Volume 35,Issue 5,2019 Table of Contents

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  • 1  The Transport Mechanism of Polysaccharides from Dendrobium aphyllum Studied Using a Caco-2 Cell Monolayer Model
    WANG Qin LIANG Jia-xi WU Hui LIU Hui-fan
    2019, 35(5):1-6. DOI: 10.13982/j.mfst.1673-9078.2019.5.001
    [Abstract](632) [HTML](527) [PDF 37.40 M](851)
    Abstract:
    Dendrobium aphyllum polysaccharides (DAP) was used as the study object, and the monolayer cell model of the human intestinal epithelial (Caco-2) cells (the human colon carcinoma cell line) was used to simulate in vitro the transport/translocation of DAP in the small intestine. Based on the DAP obtained at the early stage, the influence of the viscosity of DAP on its transport was investigated, and the Caco-2 cell model was established at the same time. The effect of DAP on the survival rate of Caco-2 cells was determined by the MTT method, and the absorption and transport of DAP in the small intestine were investigated. The results showed that the viscosity of DAP was negatively correlated with its transport capacity in the Caco-2 cells. The higher the viscosity, the lower the transport rate was. The TEER value and the permeation of sodium luciferin were measured, while the morphology of the Caco-2 cells was observed. The obtained results indicated that a suitable cell model was established. In the presence of DAP, the survival rate of the Caco-2 cells was greater than 91.8%, thus, DAP had no effect on the survival of the Caco-2 cells. The transfer rates of DAP in different Caco-2 monolayers were 0.35%±0.02% and 0.32%±0.02% respectively, with the apparent permeability being (0.42±0.02)×10-6 cm/s and (0.19±0.18)×10-6 cm/s, indicating that DAP was not easily absorbed in the small intestine. The findings obtained in this study lay a foundation for further study on the absorption mechanism of DAP in the intestinal tract.
    2  Isolation, Identification and Taste Characteristics of Umami Dipeptides from Soy Sauce
    SU Guo-wan ZHAO Xuan ZHANG Jia-nan ZHAO Mou-ming WU Jin-wei WU Jun
    2019, 35(5):7-15. DOI: 10.13982/j.mfst.1673-9078.2019.5.002
    [Abstract](798) [HTML](370) [PDF 912.65 K](843)
    Abstract:
    In order to determine the structural sequence of the umami peptides in soy sauce, umami peptides were isolated and identified for systematic study on their taste characteristics. Four fractions (F1, F2, F3 and F4) were obtained through membrane ultrafiltration (membrane flux: 5 ku, 3 ku and 1 ku), with F4 (< 1 ku) having the strongest umami taste based on sensory evaluation. F4 was then selected for further separation by Sephadex G-15 gel chromatography to generate eight sub-fractions (P1, P2, P3, P4, P5, P6, P7 and P8). Among which, P2 exhibited the strongest umami taste in sensory analysis. P2 was analyzed by ultra-high pressure liquid chromatography-tandem mass spectrometry. Four new umami peptides were identified through De novo sequencing. They were all dipeptides with sequences as Asn-Pro (230.1135 u), Ala-His (227.1026 u), Gly-Pro (173.0929 u) and Gly-Leu (189.1230 u), respectively. Then, four peptides were synthesized by solid-phase peptide synthesis and analyzed by sensory evaluation and electronic tongue analysis. The obtained results showed that all the four synthesized peptides had distinct umami taste or umami-enhancing effect. Further studies showed that the umami taste of soy sauce was not only derived from umami amino acids such as glutamic acid and aspartic acid, but also from certain small peptides (which were important contributors to the umami taste of soy sauce).
    3  Anti-inflammatory and Immunoactive of Different Solvent Extracts of Lingonberry
    FAN Zi-luan ZHAO Xiang CHEN Kai-li FU Yu-jie
    2019, 35(5):16-22. DOI: 10.13982/j.mfst.1673-9078.2019.5.003
    [Abstract](609) [HTML](279) [PDF 507.38 K](833)
    Abstract:
    In this work, the effects of different solvent extracts of Vaccinium vitis-idaea L. on the anti-inflammatory and immune functions of inflammatory mice were studied. Continuous oral gavage for 15 days at doses of 100 mg/kg body weight was conducted. The content of glutathione (GSH), malondialdehyde (MDA) and total superoxide dismutase (T-SOD), glutathione reductase (GR) in serum and liver of mice were measured. An ear swelling inflammation model was established to evaluate the inhibition of ear swelling by different solvent extracts. The sepsis model LPS was established to investigate the change in the content of NO and PGE2 by enzyme-linked immunoassay ELISA kit method. The results showed that, for all the four groups treatment, the activity of antioxidant enzymes and the content of GSH increased, whlie the content of MDA decreased. Among them, the GSH content in the n-butanol group was the highest, which increased by 33.47%. The GSH content in the petroleum ether group was the highest in the liver, which increased by 38.61%. For the ethyl acetate group, the T-SOD activity in the blood increase significantly and the MDA decreased by 27.97%. For the content of n-butanol group, the activity of GR in blood and viscera increase significantly by 44.44% and 35.68%, respectively. For all the four groups, the production of NO and PGE2 induced by LPS coukd be inhibited significantly. The effect of inhibition of the ethyl acetate group was slightly worse than the positive control dexamethasone group. This experiment confirmed that Lingonberry extract can not only effectively increase the level of antioxidant enzymes in the body, but also protect cells. It can also reduce PGE2 and NO caused by oxidative stress inflammation. This work provided a theoretical basis for the comprehensive development of lingonberry.
