Volume 35,Issue 12,2019 Table of Contents

1 Effect of Intermittent Intervention of Probiotics on Short-chain Fatty Acid Content in Feces of Rats with Hyperlipidemia

HUANG Yu-jun , YAO Yao , ZHOU fan , GU Rui-xia

2019, 35(12):1-7. DOI: 10.13982/j.mfst.1673-9078.2019.12.001

[Abstract](489) [HTML](203) [PDF 15.27 M](887)

Abstract:
To explore the effect of probiotics intervention on the short-chain fatty acid content in feces of hyperlipidemic rats, the hyperlipidemia rat model was established, and the experimentally preserved Lactobacillus plantarum 67, Lactobacillus fermentum 83 and Lactobacillus rhamnosus LGG with good cholesterol-lowering effect were used, combined with "5:2 light fasting law".The model rats were subjected to probiotic intervention, five times a week, and the content of SCFAs in the feces of rats was determined after 6 weeks of intervention. Compared with the model group, the contents of butyric acid and valeric acid increased by 37.97% and 41.22% (p<0.05) respectively, the content of propionic acid increased by 1.25% (p>0.05), the content of acetic acid reduced by 3.19% (p<0.05) and the contents of isobutyric acid and isovaleric acid were respectively reduced by 2.11% and 14.16% (p>0.05) after the intervention of Lactobacillus plantarum 67. After intervention with mixed strains, the contents of propionic acid, butyric acid, valeric acid and isobutyric acid increased by 31.25%, 70.92%, 103.98% and 24.48%, respectively (p>0.05), the content of acetic acid reduced by 23.38% (p<0.05), and the content of isovaleric acid decreased by 7.38% (p>0.05). Compared with the positive control group, Lactobacillus plantarum 67 significantly increased the contents of acetic acid,, isobutyric acid and isovaleric acid, which were increased by 31.69%, 40.33% and 82.83%, respectively (p<0.05), the content of valeric acid increased by 12.74% (p>0.05), the content of propionic acid decreased by 23.58% (p<0.05), the content of butyric acid decreased by 2.38%(p>0.05). The mixed strain significantly increased the contents of acetic acid, butyric acid, isobutyric acid, valeric acid and isovaleric acid, which increased by 4.23%, 20.37%, 78.44%, 62.84% and 109.48%, respectively (p<0.05), and the propionic acid content decreased by 0.94% (p>0.05). Single probiotics and mixed probiotics can improve the level of intestinal SCFAs, help to regulate the intestinal environment, and the effect of mixed strains is better.

2 The Effects of Total Extract of Panacis japonici Rhizoma on LPS Induced BV2 Microglia Inflammation

ZHENG Jie , ZHAO Qing-qing , WANG Jin-xin , WANG Rui , ZHANG Xu-lan , WANG Ting , ZHOU Zhi-yong

2019, 35(12):8-13. DOI: 10.13982/j.mfst.1673-9078.2019.12.002

[Abstract](401) [HTML](337) [PDF 23.25 M](717)

Abstract:
To investigate the protective effects of total extract of Panacis japonici Rhizoma on lipopolysaccharide-induced inflammation in BV2 cells and its underlying mechanisms. The viability of BV2 cells was detected by MTT. Nitric oxide (NO) levels were measured by Griess. The mRNA expression of TNF-α, IL-1β and iNOS were evaluated by PCR. Immunofluorescence was performed to detect the expression and location of NF-κB. MTT results showed that different concentrations of total extract of Panacis japonici Rhizoma (3.125~50 mg/L) have no effect on the growth of microglia, regardless of normal state or LPS(1 μg/L)-induced inflammatory condition. Compared with the normal group, the release of NO in the model group was 11.82 times, and the mRNA expressions of TNF-α, IL-1β and iNOS in the model group were 1.35 times, 1.78 times and 2.50 times, respectively. There was an obvious nuclear shift of NF-κB after LPS induction. After administration of total extract of Panacis japonici Rhizoma (3.125~50 mg/L), over-expression of IL-1β, TNF-α, iNOS and NO induced by LPS were effectively reversed. Moreover, total extract of Panacis japonici Rhizoma (25, 50 mg/L) can effectively inhibit nuclear translocation of NF-κB. Total extract of Panacis japonici Rhizoma can effectively improve LPS-induced inflammatory response in BV2 microglia. The underlying mechanism is mainly to inhibit nuclear translocation of NF-κB and thereby reducing the secretion of inflammatory factors.

3 Anti-inflammatory Effect of Tanshinone on Knee Osteoarthritis Rats

SUN Xiao-juan , HOU Na

2019, 35(12):14-19. DOI: 10.13982/j.mfst.1673-9078.2019.12.003

[Abstract](324) [HTML](106) [PDF 1.98 M](714)

Abstract:
In this study, the anti-inflammatory effect of tanshinone on knee osteoarthritis was studied based on the concentration of tanshinone and the changes of various indexes. Four groups of adjuvant arthritis rat models were constructed, each group was given 21 days. Knee osteoarthritis index in rats was determined by knee osteoarthritis evaluation criteria and knee bone diameter measurement. Isolated vascular ring perfusion and double-antibody sandwich abc-enzyme-linked immunosorbent assay were used to determine the content of acetylcholine-influenced endothelium-dependent relaxation function and von willebrand factor in each group. Cell fluorescence values were collected from the samples of tanshinone and the anti-inflammatory activity of tanshinone was determined by the activity of luciferase reporter gene. The results showed that the evaluation value of knee osteoarthritis in tanshinone group was about 5.26, which was lower than that in methotrexate group and fengyang ethanol extract group. After the injection of acetylcholine the relaxation rate was about 88.72 η/%, no significant fluctuations; The vascular haemophiliac factor content was approximately 35.22 λB/U?L-1, the closest to the control group. In the 9 samples of tanshinone, the luciferase reporter activity of 55% eluent was approximately 89.26, with the best anti-inflammatory effect, indicating that tanshinone can repair endothelial cells, and has a good anti-inflammatory effect on knee osteoarthritis model rats.

4 Maillard Reaction of Xylooligosaccharides with Whey Protein Isolate (WPI) under Wet Heating Conditions and Emulsification and Rheology of Maillard Reaction Products

LIAO Yang , HU Ju-wu , MA Yong-hua , XIONG Hua , ZHAO Qiang

2019, 35(12):20-27. DOI: 10.13982/j.mfst.1673-9078.2019.12.004

[Abstract](295) [HTML](130) [PDF 1.26 M](718)

Abstract:
In this work, the effect of mixing ratio (1:1, 1:2, 1:3, 1:4, W/W) on Maillard reaction between xylooligosaccharides and whey protein isolate (WPI) under wet heating conditions and emulsification and rheology of Maillard reaction products (MRPs) were investigated. Significant changes in browning intensity, pH and particle size showed that MRPs of WPI and xylooligosaccharides were successfully prepared. Results showed that the degree of Maillard reaction was the highest when the mixing ratio was 1:2. Compared to a system that has not undergone Maillard reaction, the average particle size of MRPs was reduced, and the largest value reached at the ratio of 1:2. The Maillard reaction improved the emulsification activity and emulsion stability of WPI, the MRPs showed the best emulsification activity (38.63 m2/g) and emulsion stability (65.23%) at a ratio of 1:2. Rheological tests showed that Maillard reaction modification enhanced the gelation of WPI, and the storage modulus of MRPs at a ratio of 1:3 had the biggest increase in which G' reached a value of about 97,000 Pa, seven times the value obtained in the initial WPI gel. At the same shear rate, the apparent viscosity of MRPs solution increased compared to WPI, while the effect of WPI addition on the viscosity of the system predominates. The above results showed that the rheological properties and emulsifying properties of WPI could be modified after Maillard reaction.

5 Effects of Glucose Oxidase and Catalase on Dough and Bread Quality

DENG Jia-luo , LU Li-xia , YAO Li-li , LIN Li-jun , XIONG Xiao-hui

2019, 35(12):28-40. DOI: 10.13982/j.mfst.1673-9078.2019.12.005

[Abstract](483) [HTML](357) [PDF 32.29 M](869)

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The effects on fermentation volume of dough and the water holding rate, sulfhydryl group, disulfide bond and microstructure of dough and gluten were analyzed by adding glucose oxidase (GOD), catalase (CAT) and their complex enzymes. Then the effects on the weight, specific volume, sensory index and texture index of bread were compared and clarified. The results showed that when the concentration of GOD was at 15 mg/kg, the specific volume of the bread was increased from 4.33 mL/g to 5.52 mL/g. Then, when the concentration of GOD was at 20 mg/kg, the hardness, stickiness and chewiness of the bread were the lowest, such as 233.33 g, 141.00 mJ and 704.82 mJ, which was significant difference (p<0.05) with the control group. However, adding GOD has no significant difference in internal cohesion. The concentration of CAT was at 10 mg/kg, the specific volume of the bread was increased to 4.98 mL/g. When the concentration of CAT was at 15 mg/kg, the hardness, adhesive viscosity and chewiness of the bread were reduced significantly (p<0.05), while cohesion was significantly enhanced. The volume of dough fermentation was increased by complex GOD and CAT. The effects of complex enzyme on the volume of the dough were better than that of single enzyme. The water-holding rate of dough could be increased to 64.38 percent by adding GOD, while it was significantly (p<0.05) reduced by adding CAT and complex enzyme in the water-holding rate of dough and gluten. The content of sulfhydryl group in dough was significantly reduced but increased in the content of disulfide bond of the dough by adding GOD and CAT. While the change rate of sulfhydryl group and disulfide bond was the largest in complex enzyme group. About the microstructure of the dough and gluten by adding GOD and CAT, gluten network was improved and more even, unbroken and continuous than that in the control group.

