10 K](499)

Abstract:
The effects of microwave power, slice thickness and loading amount on the quality attributes of persimmon slices such as color, hardness, chewiness, rehydration ratio and sensory score through using microwave drying technology. The results showed that the increase of microwave power resulted in the significant reduction (p<0.05) of the L* value and b* value of persimmon slices, while causing opposite changes in the a* value, color difference (ΔE), hardness and chewiness. The rehydration ability and sensory score first increased and then decreased, and both reached the peak values at 280 W. With the increase of slice thickness, the color of persimmon slices changed from burnt black to bright yellow, and their hardness, chewiness and sensory score improved significantly (p<0.05), with their rehydration capacity showing a downward trend. However, when the thickness exceeded 2.00 cm, the dried products exhibited reddish brown color, and L* value, b* value and sensory score decreased significantly (p<0.05), with the persimmon slices being relatively hard, sticky and difficult to chew. As the loading amount increased, the color of the dried samples was closer to that of fresh persimmon, and the hardness and toughness decreased significantly, with the rehydration ratio and sensory score increasing first then decreasing. In summary, when the microwave power was s 280 W, slice thickness was 2.00 cm, and the loading amount was 1.60 kg/m2, the values of L*, a*, b* and ΔE of the persimmon slices were 48.39, 12.89, 33.61, 24.94, respectively, the hardness was 2316.23 g, chewiness was 1106.97 g, rehydration ratio was 1.77, and sensory score was 87.80. At this moment, the product was bright in color, moderate in softness/hardness and chewy, and has good rehydration ability and advantages in terms of rich persimmon flavor and excellent sensory quality.

22 Preparation and Characterization of Amphiphilic Chitosan/Modified Gellan Gum Composite Membranes

GUAN Chen , ZHOU Chuang , YANG Ziming , HE Zuyu , WANG Chao , LIU Yunhao , LI Xiujuan , YU Lijuan , LI Xuerui , QU Yunhui , LI Puwang

2022, 38(3):176-184. DOI: 10.13982/j.mfst.1673-9078.2022.3.0991

[Abstract](234) [HTML](399) [PDF 2.90 M](478)

Abstract:
To develop food preservation materials with better performance and biodegradability, edible composite membranes were prepared using chitosan and gellan gum as raw materials. In the present work, chitosan was modified via carboxymethylation and cholic acid, which conferred amphiphilic properties and allowed ready dissolution of the modified chitosan in water. Gellan gum was modified via carboxymethylation to prevent gel formation and make it uniformly water-soluble at room temperature. The structures of the modified materials were characterized using Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. The modified chitosan was used as the main film-forming material, gellan gum as the reinforcing phase, and glycerol as the plasticizer in the preparation of amphiphilic chitosan/modified gellan gum composite membranes. Subsequently, the mechanical, thermal, and optical properties of the composite membranes were investigated. Results indicated that, under conditions of drying at 55 ℃ for 24 h wherein the mass ratio of amphiphilic chitosan to modified gellan gum was 5:2 and the content of added glycerol was 2%, the temperature at which the thermal degradation rate of the composite membrane reached a maximum was increased to approximately 260 ℃. Moreover, a membrane transparency of 84% was achieved. Tensile strength reached a maximum of 3.35 MPa, and the elongation at break was increased to 111.00%. Under these conditions, the composite membrane achieved optimum thermal stability and mechanical properties, high transparency, and good sensory evaluation results. Therefore, the addition of gellan gum improved the thermal stability and mechanical properties of chitosan.