    4  Effect of Polypeptide from Moringa oleifera on Antioxidant Capability in D-galactose Induced Aging Mice
    PANG Qi-qi QIAN Bo WANG Cheng-qiang ZENG Zhen LEI Shao-ling SONG Jia-le
    2019, 35(5):23-29. DOI: 10.13982/j.mfst.1673-9078.2019.5.004
    [Abstract](622) [HTML](275) [PDF 520.23 K](752)
    Abstract:
    To investigate the effect of polypeptide from Moringaoleracea (MOPP) on the antioxidant capability of D-galactoseinduced aging mice, the aging model was established by intraperitoneal injection of D-galactose (120 mg/kg) in mice. The model mice were divided into normal group, D-galactose aging group, vitamin C group, MOPP low dose (10 mg/kg) and high dose (100mg/kg) group. After 6 weeks of continuous administration, the serum level of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), as well as malondiadehycle (MDA) in serum and main organs including brain, heart and liver were determined by commercial assay kits. The mRNA expressions of Mn-SOD, Gu/Zn-SOD and CAT in liver were determined by qRT-PCR assay. Compared with the aging group, MOPP treatment could significantly improve the serum levels of T-AOC (to 13.73~17.98 U/mL) and activity of SOD(8.04~11.65 U/mg protein), CAT (4.56~6.45 U/mg protein) and GSH-Px (7.28~10.65 U/mg protein) in aging mice. MOPP treatment also increase the activities of SOD, CAT and GSH-Px in main organs (brain, heart and liver) of aging mice (p<0.05). High dose of MOPP also reduced the contents of MDA in the serum, brain, heart and liver revealed a reducing trend by 43.6%, 44.7%, 31.4% and 56.0% (p<0.05), respectively. In addition, MOPP treatment enhanced mRNA transcription of antioxidant factors (SOD, CAT, GSH-Px) in liver of aging mice. The results of this work suggested that MOPP could significantly improve the antioxidant status of D-galactose-induced mice.
    5  The Anti-hyperglycemic Effects and Mechanism of Egg Oil from Portunus trituberculatus
    HU Shi-wei LI Shi-jie JIANG Wei LIU Yu
    2019, 35(5):30-36. DOI: 10.13982/j.mfst.1673-9078.2019.5.005
    [Abstract](556) [HTML](229) [PDF 627.81 K](730)
    Abstract:
    The aim of the present study is to investigate the effects and mechanism of egg oil from Portunus trituberculatus (Pt-egg oil) on hyperglycaemia improvement in diabetic mice. The diabetes model rats were established by intraperitoneal injection of streptozotocin. The diabetic rats were given Pt-egg oil at 100 and 400 mg/(kg·body weight) for 60 days, respectively. The fasting blood glucose level, serum insulin concentration, and glucose tolerance were determined. The mRNA expression of the key genes in insulin signaling in skeletal muscle of diabetic rats was measured by the quantitative real time PCR assays. The proteins expression levels in insulin signaling in skeletal muscle of diabetic rats was analyzed by Western blotting. Results showed that Pt-egg oil could significantly reduce fasting blood glucose level by 36.52% (p<0.01), increase serum insulin concentration by 40.21% (p<0.01), and improve glucose tolerance. The phosphatidylinositol 3-hydroxy kinase (PI3K), protein kinase B (Akt), and glucose transporter 4 (Glut4) gene mRNA expression in skeletal muscle increased by 114.52%, 83.17%, and 90.06%, respectively. The protein expression of these three genes increased by 1.54-fold, 1.61-fold, and 1.37-fold, respectively. Glut4 protein expression in membrane was also enhanced by 1.27-fold (p<0.01). These indicated that Pt-egg oil might exhibit the effects on hyperglycaemia improvement via activation of PI3K/Akt insulin signal pathway in diabetic rats.
    6  Effects of Mulberry Leaves Water Extract on Cholesterol Metabolites in Feces of High-fat Diet Fed Mice
    HE Yan ZOU Li-fang HUANG Xian-zhi DING Xiao-wen
    2019, 35(5):37-45. DOI: 10.13982/j.mfst.1673-9078.2019.5.006
    [Abstract](584) [HTML](342) [PDF 698.59 K](778)
    Abstract:
    In order to provide data support for hypolipidemic function of mulberry leaves, the effect of water extract of mulberry leaves on cholesterol metabolites in feces of high-fat diet mice was studied. The water extract of mulberry leaves was set to three dose groups of high (8.0 mg/kg·bw), medium (4.0 mg/kg·bw) and low (2.0 mg/kg·bw) according to their DNJ content. The mice were fed with high-fat diet for 4, 8, 12, and 16 weeks. The serum pH, fecal sterol, bile acid, and short-chain fatty acids (SCFAs) were measured in each group, and correlation analysis between SCFAs and serum cholesterol (Total Cholesterol, TC) levels and atherosclerosis index (AI) were analyzed. Compared with the high-fat control group, the water extract of mulberry leaves (8 mg/kg·bw DNJ) was intragastrically administered for 16 weeks, the fecal sterol increased by 22.31%, the bile acid increased by 22.31%, and the SCFAs increased by 36.76%, acetic acid increased by 39.25%, propionic acid increased by 96.52%, butyric acid increased by 60.43%, isobutyric acid increased by 68.05%, valeric acid increased by 74.21%, isovaleric acid increased by 23.78%, and fecal pH decreased by 2.05%. The changes in the indicators were all significant (p<0.05). Serum TC and AI were significantly negatively correlated with acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid and isovaleric acid (p<0.01). Mulberry leaf water extract can improve the intestinal environment of mice with high-fat diet, promote intestinal microbial fermentation to produce SCFAs, promote the excretion of fecal sterol and bile acid, and thus help reduce blood fat.
    7  The Study of Anti-alcoholism Effect and Protecting Liver by Sober-up Drink of Gardenias in Temulentia Mice
    YANG Jing TANG Can YAN Fei-li YIN Li-jun DING Chao HAN Xiao-fei YANG Shi-zhuo
    2019, 35(5):46-51. DOI: 10.13982/j.mfst.1673-9078.2019.5.007
    [Abstract](620) [HTML](243) [PDF 513.40 K](842)
    Abstract:
    In order to investigate the sobering effects of the different doses of sobering drinks and the protection of alcohol-induced liver injury on temulentia mice, the abilities of rods and runners, biochemical and histological examinations of blood, liver and kidney were compared . The results showed that the number of drops and level of climbing in low and high dose groups were less than those in model group (p<0.05), and the first drop time and climbing time were longer than those (p<0.05). Compared with model group, the vacuolar degeneration was reduced, the cell swelling and inflammation were lessened, and the renal tubular water degeneration of kidney was decreased in the drug-administered group. And the values of AST were diseased by 33.13% and 29.54%, as well as the values of ALT were reduced by 39.41% and 38.91% in low and middle dose groups. The content of SOD was increased by 30.34% in high dose group, and the administered groups had less influence on CYP2E1. The findings indicated that the sobering drink has a certain sobering effect on temulentia mice, and has certain protective effects on alcohol-induced live injury in mice.