6 Effect of Water Extract of Rhizoma Arisaema on the Expression of PKM2 and mTOR Genes in Gastric Cancer Rat Cells

LI Feng , KONG Jian-fei

2019, 35(12):41-46. DOI: 10.13982/j.mfst.1673-9078.2019.12.006

[Abstract](325) [HTML](159) [PDF 13.75 M](702)

Abstract:
To investigate the effect of water extract of Rhizoma Arisaema on the expression of PKM2 and mTOR in gastric cancer rat cells. 50 SD male rats were selected, 10 of which were used as the normal group, and the remaining 40 were used to establish the gastric cancer model. The rats were divided into gastric cancer group, drug control group, low and high concentration group, and were treated with intervention. The proliferation and apoptosis of cancer cells in gastric cancer rats were observed, and the expressions of motilin, gastrin, PKM2, mTOR, bcl-2, PI3K and Akt in each group were detected. The results showed that the levels of motilin and gastrin in the high-concentration group were 137.65 pg/ml and 88.76 pg/ml, respectively, and the apoptosis rate was 49.73%, which were all higher than those in the gastric cancer group, drug control group and low-concentration group (p<0.05). The proliferation rate of rats in the high-concentration group was 7.55%, and the relative expression levels of PKM2, mTOR, bcl-2, PI3K and Akt were 1.37, 1.35, 1.37, 1.42 and 1.39, respectively, which were lower than those in the gastric cancer group, drug control group and low-concentration group (p<0.05). The results showed that the gastric function of gastric cancer rats was improved, the proliferation rate of cancer cells was decreased and the apoptosis rate was increased. The expression of PKM2, mTOR, Bcl-2, PI3K and Akt was obviously regulated by the water extract of rhizoma Arisaema. The anticancer ability of the water extract of Rhizoma Arisaema was concentration-dependent, indicating that the water extract of Rhizoma Arisaema could inhibit the proliferation of gastric cancer cells, promote apoptosis of gastric cancer cells and provide a theoretical basis for clinical treatment of gastric cancer.

7 Effect of Mixed Preservative on Color and Odor of Fresh Lotus Root during Storage at Refrigerated Temperature

FAN Chuan-hui , CHEN Xue-ling , HE Jian-jun , CHEN Hang-jun , HAN Yan-chao

2019, 35(12):47-53. DOI: 10.13982/j.mfst.1673-9078.2019.12.007

[Abstract](458) [HTML](127) [PDF 25.39 M](808)

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ER Lotus No. 5' lotus root was used as test materials. The color and odor of lotus root were measured after lotus root immersed in mixture solution and stored at 4°C. The mixture solution contained citric acid 0.02%, EDTA-Na2 0.05%, D- ascorbic acid 0.02%, sodium dehydroacetate 0.01%, sulfite 0.02%. The sample treated with mixture solution was marked as EX group. In the control group (CK), the lotus root was immersed in sterile water and the others were the same with that in EX group. The results showed that the content of total polyphenol and activity of polyphenol oxidase (PPO) of lotus root in EX group decreased by 29.24% and 73.88% respectively. The browning of the surface of the lotus root was significantly inhibited in EX group. According to the electronic nose analysis, there was an insignificant effect on the initial odor of lotus root between CK group and EX group. However, the storage time had a significant effect on the odor of lotus root in both CK group and EX group. The main substances that affected the odor of lotus root were nitrogen oxides, methyl compounds, sulfides, aldol aldehydes and organic sulfides which were represented by sensors R(2), R(6), R(7), R(8) and R(9). The mixture solution could significantly inhibit the brown of the lotus root peel and did not affect the original smelling flavor of the lotus root. The best shelf life of lotus root after immersion in mixture solution was 32 days. The results of this work provided basic theoretical support for the shelf life of fresh lotus roots under refrigerated conditions.

8 Apoptotic Effect of Sophora Flavescens Polysaccharide on Human Lung Cancer A549 Cells

WANG Jing , MENG Shu , LI Fang

2019, 35(12):54-60. DOI: 10.13982/j.mfst.1673-9078.2019.12.008

[Abstract](365) [HTML](242) [PDF 19.30 M](564)

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To explore the effects of Sophora flavescens polysaccharide on proliferation, apoptosis, invasion and migration of human lung cancer cell lines, human lung cancer A549 cell lines were cultured and divided into blank group, drug control group and low, medium and high concentration groups. Cell proliferation, apoptosis, invasion and migration ability were detected in each group, and the expressions of apoptosis-related proteins Bcl-2, PI3K and Akt were determined. The results showed that the cell proliferation rate and apoptosis rate of the high concentration group, at 72 h, were 18.65% and 79.55% respectively, which were superior to those of the other control groups. The number of cell invasion and migration in high concentration group was lower than that in other groups (p<0.05). The relative expressions of Bcl-2, PI3K and Akt in high concentration group were 0.32, 0.40 and 0.34 respectively, which were lower than those in other groups (p<0.05). Under the intervention of Sophora flavescens polysaccharide, the proliferation rate of lung cancer cells decreased, the apoptosis rate increased, the invasion and migration ability were inhibited obviously, and the expression of apoptosis-related proteins Bcl-2, PI3K and Akt were obviously regulated, and their ability showed obvious concentration dependence. This indicated that Sophora flavescens polysaccharide could inhibit the proliferation, invasion and migration of lung cancer cells, promote apoptosis of lung cancer cells and provide a theoretical basis for clinical treatment of lung cancer.

9 Effects of Alkaline Salts on Gluten Characteristics of Wheat Flour and Protein Composition of Derived Noodles

FAN Hui-ping , CHEN Yue-hua , FU Feng , AI Zhi-lu , BIAN Ke

2019, 35(12):61-69. DOI: 10.13982/j.mfst.1673-9078.2019.12.009

[Abstract](379) [HTML](199) [PDF 80.74 M](567)

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In order to investigate the effects of alkaline salts (composed of sodium carbonate and potassium carbonate) on the quality of wheat flour and derived noodles, three wheat varieties with different gluten strengths were used as the experimental materials for the study on the impacts of different mass ratios of sodium carbonate to potassium carbonate and the amounts of alkaline salts for addition on the gluten characteristics of wheat flour, and the protein composition and molecular weight changes of derived noodles. The effects of alkaline salts on the molecular weight distribution of proteins in the noodles were investigated by SDS-PAGE electrophoresis. The results showed that the addition of alkaline salts could decrease the wet and dry gluten contents in the three varieties of wheat flours while increasing the gluten index. Among which the wet gluten of Xinong 979 declined from 36.04% to 26.58%, with its dry gluten content decreasing from 12.22% to 7.74%. Alkaline salts could increase the overall contents of albumin and salt-soluble proteins while decreasing significantly the contents of globulin and gluten proteins in the three kinds of noodles. The content of GMP did not change significantly, whilst the contents of gliadin and glutenin decreased upon the addition of alkaline salts. With the increase of added alkaline salt, the content of gliadin in the noodles made from Aikang 58 decreased from 4.12% to 1.69% with the content of glutelin also decreasing from 4.44% to 2.77%. The research results provide a theoretical basis for the industrial production of noodles.

10 Effect of Postharvest Low Dose Electron Beam Irradiation on the Antioxidant Capacity of Lentinula edodes

ZHANG Yu , ZHOU Ran-ran , GAO Hong , CHEN Zhe-ya , FAN Xiu-zhi , YING Chao-ming , YAO Fen , SHI De-fang

2019, 35(12):70-76. DOI: 10.13982/j.mfst.1673-9078.2019.12.010

[Abstract](317) [HTML](200) [PDF 11.12 M](818)

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Fresh Lentinula edodes are susceptible to decay after harvest. In order to improve its post-harvest storage quality, fresh Lentinula edodes were subjected to electron-beam irradiation at doses of 1.0, 2.0 and 3.0 kGy in this study, before a storage at 4±1 ℃ and 80%±5% relative humidity. Then, the effect of low dose electron beam irradiation on the antioxidant capacity of fresh Lentinula edodes was examined based on the evaluation indices such as color, total phenol content, malondialdehyde content, DPPH radical scavenging ability, and activities of antioxidant enzymes (SOD and CAT). The results showed that compared with other doses, the treatment at 2.0 kGy could delay the browning of Lentinus edodes, maintain the total phenol content at a relatively high level, and reduce the accumulation of malondialdehyde (only 0.54 nmol/g at the end of storage). The irradiation dose of 2.0 kGy exhibited significant differences as compared to other groups: scavenged significantly more DPPH free radicals, and maintained higher activities of SOD and CAT (which decreased only by 3.78% and 27.90%, respectively). The above results indicated that electron beam irradiation at 2.0 kGy can enable fresh Lentinus edodes to maintain high post-harvest antioxidant activity thereby delaying the oxidation reaction in Lentinula edodes and prolonging its postharvest shelf life.