23 Improving the Quality of the Dried Minced Pork Slices by Mulberry Polyphenols and Its Microcapsules

SHEN Shuangwei , LI Denglong , LIN Weiling , ZHANG Xianbin , LIU Xueming , LIN Yaosheng , TANG Daobang , WANG Xuping , CHENG Jingrong , ZHU Mingjun

2022, 38(3):185-194. DOI: 10.13982/j.mfst.1673-9078.2022.3.0545

[Abstract](233) [HTML](292) [PDF 874.83 K](367)

Abstract:
In the present study, mulberry polyphenols (MP) were embedded in β-cyclodextrin (β-CD) by ultrasound to produce mulberry polyphenol-β-cyclodextrin on the physicochemical properties, antioxidant activity, and oxidation stability of the dried minced pock slice were microcapsules (MPM). The protective effect of β-cyclodextrin on mulberry polyphenols was verified, and the effects of mulberry polyphenols investigated. The results showed that β-cyclodextrin could improve the stability of polyphenols and facilitate the slow release of phenolic compounds. After 28 days of storage, the retention rate of total phenolics in dried minced pork slices made with 0.2% MPM reached 54.55%, which increased by 71.06% compared with the control (supplemented with 0.2% MP). At the same time, the inclusion effect of β-cyclodextrin further improved the texture and color of the mulberry polyphenols-enriched dried minced pork slices. Compared with the blank control group, the ABTS free radical scavenging ability, FRAP reduction ability, and DPPH free radical scavenging rate of the meat prepared by of replaced partially MP with MPM increased by 1.05 times, 20.99 times, and 1.04 times, respectively. The peroxide value, TBARS value, and carbonyl content decreased by 75.11%, 19.16%, and 44.77%, respectively, with the conversion of sulfhydryl groups to disulfide bonds being significantly inhibited. This research will help to promote the application of mulberry polyphenols in the development of functional meat products and provide technical reference for improving the stability of plant polyphenols in thermal processed food products.

24 Effects of Different Levels of Onion Pulp Addition on the Quality of Naan

Gulnazar Sireyil , Aygul Alim , FU Wenqian , Aliye Mutalip , FENG Zuoshan , HUANG Wenshu

2022, 38(3):195-202. DOI: 10.13982/j.mfst.1673-9078.2022.3.0551

[Abstract](213) [HTML](320) [PDF 622.67 K](369)

Abstract:
By measuring the texture characteristics of dough, sensory score, color and texture of naan, the effects of different levels of onion pulp addition (0, 10%, 20%, 30%, 40% and 50%) on the quality of naan were studied. The flavors of naans with different onion pulp contents were evaluated by an electronic nose. The results showed that different addition levels of onion pulp led to significant differences in the texture characteristics of dough as well as sensory score, color and texture characteristics of naan. With the increase in the amount of added onion pulp, the hardness of the naan dough decreased readily, whilst the viscosity, elasticity and resilience increased first then decreased; The sensory score increased first then decreased; The brightness L* value, redness a* and yellowness b* of naan increase readily. When the addition amount was greater than 30%, the increment of the color difference value was very small; the hardness, viscosity and chewiness of the core and edge of naan first increased then decreased, and the elasticity also increased gradually. The overall quality of naan was improved when the content of onion pulp was 30%. The results of electronic nose analysis facilitated the effective distinguishment of the flavors of 6 kinds of onion pulp-added naan. The contribution rates for the first and second principal components of PCA were 97.40% and 2.04%, respectively, with the total contribution rate being 99.44%. The contribution rates for the first and second principal components of LDA were 67.67% and 20.33%, respectively, with the total contribution rate being 88%. The quality of naan can be improved by adding an approriate amount of onion pulp.

25 Optimization of Process Parameters for Ultra High Pressure Treatment of Xuehua Pear Juice

WANG Mingxue , ZHAO Jiangli , CHENG Yudou , GUAN Junfeng , WANG Yongxia

2022, 38(3):203-210. DOI: 10.13982/j.mfst.1673-9078.2022.3.0645

[Abstract](279) [HTML](190) [PDF 1.39 M](492)