    8  Composition and Anti-inflammatory Activity of Soy Isoflavone Aglycones in the Soy Sauce Residues of Different Sources
    LI Wei DU Jie ZHANG Xiao-ying DAI Wei-jie HUANG Zao-cheng GUO Da-di CAO Yong
    2019, 35(5):52-58. DOI: 10.13982/j.mfst.1673-9078.2019.5.008
    [Abstract](491) [HTML](260) [PDF 638.97 K](795)
    Abstract:
    In order to further study the composition and physiological activity of soy isoflavone aglycones from soy sauce residue, compositional analysis of soy isoflavone aglycones was performed before and after soy sauce residue of different sources being defatted, and their anti-inflammatory activities were evaluated using a RAW264.7 macrophage model. The results showed that defatting did not affect the type of isoflavone aglycones in the soy sauce residues of different sources (p > 0.05), and the total amount of soy isoflavone aglycones in the soy sauce residue from company ② was significantly higher than those for other companies (p < 0.01). After washing with water, extraction with ethyl acetate and adsorption by neutral alumina, the content of soy isoflavone aglycones in the soy sauce residue from company ② reached 30.35%±1.34%. After purification, the soybean isoflavone aglycones from Company② significantly reduced NO, TNF-α, IL-1β and IL-6 induced by lipopolysaccharide (LPS) in RAW264.7 macrophages (p < 0.01), with the highest inhibitory rates as 80.65%,75.94%, 78.52% and 85.84%, respectively (p < 0.01), thus possessing extremely significant anti-inflammatory activities. In this research, the composition and anti-inflammatory activity of soy isoflavone aglycones in the soy sauce residues of different sources were preliminarily studied, which provided a theoretical basis for further development and utilization of soybean isoflavone aglycone resources.
    9  Effect of the Degree of Polymerization of Amylopectin on the Retrogradation Properties of Jackfruit Seed Starch
    ZHANG Yu-tong ZHANG Yan-jun XU Fei ZHU Ke-xue TAN Le-he LI Shi-ze
    2019, 35(5):59-67. DOI: 10.13982/j.mfst.1673-9078.2019.5.009
    [Abstract](543) [HTML](379) [PDF 699.73 K](934)
    Abstract:
    In this study, jackfruit seed starch (JFSS) was used as the raw material and subjected to separation into amylose and amylopectin. The obtained amylose was mixed, at a mass ratio of 1:1, with five types of amylopectin with different degrees of polymerization, and the resultant mixtures were subjected to gelatinization / retrogradation to prepare retrograded JFSS with different degrees of polymerization of amylopectin (RJFSS: M1’, M5’, M6’, M11’, and BD’). M1’ had the lowest degree of polymerization of amylopectin, while BD’ had the highest. The five RJFSS samples varied significantly: from a compact structure to a loose structure. High syneresis led to the formation of a compact structure, whilst low syneresis had the opposite effect. Increasing the degree of polymerization of amylopectin raised the Avrami exponent and transition temperature, while decreasing the recrystallization rate, retrogradation enthalpy, degree of retrogradation, relative crystallinity, absorbance ratio of the five RJFSS samples. The results of the thermodynamic properties, crystalline structure, and short-range molecular order confirmed the retrogradation behaviors of RJFSS with different degrees of polymerization of amylopectin. All the obtained results indicated that the degree of polymerization of amylopectin is an important structural factor affecting the retrogradation behaviors of starch during storage.
    10  Aloe Polysaccharide Combined with Fructose-oligosaccharide in the Treatment of Alcoholic Liver Injury in Mice
    LIU Ze-xin LIU Chang QIAN He
    2019, 35(5):68-74. DOI: 10.13982/j.mfst.1673-9078.2019.5.010
    [Abstract](511) [HTML](238) [PDF 680.70 K](372)
    Abstract:
    The protective effects of aloe polysaccharide combined with fructose oligosaccharide on liver injury induced by chronic alcohol in mice were investigated. Aloe polysaccharide combined with fructose oligosaccharide was used to protect mice from chronic alcoholic liver injury. The liver index of mice was measured. Serum biochemical indexes, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC) and triglyceride (TG), and liver biochemical indexes such as reduced glutathione (GSH), superoxide dismutase(SOD), glutathione peroxidase (GSH-PX), tumor necrosis factor (TNF-α) and interleukin-6 (IL-6), were analyzed to to evaluate the protective effect of aloe polysaccharide combined with fructose oligosaccharide on liver in mice. The histopathological changes were also observed. The results showed that aloe polysaccharide combined with fructose oligosaccharide could significantly decrease ALT、AST、TCand TGto (23.37±0.80) U/L, (106.50±4.58 ) U/L (2.85±0.10) mmol/L, (1.38±0.12) mmol/L, and increase the antioxidant enzyme GSH、SOD、GSH-Px inliver to (93.65±4.93), (61.24±3.13) and (82.75±7.04) U/(mg pro) (p<0.05), respectively. However, the levels of IL-6 and TNF- α decreased to (28.24 ±0.45) and (155.90±9.67) pg/(mg pro), respectively. The protective effect of liver in high dose group was more obvious than that of silythistle. Its main protective mechanism was antioxidation. Therefore, this work provided a theoretical support for Aloe polysaccharide combined with fructose oligosaccharide compound to alleviate alcoholic liver injury.