11 Effects of Electronc Beam Irradiation on the Lipid Oxidation and Quality of Pine Pollen

ZHAO Qiao-li , LIU Qi-song , SHI Li-hua , SHAN Yue , LI Jin-wei , LIU Yuan-fa

2019, 35(12):77-86. DOI: 10.13982/j.mfst.1673-9078.2019.12.011

[Abstract](401) [HTML](185) [PDF 26.35 M](579)

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The effects of electron beam irradiation on the bactericidal effect, lipase activity, lipid oxidation performance and nutritional quality of pine pollen were studied. The changes of color, peroxide value and volatile constituents of wall-breaking pine pollen during accelerated oxidation were also analyzed. The results showed that electron beam irradiation could significantly reduce the microbial content of pine pollen, and the sterilization effect with a dose-dependent manner, the D10 values of total bacterial count, mold-yeast and coliform were 2.20, 1.95 and 1.84 kGy, respectively. The lipase activity, carotenoid and free fatty acid contents of pine pollen were decreased significantly with the increase of irradiation dose, while the peroxide value was still at a low level. At the irradiation dose of 8.0 kGy, the inactivation rate of lipase was 53.52%, the retention rate of carotenoid was 60.81%, the content of free fatty acid was 1.38 mg/kg, and the peroxide value was 0.46 meq/kg, respectively. In addition, the irradiation of 8.0 kGy dose had no significant effect on the basic nutritional components, amino acid content, and color of pine pollen and effectively prevent the increase of peroxide value, hexanal and caproic acid contents in the process of accelerated oxidation. These results indicated that electron beam irradiation of 8 kGy dose could effectively kill the microbes, inhibit lipid oxidation, keep the original nutritional quality and improve the storage stability of pine pollen.

12 Intervention Effect of Momordica grosvenori Extract on Hypothyroidism Model Rats

GUO Wei , LIU Ming-qing , YAN Rui-xia , WANG Chen , ZHANG Qiu-yu

2019, 35(12):87-93. DOI: 10.13982/j.mfst.1673-9078.2019.12.012

[Abstract](409) [HTML](201) [PDF 19.90 M](603)

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The intervention effect and mechanism of Momordica grosvenori extract on hypothyroidism model rats was investigated in this work. Fifty healthy SD rats were selected as normal group, 10 as normal group, and 40 as hypothyroidism model. After successful modeling, the rats were divided into model group, positive control group (1 ml/100 g 0.08% thyroid tablet suspension), low dose group (100 mg/kg Momordica grosvenori extract), high dose group (160 mg/kg Momordica grosvenori extract), 10 rats each. The levels of hypothalamus-pituitary-thyroid axis, hypothalamus-pituitary-gonadal axis factor and the expression of Shh signaling pathway gene were detected. The results showed that the levels of free triiodothyronine (FT3), free thyroxine (FT4), triiodothyronine (T3), thyroxine (T4), thyrotropin releasing hormone (TRH) in the high dose group increased to 4.25 pmol/L, 16.58 pmol/L, 1.20 nmol/L, 56.35 nmol/L and 4.13 μIU/mL, respectively, and Thyrotropin (TSH) decreased to 1.96 μIU/mL, which was significantly different with other groups (p<0.05). The levels of follicle-forming hormone (FSH), luteinizing hormone (LH), estradiol (E2) and progesterone (P) of female rats in the high-dose group increased to 12.63 IU/L, 14.35 IU/L, 31.24 ng/L and 186.59 ng/L respectively, which were higher than those in the positive control group and the low-dose group (p<0.05). FSH, LH and testosterone (T) increased to 10.25 IU/L, 12.35 IU/L and 369.23 ng/L in the high dose group of male rats, respectively, which were higher than those in the positive control group and the low dose group (p<0.05). The mRNA expression levels of Shh, Patched-1, and Gli-1 in the high-dose group was higher than those of the positive control group and the low-dose group (p<0.05). Momordica grosvenori extract can regulate abnormal thyroid biological effects by acting on Shh signaling pathway, improve thyroid function, increase thyroid hormone secretion, and maintain the dynamic balance of TRH, TSH and thyroid hormone.

13 Effects of Ethylene and 1-MCP Treatments on Softening and Cell Wall Degradation of Bethekxin Melon Fruit

ZHU Wan-tong , FENG Zuo-shan , BAI Yu-jia , Reheman•Aila , WANG Jin , Gulipiye•Ahaimaiti

2019, 35(12):94-101. DOI: 10.13982/j.mfst.1673-9078.2019.12.013

[Abstract](372) [HTML](134) [PDF 17.45 M](491)

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“Bethekxin” melon is a typical climacteric fruit that softens rapidly 3 to 5 days after harvest. Treatment of “Besekxin” melon with 1 μL/L 1-methylcyclopropene (1-MCP) and 300 mg/kg ethephon to study the softening mechanism of “Bethekxin” melon and analyze the hardness and pectin substance Changes in the content, cellulose degradation, cellulase (Cx), β-glucosidase (β-Glu), polygalacturonase (PG), pectin methylesterase (PME) activity. The results showed that the 1-MCP treatment group delayed the decrease of melon hardness, and the original pectin and cellulose content were significantly higher than that of the control and ethephon treatment. The original pectin was 22% higher than the control group (p<0.05), and the cellulose content was 26.13% higher than the control group (p<0.05). The activity of PG, PME, Cx and β-Glu treated by 1-MCP was significantly lower than that of the control and ethylene. Processing group. The activities of PG, PME, Cx and β-Glu were lower than those of the control group. The peak enzyme activity was 8.92%, 25.73%, 32.45% and 14.82% lower than the control group. The activities of PG, Cx and β-Glu in ethephon treatment were higher than those in the control group, and the peak of enzyme activity was 2.84%, 21.83% and 14.95% higher than that of the control group. With the increase of storage time, 1-MCP treatment slowed the cell softening process by regulating the activity of “Bethekxin” melon pectin, cellulose content and cell wall degrading enzyme, and improved the storage quality of “Bethekxin” melon.

14 Structural Analysis of the Degradation Products of Chondroitin Sulfate from Sturgeon Cartilage

WANG Jun , ZHANG Yang-xing , XIONG Guang-quan , WU Wen-jing , HUANG Lei , WANG Lan

2019, 35(12):102-111. DOI: 10.13982/j.mfst.1673-9078.2019.12.014

[Abstract](390) [HTML](198) [PDF 49.16 M](674)

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Using sturgeon cartilage as the raw material, chondroitin sulfate was extracted via the alkaline extraction-enzymatic-ethanol precipitation process, degraded by conventional comminution and superfine pulverization combined with irradiation technology, and then subjected to chemical and structural analyses of chondroitin sulfate using ion chromatography, ultraviolet-visible spectroscopy, infrared absorption spectroscopy and nuclear magnetic resonance spectroscopy. Monosaccharide analysis showed that the content of rhamnose in the crude sample increased from 56.16% to 59.31% after the co-treatment of superfine comminution combined with irradiation, and the content of glucuronic acid in the crude sample decreased from 33.69% to 31.84% after the co-treatment of superfine comminution combined with irradiation, The final purified samples contained 88.77% glucuronic acid. Ultraviolet spectroscopy revealed that the co-treatment by superfine pulverization combined with irradiation caused breakdown in the molecular structure of chondroitin sulfate i.e. the cleavage of glycoside bonds and the production of C=O groups. The results of infrared spectroscopy showed that the chondroitin sulfate treated by conventional comminution or the co-treatment of superfine comminution combined with irradiation treatment. The nuclear magnetic resonance analysis showed that the proton signals of acetylgalactosamine and glucose on chondroitin sulfate were enhanced after the treatment of superfine pulverization combined with irradiation. It is speculated that the chondroitin sulfate from sturgeon cartilage contained GlcA (β1→3) GalNAc-4SO3 and GlcA (β1→3) GalNAc-6SO3 repeating structural units.