Abstract:
In order to provide reference for the application of non heat treatment technology and product development of ‘Xuehua’ pear juice, the ultra-high pressure (UHP) treatment was used and the parameter optimization was carried out. The UHP treatment process was optimized by single factor and response test, and electronic tongue and gas chromatography-mass spectrometry (GC-MS) were used to analyze the sensory flavor and volatile components of ‘Xuehua’ pear juice treated by UHP. The results showed that the optimal process parameters of UHP treatment were adjusted to pH 4.3 and continuously treated with UHP at 480 MPa for 16 min. Under these conditions, the total number of colonies, molds and yeasts of ‘Xuehua’ pear juice treated by UHP were 0, and nine kinds of flavors were detected by electronic tongue, mainly sweet and sour, and 13 volatile components were detected by GC-MS, including 3 aldehydes, 2 alcohols, 3 esters, 3 alkanes, 1 ketone and 1 olefin. There was no significant difference in flavor of the pear juice following UHP treatment. Therefore, using UHP technology to treat ‘Xuehua’ pear juice can ensure the sanitary condition and meanwhile maintain its flavor quality, which has a certain application value.

26 Comparison and Analysis of the Special Flavor and Antioxidant Activity of Black Soybean Soaked in Vinegar by Five Kinds Processing Techniques

WANG Juanjuan , LIU Dan , LI Yingtian , XIE Tiange , CUI Meilin , ZHAO Wei , ZHANG Xiuhong

2022, 38(3):211-218. DOI: 10.13982/j.mfst.1673-9078.2022.3.0667

[Abstract](270) [HTML](327) [PDF 720.98 K](594)

Abstract:
Using high-quality black beans and aged vinegar as raw materials, the flavor and antioxidant activity of vinegar soaked black beans under cooking, frying, baking, high pressure and raw conditions were compared and analyzed. On the basis of sensory evaluation, the time of four kinds of thermal treatment were selected as follows: boiling for 40 min, frying for 10 min, roasting for 20 min, high-pressure for 30 min. The volatile components of raw black beans (without treatment) and soaked black beans with five kinds of vinegar were compared by electronic nose, which found that the vinegar soak treatment significantly improves the odor of black beans. The raw (no contact with water), roasted, and fried groups of the five processes were relatively similar, while the cooking and steam high-pressure treatment groups were relatively close. By the total antioxidant capacity, total phenol content and free radical scavenging rate, the antioxidant activity of black beans soaked in vinegar of five different processing techniques showed significantly differences. The order of the antioxidant activity was roasting, stirfrying, raw black beans without treatment, high pressure and boiling. Under roasting conditions, total phenol content was up to 6.321 mg/g, the total oxidation resistance was 0.40 mmoL/L, and free radical scavenging rate of •OH, DPPH•, and ABTS+• were 81.40%, 92.20% and 48.00%, respectively. Soaking in vinegar after baking can produce health functional food with better sensory evaluation and strong antioxidant capacity. Therefore, the roasted black beans are soaked in old vinegar to produce a health functional food with excellent sensory quality, good flavor and strong antioxidant capacity.

27 Optimization of Processing Formula of Laoxianghuang Fruit Cake

LIN Wanling , HOU Xiaozhen , WANG Jinxu , LIU Hanxu , LIU Mouquan , FAN Yanlu , LUO Donghui , LI Jiajun

2022, 38(3):219-227. DOI: 10.13982/j.mfst.1673-9078.2022.3.0705

[Abstract](249) [HTML](368) [PDF 552.76 K](542)

Abstract:
A plant-type fruit cake with Laoxianghuang was prepared with high ester pectin, locust bean gum and carrageenan as colloid materials. By single factor experiment, the colloid formula range of high ester pectin, locust bean gum carrageenan and Laoxinghuang were 1.0%~1.4%, 0.35%~0.65%, 0.35%~0.65% and 2%~4%, respectively, taking color, texture, taste and flavor as indexes. On this basis, the fuzzy mathematics sensory evaluation method and orthogonal experiment were used to optimize the formula of Laoxianghuang fruit cake. Finally, the best formula for Laoxianghuang fruit cake was determined as follows: high ester pectin was 1.4%, locust bean gum was 0.5%, carrageenan was 0.5% and Laoxianghuang paste was 4%. The process parameters included drying temperature and drying time, which were 60 ℃ and 24 h, respectively. Under these technological condition, the quality standard of Laoxianghuang fruit cake was as follows: moisture content 17.02%, total sugar content 56.21%, the total number of bacterial colony <1000 CFU/g, coliform group <50 MPN/100 g, pathogenic bacteria (Salmonella, Shigella, etc.) not detected and mold <50 CFU/g. The Laoxianghuang fruit cake has bright yellow brown color, fine and uniform texture, smooth and flat surface, strong smell of Laoxianghuang, sour and sweet, moderate hardness and chewiness.