    11  Effect of Microwave Cooking on the Quality of Astragalus membranaceus Stewed Chicken Soup
    HAN Zhong SHI Rui LIANG Han-ni CHENG Jun-hu YU Xu-cong SUN Da-wen
    2019, 35(5):75-80. DOI: 10.13982/j.mfst.1673-9078.2019.5.011
    [Abstract](490) [HTML](387) [PDF 440.32 K](571)
    Abstract:
    To study the effect of microwave processing on the quality of chicken soup, chicken breast meat and astragalus root were used as raw materials, and the microwave cooking process of astragalus membranaceus stewed chicken soup was optimized through orthogonal experiments with water-soluble protein, the nutritional index, as the evaluation index. The optimal cooking conditions were heating power, 300 W; cooking time, 60 min; ratio of material to liquid, 1:5. Under which, the water-soluble protein content in the chicken soup was the highest (1.66 mg/g). Comparisons were made on the contents of nutrients and flavor substances (water-soluble proteins, free amino acids, polysaccharides) and health and safety index (the purine content) of the chicken soups prepared using the traditional electric stew pot cooking and the optimized microwave cooking. The obtained results showed that such a microwave cooking did not damage the important nutrients (protein, fat, etc.) in the soup, thus, can meet people’s demands for nutrition through soup intake. The optimized microwave cooking produced a chicken soup with nutrition and flavor similar to that prepared by the traditional electric cooker for 4 h. The content of purine in the chicken soup prepared by microwave cooking was significantly lower than that cooked by an electric stewpot, with the total purine content essentially unchanged. Based on the comparison between the two methods for cooking soup, the microwave cooking was a more energy-efficient method.
    12  Comparison on Characterization of Orange Oil Nanocapsules Prepared by Two Coacervation Methods
    PENG Qun DENG Lin WANG Chao DUAN Han-ying
    2019, 35(5):81-86. DOI: 10.13982/j.mfst.1673-9078.2019.5.012
    [Abstract](796) [HTML](372) [PDF 594.46 K](541)
    Abstract:
    To compare the characterization of nanocapsules (Nano) prepared by complex coacervation (CC) and simple coacervation (SC) method, in this study orange oil Nano were prepared by CC and SC method, with gelatin, sodium alginate and chitosan as wall materials respectively. Two Nanos were then characterized by means of encapsulation efficiency (EE), size distribution, sustained release properties, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and nanoemulsion stability. The results showed that average particle size of two Nanos obeyed normal distribution, and their sizes were relatively uniform. SC-Nano had the smallest average particle size of 76.51±8.04 nm, wheras CC-Nano had the highest EE (82.97±1.49)% and yield (82.31±0.67)%. FE SEM manifested that the morphology of two Nanos were different, uniform in size, and smooth. FT-IR results confirmed that orange oil was successfully encapsulated. Each Nano had good sustained release properties, high zeta potential, and good nanoemulsion stability. TGA curves showed that SC-Nano had higher heat-resistance ability than CC-Nano. Thus, two Nanos can be applied to different food by their properties.
    13  Effects of Interaction between Pectin and Tannin on the Deastringency of Different Varieties of Persimmons during Maturing
    WANG Yue LI Kai-kai LI Chun-mei
    2019, 35(5):87-94. DOI: 10.13982/j.mfst.1673-9078.2019.5.013
    [Abstract](697) [HTML](220) [PDF 725.72 K](633)
    Abstract:
    To investigate the possible relationship between deastringency of persimmon and the interaction of persimmon tannin and pectin, the effect of pectin on tannin astringency was evaluated by a electronic tongue. The astringency of a solution of tannins from persimmon fruit was significantly reduced by the addition of pectin, suggesting that the interaction between tannin and pectin during the persimmon maturation might play an important role in reducing persimmon astringency. The content of both tannin and pectin and their morphological distribution in two non-astringent cultivars (‘Shangxizaosheng’ and ‘Eshi 1’) and one astringent cultivar (‘Gongchengshuishi’) during maturity were determined. The results of morphological distribution of both tannin and pectin showed that the tannin and pectin of the three varieties of persimmon fruit might contact and combine with each other during the maturing process. The soluble tannin contents of the two non-astringency persimmons were reduced to less than 0.1%, and the tannin content of astringency persimmon decreased to 0.4% during maturity. The increases in water-soluble pectin content of all the three kinds of persimmons were not found, indicating that the soluble tannin might be combined with the water-soluble pectin. Their combination was the cause of deastringency of the persimmon. The effects of interaction between tannin and pectin on deastringency during the different varieties persimmons maturation were different.
    14  Effect of Solid-State Fermentation with Monascus anka on the Compositions, in Vitro Antioxidation and Amylase-inhibitory Activity of Oat Polysaccharides
    LIU Yan LUO You WEI Dai-yue GUO Zhi-peng WU Zhen-qiang
    2019, 35(5):95-101. DOI: 10.13982/j.mfst.1673-9078.2019.5.014
    [Abstract](587) [HTML](285) [PDF 535.49 K](486)
    Abstract:
    In this work, the changing trends of the amount, composition and bioactivities of oat polysaccharides were investigated using oat as the fermentation substrate and through the combined use of enzymatic pretreatment and Monascus fermentation technology., Results revealed that the yield of polysaccharides reached to 4.50% (W/W) after β-glucosidase hydrolysis followed by Monascus fermentation, which was 1.21 times as high as that for the conventional fermentation group, and 2.23 times as high as that for the unfermented group. HPLC analysis revealed that the fermentation process led to increased molecular weights: 91.12% for molecules in the range of 10~100 ku before fermentation whilst 83.91% with molecular weights greater than 100 ku after fermentation, with the highest molecular weight up to 2.57×103 ku. The composition of monosaccharides changed significantly after fermentation, the proportions of mannose and galactose significantly increased, whilst the proportion of glucose decreased with rhamnose not detected. After fermentation, the oat polysaccharides were composed of mannose (Man), glucose (Glc), galactose (Gal), xylose (Xyl) and arabinose (Ara), at a molar ratio of 2.50 : 6.81: 4.14 : 1.09 : 2.13, and had improved bioactivities. The polysaccharides from fermented oats exhibited a higher hydroxyl radical scavenging activity, ABTS+ radical scavenging ability and a-amylase inhibitory activity, compared to those from unfermented oats. The results of this research present a new approach for deep processing of oats.