15 Effect of Quinoa on the Behavior and Bread Quality of Frozen Dough

ZHONG Ya-yun , WU Lei-yan , ZHOU Jin-feng , TU Jin , DONG Wu-hui , LUO Deng

2019, 35(12):112-121. DOI: 10.13982/j.mfst.1673-9078.2019.12.015

[Abstract](457) [HTML](198) [PDF 80.43 M](578)

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The quinoa and wheat flour were mixed in a certain proportion. The gelatinization characteristics of the mixed powder were evaluated by rapid viscosity analysis. The rheological properties of the wheat-quinoa frozen dough during the frozen storage were determined by rheometer. The moisture, water migration and fermentation volume of the dough during were detected by nuclear magnetic resonance. The relationship between the characteristics of the frozen dough and their product quality was analyzed. The results showed that quinoa flour can improve the quality of wheat flour, dough and bread. The quinoa flour can reduce the gelatinization viscosity and disintegration value of the mixed powder system. When added 5% quinoa, after frozen storage, the elastic modulus and viscous modulus of the frozen dough increased, the loss tangent value of the frozen dough of wheat flour increased by 4.73%, and the loss tangent of the frozen dough increased by only 0.41%. The free water content of wheat frozen dough increased by 3.90% after frozen storage, but that of wheat-quinoa frozen dough only increased by 2.40%. It can be seen that the quinoa flour can reduce the degree of water migration of the dough. The addition of quinoa flour can also maintain the integrity of the dough gluten network structure, and the fermentation volume increased from 26.42 mL/h to 29.17 mL/h. Different amounts of quinoa flour have different quality improvement on dough and bread. The optimum addition amount was 10%. After baking, the specific volume of bread was 3.08 mL/g and the hardness was 2803.48 g. This study could provide a theoretical basis for the development of quinoa frozen dough and had important guiding significance in the development of new products for quinoa.

16 Effect of Light Treatment on Qualities of Fresh-cut Melon during Shelf Life

WANG Yu-bin , FENG Yu-qing , MA Yue , HE Chao-jun , ZHAO Xiao-yan , ZHANG Chao

2019, 35(12):122-129. DOI: 10.13982/j.mfst.1673-9078.2019.12.016

[Abstract](387) [HTML](170) [PDF 39.21 M](846)

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The effect of light treatments on qualities of fresh-cut melon during the shelf life was evaluated. The white light treatment was used as the control. The weight loss rate, soluble solids content, titratable acid content, malondialdehyde content, hardness, browning degree, color and flavor of the fresh-cut melon treated by the red, blue, green lights and no light treatments during the shelf life at 5 ℃ were compared. The results showed that the spectrum of the blue light treatment was located on the main wavelength trajectory of 442 nm with the source purity of 100%, and the intensity of 128±17.10 Lux. Compared with the control, the blue light treatment could decrease the browning degree of the fresh-cut melon by 10.70%, reduce the weight loss rate by 3.76%, and raise the hardness of the fruits by 60.60%. Moreover, the blue light treatment retarded the flavor deterioration of the fresh-cut melon. Hence, the blue light treatment maintained the texture, color and retarded the flavor deterioration of the melon during the sales and display. Therefore, the blue light treatment was beneficial to prolong the shelf life of fresh-cut melon.

17 Effects of 1-MCP Treatment on the Physiology and Quality of Early-maturing Apples Stored at Ambient Temperature

FENG Yun-xiao , HE Jin-gang , CHENG Yu-dou , LI Li-mei , LI Xue-ying , FENG Jian-zhong , GUAN Jun-feng

2019, 35(12):130-136. DOI: 10.13982/j.mfst.1673-9078.2019.12.017

[Abstract](491) [HTML](123) [PDF 121.63 M](701)

Abstract:
Early-maturing apple cultivars have a short shelf-life and can’t be stored long. In this study, four early-maturing apple cultivars (lines), ‘Jiping 3’, ‘6-25’, ‘4-25’ and ‘Gala’, were used as the research fruits. The effects of 1-methylcyclopropene (1-MCP) treatment on the respiration rate, ethylene production rate and fruit quality of the early maturing apples stored at ambient temperature (25 ℃) were investigated. Compared with the control group, 1-MCP treatment effectively inhibited the rate of respiration, reduced the release of ethylene, delayed the decrease of fruit firmness, and maintained the soluble solid content (except for the Jiping 3) and titratable acid content. Further studies revealed that 1-MCP treatment reduced significantly the flesh browning in ‘Jiping3’ and ‘6-25’ apples, compared with the control group. After 14 days of storage, the incidence of flesh browning in the 1-MCP-treated ‘Jiping3’ and ‘6-25’ fruits were zero and only 17.78%, respectively, which were significantly lower than that for the control group (‘Jiping3’CK: 87.87%; ‘6-25’CK: 90.48%). However, 1-MCP treatment had no significant effect on the decay of four early-maturing apple varieties. Thus, the 1-MCP treatment can effectively delay the ripening and aging process of early-maturing apples, maintain their fruit quality, delay the fruit ripening and senescence, thereby effectively improving the preservation of the early-maturing apples stored at ambient temperature and prolonging the shelf life.

18 Efficient Expression of Escherichia coli AppA Phytase in Pichia pastoris

GAO Jiao , ZHENG Xue-yun , LIN Ying , LIANG Shu-li

2019, 35(12):137-144. DOI: 10.13982/j.mfst.1673-9078.2019.12.018

[Abstract](420) [HTML](249) [PDF 28.85 M](643)

Abstract:
In this study, the phytase gene, AppA, derived from Escherichia coli B48 was synthesized by whole gene, and cloned into PHKA vector for secretion expression in Pichia pastoris GS115. In order to further increase the expression of phytase in Pichia pastoris, this study adopted the optimization method based on the combination of signal peptide, promoter, gene dose and protein folding flux, which led to an ultimate increase of the phytase activity in Pichia pastoris from 329.41 U/mL to 1892.51 U/mL (5.75 times as high as that of the original strain). The basic enzymatic properties of phytase AppA were preliminarily determined, and the optimum temperature and pH were 60 ℃ and 4.5, respectively. After a 60-min treatment at 60 ℃, 40% of the phytase activity was retained, indicating poor thermal stability. After a 6-h treatment at pH 6.0~7.0, 87% of the enzyme activity was retained, indicating good stability in a weak acid environment. The effect of divalent metal ions on phytase activity was also studied. Fe2+ could activate phytase AppA, while ions such as Cu2+, Ni2+ and Mn2+ may inhibit the activity of phytase AppA through forming a complex with phytic acid. The high stability of the enzyme under acidic conditions is advantageous for its application in the field of food processing.

19 Effect of Brewing Process on Wort Protein and Its Oxidative Characteristics

CHANG Bin , CAI Lin-fei , ZHAO Hai-feng

2019, 35(12):145-150. DOI: 10.13982/j.mfst.1673-9078.2019.12.019

[Abstract](307) [HTML](119) [PDF 12.77 M](544)

Abstract:
The effects of beer brewing process, especially mashing process on protein content, free thiol groups content and antioxidant activity of wort were examined. The results showed that the degradation of macromolecular proteins was accompanied by the formation of protein with low molecular weight during mashing. Protein and free thiol groups contents showed a pattern of increasing first and then decreasing, and both of them decreased from 310.63 μg/mL to 229.18 μg/mL, and from 0.61 μmol/g to 0.04 μmol/g, with the reduction of 26.22% and 93.44%, respectively after mashing, which indicated that mashing was an important stage in the key changes of protein and thiol groups. There were significant (p<0.01) positive correlations among protein content, free thiol groups content and ABTS free radical scavenging activity. Extension of the mashing time and increase of mashing temperature were beneficial to the dissolution and accumulation of protein in wort, which significantly improved the ABTS free radical scavenging activity, and increased the color and TBA of wort. Therefore, the protein in wort, especially lipid transfer protein 1 (LTP1) with antioxidant activity, had a positive effect on the oxidative stability of wort.

20 Effect of Modified Atmosphere Packaging on the Shelf-life of Fresh-cut Chinese Cabbage

FENG Yan-yan , WANG Qing-guo

2019, 35(12):151-156. DOI: 10.13982/j.mfst.1673-9078.2019.12.020

[Abstract](298) [HTML](136) [PDF 19.45 M](616)

Abstract:
The combination of the packaging bags with the modified atmosphere windows of different permeability and areas were studied for extending the shelf life of fresh-cut Chinese cabbage. The sensory quality and gas composition in the packaging bags were analyzed in order to screen the optimum modified atmosphere packaging (MAP) of fresh-cut Chinese cabbage. The results showed that the optimum MAP could effectively improve the storage quality of fresh-cut Chinese cabbage. The suitable modified atmosphere window for fresh-cut Chinese cabbage was as follows: the transmittance rates of O2 and CO2 were 4×105 and 1.6×106 cm3/m2·d·atm respectively, the permeability ratio was 1:4, and the area of Chinese cabbage needed was 1~2 cm2/kg, which can solve the problem of odor, and can maintain shelf quality for more than 4 days. Compared with the permeability of modified atmosphere window and film, the permeability amount of O2 and CO2 in packaging bags suitable for fresh-cut Chinese cabbage should be 1.85×103~2.08×103 and 8.59×103~9.51×103 cm3/kg·d·atm respectively, and O2 was 3.63%~5.10% and CO2 was 7.77%~8.07%,when the appropriate gas concentration was reached. The MAP bag not only can make fresh-cut Chinese cabbage in the appropriate gas state, but also can solve the odor problem caused by anaerobic breathing, retain the original smell of fresh-cut cabbage, and prolong its shelf life, so as to provide strong technical support for fresh-cut enterprises.