28 Preparation of Ampelopsis grossedentata Compound Teabag and Its in Vitro Hypoglycemic Effect

LI Dongmei , LI Chunlian , WEN Yan

2022, 38(3):228-236. DOI: 10.13982/j.mfst.1673-9078.2022.3.0605

[Abstract](269) [HTML](208) [PDF 926.87 K](483)

Abstract:
In this study, Ampelopsis grossedentata, Cyclocarya paliurus and mulberry leaves were used as the raw materials to develop compound teabags, and its in vitro hypoglycemic effect was evaluated. The sensory score, total flavonoids and total polysaccharide contents were used as evaluation indicators, the effects of the compound ratio of Ampelopsis grossedentata, Cyclocarya paliurus and mulberry leaves, teabag packaging materials, brewing water temperature, soaking time and water addition amount on the quality of compound teabags were studied by single factor experiments, to determine the optimal levels of these factors. On the basis of these results, the teabag brewing process was optimized by the orthogonal test. The optimal process parameters for developing compound teabags were: the compound ratio of Ampelopsis grossedentata, Cyclocarya paliurus and mulberry leaves 2:1:2 (m:m:m), non-woven fabrics for tea bags, brewing water temperature 85 ℃, soaking time 4 min, amount of water 150 mL. Under these conditions, the sensory score of compound teabag was 83, and the total flavonoid and total polysaccharide contents were 627.45 μg/mL and 200.05 μg/mL, respectively, with the comprehensive score was 96.89; the inhibitory activities against α-glucosidase and α-amylase were 42.75% and 38.85%, respectively, which were comparable to the effect of acarbose and much higher than those of teabags made with Ampelopsis grossedentata, Cyclocarya paliurus or mulberry leaves, or a combination of any two of these raw materials. The Ampelopsis grossedentata compound teabags were convenient to brew, and the soup had an orange-yellow, clear and bright color, a unique aroma, and a slightly bitter and sweet taste, with high total contents of flavonoids and polysaccharides, and an excellent in vitro hypoglycemic activity, indicating broad market prospects.

29 Analysis of Moisture Migration Law of Silkworm Pupa during Different Drying Processes by LF-NMR

WU Zhaolong , LIN Fang , TANG Xiaoxian , CHEN Zhenlin

2022, 38(3):237-243. DOI: 10.13982/j.mfst.1673-9078.2022.3.0573

[Abstract](209) [HTML](283) [PDF 3.72 M](483)

Abstract:
In this study, low-field nuclear magnetic resonance (LF-NMR) technique combined with drying curve was used to investigate the influence of heat pump drying and variable temperature differential pressure puffing drying (EPD) on the moisture migration of silkworm pupa, to reveal the state, distribution, and content of moisture inside silkworm pupa during two different drying processes. The results showed that EPD led to a more rapid moisture decrease during the drying process, and its drying rate was also higher than that of the heat pump drying (HPD). The moisture of fresh silkworm pupa could be divided into three parts: bound water T21 (0~2 ms), non-flowing water T22 (2~100 ms) and free water T23 (100~1000 ms), with their corresponding peak areas of the three peaks as 49.531, 661.651, and 1730.075, respectively, and peak area percentages as 2.03%, 27.10%, and 70.87%, respectively. With the extension of the drying time for the silkworm pupa, the T2 relaxation time of the EPD and HPD showed the same changing trend. On one hand, the peak position shifted to the left, and on the other hand, the total peak area A kept decreasing. The main state of moisture gradually became non-flowing water and bound water. The relationship equations between the moisture content on dry basis (x) and the total peak area A under the two drying methods, EPD and HPD, were A=702.01x+173.92 (R2=0.9997) and A=695.94x+229.24 (R2=0.9968), respectively. Both showed a significant linear relationship (p<0.05), with EPD showing a better fit, but HPD having a relatively uniform distribution of hydrogen proton density. Comprehensive evaluation revealed that EPD can describe better the water migration law during the drying process of silkworm pupa.