    15  Effect of LED Light Treatment on Qualities and Aroma of Fresh-cut Lettuce
    SHI Yue ZHANG Hui-jun YUAN Wei-jie DING Zhen-zhen MA Yue WANG Yu-bin ZHAO Xiao-yan ZHANG Chao
    2019, 35(5):102-108. DOI: 10.13982/j.mfst.1673-9078.2019.5.015
    [Abstract](556) [HTML](322) [PDF 600.29 K](361)
    Abstract:
    The effect of LED light treatments on qualities of fresh-cut lettuce was evaluated to inhibit their wilting and yellowing. The white, blue, green, and red LED light treatments and no light treatment were used to irradiate the fresh-cut lettuce for 5 days during the shelf display at 4 ℃. The weight loss, soluble solid content, chlorophyll content, aroma, and browning degrees were compared with the white light treatment as the control. The red LED light with the maximum emissions of 620~650 nm, purity of 77.91%, and intensity of (385.2±45.4) Lux effectively retarded the quality deterioration of the fresh-cut lettuce. After the treatment for 5 d, the weight loss of the red light treatment was 8.89 %, which was lower than that of the control (38.3%). The red light treatment maintained the chlorophyll content of lettuce, being significantly higher than that of the blue and green light treatments. The red light treatment raised the oxygen radical absorbance capacity value for 24.8 % comparing with that of the control; the electric nose analysis showed that no significant difference between the red light treatment and the control. Hence, the red light treatment was beneficial to maintain the original quality and aroma of fresh-cut lettuce.
    16  Effect of Oxygen Content and Light on Fat Oxidation during Storage of Coix Seeds
    WU Yu-zhang LU Hong-mei CHEN Li YANG Feng-yi MOU Can-can LUAN Lin-lin
    2019, 35(5):109-116. DOI: 10.13982/j.mfst.1673-9078.2019.5.016
    [Abstract](648) [HTML](302) [PDF 636.05 K](430)
    Abstract:
    The effects of changes in water content, fatty acid value, peroxide value, malondialdehyde content, lipase activity and electrical conductivity during the storage of coix seeds under different oxygen and light conditions, on the fat oxidation of coix seeds were investigated. The results showed that the fatty acid value, peroxide value, malondialdehyde content and electrical conductivity can reflect sensitively the fat oxidation of coix seeds under different storage times, oxygen contents and light conditions. With the storage time extending to 180 days, the fatty acid value, peroxide value, malondialdehyde content, electrical conductivity increased by 113.6%, 103.62%, 6.32% and 18.91, respectively, compared with the initial values, even though the oxygen content was low or not detected. At a certain level of oxygen , the indicators were 14.86%, 52.34%, 52.92% and 24.07% higher than those when the oxygen content was low or undetected; During storage of coix seeds in the dark for 180 days, the fatty acid value, peroxide value, malondialdehyde content and electrical conductivity increased by 84.85%, 132.33%, 31.34% and 12.95%, respectively. Under the influence of light conditions, these four indicators increased by 28.24%, 38.72%, 27.53% and 5.09 respectively. At a low or undetected level of oxygen, oxidation of fat could not be avoided during storage of coix seeds. The presence of oxygen and light accelerated the oxidation of fat during storage of coix seeds. In the presence of a deoxidizer, vacuum, CO2 or N2 and keeping out of light could slow down the rate of fat oxidation in coix seeds.
    17  Study on the Compound Application of Three Kinds of Proteins in Qingtuan
    SONG Lu-qing TANG Rong-xue LI Ming RUAN Zheng
    2019, 35(5):117-123. DOI: 10.13982/j.mfst.1673-9078.2019.5.017
    [Abstract](588) [HTML](301) [PDF 433.72 K](503)
    Abstract:
    In this study, glutinous rice flour, wheat starch, sticky rice flour, sweet potato powder, puerarin powder and Artemisia argyi powder were used as basic ingredients, and the effect of adding one of the three proteins (soybean protein isolate powder, whey protein powder and buckwheat protein powder) on the quality of Qingtuan was studied. In the single factor experiments, the dose of each protein was the experimental factor for examining its effect on the sensory and textural indices of glutinous Qingtuan containing puerarin and sweet potato powders. On the basis of the single factor experiments, an orthogonal experiment of 3 factors and 4 levels was carried out to optimize the formulation of the Qingtuan. The experimental results showed that the correlation coefficient of the adhesion value of the three protein powders to the Qingtuan was higher, and the influencing factors in the order from the primary to the secondary were: soy protein isolate, whey protein and buckwheat protein. The formula of Qingtuan was optimized by the Minitab software: the soybean protein isolate accounted for 6% of the mixed powder, whey protein accounted for 5% of the mixed powder, and buckwheat protein accounted for 5% of the mixed powder. The protein content of Qingtuan under such conditions was 17.42%, with the adhesion value being low, and color being pure. The results of this study provide reference data for industrial production.
    18  Study on the Interaction between Ambradiol and Bovine Serum Albumin
    WU Xiao-ming LI Li-hui HUO Jia-ying YANG Shao-xiang LIU Yong-guo TIAN Hong-yu
    2019, 35(5):124-130. DOI: 10.13982/j.mfst.1673-9078.2019.5.018
    [Abstract](596) [HTML](265) [PDF 546.08 K](784)
    Abstract:
    In this study, the interaction of ambradiol and bovine serum albumin (BSA) was investigated by fluorescence quenching, UV-Vis absorption spectroscopy and infrared spectroscopy under conditions of simulated physiological acidity. The effect of ambradiol on the fluorescence spectrum of BSA, the binding constant and the number of binding sites, thermodynamic studies presented that ambradiol quenched the endogenous fluorescence of BSA, and the hydrophobic interaction was the main driving force in the process. Ambradiol shared a binding site with warfarin on BSA. By monitoring the maximum emission wavelength of simultaneous fluorescence spectroscopy, it was confirmed that ambradiol can reduce the polarity of the tyrosine environment, increase the hydrophobicity, and increase the polarity of the microenvironment of the tryptophan residue and reduce the hydrophobicity. In addition, the results of UV-visible absorption spectroscopy, simultaneous fluorescence spectroscopy and infrared spectroscopy showed that temperature had an effect on the combination of norbornenediol and BSA, ambradiol could induced changes in microenvironment and conformation and reduced the stability of BSA.