21 Development and Application of Phase Change Coolant for Pleurotus eryngii Based on Its Freezing Point

FANG Yi-da , LI Li , LI Dong , CHEN Hang-jun , LUO Zi-sheng

2019, 35(12):157-165. DOI: 10.13982/j.mfst.1673-9078.2019.12.021

[Abstract](410) [HTML](131) [PDF 25.71 M](676)

Abstract:
Based on the aqueous solution of maltitol and potassium sulfate, nano titanium dioxide and superabsorbent polymer are added to develop a phase change coolant. The onset temperature and phase enthalpy change of the coolant were measured by the DSC method, and then its properties were also measured by a T-t curve and repeated freezing and thawing tests. Results show the best formulation of the developed coolant is: maltitol 1,72%, potassium sulfate 2.09%, nanometer titanium dioxide 0.01%, superabsorbent polymer 0.50%. Its onset temperature is -1.64 ℃, the phase enthalpy change is 295.14 J/g. In addition, the phase change coolant is not overcooled and has no phase separation. The phase change coolant was applied to the storage of Pleurotus eryngii to test its preservation effect. During the storage, the temperature of the foam box was recorded, and the sensory score, weight loss rate, color, hardness, springiness of Pleurotus eryngii were measured every day. The result shows the coolant has good effect on the application of Pleurotus eryngii’s preservation, which can significantly reduce the physiological and biochemical reactions of Pleurotus eryngii, and delay its quality deterioration, and the best mass ratio is 1:4.

22 Optimization of Plant Additive-containing Formulations for Beef Patties and Its Effect on Beef Minced Meat Quality

MENG Zi-qing , ZHAO Gai-ming , ZHU Chao-zhi , TIAN Wei , QI Xing-lei , LIU Yan-xia

2019, 35(12):166-175. DOI: 10.13982/j.mfst.1673-9078.2019.12.022

[Abstract](375) [HTML](198) [PDF 6.52 M](605)

Abstract:
In order to obtain a healthy beef patty formulation containing plant-derived additives with good quality and low fat, this study explored the effects of carrageenan, blending oil and shiitake mushrooms on the quality and microstructure of beef minced meat based on the Box-Behnken design principle. The results showed that the addition of carrageenan, vegetable oil and shiitake mushroom had significant effects on the protein content, water content, fat content, color, sensory score and hardness of beef minced meat (p<0.05). An equation was obtained via the response surface test and then verified: Sensory score=32.00+73.83?carrageenan addition amount+3.23?grease addition amount+ 4.37?mushroom addition amount-126.92?(carrageenan addition amount)2 -0.15?(grease addition amount)2 -0.16?(mushroom addition amount)2. The verification results showed that the optimized group with added mushrooms had reduced hardness, chewiness and recovery. The treatment group with added oil only had the greatest elasticity and adhesion; the optimized group with added mushrooms had a denser structure, and the traces left by degreasing were more uniform. Conclusion: The optimum amounts of plant-derived additives for addition were 0.29%, 11.04% and 13.68% for carrageenan, blending oil and shiitake mushroom, respectively. This study provides a reference for the research on low-fat healthy beef patties, and a theoretical basis for the investigations on the impact of different additives on beef minced meat quality.

23 Preliminary Study on Antibacterial Activity of Actinomycete JSD-1 and Optimization of Fermentation Conditions Affecting the Antibacterial Activity of JSD-1

ZHAO Li-jing , ZHI Yue-e , LIU Huan-ran , ZHANG Dan , ZHOU Pei

2019, 35(12):176-181. DOI: 10.13982/j.mfst.1673-9078.2019.12.023

[Abstract](354) [HTML](133) [PDF 39.67 M](656)

Abstract:
The antibacterial activity of actinomycete JSD-1 was preliminarily investigated in this work, and the fermentation conditions that affected its antibacterial activity were optimized to enhance the antibacterial effect. Using pathogenic Escherichia coli and Staphylococcus aureus as indicator bacterias, the antibacterial activity of strain JSD-1 was investigated by dilution coating, agar diffusion method and liquid co-culture method. The fermentation conditions of JSD-1 were optimized by single factor experiment and orthogonal experiment design. The optimized culture medium to affect the antibacterial activity of JSD-1 was composed of glucose 10 g/L，urea 2.5 g/L. The optimal fermentation condition was as follow: culture temperature of 35 ℃ pH 7.0, inoculation amount 3%, culture time 7 d. The antibacterial activity of JSD-1 was significantly improved. The inhibitory zone diameter increased from 10.08 mm to 18.63 mm, which was beneficial to the further development and utilization of JSD-1 as an antagonist. It was found that the growth and proliferation of pathogenic Escherichia coli and Staphylococcus aureus were inhibited by JSD-1 in their logarithmic phase, stable phase and decline phase continuously, indicating that JSD-1 had great antibacterial potential and could be used as a candidate strain for biocontrol preparation.

24 Preparation of Artificial Antigen and ELISA Identification of Mouse Polyclonal Antiserum for the Detection of Doxycycline

CAO Jin-bo , MENG Ji-qiu , LI Yan-hong , WANG Yao , SUN Ya-ning , HU Xiao-fei

2019, 35(12):182-188. DOI: 10.13982/j.mfst.1673-9078.2019.12.024

[Abstract](382) [HTML](188) [PDF 41.99 M](539)

Abstract:
To prepare complete antigen of doxycycline (DC) and obtain mouse polyclonal antiserum with good immunological characteristics, carboxyl groups were introduced into DC molecules by succinate method in this work. A Complete antigens were prepared by coupling with carrier proteins using an improved succinic acid method. The coupling effect of complete antigen was identified by UV and SDS-PAGE. Four BALB/c mouse were immunized with 30 μg artificial antigen, and the antiserum immunological characteristics were identified by indirect ELISA and indirect competitive ELISA. The results showed that the coupling effect of artificial antigen was good, the titer of antiserum of all four mouse were higher than 1:12800, the serum of all four mouse had inhibitory effect. The antiserum produced by mouse number 4 was the best. The inhibitory concentration (IC50) was 24.75 ng/mL. The cross-reaction rates of OTC, CTC and TC of their homologues were 3.4%, 3.8% and 3.0%, respectively. The cross-reaction rate with other veterinary drugs and carrier protein was less than 0.3%, and had a good specificity. This study successfully synthesized DC artificial antigens and prepared DC antiserum with good immunological properties, which provided a good foundation for the preparation of monoclonal antibody and the establishment of immunology rapid detection method.

25 Preparation of Quercetin-fortified Yogurt and Its Intestinal Flora-regulating Effect in Mice

CHEN Ying-meng , SU Li-jie , DING Jing-hua , LI Yao-lu , ZENG Yu-peng , LI Meng-shan , WANG Qiu-lan , CHEN Xiao-yi

2019, 35(12):189-196. DOI: 10.13982/j.mfst.1673-9078.2019.12.025

[Abstract](588) [HTML](197) [PDF 10.73 M](838)

Abstract:
Using sensory evaluation score and acidity as evaluation indices, the optimal fermentation conditions and optimal formula of quercetin-fortified yoghurt were determined by the single factor and orthogonal test methods. The effect of quercetin on the microbes in the yoghurt was investigated by measuring the total number of lactic acid bacteria of yogurt. Examinations were performed on the dynamic changes in the microbial community induced by quercetin-fortified yoghurt i.e. the proliferation of Lactobacillus, Bifidobacterium, Enterobacter and Enterococcus in mice. The experiments revealed that the optimal fermentation conditions and formula of quercetin-fortified yoghurt were: fermentation time 8 h, fermentation temperature 42 ℃, inoculation dosage 0.1%, added milk powder 12%, added sucrose 4%, and added quercetin added 0.1%. The obtained quercetin-fortified yoghurt had uniform color (yellow-green color) and sweet-sour balanced taste, with a pleasant and slight bitterness (which likely came from the added quercetin and some peptides derived from protein hydrolysis). The total number of lactic acid bacteria in quercetin-fortified yoghurt was (1.475±0.005)×108 cfu/mL, which was higher than that for the unfortified yogurt (p<0.05). Observations on the dynamic microbial changes revealed the alterations in the proliferation of intestinal flora in mice: the growth of Lactobacillus and Bifidobacterium in the quercetin-fortified yogurt was stronger while the growth of Enterobacter and Enterococcus was weaker, compared with that of unfortified yogurt. The results showed that the quercetin-fortified yoghurt prepared under the optimal conditions could promote the proliferation of Lactobacillus and Bifidobacteria in vitro but inhibit the proliferation of Enterobacter and Enterococcus in vitro, with its taste better than that for the commercially available yoghurt. The results of this study provide a theoretical basis for the subsequent development and utilization of quercetin-fortified functional yogurt.