30 Analysis of the Deodorization Effect of Barley Green Powder on Silver Carp Surimi Products by SPME and SDE

WU Dan , ZENG Wenhao , XIONG Shanbai , HUANG Qilin , ZHU Fangqing

2022, 38(3):244-256. DOI: 10.13982/j.mfst.1673-9078.2022.3.0690

[Abstract](292) [HTML](333) [PDF 1.47 M](396)

Abstract:
In this study, sensory evaluation, electronic nose, headspace solid phase microextraction (HS-SPME) and simultaneous distillation extraction (SDE) combined with gas chromatography - mass spectrometry (GC-MS) were used to investigate the effect of barley green powder (BGP) on the volatile compounds of silver carp surimi products. The results showed 39, 25 and 28 volatile compounds were identified in BGP, surimi products and surimi products added with BGP through SPME, 29, 45 and 56 volatile compounds were identified in BGP, surimi products and surimi products added with BGP through SDE, respectively. More hydrocarbon compounds in BGP were absorbed through SPME, and more aldehydes and alcohol compounds in surimi products were extracted through SDE. The 1-octen-3-ol, 2,4-decadienal, hexanal, heptanal, octanal, nonanal, 2-octenal, 2-decennal and 2,4-heptadienal were determined as the main volatile compounds of silver carp surimi products; phenylacetaldehyde, furfural and geranyl acetate were determined as the main volatile compounds of BGP. The contents of hexanal, heptanal and 1-octen-3-ol decreased by 42.38%、35.06% and 10.71%, respectively, and phenylacetaldehyde and furfural were increased significantly when BGP were added to the silver carp surimi products. Combined with TBARS value change, the oxidation of fat in surimi was inhibited by BGP and off-odor of surimi was masked by BGP. Therefore, there is a good deodorizing effect on silver carp surimi products with the addition of BGP, and the flavor quality of surimi products improved significantly when added 1% BGP.

31 Effect of the Time of High Pressure Steam Sterilization on the Changes of Flavor Substance in Cold-eating Rabbits

YUAN Xianling , PENG Xianjie , CHEN Chongyan , WAN Xiaoyu , LIN Hongbin

2022, 38(3):257-265. DOI: 10.13982/j.mfst.1673-9078.2022.3.0677

[Abstract](288) [HTML](204) [PDF 1.58 M](449)

Abstract:
The effects of high pressure steam sterilization time (15, 20, 25, 30, 35min) on the physicochemical indexes of flavor substances, flavor substances and flavor substances were investigated. The results showed that the time of high-pressure steam sterilization has no significant effect on the moisture, protein, lipid, pH and chloride of cold-eating rabbits. The salty taste had a significant effect. Compared with unsterilized cold-eating rabbits, the taste activity value (TAV) of chloride was most similar to that when sterilized for 20 min. The content of total free amino acids decreased significantly within 15~20 minutes, and then increased significantly. Glu is the main umami-flavored free amino acid of cold-eating rabbits after sterilization; Lys is mainly sweet-flavored free amino acid; His is mainly bitter-flavored free amino acid. The equivalent umami concentration (EUC) at 35min is the highest, and the umami taste at 35min is stronger than that of the unsterilized product. A total of 54 compounds in 10 categories were detected during the sterilization process. Compared with the characteristic flavor substances of unsterilized cold-eating rabbits, there are differences in the types of characteristic volatile flavor substances and odor activity value (OAV). Except for the corresponding increase in the OAV of (E,E)-2,4-decadienal and hexadecal, the rest are constantly decreasing. From the analysis of the degree of reproduction of characteristic volatile wind odor substances, sterilization for 20 minutes is a better time to retain characteristic This provides a theoretical basis for the use of high pressure steam sterilization time in the industrial production of cold-eating rabbits.