    19  Effect of Different Precooling Time on Storage Quality of Fresh Agricultural Products
    DING Yan
    2019, 35(5):131-136. DOI: 10.13982/j.mfst.1673-9078.2019.5.019
    [Abstract](677) [HTML](265) [PDF 523.41 K](955)
    Abstract:
    In order to reduce the quantity and quality loss of fresh agricultural products in circulation and sale, the effect of different precooling time on the storage quality of fresh agricultural products was studied in this work. Four fresh agricultural products, namely tomato, cucumber, zucchini and garlic stalk, were divided into three groups. After 10 hours and 20 hours of precooling, the samples were packed with the microporous bags and then stored in the cold storage for 18 days. The samples were analyzed every 3 days. The effects of different precooling time on the weight loss rate, hardness, respiration rate and ethylene production rate, decay rate, soluble solids content, Vc content, sensory score, malondialdehyde (MDA) and peroxidase activity of agricultural products were investigated. The results showed that when the storage time reached 18 days, the decay rate and weight loss rate of agricultural products without treatment were the highest, which were 21.51% and 63.29%, respectively. The content of soluble solids was the lowest, and the rotting rate was only 12.11%. With 10 h precooling time, the weight loss rate and soluble solids were better controlled. The antioxidant activities of samples with 10 h and 20 h precooling time were significantly higher than that of the control. The highest antioxidant activity was obtained at 10 h precooling time, and the appearance quality of agricultural products was better with this condition. The results showed that the storage quality of agricultural products treated by precooling was better than that of the control. The storage quality of agricultural products after 10 h of precooling was better than that of 20 h of pre-cooling, which could reduce the loss of agricultural products during transportation and sale. The degree of freshness of agricultural products has been guaranteed at this condition.
    20  Chemical Composition and Antioxidant Activity of Cornus officinalis
    JI Lin-lin WANG Xin ZHONG Xiang-jian LI Jin-jie WANG Zhi-xin SHANG Xiao-ya
    2019, 35(5):137-143. DOI: 10.13982/j.mfst.1673-9078.2019.5.020
    [Abstract](745) [HTML](418) [PDF 662.87 K](891)
    Abstract:
    To clarify the chemical composition and antioxidant activity of Cornus officinalis, a dual-use species for medicine and food, the ethanol extract of Cornus officinalis was used as raw material in this research for examining the antioxidant components in the 20% ethanol elution of the ethanol extract through macroporous adsorption resin. The antioxidative fraction of the alcohol extract was subjected to systematic isolation and purification by chromatography techniques such as macroporous resin column chromatography, normal phase silica gel column chromatography, Sephadex LH-20 column chromatography, flash reversed phase silica gel column chromatography, and preparative HPLC chromatography. Based on the data obtained by nuclear magnetic resonance spectroscopy and mass spectrometry and from literature, five compounds were isolated and identified from the ethanol extract of Cornus officinalis: 7-β-O-ethylmorroniside (1), 7-α-O-ethylmorroniside (2), 3-O-caffeoylquinic acid n-butyl ester (3), (7R, 9R, 10R)-3, 9-di-hidroxicalameneno (4), and vomifoliol (5), among which compounds 3-5 were isolated for the first time from Cornus officinalis. In the meantime, the antioxidant activity of the isolated monomeric compound was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and Ferric ion reducing antioxidant power (FRAP) assays. Compounds 1-3 all showed certain antioxidant activities in the DPPH and FRAP experiments, with Compound 3 exhibiting the highest antioxidant activity.
    21  Preparation of Au/XC-72 Based on Different Chemical Reduction Methods and Its Catalytic Oxidation of L-CySH
    LIU Hai-xiong LIANG Zhen-xing SUN Wei-zheng
    2019, 35(5):144-150. DOI: 10.13982/j.mfst.1673-9078.2019.5.021
    [Abstract](512) [HTML](277) [PDF 747.94 K](927)
    Abstract:
    A colloidal gold solution was prepared by the methods of ethylene glycol reduction, ascorbic acid reduction, trisodium citrate reduction, and sodium borohydride reduction and supported on XC-72 substrate. Results of X-ray diffraction (XRD) showed that the catalyst prepared by the four methods contained obvious characteristic peak of Au. The Au/XC-72 diffraction peak prepared by sodium borohydride reduction method was the most gradual. Results of transmission electron microscopy (TEM) indicated that the Au NPs prepared by the sodium borohydride reduction method achieved a particle size of less than 5 nm and revealed a uniform distribution on the surface of XC-72. The Au NPs prepared by the other three methods presented larger particle size agglomeration. These catalysts (Au/XC-72) were modified on glassy carbon electrode (GCE) and used for electrochemical oxidation of L-cysteine (L-CySH). The results showed that the preparation of Au/XC-72 modified GCE by sodium borohydride reduction exihibited the best electrocatalytic activity of L-CySH in pH 2 PBS. The L-CySH oxidation was a diffusion-controlled process. It showed a good linear relationship ranging from 1 mM to 10 mM. The sensor constructed by Au/XC-72 modified GCE with high electrocatalytic activity and small particle size has great potential in practical applications.
    22  Process Optimization of Purple Sweet Potato Noodle
    FAN Hui-ping LI Fei-fei FU Feng XU Meng-yan AI Zhi-lu
    2019, 35(5):151-158. DOI: 10.13982/j.mfst.1673-9078.2019.5.022
    [Abstract](622) [HTML](204) [PDF 638.56 K](824)
    Abstract:
    The purple potato powder content, gluten content and salt content were chosen as independent variables, the broken rate and sensory score of the cooked purple potato noodles were used as evaluation index, the best production conditions for high proportion of purple potato noodles were studied. The three-factor and three-level experiments were designed using Box-Behnken center combination principle to study the interaction of each variable and its effect on the quality of purple sweet potato noodles. The experimental results showed that the optimal processing conditions of purple sweet potato noodles were as follows: The ratio of whole purple sweet potato powder to wheat flour was 44:56, the amount of wheat gluten added was 7.0%, and the amount of salt added was 1.6%. Under these conditions, the broken rate of the cooked purple sweet potato noodles was 0.42%, and the sensory score was 84.08. According to the pilot test, this process can be scaled up.