26 Composition and Functional Enzymes of the Pure-culture Mold Community from Fermented Grains of Songhe Nongxiang Liquor

LIU Bing-bing , LIU Zheng-yu , SONG Hao-feng , WANG Wen-li , TIAN Shi-chao , LI Xue-si , YAN Pei-xun , GUO Shu-xian

2019, 35(12):197-207. DOI: 10.13982/j.mfst.1673-9078.2019.12.026

[Abstract](471) [HTML](153) [PDF 14.49 M](957)

Abstract:
In order to explore the community composition of pure-culture mold in the fermented grains of Songhe Nongxiang liquor, and to examine the activities of the functional enzymes related to the pure-culture fermentation process, the pure culture method was used to isolate the molds in fermented grains obtained after different fermentation times and from different positions. The 18S rRNA gene was cloned and sequenced according to the morphological characteristics (after the removal of those repeated ones) to determine preliminarily the classification status. Five kinds of functional enzymes related to fermented grains were screened by the point connection method. The results showed that the fermented grains of Songhe Nongxiang liquor were rich in molds, with totally 63 isolated strains, and 15 strains obtained after the removal of morphological repetition (which belonged to Cladosporium herbarum, Aspergillus niger, Talaromyces wortmannii, Talaromyces pinophilus, Aspergillus versicolor, Aspergillus oryzae, Trametes hirsuta, Penicillium citrinum, Penicillium freii, Byssochlamys nivea and two potentially new taxa). The detection rate of pure-culture molds in the fermented grains of Songhe Nongxiang liquor was higher from Day 3 to15 after fermentation, and then decreased gradually with the screening rates of amylase, cellulase, pectinase, protease and esterase were 100%, 93.3%, 33.3%, 73.3% and 46.7%, respectively, which lays a increase of fermentation time. The pure-culture mold strains in the fermented grains were rich in active functional enzymes, and the activity foundation for further development and utilization of the strains.

27 Optimization of Preparation Technology of Antioxidant Peptide from Apricot by Box-benhnken Response Surface

XUE Yu-fei , LI Fang , CHENG Yi-mei , ZHANG Rui , YANG Hai-yan , KONG Ling-ming

2019, 35(12):208-215. DOI: 10.13982/j.mfst.1673-9078.2019.12.027

[Abstract](565) [HTML](229) [PDF 29.58 M](678)

Abstract:
The preparation process of antioxidant peptides from almond meal protein was optimized. The optimal enzyme was selected from alkaline protease, neutral protease, trypsin, papain and protamex according to the hydrolysis degree and DPPH clearance rate of the hydrolysate. The effects of the amount of enzyme, pH, hydrolysis time and temperature on DPPH radical scavenging activity were investigated. On the basis of single factor test, four-factor and three-level response surface method was used to determine the preparation technology of antioxidant peptides from almond meal protein. The results showed that alkaline protease was suitable for the preparation of antioxidant peptides from almond meal protein. The optimum enzymatic hydrolysis conditions were as follows: pH 9.1, enzyme addition 10000 U/g, enzymatic hydrolysis temperature 58 ℃, enzymatic hydrolysis time 4 h, and DPPH radical scavenging activity of enzymatic hydrolysate was 74.45%. This condition was suitable for the preparation of antioxidant peptides from almond meal protein. The optimization of the preparation process of antioxidant peptides from almond meal protein can provide theoretical reference for the development and application of antioxidant peptides.

28 Antioxidant and Antibacterial Effects of Wine Added with Chitooligosaccharide

HAO Zhen-ming , SUN Zhen

2019, 35(12):216-224. DOI: 10.13982/j.mfst.1673-9078.2019.12.028

[Abstract](405) [HTML](256) [PDF 512.23 K](580)

Abstract:
The effects of chitooligosaccharides on the antioxidant and bacteriostatic effects of wine were investigated. The effects of chitooligosaccharide as antioxidant and bacteriostatic agent in wine were evaluated by DPPH, hydroxyl radical scavenging rate and bacteriostatic rate. The results showed that chitooligosaccharide had good antioxidant and bacteriostatic properties. For antioxidant evaluation, the proanthocyanidins reducing power, DPPH and hydroxyl radical scavenging rate of the wine samples added with chitooligosaccharide increased by 107.97%, 14.23%, 3.96% and 4.48%, respectively. For bacteriostasis, the colony count of the strain was negatively correlated with the concentration of chitooligosaccharide. When the concentration of chitooligosaccharide exceeded 500 mg/L, all types of spoilage bacteria could be inhibited. The effects of chitosan oligosaccharide on wine flavor were also examined. The changes of organic acids, flavor substances and biogenic amines in wine were tested by high performance liquid chromatography and gas chromatography. The results showed that the contents of tartaric acid, ketoglutaric acid, malic acid and succinic acid in the aged wine were increased by 0.01~1.52 mg/mL compared with fresh wine, the content of ethyl acetate, propanol, isobutanol, isoamyl acetate, isoamyl alcohol decreased by 0.13~1.44 mg/mL, histamine content increased by 7.35 mg/L, the content of organic acids, flavor substances and biogenic amines in aged wines with chitosan oligosaccharides was not significantly different from that of fresh wines. Our studies on the antioxidant and bacteriostatic properties of chitooligosaccharide in wine suggest that chitooligosaccharide could be a new preservative used in wine that may be a replacement to SO2.

29 Preparation and Characterization of Complexes of Tea Polysaccharide-selenium Nanoparticles

MU Jing-jing , YE Xi-guang , CHEN Zhong-zheng , ZHANG Yuan-yuan , LIN Xiao-rong , LI Bin

2019, 35(12):225-231. DOI: 10.13982/j.mfst.1673-9078.2019.12.029

[Abstract](504) [HTML](192) [PDF 23.70 M](785)

Abstract:
To explore the feasibility of using tea polysaccharides as the template for the preparation of selenium nanoparticles (SeNPs), Yunnan large-leaf green tea, black tea, and Pu’er tea, Fuding Dabai white tea, Yinghong 9 yellow tea, and Lingtou Dancong oolong tea were used as the raw materials. Crude polysaccharides were extracted from these varieties of tea through water extraction and alcohol precipitation, and their yields and contents of carbohydrates and proteins were compared. Subsequently, SeNPs were prepared by using the crude tea polysaccharides as templates. The average hydrodynamic radius, total light intensity, Zeta potential and polydispersity index of SeNPs were analyzed by dynamic light scattering and laser Doppler velocimetry. The particle size, morphology and the distribution of SeNPs were characterized by transmission electron microscopy and scanning electron microscopy. Finally, the selenium concentration of the tea polysaccharide-SeNP complexes with the highest stability was determined by inductively coupled plasma mass spectrometry, and the binding of SeNPs to the templet was characterized by Fourier transform infrared spectroscopy. The results showed the crude polysaccharides from different varieties of tea trees and tea leaves all exhibited a stabilizing effect on SeNPs, and the polysaccharides from Pu'er tea exerted the strongest effect (with the smallest SeNP diameter (75 nm), highest electrostatic stability (zeta potential: -53 mV), and the most concentrated distribution (polydispersity Index: 0.11)). The Pu’er tea polysaccharides might bind to SeNPs mainly via noncovalent interaction through the -OH, -NH2 and -C=O groups.

30 Recovery and Gelation Property of Protein Isolate from Silver Carps (Hypophthal michthys molitrix) as Affected by pH and High Intensity Ultrasonic Treatment

TIAN Jin-he , ZHANG Yan-fang , WANG Yan-jie , LI Wen-ming , ZHANG Yu

2019, 35(12):232-240. DOI: 10.13982/j.mfst.1673-9078.2019.12.030

[Abstract](434) [HTML](247) [PDF 3.19 M](617)

Abstract:
Effects of Gradient acid pH and high intensity ultrasonic treatment (HIU) were combined with isoelectric solubilization/ precipitation (ISP) process on the extraction process, protein profile and functionality of the protein isolate (PI) from gutted silver carps without head were investigated. The pH reduction significantly raised the protein recovery of PI by 21.11% from pH 4.0 to 3.0, but further decrease did not affect any more. HIU could significantly increase the protein recovery by 3.77% at pH 3.0. PIs from all extraction combination methods were primarily composed of myofibril protein, and pH reduction significantly decreased the small molecular protein amount and type in supernatant of the 2nd centrifugation, but HIU showed little effect on it. The pH reduction or HIU increased the lightness (from 89.24 to 94.25) and whiteness (from 83.24 to 88.45) of PI gel. HIU significantly increased the PI gel hardness (from 1531.74 to 1756.24 g). The pH reduction from 4.0 to 3.0 elevated the gel hardness (from 1162.55 to 1683.41 g) significantly, but further decrease did not show any effect. The springiness of the PI gel decreased when solubilization pH decreased from 4.0 to 3.5, but further decease had no effect on this index (0.792~0.823), and HIU did not show any effect on it. The cooking loss of the PI gel increased significantly as solubilization pH decreasing and HIU aiding (from 2.05% to 4.43%). Conclusion: over acid pH (pH<3.0) did not increase the protein recovery and improve the gel property. Aided by HIU, highest protein recovery and best gel property could be obtained by solubilization of pH 3.0 in ISP process.

