Volume 37,Issue 1,2021 Table of Contents

1 Cytotoxicity in Human Colon Adenocarcinoma Caco-2 Cell Induced by Selenite and Selenomethionine

QIN Yan , XU Hai-zhao , XU Jing-mao , GU Ming-hua , WEI Yan-yan

2021, 37(1):1-6. DOI: 10.13982/j.mfst.1673-9078.2021.1.0637

[Abstract](459) [HTML](160) [PDF 12.38 M](928)

Abstract:
The cytotoxicity and oxidative stress which was induced by selenite (SeIV) and selenomethionine (SeMet) in Caco-2 cells was investigated.Caco-2 cells were exposed to SeIV, SeMetat the difference dose for 24 h. At the same dose of SeIV and SeMet (0.8 μg Se/mL), the apoptosis of Caco-2 cells was detected by Annexin V-FITC/PI assay. The cell viability was evaluated by MTT assay. The leakage of lactate dehydrogenase (LDH), the activity of the superoxide dismutase (SOD), the glutathione (GSH) content were detected respectively. At the dose of 0.8 μg Se/mL, SeIV increased the apoptosis of Caco-2 cells (p<0.05), but there was no change in SeMet treatment. SeIV (≥0.4 μg Se/mL), SeMet (≥40 μg Se/mL) could all decrease the cell viability in a certain dose range (p<0.05) and as their exposure concentration increased, Caco-2 cell viability was gradually decreased. The IC50 values of Caco-2 cell exposed to SeIV and SeMet for 24 h were determined to be 2.56, 215.55 μg Se/mL, respectively. SeIV≥0.8 μg Se/mL and SeMet≥40 μg Se/mL showed the higher leakage of LDH than the control group 14.80% (p<0.05). SeIV≥4 μg Se/mL and SeMet≥4 μg Se/mL could decreased the SOD activity (56.76±3.64 U/mg prot) (p<0.05). SeIV≥4 μg Se/mL and SeMet (160 μg Se/mL) could decreased the GSH contents at the same time (61.67 μg/mg prot) (p<0.05). A certain concentration of SeIV and SeMet can induce oxidative stress in Caco-2 cells, leading to cytotoxicity and inducing apoptosis.

2 Evaluation of Antioxidant and Immunomodulatory Effects of Radix codonopsis-Poria cocos- Radix glycyrrhizae Water Extract in Mice with Learning and Memory Impairment

XU Fei-fei , WANG Zi-lin , WANG Jie , LI Qin-qing , TIAN Ya-juan , CHU Shi-feng , HE Wen-bin

2021, 37(1):7-16. DOI: 10.13982/j.mfst.1673-9078.2021.01.0647

[Abstract](458) [HTML](239) [PDF 7.26 M](1308)

Abstract:
To study the effects of traditional Chinese medicine Radix codonopsis, poria cocos and Radix glycyrrhizae water extract on learning and memory impaired mice, the antioxidant and immunomodulatory effects of water extract on learning and memory impaired mice and normal mice were evaluated. Intraperitoneal injection of scopolamine hydrobromide was used to model learning and memory impairment. ELISA was used to detect SOD, GSH-Px enzyme activity and MDA content in hippocampus of mice, serum IL-2, TNF-α level, and spleen NK cell activity. The anti-fatigue effect of water extract on normal mice was evaluated in weight-bearing swimming experiment. Thymus index and spleen index were determined by gravity method. The results showed that the high dose of water extract (40 g/kg·d) had the best effect, and the novel object recognition index of memory impaired mice could be increased by 18.35% without affecting the independent activity of mice. SOD and GSH-Px increased by 65.56 U/mg, 437.00 U/mg, and MDA decreased by 6.30 nmol/mg. IL-2 and TNF-α decreased by 78.43 pg/mL, 160.20 pg/mL, and the activity of NK cell increased by 2488.81 U/g. It was also possible to increase the weight swimming time of normal mice by 60.12 s compared with the normal group. Thymus index and spleen index increased by 0.06% and 0.10%; SOD and GSH-Px increased by 79.52 U/mg and 345.30 U/mg, respectively, MDA decreased by 1.05 nmol/mg, and NK cell activity increased by 1816.31 U/g. The results showed that the water extract of Radix Codonopsis-Poria cocos-Glycyrrhizae Radix could improve the learning and memory impairment of mice and exert anti-fatigue effect on normal mice, its mechanism was related to its anti-oxidation and immunomodulatory function.

3 Effect of Rose roxburghii Tratt Oral Liquid on Gastrointestinal Motility in Dyspepsia Mice

TU Yong-li , TAN Shu-ming , ZHOU Hong-xuan , LUO Ji-wei

2021, 37(1):17-23. DOI: 10.13982/j.mfst.1673-9078.2021.01.0660

[Abstract](248) [HTML](155) [PDF 13.19 M](894)

Abstract:
To study the effect of R.roxburghii Tratt on gastrointestinal motility in indigestion mice. The successful mice were divided into model group (MC), positive group (PC), R.roxburghii Tratt oral solution (DF), R.roxburghii Tratt oral solution (HF) and normal group (NC). Normal group and model group were given normal saline, and positive group was given dofarione suspension. R.roxburghii Tratt oral liquid DF, HF groups were gavaged with oral liquid; the diet and body mass of mice were measured before and after the modeling. After the end of administration, the gastric residual rate, small intestinal motility rate, serum motilin MTL and gastrin GAS were measured to evaluate the effect of promoting digestion. It was found that compared with MC, the diet of DF and HF mice increased by 4.42%, 10.38%, 5.87% and 7.08% respectively (p<0.05). The gastric residue reduced by 45.15% and 36.90%, and the small intestinal advance rate increased by 39.28% and 45.11% (p<0.05), respectively. Serum MTL and GAS levels increased by 35.94%, 39.05%, 32.14% and 38.45%, respectively (p<0.05). Studies have shown that R. roxburghii Tratt oral liquid has a good effect of promoting digestion and effectively promoting gastrointestinal motility.

4 Prediction the Targets and Pathways for Anti-obesity of Ginsenoside F2 by Network Pharmacology

ZHOU Jing , HE Yang , HU Wei-cheng , ZHANG Ji , YANG Xiao-jun

2021, 37(1):24-30. DOI: 10.13982/j.mfst.1673-9078.2021.01.0678

[Abstract](388) [HTML](275) [PDF 45.57 M](862)

Abstract:
Ginsenoside F2 has various physiological functions, such as anti-cancer, liver protection, anti-inflammatory, and lipid-lowing. However, its mechanism of improving obesity is still unclear. Hence, the potential targets and mechanisms of ginsenoside F2 action for anti-obesity were analyzed by network pharmacology in this study. Targets information of ginsenoside F2 and obesity was collected from PubChem and GeneCards databases. After sharing targets, the G-F2-targets-obesity network was constructed and analyzed by means of CytoScape and other platform. The anti-obesity of ginsenoside F2 was related to a total of 35 potential targets, of which included MAPK1, VEGFA, CASP3, etc. GO enrichment suggested that potential targets were mainly involved in metabolism process, binding and cellular component formation. Moreover, it may play an anti-obesity effect through EGFR tyrosine kinase inhibitor resistance, PI3K-Akt signaling pathway and neuroactive ligand-receptor interaction pathway. Network pharmacology successfully predicted the multi-targets and multi-pathways of ginsenoside F2, and it may provide a theoretical basis for further exploration of anti-obesity of ginsenoside F2.

5 Expression and Biochemical Characteristics of Unspecific Peroxygenase Derived from Agaricus bisporus var. bisporus in Pichia pastoris

PANG Neng-wei , YANG Bo , WANG Yong-hua

2021, 37(1):31-37. DOI: 10.13982/j.mfst.1673-9078.2021.01.0270

[Abstract](300) [HTML](197) [PDF 5.48 M](805)

Abstract:
In this study, an unspecific peroxygenase AbvbUPO derived from Agaricusbisporus var. bisporus was used as the target protein to achieve heterologous expression in Pichia pastoris GS115. Western blot results showed that the molecular mass of AbvbUPO was 35 ku. Biochemical characterization of the enzyme revealed that the optimal reaction temperature and pH of the unspecific peroxygenase AbvbUPO were 35 ℃ and 3.0, respectively. Hydrogen peroxide tolerance experiments revealed that hydrogen peroxide above 2.0 mM deactivated AbvbUPO. In order to maintain the activity of AbvbUPO in the reaction process, the insitu production of H2O2 occurring in the AbvbUPO enzyme cascade catalytic reaction was used for the identification of its catalytic ability. After the 4 h AbvbUPO enzyme cascade catalytic reaction with ethylbenzene as the substrate, the yield of the product β-phenylethanol reached 14.40%. The above research results show that AbvbUPO was a mesophilic enzyme that could not tolerate high temperature and high concentrations of H2O2, but can maintain good catalytic performance in the cascade reaction of insitu H2O2 production. This study provides a reference for the heterologous expression and biocatalytic application of unspecific peroxygenase.