    23  Bioactive Compounds Extracted by Different Solvents from Rosa acicularis ‘Luhe’ Leaves and Their Antioxidant Activity
    ZHAO Yu-hong SHI Shuai-shuai ZHANG Li-gang
    2019, 35(5):159-166. DOI: 10.13982/j.mfst.1673-9078.2019.5.023
    [Abstract](849) [HTML](191) [PDF 521.20 K](829)
    Abstract:
    In this study, the extraction of bioactive compounds from Rosa acicularis ‘Luhe’ leaves using ultrasonic-assisted method with different solvents (distilled water, absolute ethyl alcohol, 20% ethyl alcohol, 40% ethyl alcohol, 60% ethyl alcohol, 80% ethyl alcohol, 1-butyl alcohol, acetone and ethyl acetate) was studied. Total flavonoids, total phenols, procyanidins, and antioxidant activity (DPPH radical scavenging capacity, hydroxyl radical scavenging capacity and total reducing power) were first evaluated in the extracts of Rosa acicularis ‘Luhe’ leaves. Correlation analysis of phytochemical contents with antioxidant activity was evaluated. Results indicated that different solvent extraction effects were different. The extract with ethanol concentration of 60% V/V possessed the highest yields (23.76±0.04)% and the highest total flavonoids and total polyphenol content (74.29±0.01) mg/g and (24.02±0.24) mg/g, respectively. The highest procyanidins content (12.92±0.46) mg/g was obtained in ethanol concentration of 80% V/V. The bioactive compounds contents were positively correlated to the antioxidant activity. Total phenols and total flavonoids are the major contributors to the antioxidant activities of Rosa acicularis ‘Luhe’ leave extracts.
    24  Purification and Enzymatic Characters of Recombinant Oxidase Responsible for Zearalenone Biodegradation
    PENG Xian YANG Ji-guo ZHU Jie-ying GUO Jing-jing TANG Yu-qian
    2019, 35(5):167-174. DOI: 10.13982/j.mfst.1673-9078.2019.5.024
    [Abstract](572) [HTML](203) [PDF 54.11 M](708)
    Abstract:
    The recombinant Pichia pastoris strain GS115/pPIC9K-Oxa expressing oxidase Oxa derived from Acinetobacter sp.SM04 was studied, including purification of fermentation supernant, identification of secondary structure of recombinant Oxa, ZEN-degradating ability and enzymatic characteristics. After ethanol precipitation, anion-exchange chromatography and ultrafiltration, recombinant Oxa was puri?ed more than 20 folds and exhibited remarkable efficiency in ZEN removement by over 80% degradation rate. Its secondary structure is mainly composed of random coils and β-sheet, supplemented by less β-turn and α-helix. Oxa acted as a typical thermostable alkalase by which the ZEN degradation rate was maintained above 60% in pH 9.0-11.0 buffer from 50 to 70°C. In addition, the optimum temperature and pH were 60°C and 9.0, respectively. Some proper concentration of Cu2+, Fe2+ and Fe3+ individually in environment would accelerate degradation of Oxa. The results could be helpful to evaluate the molecular structure and mode of action of Oxa in future. It would make significant practical sense for the biodegradation of zearalanone.
    25  Effect of Hot Air Pre-drying under Different Temperatures on Longan Quality by the Combined Hot Air-vacuum Freezing Drying
    YANG Jing DENG Yuan-yuan ZHANG Yan WEI Zhen-cheng LIU Guang TANG Xiao-jun WANG Jia-jia LIAO Na ZHANG Ming-wei
    2019, 35(5):175-183. DOI: 10.13982/j.mfst.1673-9078.2019.5.025
    [Abstract](805) [HTML](326) [PDF 528.50 K](802)
    Abstract:
    Effect of hot air pre-drying under different temperatures on longan quality was analyzed, and the combined drying process of longan was established. Three different temperatures of hot air drying 80 ℃, 100 ℃, 120 ℃ were investigated to analyze the moisture content, browning degree, bulk density, total sugar content, polysaccharides content and unit energy consumption of longan, and the optimum water conversion point under different temperatures in drying process was also determined. In addition, the hardness, color feature and sensory evaluation of longan were also analyze by three different drying methods (hot air drying, vacuum freeze drying and hot air-vacuum freeze drying). Results showed that the longan dried with hot air for 3 h at 100 ℃ had the best water conversion point. The moisture content was 67.6%, browning degree was 4.89/g·DW, volume density was 1.10 g/mL, total sugar content was 2.11 mg/g·DW, polysaccharides content was 1.94 mg/g·DW, and unit energy consumption was 16.74 MJ/kg. After pre-drying, longan was dried with vacuum freeze-drying for 50 h, and the moisture content of dried longan was about 7%. Furthermore, the hardness, color feature and sensory evaluation of the dried longan with hot air-vacuum freeze drying were better than those of the dried longan with hot air drying, and more similar to the sample with vacuum freeze drying. Therefore, hot air-vacuum freeze drying method could effectively improve the quality of longan, and achieve energy saving for promoting the utilization of high quality longan in food industry.
    26  Study on the Synthesis of Resveratrol by Recombinant Saccharomyces cerevisiae
    YU Yue GUO Hui-li XUE Fei-yan PENG Cheng JIANG Meng-yan MA Lan-qing
    2019, 35(5):184-190. DOI: 10.13982/j.mfst.1673-9078.2019.5.026
    [Abstract](649) [HTML](178) [PDF 645.91 K](1091)
    Abstract:
    In order to obtain a system for rapid synthesis of resveratrol by Saccharomyces cerevisiae, the key enzyme genes of the resveratrol synthesis pathway were cloned in this study, stilbene synthase gene (STS) from Polygonum cuspidatum and 4-coumaroyl-CoA ligase (4CL) from Nicotiana tabacum, to construct the fusion gene of 4CL-(GSG)3-STS by overlap PCR amplification technology through troducing three consecutive repeats of GSG as a linker peptide. The recombinant expression vector pESC-TRP-4CL-(GSG)3-STS obtained was then transformed into S. cerevisiae. The metabolites of the recombinant S. cerevisiae were analyzed by HPLC. Finally, the induction time, and substrate concentration and addition method for the synthesis of resveratrol by the recombinant S. cerevisiae were further optimized. The result showed that the yield of resveratrol could reach 7.01 mg/L 8 h after the established recombinant S. cerevisiae cells, which had grown for 48 h, were induced to express while the substrate 4-coumarate was added at 6 mg/L once every 2 h. The synthesis of resveratrol using this current system is simple for operation and requires only a short production cycle, thus, provides a basis for realizing a large-scale microbial production of resveratrol.