31 The Preparation of Effervescent Tablets with Pomelo By-products

LI Zhen-yu , ZHONG Kun-zhi , GONG Di-wen , HUANG Jian-xi , LI Su-fen , WANG Qin , LIU Hui-fan , HUANG Jia-yong

2019, 35(12):241-248. DOI: 10.13982/j.mfst.1673-9078.2019.12.031

[Abstract](442) [HTML](207) [PDF 4.20 M](685)

Abstract:
The effervescent tablets which are made up of extracts from mature and young pomelo seeds and peel were prepared. The physical and chemical indexes of product including hardness, pH value, color difference, disintegration time and antioxidants were determined. Firstly, Limonin content in water extract was tested by HPLC to determine additive amount of Citric acid. Citric acid was used to reduce the bitterness from Limonin without removing it. Secondly, Acacia was added in tablets with different concentration and physicochemical properties were measured for improving the product’s formula and process. According to the result of experiments, we have determined that the best proportion of each ingredients among the list of ingredients for our effervescent tablets: 35.00% of citric acid, 25.00% of sodium bicarbonate, 1.50% of PVP-K30, 2.00% of PEG 6000 (in powder), 22.50% grapefruit powder, 0.75% of stevioside, 7.50% of Xylitol, 5.00% of extract from mature grapefruit skin and young grapefruit skin (8 mg/mL of Acacia was added before freeze-dry), 0.75% of extract from grapefruit kernel. Tabletting in 3.00 MPa was done after the well mixing of all ingredients. The drink made by final tablets is good in clarity. The sugar-acid ratio is in a comfortable range which gives the drink a good taste. Hardness and pH value are in a suitable level. Disintegration time is reasonable. Oxidation resistance of products solution is quite strong.

32 Fuzzy Comprehensive Evaluation and Response Surface Method in Recipe Research of Cookies of Termitomyces Albuminosus

XU Jun-qi , CAO Zheng , XIE Chun-qin , FAN Jun-min , ZHANG Xue-song , LIU Qian

2019, 35(12):249-253. DOI: 10.13982/j.mfst.1673-9078.2019.12.032

[Abstract](520) [HTML](172) [PDF 14.25 M](1158)

Abstract:
In order to develop cookies with good taste, prominent flavor and nutritional value of Termitomyces albuminosus, the formula of cookies was studied with powder of Termitomyces albuminosus, low gluten flour and butter as main raw materials and white sugar and eggs as auxiliary materials. On the basis of single factor test, a fuzzy comprehensive evaluation model was built according to the sensory evaluation standard of cookies, and the comprehensive evaluation was carried out, and the best formula of cookies was optimized by box-behnken test design. The results after response surface optimization showed that the added amount of low gluten flour was 100%, Termitomyces albuminosus powder was 14%, the granulated sugar was 38%, butter was 66%, the whole egg solution was 20%, the water was 20%, the baking soda was 0.8%, and the upper and lower fire temperatures were 180 ℃ and 170 ℃ for 15 min, respectively. The sensory quality was the best, with a sensory score of 88.12±1.22, which was better than other experimental groups. The cookies were golden in color, delicate in taste, good in texture, and in line with the quality requirements of GB 7100-2015 and GB/T 20980-2007. This study has a good guiding significance for the formulation optimization of cookie related products and the establishment of fuzzy sensory evaluation method.

33 The Differences in the Dried Tangerine Peels Stored for Different Years Revealed by Terahertz Spectroscopy and Imaging

YANG Shao-zhuang , LI Can , LI Chen , WANG Zhi-qi , HUANG Lue-lue , DING Qing

2019, 35(12):258-266. DOI: 10.13982/j.mfst.1673-9078.2019.12.033

[Abstract](591) [HTML](234) [PDF 79.89 M](765)

Abstract:
In the study, five kinds of dried tangerine peels stored for different years (3, 5, 10, 15 and 20 years) were subjected to differential characterization and identification of storage years by terahertz spectroscopy and imaging technique and statistical analysis method. The results showed that significant differences and consistent changing trends were found in the terahertz spectral parameters (including the absorption coefficient, refractive index, complex dielectric constant imaginary part and dielectric loss tangent value) as well as the contrast of terahertz frequency-domain images among the different dried tangerine peel samples: decreasing gradually with an increase of storage year for those stored for 3~15 years, whilst increasing gradually with an increase of storage year for those stored for 15~20 years. Moreover, statistical analysis and independent sample t-test were carried out for each of the terahertz spectral parameters in the range of 0.6~1.8 THz, and the spectral parameter data with high consistency and significant difference (p<0.05) were extracted to establish a highly efficient prediction model for storage years of dried tangerine peels based on the principal component analysis-support vector machine (PCA-SVM). The accuracy of the model reached over 94%. This result indicates the feasibility and superiority of the terahertz technology in the characterization of the differences between tangerine peels and in the identification of storage years for dried tangerine peels.

34 Analysis of Flavor Characteristics in Engraulis japonicas Cooking Liquid and Enzymatic Hydrolysates

XU Yong-xia , QU Shi-yao , ZHAO Hong-lei , FENG Yuan , LI Xue-peng , YI Shu-min , LI Jian-rong

2019, 35(12):267-275. DOI: 10.13982/j.mfst.1673-9078.2019.12.034

[Abstract](357) [HTML](135) [PDF 1.04 M](618)

Abstract:
The flavor characteristics of anchovy (Engraulis japonicus) cooking liquid and enzymatic hydrolysates were investigated by electronic nose, electronic tongue and solid phase microextraction (SPME)-gas chromatography-mass spectrometry (GC-MS), combined with amino nitrogen and soluble peptide content analysis. The results showed that the amino nitrogen and soluble peptide content of the protease treatment groups were significantly higher than that of the cooking liquid group (p<0.05), and the protamex group was the highest, which reached 418.60 mg/100 mL and 5327.68 μg/mL, respectively. The electronic tongue and the electronic nose could well distinguish the flavor of three groups, and there were significant differences in taste and odor characteristics between anchovy cooking liquid and enzymatic hydrolysates. Meanwhile, a total of 92 volatile flavor compounds were identified by SPME-GC-MS analysis, and 61, 60 and 65 volatiles were detected in cooking liquid, flavourzyme hydrolysate and protamex hydrolysate, respectively. Among them, aldehydes were the most abundant, followed by hydrocarbons, alcohols and heterocycles. The flavor of cooking liquid was dominated by aldehydes and hydrocarbons. Compared to cooking liquid, the content of aldehydes and heterocyclic compounds in the enzymatic hydrolysates increased obviously, and the hydrocarbons decreased significantly.

35 Rapid Analysis of Steroid Hormone Residues in Fish Flesh by High Performance Liquid Chromatography-tandem Mass Spectrometry

LU Qiao-mei , TONG Ping , CAI Hui-jian , ZHANG Lan

2019, 35(12):276-281. DOI: 10.13982/j.mfst.1673-9078.2019.12.035

[Abstract](427) [HTML](131) [PDF 47.28 M](766)

Abstract:
A rapid and efficient high performance liquid chromatography-tandem mass spectrometry method was established for the analysis of steroid hormones in fish flesh. The conditions for chromatographic separation and triple-quadrupole mass spectrometry detection were optimized. Baseline separation was achieved for most of the substances within 20 min using a Hypersil GOLD C18 column (150 mm×2.1 mm, i.d. 5 μm) and gradient elution with methanol-water (containing 0.1% formic acid, V/V, %). Most compounds were baseline separated in 20 min. Electrospray ionization in positive ion mode with selective ion pairing, along with the retention time and characteristic ion pairs of the target compound, was used for qualitative and quantitative analyses of 16 steroid hormones. The results showed that all compounds had a good linear range of 0.10~3000.00 ng/mL, with correlation coefficient R greater than 0.9987 and limit of detection in range of 0.05~5.00 ng/mL. Fish flesh was ground into powder in liquid nitrogen, and the latter was purified by solid phase extraction. The hydrocortisone drug residue in fish powder was 48.00 ng/g. The recoveries of 16 steroid hormones were in range of 82.84%~115.10%, with the RSD values lower than 9.30%. This method had high separation power and high sensitivity, and is suitable for simultaneous determination of steroid hormones in aquatic products.

36 Research on Screening and Detection Technology of Macamides with Mass Fragmentation Patterns and UPLC-Q-TOF

FANG Yan , LI Ting , GAO Jun-hai , XIAO Jin-jin

2019, 35(12):282-293. DOI: 10.13982/j.mfst.1673-9078.2019.12.036

[Abstract](342) [HTML](175) [PDF 35.24 M](557)

Abstract:
A qualitative screening library from the mass fragmentation patterns of benzyl and m-methoxybenzyl macamides was constructed based on the theory of charge or free radical center induction by ultra performance liquid chromatography-quadrupole-time of flight(UPLC-Q-TOF), and a quantitative determination method for 4 macamides was also established. The library includes retention time, mass-to-charge ratio and molecular structure of the excimer ions and fragment ions, and other information. The results showed that not only ten macamides were completely separated, but also more than 10 fragment ions for each macamide could be matched in library with a mass analysis error smaller than 10 Mu. The peak times of the macaamides (A-J) were 5.83, 5.32, 5.93, 6.50, 6.40, 5.23, 7.32, 6.58, 6.47, 7.32 min, respectively. In quantitative detection, the detection limits of 4 macamides (Mb18:3, Mo18:2, Mb18:2, Mb16) were 0.50, 1.20, 1.20, 0.50 mg/kg, respectively, and the quantitative limits were 1.50, 3.60, 3.60, 1.50 mg/kg, respectively. An average recovery rate ranged from 81.6% to 113.0% (RSD<10%) for 4 macamides. This method had high accuracy and precision, puting great significance for origin traceability, identification, quality classification and market supervision of maca and its products.