32 Effect of Heat Treatment on the Physicochemical Properties and Volatile Components of Coconut Plant-based Yoghurt

HAN Xiyan , SONG Fei , ZHANG Yufeng , ZHAO Songlin , ZHAO Xiaoming

2022, 38(3):266-275. DOI: 10.13982/j.mfst.1673-9078.2022.3.0675

[Abstract](197) [HTML](345) [PDF 3.25 M](496)

Abstract:
The heat treatment before fermentation had a great influence on the quality of yogurt. In this study, defatted coconut milk was used as the main raw material, and no animal ingredients were added to make coconut plant-based yoghurt through lactic acid bacteria fermentation, and the influences of different heat treatment conditions on the quality of coconut plant-based yoghurt were studied. By measuring the sensory, physical and chemical properties (pH value, titer acidity, water holding capacity, color difference), texture characteristics, and volatile components of the product, the appropriate heat treatment conditions were selected. It showed that the coconut plant-based yoghurt with heat treatment at 65 ℃ for 30 min had good taste, no whey separation, good tissue state, suitable viscosity, uniform color, and its sensory score was 84.97, pH value was 4.55, titer acidity was 92.67 oT, water holding capacity was 88.75%. A total of 14 volatile components were identified from coconut milk and coconut plant-based yoghurt with different heat treatments using GC-IMS method, mainly alcohols, ketones, aldehydes and esters. The content of 2,3-butanedione, an important substance of fermented flavor, was highest when the heat treatment conditions was 65 ℃-30 min. It is concluded that the coconut plant-based yoghurt prepared by heat treatment at 65 ℃-30 min had good taste and quality.

33 Correlation Analysis of Sensory Attributes and Volatile Compounds of Commercial Beef Meatballs by Partial Least Squares Regression

WU Danxuan , GAO Ziwu , WU Peng , XU Zhicheng , GAO Sumin , MENG Xiangren , WANG Hengpeng

2022, 38(3):276-285. DOI: 10.13982/j.mfst.1673-9078.2022.3.0718

[Abstract](342) [HTML](224) [PDF 1.58 M](543)

Abstract:
In this paper, 10 different brands of beef meatballs were selected. Firstly, 28 kinds of sensory properties were used as indexes for quantitative descriptive analysis (QDA). Secondly, the volatile flavor compounds in 10 kinds of beef meatballs were detected by gas chromatography-mass spectrometry (GC-MS), and the characteristic flavor components were identified by relative odor activity value (ROAV). Finally, the relationships among sensory attributes and volatile components in commercial beef meatballs were constructed by partial least square regression (PLSR). The results showed that the cumulative contribution rate of the first six principal components in the sensory evaluation system of beef meatballs was 89.9%, which was higher than 85%, which could explain most of the variation information of the sensory characteristics of beef meatballs. There were significant differences on the types and contents of volatile flavor substances in different brands of beef meatballs. 18 volatile compounds such as diallyl sulfide and (-)-β-pinene were determined as the characteristic flavor values of beef meatballs. D-Limonene, (-)-β-pinene, anethole had a significantly positive correlation with the spices; trans-2-Octen-1-ol, octanal, nonanal, trans-2-octenal were significantly correlated with the oil odor; decyl aldehyde and citral were significantly correlated with the sweet smell; diallyl disulfide were significantly correlated with the garlic flavor; diallyl sulfide had a contribution to the onion flavor. This experiment provided a theoretical basis for the construction of sensory quality evaluation system of beef meatballs.