6 Analysis of Structural Characteristics of α-L-rhamnosidase from Aspergillus Species

CAI Yu-chen , LI Meng-ze , LI Li-jun , NI Hui

2021, 37(1):38-46. DOI: 10.13982/j.mfst.1673-9078.2021.01.0648

[Abstract](222) [HTML](211) [PDF 11.56 M](684)

Abstract:
In order to study the structural characteristics of all Aspergillus-derived α-L-rhamnosidase, 300 non-repeated Aspergillus derived α-L-rhamnosidase nucleic acid sequences were collected using NCBI database and 21 of them were selected through evolutionary tree selection. Through sequence alignment analysis, the 21 sequences are independently and reliably representative. Using bioinformatics tools to analyze the physical and chemical properties, transmembrane region, and signal peptide, it was found that the isoelectric point (pI) of α-L-rhamnosidase derived from Aspergillus species was 4.66 to 7.17, and the number of amino acids, molecular weight and total number of atoms fluctuates greatly. Ten sequences have signal peptide sequences, 1 sequence is twice transmembrane protein, and 21 sequences are all hydrophilic proteins. The phylogenetic tree construction, three-level structure modeling and structure superposition show that these 21 representative sequences can be divided into two types. The first type contains one (α/α)6 barrel structure and one β sheet structure at the bottom of the barrel, and can be further divided into 4 sub-categories according to the number of additional β sheets contained; The second type has one (α/β)8 structure and β sheet structure surrounding the barrel structure domain. It elucidates the protein structure characteristics of α-L-rhamnosidase derived from Aspergillus, which helps to better clarify the common law of α-L-rhamnosidase and provide theoretical guidance for the modification of this enzyme.

7 Efficient Synthesis of Rebaudioside A Catalyzed by in vitro Coupling UDP-Glycosyltransferase and Sucrose Synthase

ZHU Qing-juan , CHEN Mei-qi , LIANG Shu-li , WANG Deng-gang , LIN Ying

2021, 37(1):47-53. DOI: 10.13982/j.mfst.1673-9078.2021.01.0172

[Abstract](507) [HTML](232) [PDF 24.00 M](850)

Abstract:
In this study, a UDP-glycosyltransferase UGT76G1 gene recombinant pichia pastoris strain GS115/pPIC9K-UGT76G1 and a sucrose synthase mbSUS gene recombinant Pichia pastoris strain GS115/ pPIC9K/pPICZA-mbSUS derived from mung bean were constructed. Methanol was used to induce the production of UDP-glycosyltransferase and sucrose synthase, and a biocatalytic cascade reaction system was constructed to catalyze the bioconversion of stevioside (ST) into rebaudioside A (RA), which realized the effective recycling of uridine diphosphate glucose (UDPG) in the cascade reaction system. Through optimization of reaction conditions, the rate-limiting enzyme in the cascade reaction was found to be the glycosyltransferase UGT76G1, with the optimal enzyme activity ratio, U(UGT76G1):U(mbSUS), as 6:1. Under the reaction conditions (pH 7.0, UDP 1 mM, sucrose 50 mM and MgCl2 3 mM), ST at 10 mM was converted to RA at 8.20±0.11 mM, with the RA yield as 82.91%. The catalytic reaction time was greatly shortened compared to the Escherichia coli expression system. The in vitro coupling of UDP-glycosyltransferase and sucrose synthetase can lead to effective catalysis for the efficient synthesis of RA, and this research provides technical support for RA enzymatic biosynthesis and associated industrial application.

8 Optimization of Synergistic Fermentation Conditions of Acid Producing Bacteria in Luzhou-flavor Liquor Mud

WEI Chun-hui , ZHANG Lan-lan , LUO Hui-bo , LIU Miao , ZHANG Su-yi , HUANG Zhi-guo , DENG Jie

2021, 37(1):54-64. DOI: 10.13982/j.mfst.1673-9078.2021.01.0731

[Abstract](254) [HTML](161) [PDF 61.80 M](877)

Abstract:
The content of hexanoic acid and butyric acid in Luzhou-flavor liquor affects the content of ethyl caproate and ethyl butyrate, which affected the flavor of liquor. In order to increase the content of hexanoicacid and butyric acid in Luzhou-flavor liquor, three strains of Bacillus tequilensis, Bacillus aerius, and Clostridium butyricum subsp were used in this paper. The acid-producing functional bacteria carry out cooperative fermentation; SJ-1, SJ-3, SJ-8 and high-quality pit mud-enriched bacteria liquid were inoculated in equal amounts for cooperative fermentation, and single-factor test were used to optimize the fermentation conditions of synergistic fermentation broth to produce hexanoic acid and butyric acid. The fermentation medium of hexanoic acid and butyric acid was optimized by fractional factorial designs, the steepest climbing test and the Box-Behnken test design model in response surface method. The optimized results were, inoculum volume 3%, culture temperature 28℃, fermentation time 12 d, pH 6.4, peptone 5.10 g/L, sodium acetate 5.04 g/L and sodium butyrate 4.45 g/L. Under these conditions, the output of hexanoic acid and butyric acid were 1156.21 mg/100 mL、and 2345.84 mg/100 mL, which were 3.32 times and 3.22 times higher than before optimization. This research aims to provide a theoretical basis for improving the flavor substances of liquor and the maintenance of pits.

9 Exogenous Induction of Ergosterol Synthesis in Agaricus blazei

FAN Xiu-zhi , YAO Fen , YIN Chao-min , SHI De-fang , GAO Hong

2021, 37(1):65-72. DOI: 10.13982/j.mfst.1673-9078.2021.01.0747

[Abstract](245) [HTML](142) [PDF 623.26 K](500)

Abstract:
To increase the content of ergosterol in Agaricus blazei, the content of ergosterol in hyphae was increased by adding exogenous inducer under liquid culture condition. In this study, methyl jasmonate (MeJA) and salicylic acid (SA) were used as inducers, the concentration, adding time and duration of induction were optimized, and the transcriptional level of genes involving in ergosterol synthesis of A. blazei was analyzed by quantitative real time PCR. As results, the best induction conditions for ergosterol synthesis of A. blazei were adding 70.00 μmol/L of MeJA and 10.00 μmol/L of SA to the culture broth when the hyphal was culture to 8 d and 6 d, respectively, and continuously culturing 2 days under these conditions. The content of ergosterol in the harvested hyphae was respectively 2.35 mg/g and 2.43 mg/g, which increased by 147.37% and 155.79% than control group. Moreover, based on the gene expression profiles involving the ergosterol synthesis of A. blazei, it can be speculated that the induction mechanism of MeJA and SA on ergosterol may be they directly or indirectly initiate the expression of upstream key enzyme genes involving in the ergosterol synthesis, and the synthesis was regulated by the interaction of anabolic-related enzymes participating in metabolism. As a conclusion, the content of ergosterol in mycelia obtained by short time exogenous induction culture has exceeded that in fruiting body, so the mycelia obtained in this study can replace the fruiting body to research and apply the ergosterol of A. blazei.

10 Nutrient Composition and Antioxidant Effect of Main Black Corn in Shanxi

LU Xin , LIANG Xia , MENG Ting-ting , ZHOU Bai-ling , TIAN Zhi-fang

2021, 37(1):73-83. DOI: 10.13982/j.mfst.1673-9078.2021.01.0704

[Abstract](330) [HTML](150) [PDF 38.45 M](888)

Abstract:
The whole flours of 9 different main black corn varieties in Shanxi were used as experimental materials, the main nutrients, amino acid components, viscosity characteristics, anthocyanin pigment content and antioxidant activity were measured, the correlation between anthocyanin pigment content and antioxidant capacity was tested, and the nutritional values of 9 black corn varieties were evaluated. The results showed that different varieties of black corn whole flour have significant differences in carbohydrate, crude protein, crude fat and crude fiber content (p<0.05). The histidine content of all varieties is much higher than the 22.00 mg/g pro standard of the whole egg model, which are Heiyu 194 (51.41 mg/g pro); Heiyu 195 (42.53 mg/g pro); Ziyu 119 ( 39.70 mg/g pro); Jinnuo No.8 (33.13 mg/g pro); Jinnuo No.10 (43.90 mg/g pro); Jinnuo 20 (42.98 mg/g pro); Zinuo 511 (44.06 mg/ g pro); Heiyu two-in-one (55.11 mg/g pro); Heinuo 158 (49.48 mg/g pro). The leucine content of Heiyu 195 is higher than the 70.00 mg/g pro standard of FAO/WHO model. In addition, the leucine contents of other varieties are greater than the 86.00 mg/g pro standard of the whole egg model: Heiyu 194 (107.71 mg/g pro); Ziyu 119 (101.57 mg/g pro); Jinnuo No. 8 (112.47 mg/g pro); Jinnuo No. 10 (98.50 mg/g pro); Jinnuo No. 20 (129.98 mg/g pro); Zinuo 511 (113.83 mg/g pro); Black jade combo (148.11 mg/g pro); Heinuo 158 (102.76 mg/g pro). The anthocyanin pigment content of different varieties of black corn is quite different, between 13.3~42.6 mg/100 g. In vitro, the ability of black corn to inhibit DPPH free radical is 1.68 times that of vitamin C. Moreover, there is a significant positive correlation at 0.01 level (bilateral) between the anthocyanin pigment content of black corn and the ability to scavenge DPPH.