37 Determination of Glycidyl Esters in Edible Vegetable Oils by Ultra High Performance Liquid Chromatography-triple Quadrupole Mass Spectrometry (UPLC-TQ-MS/MS)

LI Jia-hui , LIU Guo-qin

2019, 35(12):294-301. DOI: 10.13982/j.mfst.1673-9078.2019.12.037

[Abstract](419) [HTML](174) [PDF 17.11 M](712)

Abstract:
This study investigated the application of ultra-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS) in the analysis of glycidyl esters (GEs) in edible vegetable oils. By increasing the loading quantity of sample for pretreatment, the analytical concentration of the target substance was increased while satisfying the detection requirements for samples with lower GE contents. The elution procedure for the mobile phase was optimized to avoid mobile phase-induced loss of stationary phase and reduce the use of organic solvents. As a result, the total elution time was only 15.2 min, which made the analysis more efficient. After the quantitative ion pairs and collision energies were optimized in daughter ion mode, the multiple reaction monitoring mode (MRM) was adopted to quantify the five GEs in more specific way. The minimum detection limit of the five GEs ranged from 0.0045 to 0.023 mg/kg, and the average recovery rate was 96.16%~107.02% with the relative standard deviation as 1.98%~5.74%. Accordingly, this method has strong operability, high sensitivity and good reproducibility, and can meet the requirements for efficient, accurate and quantitative analysis of GEs in actual edible vegetable oils.

38 Comparative Study of Determination Methods of Total Flavonoids in Vine Tea (Ampelopsis grossedentata)

QIN Ya-ru , ZHANG You-sheng , ZHANG Kai , DING Zhen-dong , ZENG Ping , KONG Fan-sheng

2019, 35(12):302-309. DOI: 10.13982/j.mfst.1673-9078.2019.12.038

[Abstract](556) [HTML](183) [PDF 17.49 M](531)

Abstract:
The accuracy of direct measurement method, Al(NO3)3-NaNO2-NaOH colo rimetric method, AlCl3 colorimetric method and differential spectrophotometry for determining the total flavonoids in vine tea ( Ampelopsis grossedentata) were studied in this work. The accuracy, repeatability, stability, recovery rates of four methods were evaluated. The effects of white granulate sugar, β-CD, CMC-Na, fructose syrup and caramel on the interference for four methods were investigated. The results were validated by high performance liquid chromatography. The result showed that differential spectrophotometry was the most suitable method for determining the total flavonoids in vine tea with dihydromyricetin as the control and without interferent. The RSD for accuracy, repeatability, stability and recovery rates were 0.19%, 2.26%, 1.67% and 100.97%±1.63%, respectively. The addition of interferent with different concentration could cause the obvious interference to the detection results of the four methods. In the presence of complex interferent, the contents of total flavonoids determined by direct measurement method were most close to that determined by high performance liquid chromatography.

39 Acetylcholinesterase Amperometric Biosensor Based on Screen-printed Carbon Electrodes for the Detection of Aﬂatoxin B1

DONG Yan-jie , WANG Yi-ran , ZHAO Shan-cang , LIANG Jing-yun , YUAN Xue-xia , FAN Li-xia , WANG Lei

2019, 35(12):310-314. DOI: 10.13982/j.mfst.1673-9078.2019.12.039

[Abstract](334) [HTML](219) [PDF 26.99 M](711)

Abstract:
In order to realize rapid and real-time detection of aflatoxin B1, an electrochemical sensor for detecting aflatoxin B1 was constructed using the screen-printed electrode (which is advantageous in low production cost, fast response, good repeatability and small sample amount), and acetylcholinesterase (which inhibits aflatoxin B1). Using graphene, Prussian blue, chitosan and gold nanoparticles as the modification materials for the screen-printed electrodes, the reaction conditions for the sensor were optimized by cyclic voltammetry. The optimal conditions for the detection of aflatoxin B1 were: pH 7.5, enzyme loading 0.25 U, and inhibition time 14 min. Acetylcholinesterase was used as an inhibitor of the aflatoxin B1, and the obtained biosensor exhibited a linear detection range for aflatoxin B1 from 1 to 64 μg/mL (with a correlation coefficient of 0.9948 and detection limit of 0.05 μg/mL). For the detection of peanut samples, the sensor had a spiked recovery rate in the range of 82.5%~114.1%, with good reproducibility, stability and selectivity. The detection limit was lower than that for the aflatoxins in the peanuts in China, and the developed sensor can be used for the detection of aflatoxin B1 in peanuts.

40 Determination of Tetrahydrocannabinol, Cannabidiol and Cannabinol in Four Food Matrices by Ultra Performance Liquid Chromatography-Triple Quadrupole Mass Spectrometry

ZHOU Ying , CHEN Nian-nian , HAN Li , NIU Bing , DENG Xiao-jun

2019, 35(12):315-321. DOI: 10.13982/j.mfst.1673-9078.2019.12.040

[Abstract](356) [HTML](259) [PDF 23.20 M](671)

Abstract:
A method for the simultaneous determination of trace amounts of tetrahydrocannabinol, cannabidiol and cannabinoids in food by UPLC-MS/MS was developed. The sample was purified by methanol and the extract was purified by HLB solid phase extraction column. Athena C18- WP column (2.1×150 mm, 3 μm) was used to separatethe samples. The methanol-water was used as mobile phase gradient. The electrospray negative ion scanning and multiple reaction monitoring mode detection were employed. Matrix effects were eliminated by matrix labeling and quantified by THC-D3 internal standard method. The linear correlation coefficient (r2) of this method was greater than 0.999 in the concentration range of 0~10 μg/L. Cannabisdiol (CBD) and cannabinol (CBN) had an LOD of 0.03 μg/kg and an LOQ of 0.1 μg/kg. Tetrahydrocannabinol (THC) had an LOD of 0.15 μg/kg and an LOQ of 0.5 μg/kg. The spiked recoveries of three cannabinoids in four different food matrices were investigated. Under the spiked levels of LOQ, 5 LOQ and 10 LOQ, the spiked recoveries of the three cannabinoids ranged from 81.1% to 114.7%. The relative standard deviation (RSD) was 0.25% to 4.63% (n=6). The results showed that the method had good stability and high sensitivity, and was suitable for simultaneous determination of three cannabinoids in common food matrices.

41 Research Progress in Defining Marker Substances Characteristic for Manuka Honey and Developing Their Analytical Methods

KANG Hai-ning , CHEN Bo , LAN Fang , ZHANG Feng , FENG Feng , GONG Ben-ning , LIANG Tong-wen , CHEN Pei-jin

2019, 35(12):322-328. DOI: 10.13982/j.mfst.1673-9078.2019.12.041

[Abstract](451) [HTML](399) [PDF 16.92 M](550)

Abstract:
Manuka honey is a medical grade honey from New Zealand, and has unique non-peroxide antibacterial activity. The antibacterial activity of manuka honey is closely related to its characteristic marker substances. With the increase of the number of in-depth studies on the antibacterial substances in manuka honey by foreign scholars, more and more antimicrobial substances have been found and confirmed in manuka honey. The characteristic markers of manuka honey that have been found so far include methylglyoxal, leptosperin, 3-phenyllactic acid, 2'-methoxyacetophenone, 2-methoxybenzoic acid, 4-hydroxyphenyllactic acid, lepteridine, etc. These compounds have also been used in quality evaluation and authenticity identification for manuka honey. Manuka honey accounts for an increasing proportion of imported honey into China, but the domestic study on manuka honey started relatively late. In order to offer a reference for quality evaluation and authenticity identification of manuka honey, this paper provides an overview of the marker substances characteristic for manuka honey and relevant to the quality evaluation and authenticity identification, together with their analysis methods.

42 The Development of Formulations for Enhancing the Stability of Lycopene

ZHAO Wen-hong , YAN Ting-ting , YIN Wen-ting , GUAN Er-qi

2019, 35(12):329-336. DOI: 10.13982/j.mfst.1673-9078.2019.12.042

[Abstract](388) [HTML](183) [PDF 956.54 K](478)

Abstract:
Lycopene has many physiological functions such as immunity enhancement, cancer prevention, and delay in chronic disease onset. As a natural carotenoid, lycopene has an isoprene structure with 11 conjugated and 2 non-conjugated double bonds. This multi-conjugated double bond structure makes lycopene offer strong antioxidant activity, but exhibit high susceptibility to light-/oxygen-/heat-initiated oxidative degradation and poor stability (which limits its development). Formulation can effectively improve the stability of lycopene, which is beneficial to its preservation, transportation and industrial application. At present, the formulations that enhance lycopene stability mainly comprises inclusion complex and microcapsule preparations produced by using various types of dextrin, protein and starch as carriers, as well as microemulsion and liposome preparations produced by using small molecule lipids or phospholipids as carriers. This paper summarizes the research progress in the preparation methods and characteristics of lycopene-containing formulations, in order to provide a theoretical basis for the development and utilization of lycopene formulations with high stability.

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Volume 35,Issue 12,2019 Table of Contents