34 Rapid Determination of Malachite Green and Crystal Violet Residues in Aquatic Products by Raman Spectroscopy

LI Chen , ZHAO Chaomin , GU Shuqing , DENG Xiaojun , ZHAO Zhihui

2022, 38(3):286-292. DOI: 10.13982/j.mfst.1673-9078.2022.3.0689

[Abstract](419) [HTML](312) [PDF 1.52 M](651)

Abstract:
In order to realize the rapid detection of malachite green and crystal violet residues in aquatic products, a rapid surface enhanced Raman spectroscopy method (SERS) for malachite green and crystal violet residues in aquatic products was established. By means of acetonitrile extraction, petroleum ether purification, potassium borohydride reduction and DDQ oxidation, the amount of colloidal gold, extract and coagulant was determined. The Raman characteristic displacement of malachite green was 795, 939, 1215, 1610 cm-1. The Raman displacement of crystal violet was 795, 939, 1610 cm-1. According to its Raman spectrum characteristic peak and its intensity, the malachite green and crystal violet were determined qualitatively and rapidly. Combined with the detection probability model (POD), the detection limit of malachite green and crystal violet shrimp and crab was determined to be 1.00 μg/kg, the detection limit of fish and shellfish is 0.50 μg/kg, sensitivity ≥95%, specific ≥95%, false negative ≤5%, false positive ≤5%, which meets the qualitative requirements of rapid testing. The method is simple, rapid and accurate. It only takes 40 minutes from sample pretreatment to result display. It can be used for the on-site rapid detection of malachite green and crystal violet in aquatic products.

35 Determination of Aluminum Potassium Sulfate Content in Vermicelli Using an Excitation Equipotential Method

YANG Na , ZHOU Yuyi , XU Zhenlin , MENG Man , CHEN Xinwen , SUN Yuanming

2022, 38(3):293-298. DOI: 10.13982/j.mfst.1673-9078.2022.3.0749

[Abstract](213) [HTML](292) [PDF 751.41 K](345)

Abstract:
Herein, an excitation equipotential method was established to determine the content of aluminum potassium sulfate in vermicelli. Sinusoidal AC signals with an excitation voltage of 5~20 V at 300~700 Hz were applied to a primary coil to analyze the electrical characteristics of aluminum potassium sulfate solution in a secondary coil (or sample coil). The impact of excitation voltages on ground voltages was greater than that of frequencies with the same mass fraction of aluminum potassium sulfate solutions. Increasing mass fractions of aluminum potassium sulfate solutions enhanced potential differences with increasing frequency and excitation voltage. On altering the excitation voltage from 5 V to 20 V, the potential difference of 20 mg/kg aluminum potassium sulfate solution increased by 78.79%. Parameters in the excitation equipotential method were linearly correlated, presenting a correlation coefficient (r) of 0.94. Four kinds of commercial vermicelli products were examined at 300 Hz and 20 V, and the relative standard deviations of detection results were within 1.50%. The excitation equipotential method exhibited repeatability. It also showed better accuracy than the chemical method, with relative errors for detection results within 2.00%. This excitation equipotential method helps analyze pretreated solutions of vermicelli at the secondary coil, determining its electrical characteristics to quantify the aluminum potassium sulfate content. This study provides a novel method for detecting aluminum potassium sulfate content in food.

36 Sensitive Detection of Aflatoxin B1 in Rice Flour by Enzyme-linked Immunoassay Based on Metal Organic Framework (ZIF-8)

HUANG Zhoumei , WU Xuyue , HUANG Jinfa , YUAN Zhenhong , BI Jie , WANG Jiahua , SHU Zaixi , XIAO Anhong , DAI Huang

2022, 38(3):299-306. DOI: 10.13982/j.mfst.1673-9078.2022.3.0691

[Abstract](318) [HTML](250) [PDF 1.56 M](455)