11 Analysis in the Physical and Chemical Qualities of Fragrant Glutinous Rice as Raw Materials for Rice Wine Brewing in Congjiang County

SHEN Ke , WANG Xiao-dan , QIU Shu-yi , ZHOU Hong-xiang , BAN Shi-dong , LUO Xiao-ye

2021, 37(1):84-91. DOI: 10.13982/j.mfst.1673-9078.2021.01.0700

[Abstract](352) [HTML](174) [PDF 13.32 M](822)

Abstract:
In this study, the sensory qualities and nutritional components of four kinds of fragrant glutinous rice, Gou jin gao No. 1, Gou li zhu, Gou jin gao No. 2 and Gou yang dang as the raw materials of rice wine in Congjiang county, Guizhou province, were measured and analyzed. The results showed that the four kinds of fragrant glutinous rice are rich in nutrients and the content meets the national standard limit. The amylopectin content and protein content of fragrant glutinous rice which named Gou yang dang was 84.17±1.18 g/100 g and 8.26±0.01 g/100 g, respectively. Based on the principal component analysis and the establishment of the physical and chemical index evaluation model, it is known that there are certain differences in the physical and chemical quality of the four kinds of fragrant glutinous rices and their qualities are affected by three physical and chemical indicators. Among them, the quality of fragrant glutinous rice which named Gou yang dang was influenced by total starch content, protein content and fat content. The quality of fragrant glutinous rice which named Gou jin gao No. 1. was influenced by amylose content, ash content and moisture content. It is found that the comprehensive scores F of the principal components of the four fragrant glutinous rice samples are Gou yang dang (F=7.07), Gou li zhu (F=6.98), Gou jin gao No. 2 (F=6.80) and Gou jin gao No. 1 (F=6.63). Fragrant glutinous rice which named Gou yang dang has the best quality. It not only provides theoretical support for the cultivation of fragrant glutinous rice and product quality management, but also provides a basis for the development and utilization of characteristic resources in the area and the development of the rice wine industry.

12 Extraction of Rosmarinic Acid from Different Varieties of Perilla Leaves and Its Biological Activity

REN Zhi-qing , LI Hui-zhen , ZHANG Zhi-jun , N. Vasudeva Reddy , ZHAO Ya-na , LI He

2021, 37(1):92-100. DOI: 10.13982/j.mfst.1673-9078.2021.01.0649

[Abstract](467) [HTML](152) [PDF 50.94 M](814)

Abstract:
Forty-five different varieties of Perilla leaves were used as raw materials, the Perilla rosmarinic acid was prepared by ultrasonic-assisted water extraction. Three varieties with high rosmarinic acid content were selected and purified by XDA-8 type macroporous resin and medium pressure preparative chromatography. The scavenging ability of DPPH free radicals and ABTS free radicals were tested. The bacteriostatic ability was compared by measuring the diameter of the bacteriostatic zone. The results showed that there were significant differences in the rosmarinic acid content in the crude extracts of 45 different varieties of Perilla leaves. Among them, the crude extracts of ZY7-1, ZB3 and DZ-1 had the highest rosmarinic acid content, 7.87%, 7.34% and 7.32% respectively. The IC50 values of DPPH free radicals were 85.18, 87.22 and 88.45 μg/mL, respectively, and the content of rosmarinic acid was significantly positively correlated with the antioxidant capacity of the extract (p<0.05). After purification, the content of rosmarinic acid increased to 59.28%, 54.41% and 51.13%, respectively. The IC50 values for removing DPPH free radicals were 15.03, 19.08, 20.91 μg/mL, the IC50 values of scavenging ABTS free radicals were 26.57, 33.11, 36.59 μg/mL, respectively. The inhibitory ability against the growth of Escherichia coli, Staphylococcus aureus, Bacillus subtilis was tested, showing different antibacterial ability, and as the concentration increases, the antibacterial effect is more obvious. The maximum diameter of ZY7-1 and ZB3 against Staphylococcus aureus is 12.50 mm and 11.80 mm, respectively; the maximum diameter of DZ-1 against Bacillus subtilis is 12.40 mm. Conclusion: the content of rosmarinic acid in different varieties of Perilla is different. The crude extracts of ZY7-1, ZB3 and DZ-1 with the highest rosmarinic acid content are selected for purification to obtain high-content rosmarinic acid for biological activity detection, which shows that they have good antioxidant and antibacterial properties.

13 Comparative Analysis of Structural and in vitro Digestion Properties of Starch in Cotyledon Cells of Pinto Bean Processed by Different Methods

WANG Miao-miao , DING Li , ZHANG Xin , DENG Hui-jun , TAO Zui , ZHANG Bin , HUANG Qiang , WANG Gui-dan

2021, 37(1):101-110. DOI: 10.13982/j.mfst.1673-9078.2021.01.0123

[Abstract](306) [HTML](158) [PDF 4.67 M](658)

Abstract:
In this paper, intact cotyledon cells isolated from pinto bean were used as a whole food model and kidney bean starch was used as the control, the effects of four heat processing methods (normal-pressure cooking/boiling, high-pressure cooking/autoclaving, high-temperature baking and deep frying with oil) on the particle morphology, crystalline structure and in vitro digestion kinetics of starch in intact pinto bean cells were studied. The results showed that after high-pressure and normal-pressure cooking, the birefringence polarization cross of pinto bean cells was significantly weakened, the crystallinity decreased by about 12%, and the gelatinization peak could not be detected. However, high-pressure and normal-pressure cooking destroyed the granular structure of pinto bean starch and caused the disappearance of the birefringence polarization cross. The deep frying and high-temperature baking did not change significantly the morphology of pinto bean cells and starch but decreased the enthalpy of gelatinization and relative crystallinity. The digestion rate of pinto bean cells with/without different heat treatments decreased in this order: high-pressure cooking (89.45%, 0.0132 min-1) > normal-pressure cooking (47.77%, 0.0033 min-1) >high-temperature baking (3.15%, 0.0001 min-1) ≈ deep frying (2.31%, 0.0003 min-1) ≈ untreated (1.80%, 0.0001 min-1). Regardless of the thermal processing methods, the apparent digestion rate and degree of digestion of pinto bean cells were much lower than those of the starch subjected to the same heat treatment, possibly due to the adsorption of digestive enzymes and physical barrier effect of substances such as cell walls and intracellular proteins. The research results indicate that low GI pinto bean products can be obtained by high-temperature baking and deep frying with oil.

14 Experiment and Numerical Simulation of Grain Temperature Field in Underground Ecological Granary

JIN Li-bing , DUAN Hai-jing , XUE Ya-qi , WANG Zhen-qing , WU Qiang

2021, 37(1):111-116. DOI: 10.13982/j.mfst.1673-9078.2021.01.0670

[Abstract](375) [HTML](196) [PDF 30.96 M](688)

Abstract:
Grain temperature is an important factor affecting grain security. The variation of grain temperature in underground ecological granary was analyzed by combining simulation test silo, engineering test silo and numerical simulation. The temperature change law of each measuring point was obtained by setting up the measuring cables in the test silo and monitoring the temperature at regular time. Basing on the boundary conditions of grain storage environment, the physical model of underground simulation test warehouse was established, and the grain temperature field in the warehouse was analyzed by numerical method. The effectiveness of numerical simulation method was verified by comparing with the test results. By using the same numerical simulation method, the grain temperature field of underground-engineering-test warehouse with different entry time was analyzed; it was found that loading in winter was better than in summer. In order to realize low temperature grain storage, appropriate ways (such as ventilation in the winter) should be taken for the grain to reduce the grain temperature, because the temperature was high in summer. It was found that the grain storage effect of deep underground silo (engineering test silo) was better than that of shallow depth underground silo (simulation test silo). The grain temperature in the underground ecological granary was gradually tended to be stable with the increasing storage time. The grain temperature of simulation test silo was about 20 degrees. The engineering test silo was about 17 degrees. The above-ground silo was about 25 degrees; the local temperature of the above-ground silo was as high as 30 degrees, and varied greatly with the seasons. Therefore, the underground ecological silo had the advantage of constant low temperature grain storage, which could ensure grain quality and grain storage safety.

15 Changes in Protein Characteristics of Minced Shrimp (Litopenaeus vannamei) Meat during Deep-frozen Storage

LI Zhi-peng , ZHOU Xiao-jiao , ZHANG Bin , SU Lai-jin , SHUI Shan-shan

2021, 37(1):117-124. DOI: 10.13982/j.mfst.1673-9078.2021.01.0568

[Abstract](366) [HTML](224) [PDF 21.64 M](726)

Abstract:
In this study, the changes of protein characteristics of minced shrimp (Litopenaeus vannamei) meat during frozen storage were investigated. Using shrimp as the control group, the changes in pH, Ca2+-ATPase activity, hydrophobic bond, disulfide bond, water-soluble protein, salt-soluble protein, ionic bonds and sulfhydryl groups of both the minced shrimp meat and shrimp on day 0, 20, 40, 60, 80, 100 and 120 of the frozen storage were examined. With the extension of frozen storage time, the pH, hydrophobic bond and disulfide bond of both the shrimp and minced shrimp meat increased, with those of minced shrimp meat all lower than those of the shrimps (by 0.18, 3.28 mg/g and 2.64 mg/g, respectively on day 120). The contents of water-soluble and salt-soluble proteins, Ca2+-ATPase activity, total sulfhydryl groups, active sulfhydryl groups and ionic bond content of both the shrimp and minced shrimp meat decreased as the frozen storage proceeded, with the decrease for the minced shrimp smaller than that for the shrimps (those of the minced shrimp were higher than those of the shrimps by 3.62 mg/g, 12.14 mg/g and 5.73 mg/g, respectively on day 120). On day 120, the content of myofibrillar protein of the shrimps and minced shrimp meat dropped to 38.21% and 43.36%, respectively, of that of fresh shrimps. Results indicated that storing in the form of minced shrimp is more advantageous than the form of whole shrimps for frozen storage. The results of this study provides a theoretical basis for the evaluation of the protein and other physicochemical indices, and also a scientific basis for the deep processing of shrimp products.

16 Use of Dry-processed Carrots to Improve the Sensory Quality and Drying Characteristic of Composite Pork Jerky

RUAN Zheng , YANG Xing-ju , LI Bian-sheng , LI Dan-dan

2021, 37(1):125-133. DOI: 10.13982/j.mfst.1673-9078.2021.01.0122

[Abstract](297) [HTML](284) [PDF 6.20 M](641)

Abstract:
To solve the quality deterioration problems of composite diced carrot-jerky such as over-drying and cracking of composite jerky as well as diced carrot fall-off, the effects of diced carrots pre-dried to different extents (ND, D70, D50, D30 and D10 that represent the samples containing diced carrots without pre-drying (ND) or with different moisture contents: 70%, 50%, 30% and 10%) on the sensory quality and drying characteristics of composite jerky (represents sample with diced carrot without drying), along with the energy consumption, were examined. The results showed that pre-drying of diced carrots improved appearance, mouth feel and tissue structure of composite jerky, increased significantly (p<0.05) the L* value of composite jerky, reduced significantly (p<0.05) the a* and b* values. Excessive drying of diced carrotsled to declined color and texture of composite jerky. The shear force of composite jerky ranged from 19.36 to 24.34 kg·s: ND> D10>D30>D50>D70. Correlation analysis revealed a significant and positive correlation between the drying time of composite jerky and the moisture content of diced carrots (p<0.05), and the same moisture absorption isotherm for all the groups. During the drying process of composite jerky, there was a moisture difference between the minced meat and diced carrots, with the decrease in the moisturecontent of diced carrots lagging behind that of the minced meat. The low-field nuclear magnetic resonance analysis revealed that the moisture in diced carrots was more difficult to remove than that in meat. After drying, the moisture was mainly concentrated in diced carrot located in the center of composite jerky, with T2 relaxation time generally decreasing, and the contents of bound water and non-flowing water increasing significantly. Pre-drying of diced carrots could reduce 10.27%~30.47% of the total energy consumed during the drying of composite jerky, and the total energy consumption decreased with an increase in the degree of pre-drying of diced carrots, with the difference in total energy consumption between D10 and D30 being insignificant. Key words:

17 Relationship between Pectin Properties and Texture of Pumpkin during Vacuum Microwave Drying

ZHANG Zhong-yuan , NIE Mei-mei , XIAO Ya-dong , LI Da-jing , SONG Jiang-feng , LIU Chun-quan , WANG Xiao-yan , LIU Chun-ju , XU Ya-yuan , NIU Li-ying , JIANG Ning

2021, 37(1):134-141. DOI: 10.13982/j.mfst.1673-9078.2021.01.0730

[Abstract](272) [HTML](230) [PDF 6.36 M](946)

Abstract:
In order to find out the effect of pectin property change on texture during microwave vacuum drying (MVD), pumpkin were used as raw materials and treated with different microwave power. The hardness, crispness, microstructure, pectin content, esterification degree and monosaccharide composition of dehydrated pumpkin were analyzed. The results showed that when the microwave power was 9 W/g, pumpkins obtained higher crispness, moderate hardness and uniform pore structure. With the increase of microwave power, the content of water-soluble pectin (WSP) of pumpkin decreased first and then increased, and the content of chelating pectin (CSP) increased first and then decreased. After microwave treatment, the molecular chains of pumpkin pectin were broken and the molecular weight decreased. With the increase of microwave power, the content of unsaturated galacturonic acid (UG) and pectin ester degree in pumpkin increased first and then decreased, when the microwave power was 9 W/g, the content of UG was higher, reaching 10.54 mg/g. In summary, UG content is one of the main factors affecting the hardness of pumpkin during MVD, and the degree of esterification and WSP content affect the formation of its crispness and porous structure.

18 Antioxidant Properties Analysis in vitro of Lactic Acid Bacteria Fermentation Blueberry and Whey Mixture System

WANG Wen-qiong , SUN Zhi-yong , HUANG Dong-cheng , ZHANG Jie-long , ZHANG Zhi-xian , LI Ying , LU Mao-lin , GU Rui-xia

2021, 37(1):142-149. DOI: 10.13982/j.mfst.1673-9078.2021.01.0744

[Abstract](239) [HTML](238) [PDF 21.59 M](1056)

Abstract:
In this paper, Streptococcus thermophilus, Lactobacillus bulgaricus and mixed bacteria were used to ferment the mixture of whey protein and blueberry juice. The effects fermented time of initial, 24 h, 36 h and 48 h on the antioxidant properties of whey protein, blueberry juice through single and mixed fermentation were investigated. The results showed that the reduction capacity of the mixed whey protein and blueberry system fermented by Streptococcus thermophilus was higher than that of the single fermentation of whey protein and blueberry, and the DPPH free radical scavenging capacity reached up to 63% fermented at 24 h. At the same time, the scavenging capacity of superoxide anion radical was increased by 54.94% compared to the initial. Furthermore, the blueberry and whey system fermented at 36 h had the strongest reduction ability and hydroxyl radical scavenging ability. When Lactobacillus bulgaricus fermented whey protein and blueberry for 36 h had the strongest ABTS+? scavenging ability. The anti-lipid peroxidation ability was increased by 24.33% compared with the initial. When mixed strains of Streptococcus thermophilus and Lactobacillus bulgaricus were used to ferment blueberry and whey system for 24 h, the anti-lipid peroxidation ability was higher than that of the system before fermentation for about 24.33%. Therefore, Lactobacillus fermentation can improve and stabilize the antioxidant capacity of the mixed system of whey protein and blueberry juice. The purpose of this study is to provide the theoretical basis for the development of functional blueberry and whey mixed products fermented by lactic acid bacteria, and to provide the research basis for the application of blueberry whey mixed fermentation products in the field of food and medicine.

19 Comparison of Physicochemical Properties of Wheat Bran and Its Dietary Fiber Subjected to Conventional Crushing and Superfine Grinding

SHI Jian-bin , SUI Yong , CAI Sha , HE Jian-jun , XIONG Tian , FAN Chuan-hui , CHEN Xue-ling , WANG Shao-hua , CAI Fang , MEI Xin

2021, 37(1):150-156. DOI: 10.13982/j.mfst.1673-9078.2021.01.0597

[Abstract](334) [HTML](293) [PDF 14.65 M](702)

Abstract:
To compare clarify the effect of ordinary crushing and superfine grinding on the physicochemical properties of wheat bran and wheat bran dietary fiber, the water-holding capacity (WHC), oil-holding capacity (OWC), water-swelling capacity, viscosity, cation exchange capacity, and adsorption capacitiesfor lipids, cholesterol, bile salts and glucose were determined. The results showed that wheat bran dietary fiber had higher WHC and OWC than wheat bran. Superfine grinding could further increase the WHC and OWC of wheat bran dietary fiber (4.99 mg/g and 6.30 mg/g, respectively). At a sodium bile acid concentration of 3 mg/mL, the capacities of ultrafine wheat bran and wheat bran dietary fiber for sodiumbile acid absorption were the highest (40.58 mg/g and 46.08 mg/g, respectively). The absorption capacities of wheat bran and wheat bran dietary fiberfor glucose (in the range of 50~100 mmol/L) increased significantly after superfine grinding. At pH 7, the cholesterol absorption capacity of wheat bran subjected to conventional crushing was lower than that of conventionally crushed wheat bran dietary fiber, whilst the cholesterol absorption capacity of wheat bran after ultrafine grinding was higher than that of ultrafine wheat bran dietary fiber. The conventionally crushed wheat bran had the highest adsorption capacities for unsaturated fatty acids and saturated fatty acids (1.56 g/g and 1.13 g/g, respectively).This research showed that the wheat bran and the wheat bran dietary fiber table exhibited different physicochemical properties after the treatments, which provides a theoretical basis for the food utilization of wheat bran and studies onits influences on the physicochemical properties of the resulting food systems.