Abstract:
In order to solve the problem of poor stability of signal markers in the rapid detection method of aflatoxin B1 (AFB1), an enzyme-linked immunoassay based on metal organic frameworks (MOFs) was established to detect AFB1 in rice flour. In this study, a biomimetic mineralization method was used to encapsulate horseradish peroxidase (HRP) in the zeolite imidazole framework structure material-8 (ZIF-8) as a signal marker. HRP@ZIF-8 composites could maintain stable catalytic activity under extreme conditions such as alkaline condition and high temperature. On this basis, an indirect competitive immunocolorimetry was established to detect AFB1. The samples containing AFB1 can be directly identified by naked eyes. Under the optimum conditions, the absorbance decreased in the range of 0.01~20 ng/mL with the increase of AFB1 concentration, showing an obvious linear relationship with y =0.03×C[AFB1]+0.78, R2=0.99. The limit of detection was 72 pg/mL, and the precision and specificity were both acceptable. The recoveries of AFB1 in rice flour and flour were 96.00~105.00% and 82.00~110.00%, respectively, with relative standard deviations less than 5%. The method is simple, rapid, sensitive and specific. It can be used for trace determination of AFB1 in cereals such as rice flour and flour.

37 N-Doped Carbon Dot-based Homogeneous Fluorescence Assay for the Rapid Detection of Copper Contamination in Food

LIN Xiaoya , DENG Ruijie , LI Haitao , YANG Hao , LIU Jun

2022, 38(3):307-313. DOI: 10.13982/j.mfst.1673-9078.2022.3.0734

[Abstract](198) [HTML](309) [PDF 716.87 K](499)

Abstract:
The current methods for the detection of copper contamination in foods are generally limited by problems such as cumbersome operation, complex sample pretreatment processes, time intensiveness, and high testing cost. Here, Cu2+-specific fluorescent N-doped carbon dots (CDs) were synthesized, and a homogeneous rapid detection of Cu2+ contamination was developed. The CDs showed high water solubility, excellent biocompatibility, and a fluorescence quantum yield of 33.27%. This method allowed for a high-sensitive detection of Cu2+ in a centrifuge tube at room temperature, with a dynamic detection range of 5~50 μmol/L and detection limit of 5.48 μmol/L. Moreover, this method was successfully applied in measuring Cu2+ in water samples. Thus, the CDs developed in this study may be an effective tool to detect copper contamination in foods and may be used in the detection of Cu2+ in crops, water and soil, contributing to the prevention and control of copper contamination in foods. In addition, the proposed detection method have several advantages such as good timeliness, high accuracy, high stability, low cost, and low detection requirements, which are in line with current requirements for the safety supervision of heavy metals in foods.

38 Spice Extracts and Their Application of Antimicrobial and Preservation Activities in Meat Products

YANG Yixi , CUI Zhaowei , WANG Wei , Jaekel Carsten Stephan Herbert , ZHANG Jiamin , LIU Yaning , GUO Yutao

2022, 38(3):314-327. DOI: 10.13982/j.mfst.1673-9078.2022.3.0655

[Abstract](340) [HTML](351) [PDF 923.79 K](684)

Abstract:
Meat spoilage is one of important economic and health issues in the area of food industry. The application of antimicrobial agents to meat products is one of major tool for inhibiting chemical deterioration and microbial growth. Due to consumers’ concerns about the safety of some chemical preservatives, people are increasingly interested in natural or "green" alternatives. Many researches demonstrated that the natural spice extract has significant antibacterial and antioxidant properties. Its mechanism is based on the degradation of microbial cell wall, the destruction of cell membrane, the damage of membrane protein, the leakage of cell content and the consumption of Proton source. In this paper, the sources, extraction methods, main active components, antibacterial mechanisms, in vitro antimicrobial experiments and synergistic effects were summarized, and the research progress of antimicrobial effects and the applications particularly in meat products were reviewed, in order to provide the reference for seeking more safe and effective preservative methods in meat products processing.

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Volume 38,Issue 3,2022 Table of Contents