20 Pulsed Electric Field Combined with Enzymatic Hydrolysis Improves the Preparation Efficiency and Oil Absorption of Porous Starch

YU Ya-qian , LI Song-nan , SUN Chun-rui , Wei Shan Lim , JIA Xiang-ze , ZENG Xin-an , ZHANG Bin , HUANG Qiang

2021, 37(1):157-163. DOI: 10.13982/j.mfst.1673-9078.2021.1.0385

[Abstract](476) [HTML](212) [PDF 8.67 M](685)

Abstract:
Porous starch was prepared by pulsed electric field (PEF) combined with enzymatic hydrolysis using waxy corn starch as the raw material, and their effects on the preparation efficiency and oil absorption of porous starch were studied. The results showed that after PEF modification, the hydrolysis time required when the starch hydrolysis rate reaches 24.28% was shortened by half; under the same conditions (enzyme amount and enzymolysis time), after PEF modification, the starch hydrolysis rate is 23.11%, which is significantly higher than that of the original starch. It shows that PEF treatment can shorten the time of enzymolysis and reduce the amount of enzyme added in the enzymolysis process. When PEF treated starch was subjected to enzymatic hydrolysis for 6 h using 0.8×10-2 mL/g of enzyme, the degree of hydrolysis was recorded at 23.11%, degree of oil absorption at 145.11%, specific surface area of 1.25 m2/g and total pore volume of 4.31 cm2/g×10-3. In contrast, when PEF was absent, the same enzymolysis time and amount generated lower degree of hydrolysis at 18.38%, lower degree of oil absorption at 119.47%, lower specific surface area of 1.16 m2/g and lower total pore volume at 4.15 cm2/g×10-3. Scanning electron microscopy results showed that PEF modification can produce a grooved-like structure on the starch surface. Laser confocal electron microscopy observations showed that PEF modification improves the sensitivity of starch granules to enzymes. The thermal results indicated that the enthalpy of gelatinization of PEF modified porous starch was lower than that of native starch, indicating that the PEF treatment possibly destroyed the part dense crystalline area of starch granules. This study reveals the structure-activity relationship of PEF modification on starch granules and the enzymatic hydrolysis of porous starch, provides a new idea for the efficient preparation of porous starch, and expands the application of PEF.

21 Comparative Analysis of the Cooking Quality of Chinese Dried Noodles under Different Drying Parameters

ZHANG Ying-quan , HUI Ying , ZHANG Bo , GUO Bo-li , ZHANG Guo-quan , WEI Yi-min

2021, 37(1):164-171. DOI: 10.13982/j.mfst.1673-9078.2021.01.0687

[Abstract](246) [HTML](240) [PDF 2.20 M](750)

Abstract:
Temperature and relative humidity in drying chamber are the two main parameters affecting cooking quality of Chinese dried noodles (CDN). To clarify the effects of temperature, humidity and temperature-humidity interactions on quality performance of CDN, the flour of Chinese wheat variety Ningchun 4 was used for small-scale industrial making of CDN under different drying conditions in laboratory. Three temperatures (40 ℃, 60 ℃ and 80 ℃) and three relative humidity (65%, 75% and 85%) were selected for designing the CDN drying experiment with two factors of three levels each. The quality evaluation of CDN showed that the cooking quality and texture of cooked CDN were significantly or extreme significantly affected by drying temperature, relative humidity, and their interaction. Complex quality changes of CDN were observed with the increase of drying temperature or humidity. Drying temperature was identified as the main factor affecting the cooking characteristics of the CDN, followed by temperature-humidity interaction and humidity. Temperature (with the variation contribution rate over 70%) had the greatest influence on the optimum cooking time and texture of cooked noodles. Compared with the traditional drying process condition (40 ℃ and 75% ), the quality of CDN was improved when it was dried at 60 ℃ and 75%. The results in this study will provide reference for the drying process optimization and quality control of CDN.

22 Optimization of Gel Quality of Pig Skin Jelly by Adding Polysaccharides and Calcium Chloride

WANG Juan-juan , ZHOU Chang-yu , WANG Chong , YE Ke-ping , DING Shi-jie , LI Chun-bao , ZHOU Guang-hong

2021, 37(1):172-181. DOI: 10.13982/j.mfst.1673-9078.2021.01.0727

[Abstract](265) [HTML](379) [PDF 61.70 M](846)

Abstract:
In order to study the effect of adding polysaccharides (gellan gum and inulin) and CaCl2 on the gel quality of pig skin jelly, the hardness, springiness, melting point and sensory score were used as response value in the single factor experiment, then box-behnken response surface analysis was used to establish the regression equation of sensory score to get the optimal value. The results showed that the addition of gellan gum increased the melting point, hardness and springiness of pigskin jelly, the addition of CaCl2could promote gellan gum to increase the melting point of pigskin jelly, and the addition of inulin improved mouthfeel. Overall, adding gellan gum, inulinand CaCl2 into the pig skin jelly increased the sensory score (unoptimized: 7.58, optimized: 8.85). Conclusion: the optimal addition conditions were 0.45 g/100 g of gellan gum, 0.06 g/100 g of CaCl2, and 3.77 g/100 g of inulin. And the predicted sensory score of the pig skin jelly was 8.91. Conclusion: under these conditions, the actual sensory score of the optimized pig skin jelly was 8.85, which was close to the predicted value. Moreover, the hardness, springiness, and melting point of the optimized pig skin jelly were 340.08 g, 0.92 and 43.4 ℃, respectively, and its microstructure was more compact. Therefore, it is feasible to improve the quality of pig skin jelly by adding gellan gum, inulin and CaCl2. This study provides a reference for further processing of pig skin jelly and development of related products.

23 Adding Antioxidants during Pickling to Improve the Interior Quality of Salted Egg Yolk

SUN Jing , DU Jin-ping , YANG Hua , XIANG Jun , HU Tian-ping

2021, 37(1):182-191. DOI: 10.13982/j.mfst.1673-9078.2021.01.0619

[Abstract](337) [HTML](373) [PDF 2.57 M](504)

Abstract:
In order to solve the hard-core and black-circle problems of salted egg yolk in actual production, three natural antioxidants were added to the coating mud for salted eggs during pickling, and their effects on the physical and chemical indices of salted egg interior quality were compared. The results showed that the addition of tea polyphenols, astaxanthin, and yeast selenium to the mud did not change the maturity period of salted eggs (19 d), but significantly reduce the mass ratio of yolk hard core to whole yolk (5.75%, 6.68%, 9.06%, respectively, with 15.32% for the control), and inhibited the formation of black circles (1%~6%, 2%~5%, 8%~15%, respectively, with 18%~41% for the control). The treated eggs had black circles in lighter color (light gray color) and significantly reduced hardness, springiness and chewiness. Compared with the control group, the tea polyphenols and astaxanthin groups had decreased ratios of the primary oxidation product, conjugated dienoic acid (CDA; by 37.50% and 31.25% respectively),decreased contents of the secondary oxidation product malonaldehyde (MDA; by 23.31% and 41.56% respectively) (p<0.05), and insignificant changes of yeast selenium (p>0.05). Compared with the control group, the types of free fatty acids in the treated egg yolk essentially remained unchanged, but their relative contents changed slightly: the total content of unsaturated fatty acids, oleic acid, and linoleic acid increased significantly for the tea polyphenol group and the astaxanthin group, with those of the yeast selenium group exhibiting insignificant changes. Taken together, the organoleptic quality of the treated egg yolk was greatly improved, with orange-red color detected in the yellow color of egg yolk and a reduced degree of lipid oxidation/decomposition of egg yolk, compared with the control group. Considering the lower original cost of tea poly-phenols, tea polyphenols are most suitable for the rapid production of salted eggs by the salt-infused mud coating method.

24 Processing Technology and Quality Evaluation of the Preserved Cracked Large Low-sugar Cherry Fruits

YANG Shuo , ZHANG Shuang-ling , JIANG Wen-li , KANG Meng-chen , FU Juan-juan , XIU Tian-tian , HU Yue

2021, 37(1):192-198. DOI: 10.13982/j.mfst.1673-9078.2021.01.0627

[Abstract](258) [HTML](180) [PDF 11.37 M](849)

Abstract:
In order to reduce the loss of big cherries caused by cracking and realize the high-value utilization of big cherry fruits, the cracked fruits of the Yunshan big cherries were used as the raw material. The types of sugar, amount of added sugar, amount of added acid, time of sugar preparation and acid to sugar ratio were used as experimental factors, with sensory score as an indicator, to design single-factor experiments. Taking the amounts of added sugar addition and added acid and sugar preparation time as experimental factors, sensory score and texture profiles analysis (TPA) as indicators, L9 (33) orthogonal experiments were designed to optimize the processing of cracked large low-sugar cherry fruits. The results showed that the quality of the preserved fruits were the best under the following conditions: selected sugar was a mixture of white granulated sugar and maltitol (1:1 m/m), amount of added sugar was 30% (m/m), amount of added acid was 0.60% (m/m, citric acid), sugar preparation time was 21 h, and acid-sugar ratio was 2.00%. Based on the analyses, the total sugar content, moisture content and microbiological indicators in the preserved fruits all met the national standards. Therefore, the processing procedure of cracked low-sugar large cherry fruits was established.

25 Optimization of Ultrasonic Assisted-Green Deep Eutectic Solvent Extraction of Flavonoids from Jasmine

DU Hong-xia , LIU Yan-xiu , YAN Zhong-jie , HU Zi-heng , LIU Gao-rong , WU Chen-yu

2021, 37(1):199-206. DOI: 10.13982/j.mfst.1673-9078.2021.01.0737

[Abstract](398) [HTML](265) [PDF 28.67 M](806)

Abstract:
Ten extract solvents including water, ethanol and eight types of deep eutectic solvents with microwave-assisted extraction and ultrasonic -assisted extraction were studied in order to explore a green and efficient technology for extraction of total flavonoids from jasmine. The effects of molar ratio of deep eutectic Solvents, water content, liquid - material ratio, ultrasonic time and ultrasonic power on the yield of flavonoids were investigated by single factor test. Based on single-factor tests, the quadratic regression parasitism model was established for obtain the optimal extraction conditions of flavonoids from Jasmine through the response surface methodology. It was found that the optimal extract process was ultrasonic assisted-green deep eutectic solvent, and extraction conditions were betaine hydrochloride/sucrose/H2O (1:1:94.50), liquid-material ratio 149:1 mL/g, time 20 min, ultrasonic power 90 W, the maximum yield of total flavonoids reached 15.24 mg/g, which is 677% of water extraction and 200% of orthogonal design-ultrasonic extraction. Response surface methodology was proved to be applicable for optimization of ultrasonic assisted-green deep eutectic solvent extraction of total flavonoids from Jasmine. Data support was provided for the further development and utilization of Jasmine resources.

26 Changes in the Quality and Antioxidant Capacity during the Fermentation of Betavulgaris L. with Lactic Acid Bacteria Isolated from Natural Fermentation

LI Yao , GUO Rui , YAN Ming-zhe , WANG Ping

2021, 37(1):207-215. DOI: 10.13982/j.mfst.1673-9078.2021.01.0491

[Abstract](256) [HTML](168) [PDF 21.66 M](681)

Abstract:
In this study, fermentation of red beetroot pulp or slices was carried out using the Enterococcus lactis and Lactobacillus plantarum isolated from natural fermentation broth of red beetroot. The pH, total acid, number of lactic acid bacteria, total phenolic content, flavonoid content, total antioxidant capacity, and DPPH· and ABTS+·scavenging capacities were measured over the 48 h fermentation process. The results showed that the pH of the fermented red beet pulp and slices decreased significantly (p<0.05) (the lowest as 3.95). After fermentation, the total acid content increased (the highest as 16.78 g/kg). The maximum number of viable bacteria was 7.17 log(cfu/L) for the red beet pulp fermented with Enterococcus lactis. Compared with the unfermented samples, the greatest increase in the total phenol content was with fermented samples by Enterococcus lactis (755.30 mg/L; increased by 72.55%). The slices fermented by Lactobacillus plantarum had the highest flavonoid content as 0.92 mg/L (increased by 113.95%). The content of betacyanins in the pulp fermented by Lactobacillus plantarum decreased the fastest (decreased to 6.01 mg/100 mL; a decrease of 38.10 %). Opposite changes were found in the fermentation broth of red beetroot slices: the betalains content increased by 128.81% and 137.71%, respectively, with the betaxanthin in each sample increasing significantly in the first half of fermentation (p<0.05). The DPPH· scavenging capacities of the fermented samples were all enhanced, with the inhibition rate of the red beet slices fermented with Enterococcus lactis being the highest (55.32%). The total antioxidant capacity and ABTS+· scavenging capacity of the slices fermented with Enterococcus lactis or Lactobacillus plantarum increased significantly (maximum values were 1.14 mM FeSO4/L and 69.69%, respectively). This study provides basic data and theoretical basis for subsequent research and development of red beetroot lactic acid fermented products.

27 Preparation and Characterization of CdTe/CdS Quantum Dots Fluorescent Detection Probe

TIAN Yu , WANG Zhou-li , CAI Rui , YUE Tian-li , YUAN Ya-hong , CUI Lu

2021, 37(1):215-259. DOI: 10.13982/j.mfst.1673-9078.2021.01.0705

[Abstract](226) [HTML](178) [PDF 61.43 M](714)

Abstract:
It is important to optimize the establishment of simple quantum dots preparation method and obtain the excellent quantum dots material for food safety. The core-shell CdTe/CdS quantum dots were prepared by hydrothermal method using thioglycolic acid as stabilizer. The optical properties of quantum dots were evaluated by fluorescence emission spectroscopy and UV-Vis spectra. Then, the stability of quantum dots was investigated. The results showed that the quantum dots with excellent performance were prepared under the conditions of 80 ℃ reflux, nucleation 40 min, cladding 40 min, pH=11, n(Cd2+) : n(Te2-):n(TGA)=1:0.2:7. Quantum particle size, size distribution range and fluorescence intensity varied with the change of above experimental conditions. The results of the stability study showed that the photoluminescence intensity of the prepared CdTe/CdS quantum dots increased with the irradiation time, and the quantum yield increased significantly from the 7.80% to 20.10% and reached the maximum at 11th day. The research and establishment of the preparation method can be used as a fluorescent probe to adjust the synthesis conditions according to the needs to control the size of the quantum dots and provide technical support for the detection of quality safety factors in food, which can play an important role in ensuring food safety.

28 Comparative Analysis of Volatile Flavor Components of Different Sansui Duck Eggs

YU Pei , WANG Xiu-jun , LIU Lin-xin , YANG Li-ping , CHEN Yan-hong , NIE Qian-li , YANG Wan-yun , YAO Bi-qiong

2021, 37(1):216-222. DOI: 10.13982/j.mfst.1673-9078.2021.01.0721

[Abstract](244) [HTML](123) [PDF 9.24 M](829)

Abstract:
To study the effects of two breeding methods and varieties on the volatile flavor components of Guizhou Sansui duck eggs, solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) technology was used to analyze and compare three kinds of duck eggs (farmers free-raising Sansui Ma duck eggs, enterprise-scale breeding Sansui Ma duck eggs, enterprise-scale breeding pure white duckegges). The composition and difference of flavor substances of duck and duck eggs, and the relative odor activity value (ROAV) method were applied to analyze the contribution of different flavor substances to the overall flavor. The results showed that 33 kinds, 29 kinds and 24 kinds of flavor substances were detected in the three kinds of duck eggs, respectively. The relative content of alkanes is the highest in Sansui Ma duck eggs (farmer-raised) and pure white duck eggs (corporate-scale breeding), and the relative content of ketones in Sansui Ma duck eggs (business-scale breeding) is the highest. Ethanol, 3-methylbutanal, valeraldehyde, hexanal, heptanal, benzaldehyde, octyl aldehyde, nonanal,decanal ether, butyl ether, 2-pentanone, 2-heptanone, 2-nonanone, benzene Ethylene, dodecane, tridecane, 1-octene, and methylcyclopentane are the flavor substances shared by the three duck eggs. Combined with ROAV analysis, it is obtained that the flavor substances that have a greater degree of contribution to the overall flavor of the three duck eggs are nonanal, 3-methylbutanal, valeraldehyde, hexanal, heptanal, octanal, decanal, and 2-nonanone. Sansui Ma duck eggs raised by farmers in a free-range manner have the richest flavor components, and their flavor quality is better than Sansui Ma duck eggs (corporate-scale breeding), and their fat flavor and egg smell are more prominent. The overall flavor of the two species of the same Sansui Ma duck eggs is better than the pure white duck eggs (corporate-scale breeding).

29 Specific Detection of Emetic Bacillus cereus in Foods by Loop Mediated Isothermal Amplification (LAMP) Method

XU Xiao-ke , GUO Hui , DENG Mei-qing , ZHANG Ju-mei , WU Qing-ping , DING Yu

2021, 37(1):223-228. DOI: 10.13982/j.mfst.1673-9078.2021.01.0664

[Abstract](332) [HTML](191) [PDF 28.77 M](1078)

Abstract:
The loop-mediated isothermal amplification (LAMP) assay for the detection of emetic Bacillus cereus was developed by designing four primers including two inner primers and two outer primers that specifically amplify segments of the cesB gene. Analysis of two emetic B. cereus strains, nineteen B. cereus strains and forty-one non-B. cereus strains demonstrated that this LAMP assay was specific. The detection limit of the LAMP method was 1.49 pg/μL with genomic DNA, 5×103 cfu/mL in pure culture. The detection limit of the LAMP method was 2 cfu/g in arti?cially contaminated rice for either boiling or kit-based DNA isolation method after enrichment at 37 ℃ for 6 h. Among seventy-two food samples, two was identified to be positive by this LAMP method, which was consistent with the international standard method. The result demonstrated that the specific LAMP assay can be used for rapid detection of emetic B. cereus strains in food.

30 Rapid Screening and Quantification of 64 Kinds of Illegally Added Compounds in Different Wines by Ultra Performance Liquid Chromatography-Quadrupole/Electrostatic Field Orbitrap High-Resolution Mass Spectrometry

ZHOU Nan , HUANG Shan , CHEN Zhuo , YUAN Li-jie , LI Tong-hui

2021, 37(1):229-242. DOI: 10.13982/j.mfst.1673-9078.2021.01.0594

[Abstract](556) [HTML](340) [PDF 33.59 M](762)

Abstract:
In this study, a method for rapid screening and quantitative analysis of 64 kinds of illegally added compounds in alcohol samples by ultra-performance liquid chromatography-quadrupole/electrostatic field orbitrap high-resolution mass spectrometry (UPLC-HRMS) was established. The samples were heated to remove alcohol, and then methanol was added for ultrasonic extraction. The resulting extract was topped up to a fixed volume, filtered through a microporous membrane, and separated by a ThermoHypersil GOLD C18 column (100 mm×2.1 mm, 1.9 μm; ammonium formate and acetonitrile as the mobile phase for gradientelution), before analysis. Mass spectrometry conditions were: simultaneous scanning of positive and negative ions, and full scan/data-dependent secondary scan (Full MS/dd-MS2) mode. High-throughput screening and quantitative analysis of commercially available alcohol samples were carried out with the database set up based on the retention time of the analyte, primary parentions, and automatically collected secondary fragment ions. The results showed a good linear relationship for each target compound within a certain mass concentration range, with correlation coefficients (r2) >0.99, limits of quantitation (LOQs) ranging from 0.1 to 2.5 mg/kg, recoveries in the range of 88.3%~127.9%, and relative standard deviations as 0.2%~6.2% (n=6). This method is simple, highly selective, rapid, accurate and reliable, there by suitable for rapid screening and verification of 64 kinds of illegally added compounds in alcohol samples.

31 Detection Sulfonamide in Food by Upconversion Fluorescence Nanotechnology

GUI Li-juan , LIANG Zi-lu , LUO Yong-wen , ZHUANG Jian-le , BI Shui-lian

2021, 37(1):243-250. DOI: 10.13982/j.mfst.1673-9078.2021.01.0667

[Abstract](241) [HTML](160) [PDF 41.36 M](870)

Abstract:
In this study, a sensitive and stable method for detecting five-membered heterocyclic sulfonamides in foods was established based on up-conversion fluorescent nanoparticles technology. Using upconverting nanoparticles as energy donors and gold nanoparticles as energy acceptors, a fluorescence resonance energy transfer system was constructed, and the free antigen was quantified by the amount of recovered fluorescence to achieve rapid detection of five-membered heterocyclic sulfonamides. The results showed that the upconverting luminescent nanomaterials conjugated with the antibody and the gold nanoparticles coated with the antigen can be well combined with good sensitivity and specificity. The fluorescence quenching of the upconversion fluorescent nanoparticles was linearly correlated with the concentration of the sulfonamide antigens (in the range of 0.08~100 ng/mL) present in the system, the correlation coefficient was 0.99371, enabling quantification of the sulfonamides and the lowest detection limit was 0.08 ng/mL. At the same time, this method has been successfully applied to milk, and can identify drugs containing five-membered heterocyclic sulfonamides, with simple operation and good specificity. The method of constructing a fluorescence resonance energy transfer system based on upconversion fluorescent nanoparticles technology can provide new ideas to detect residues of five-membered heterocyclic sulfonamides in food.

32 Investigation and Risk Analysis of Pseudomonas cocovenenans subsp. farinofermentans from Rice and Edible Starch

CHEN Rong-qiao , CHEN Han-Jin , HU Jun-peng , XIAN Yan-ping , YANG Jing , WANG Bin , ZHU Wen-xin , LIU Dong-hong , HOU Xiang-chang , LIU Chun-sheng , WU Yu-luan , ZHOU Ying-xuan

2021, 37(1):260-267. DOI: 10.13982/j.mfst.1673-9078.2021.1.0685

[Abstract](379) [HTML](504) [PDF 71.21 M](873)

Abstract:
By investigating the contamination of Burkholderia gladioli in rice and edible starch which commonly used in the food industry in some provinces of southern China, it is the first time that Pseudomonas cocovenenans subsp. farinofermentans was isolated and identified from imported broken rice, which provided early warning of potential risk. In this study, 129 samples including 47 rice, 18 broken rice, 64 edible starch were collected from southern provinces where “bongkrekic acid poisoning incident” had occurred. Burkholderia gladioli and bongkrekic acid were detected according to GB/T 4789.29-2003 and GB 5009.189-2016, respectively. The results showed that 6 strains of Burkholderia gladioli were isolated and identified from 4 imported broken rice and 1 domestic broken rice, and the detection rate in broken rice samples was 27.78% (5/18); through toxin-producing cultivation and toxicity test, 4 strains produced bongkrekic acid. The mice all died within 24 hours after oral gavage of crude toxin extract. It was confirmed that the toxin was Pseudomonas cocovenenans subsp. farinofermentans, and all derived from 4 imported broken rice samples (two of them were detected with bongkrekic acid), accounting for 23.53% (4/17) of imported broken rice samples. It shows that there are safety risks in imported broken rice, and the relevant enterprises and regulatory authorities should strengthen the risk prevention and control.

33 Determination of Organotin Pesticide Residues in Fruits and Vegetables by Gas Chromatography-tandem Mass Spectrometry with Isotope-labeled Internal Standards

LIANG Yi-xin , LI Jie , LIU Kang-shu , CAI Qiu , ZHU Ming , DAI Wei , WANG Mian , WANG Xing-ning

2021, 37(1):268-275. DOI: 10.13982/j.mfst.1673-9078.2021.01.0607

[Abstract](418) [HTML](148) [PDF 33.79 M](777)

Abstract:
A gas chromatography-tandem mass spectrometric (GC-MS/MS) method with isotope-labeled internal standards was developed for the determination of organotin pesticide residues such as cyhexatin, azocylotin, fentin-acetate, triphenyltin hydroxide and fenbutatin oxide in vegetables and fruits. Samples were extracted with 1% glacial aceticacid-acetonitrile, derivatized with sodium tetraethyl borate, purified with a PC/NH2-SPE column, eluted with n-hexane-acetone (99:1, V/V), and determined using an EI source. The results showed that good linearity was found in the concentration range of 0.05~1.00 mg/L for the determination of the three organotin pesticides, with all the correlation coefficients higher than 0.998. The recovery rates of organotin ranges in the negative samples spiked at the three levels (0.04, 0.10 and 0.20 mg/kg) ranged from 81.64% to 106.23%, with the relative standard derivations (RSDs) all lower than 6.33% (n=6). The limits of quantification (LOQ) of the proposed method for cyhexatin, fentin-acetate, and fenbutatin oxide were 0.01, 0.009 and 0.039 mg/kg, respectively. This method is stable, reliable and highly sensitive, thereby suitable for the determination of organotin pesticide residues in agricultural products such as fruits and vegetables. This method also provides a reference for the determination of organotin pesticide residues in other foods.

34 Residual Elimination of Furazolidone Metabolites in Crucian Carp under the Action of Different Antibiotics

FANG Shuang-qi , ZHANG Shuai , CHEN Yan , ZHANG Xiao-jun , MEI Guang-ming

2021, 37(1):276-281. DOI: 10.13982/j.mfst.1673-9078.2021.01.0726

[Abstract](262) [HTML](187) [PDF 7.03 M](857)

Abstract:
In this article, the residue elimination rule of furazolidone metabolite 3-amino-2-oxazolidinone (AOZ) in crucian carp was studied after oxytetracycline, enrofloxacin, sulfamethoxine and furazolidone were administered in combination with bath. The results showed that furazolidone was rapidly metabolized into AOZ after entering the crucian carp, after the drug was stopped for 0 hours, the furazolidone control group had the highest residual AOZ in the kidney, liver, and muscle of the crucian carp, which were 88.87, 59.20, and 14.91 μg/kg, respectively, with an average elimination rate. 0.86, 0.52, 0.15 μg/(kg·h), respectively. Compared with the control group, the maximum residual concentration of AOZ in the kidney, liver, and muscle of crucian carp in the oxytetracycline-furazolidone group was significantly increased, which were 152.46, 125.39, 8.69 μg/kg, respectively, and the average elimination rate was 1.71, 1.17, 0.31 μg/(kg·h), respectively. However, the maximum residual concentration of AOZ in the kidney, liver, and muscle of Carassius auratus in the enrofloxacin-furazolidone group was significantly reduced compared with the control group, only 33.68, 49.77, 9.69 μg/kg, respectively, and the average elimination rate was 0.36, 0.31, 0.03 μg/(kg·h), respectively. The maximum residual amount of AOZ and the average elimination rate of AOZ in the crucian carp in the sulfamonomethoxine-furazolidone group were also different from those in the control group, but there was no significant change. After 96 hours of elimination, a large amount of AOZ remained in the crucian carp in each experimental group. It was initially found that in this experiment, AOZ is difficult to be eliminated in crucian carp. Oxytetracycline, enrofloxacin, and sulfamonomethoxine can affect the elimination of AOZ in crucian carp to varying degrees, and provides a theoretical basis for aquatic product quality and safety supervision and fishery drug residue research.

35 Analysis of Chemical Components of Perilla frutescens Based on Ultra High Performance Liquid Chromatography-Quadrupole / Time of Flight Mass Spectrom (UHPLC-Q/TOF MS)

MAO Qi-ping , HE Ming-zhen , HUANG Xiao-fang , DU Hui , LUO De-wei , ZHANG Hao-qun , OUYANG Hui , FU Guo-qiang , PEI Na , ZHONG Ke

2021, 37(1):282-291. DOI: 10.13982/j.mfst.1673-9078.2021.1.0973

[Abstract](388) [HTML](205) [PDF 35.19 M](861)

Abstract:
UHPLC-Q/TOF MS was used to qualitatively analyze the chemical components of Perilla frutescens treated by shade-drying menthod or freeze-drying method, and the material basis of the differences between the two treatments from the same source was discussed. High performance liquid chromatography (HPLC) conditions were as follows: Welch Ultimate UHPLC C18 column (2.1mm X100mm, 1.8 μm), the mobile phase gradient elution with 0.1% formic acid water solution and acetonitrile. The mass spectrometry conditions were as follows: AB Sci ex Triple TOF 5600 high resolution tandem mass spectrometry, electrospray ionization (ESI) ion source, data collection in positive and negative mode, fragmentation by retention time, accurate molecular ion peak, and two stage mass spectrometry. A total of 51 compounds were detected in Perilla frutescens, 45 compounds in shade-drying Perilla frutescens, 35 compounds in freeze-drying Perilla frutescen (including flavonoids, styrene acrylic element class, organic acids, etc.). There are nine compounds (four organic acids, four flavonoids, one element of styrene acrylic) was the first identified in Perilla. The composition could be changed after Perilla treated with the shade-drying or freeze-drying. The chemical components were different between Perilla treated with shade-drying method and Perilla treated with freeze-drying method. The results were helpful to choose different treatment methods of Perilla for certain medicinal value. It could be also helpful in further evaluation for Perilla, and their medicinal substances in the body.

36 Determination of Safrole in Ginger by Gas Chromatography-Tandem Mass Spectrometry

HAN Mei , HOU Xue , HE Guang-yun , QUE Shi-ting , WANG yue-han , ZOU Ping

2021, 37(1):292-297. DOI: 10.13982/j.mfst.1673-9078.2021.01.0639

[Abstract](569) [HTML](177) [PDF 10.24 M](828)

Abstract:
An analytical method for the determination of safrole in ginger by solid-phase purification combined with gas chromatography-mass spectrometry was developed. The conditions of sample pretreatment and analysis by chromatographic mass spectrometry were optimized. The samples were extracted with acetonitrile, centrifuged at a high speed, and then enriched and purified by a Carb-NH2 solid-phase cartridge. The eluate was concentrated by a rotary evaporator. Gas chromatographic separation and multiple reactive ion monitoring mode (MRM) were applied to determine safrole. The matrix-matched external calibration involving standard solutions was used for quantitative analysis. The experimental results show that safrole exhbited a good linear relationship in the range of 0.005~0.5 μg/mL, with the correlation coefficient (R2) higher than 0.999, the limit of detection (S/N=3) as 0.42 μg/kg, and the limit of quantification (S/N=10) as 1.41 μg/kg. The average recoveries of the samples spiked with safrole standard at 5, 25 and 50 μg/kg were 107.7%~111.9%, with the relative standard deviations (RSDs) in the range of 2.02%~2.32%. This method has the advantages of high sensitivity, good enrichment and high recovery rate, and provide technical support for the screening of safrole in ginger and its derived products. Using the developed method, a trace amount of safrole was detected (concentration: 0.45~1.3 μg/kg) in 151 ginger samples.

37 Degradation of Pesticide Residues in Instant Tea by NC-100 Macroporous Resin

PEI Shao-fen , SHAO Zeng-lang , WANG Xiao-xia , TANG Xing-yan , HUANG Ye-fei , HUANG Ming

2021, 37(1):298-307. DOI: 10.13982/j.mfst.1673-9078.2021.01.0614

[Abstract](165) [HTML](136) [PDF 2.33 M](554)

Abstract:
In this study, the resin adsorption effect on the 5 kinds of pesticide residues in instant tea solutions was studied. Through the comparison on the adsorption properties of two macroporous resins for pesticides residues and tea polyphenols of instant tea solutions by static adsorption experiments, the NC-100 resin with higher adsorption rate was screened out. The optimal adsorption parameters of dynamic adsorption were determined by the orthogonal experimental design and statistical method: sample flow rate was 3.0 BV/h, pH was 5, temperature was 80 ℃, and concentration was 100 mg/mL. Under such process conditions, the removal rates for the five kinds of pesticides reached 75.1%~90.4%, with the loss rate of tea polyphenols being 17.6%. The established detection method for pesticides has good accuracy and precision, with a good linearity in the range of 0.2~50 μg/L, correlation coefficient (r2) higher than 0.995, and limit of quantification as 0.01 mg/kg. After pesticide was spiked at 0.01 or 0.04 mg/kg into the blank tea powder, the recovery rates were 76.4%~114.5% with relative standard deviations (RSD) as 2.3%~4.8% (n=3). Based on the detection method and comprehensive analysis of the process and results, the adsorption mechanism was examined to provide a theoretical and practical basis for the application of resin to removing the pesticide residues in instant tea.

38 The Relationship between the Structure and Function of Dendrobium Polysaccharides: a Review

LIU Hui-fan , GUO Shuo-xuan , LIN Ying-yu , WU Hui , LAI Fu-rao , LIU Jian-gao , LI Zhong-liang , REN Hong , ZHONG Yu-ming , MA Lu-kai

2021, 37(1):308-338. DOI: 10.13982/j.mfst.1673-9078.2021.01.0790

[Abstract](571) [HTML](150) [PDF 229.72 M](1029)

Abstract:
Based on the high content of polysaccharides in Dendrobium, the structure and activity of Dendrobium polysaccharides have been studied deeply in recent years. In this review, the monosaccharide composition, glycoside bond, acetyl group and branching degree of Dendrobium polysaccharides have been sorted out. The mechanism of activity of Dendrobium polysaccharides in antioxidant, immunomodulatory and anti-diabetic activities has been summarized. This paper calculated the EC50 value of free radicals scavenging DDPH Dendrobium polysaccharides with antioxidant activity, and established a random forest model from the point of view of the composition and relative abundance of polysaccharides monosaccharides of Dendrobium officinale with antioxidant activity. The model predicted the antioxidant activity of Dendrobium polysaccharides, and the accuracy of the model was 70.00%. The results showed that the monosaccharide which had the greatest influence on the antioxidant activity of Dendrobium polysaccharides was glucose. The linear relationship between the antioxidant activity of Dendrobium polysaccharides, mannose and galactose and the linear relationship between mannose and arabinose was related. This paper provides a reference for exploring the qualitative and quantitative relationship between polysaccharide activity of Dendrobium officinale with different structures.

Home

About the journal

Notes for submission

Acceptable topics

Author garden

Open access

中文

Volume 37,Issue 1,2021 Table of Contents