    27  Lipase Treatment of Distiller's Grains Wine to Promote Its Quality
    LI Zhan-sheng YAN Chen-lin JIANG Ning WU Xuan LIN Ying HAN Shuang-yan
    2019, 35(5):191-197. DOI: 10.13982/j.mfst.1673-9078.2019.5.027
    [Abstract](649) [HTML](225) [PDF 610.37 K](1255)
    Abstract:
    In this study, distiller’s grains of Luzhou-flavor liquor were used as the research object, and the effects of processing conditions such as pasteurization, reaction temperature, edible alcohol addition, Candida antarctica lipase B (CALB) and reaction time on alcohol esterification were studied. The experimental results showed that the greatest enhancement on ester content and flavor occurred after pasteurization and reactions under the following conditions: Dose of edible alcohol (95%, V/V), 20 mL/100 g; amount of CALB enzyme, 1.5 ‰ (W/W), reaction temperature and time, 20 ℃ and 3 days. Under which, the contents of ethyl acetate, ethyl hexanoate, ethyl lactate and total ester were 3.17 g/L, 0.59 g/L, 0.76 g/L and 4.53 g/L in the product, respectively. Accordingly, further experiments using 1 kg of distiller's grains were carried out, and the contents of ethyl acetate, ethyl hexanoate, ethyl lactate and total ester were 3.44 g/L, 0.85 g/L, 0.70 g/L and 4.98 g/L, respectively. The amounts of the main aroma substances of Luzhou-flavor liquor, ethyl acetate and ethyl hexanoate, in the CALB-treated sample were increased by 16.38 times and 16.67 times, respectively, compared to those without CALB enzyme treatment, and the contents of individual esters remained constant after amplification. This study provides a basis for further amplification experiments, and is of great significance to lipase-catalyzed recycling of distiller’s grains.
    28  Preparation Process Optimization and Quality Analysis of Bergamot Essential Oil Microcapsules
    LUO Xu-guang YANG Hui LIU Xiao-juan XIAO Su-yao ZHOU Ai-mei HUANG Kai-xin
    2019, 35(5):198-205. DOI: 10.13982/j.mfst.1673-9078.2019.5.028
    [Abstract](542) [HTML](298) [PDF 735.12 K](823)
    Abstract:
    In this study, the preparation process of microcapsules using bergamot essential oil as the raw material was optimized, including wall material combination, emulsification process (emulsifier composition and dosage, core-to-wall material ratio ) and spray drying conditions (inlet air temperature, atomizer frequency, feed flow rate). The optimal process parameters for microencapsulation of bergamot essential oil were first determined, and then the quality and microstructure of the resulting essential oil microcapsule products were analyzed. The results showed that the optimal conditions for preparing the bergamot essential oil microcapsules were: (1) The optimum ratio of wall material (arabic gum : β-cyclodextrin : maltodextrin) was 9:7:4 (g:g:g); (2) The optimum conditions for emulsification included the ratio of composite emulsifier (monoglyceride : sucrose ester) as 3:7 (g:g), a dosage of 0.8% for this composite emulsifier ,and the core-to-wall material ratio as 3:7 (g/g); (3) The optimized spray drying process was at an inlet air temperature of 180 ℃, atomizer frequency of 30 Hz, and feed flow rate of 55 mL/min. Under such optimal microcapsulation conditions, the obtained bergamot essential oil microcapsules possessed good sensory, physico-chemical and sustained release properties. The encapsulation rate and solubility of the products were as high as 85.32% and 93.25%, respectively, with the water content only at 2.65%. After being heated for 15 h, the products had only a volatilization rate of 12.24%, which was 79.47% lower than the unencapsulated products. The results of scanning electron microscopy showed that the obtained bergamot essential oil microcapsules were spherical in shape with smooth and continuous surfaces. Therefore, high-quality bergamot essential oil microcapsules could be produced under the optimized conditions.
    29  Optimization of Probiotic Fermentation Process for Vegetable-fruit Juice
    HE Jia-min YU Xin LIU Xue-yun
    2019, 35(5):206-213. DOI: 10.13982/j.mfst.1673-9078.2019.5.029
    [Abstract](651) [HTML](328) [PDF 703.02 K](825)
    Abstract:
    Using sugarcane, tomato and carrot as raw materials, Lactobacillus acidophilus (La), Streptococcus thermophilus (St), Lactobacillus plantarum (Lp) as fermenting strains, response surface analysis method was applied to optimize the probiotic fermentation technology of mixed fruit and vegetable juice. After single factor experiment, the best raw material ratio of fermented fruit and vegetable juice composite was sugar cane juice: tomato juice: carrot juice=5:1:2 (V/V/V); the optimal strains ratio was Lactobacillus acidophilus (La) : Streptococcus thermophilus (St) : Lactobacillus plantarum (Lp) = 3:2:1 (V/V/V); the optimum initial pH was 6.4; the optimized fermentation temperature was 39~40℃, and the inoculum was 2.5%; By response surface analysis, the optimum fermentation process was as follows: fermentation temperature 37.91℃, initial pH 6.72, inoculum 2.88%; considering the actual operation, the parameters were slightly adjusted: fermentation temperature was 38℃, initial pH was 6.7, inoculation amount was 3%. And the quality indicators such as sensory indicators, physical and chemical indicators and microbial indicators of this fermented fruit and vegetable juice were in line with the T/CBFIA 08003-2017 China Bio-Fragmentation Industry Association group standard.
    30  Preparation and Characterization of Lysozyme / Chitosan / Polyvinyl Alcohol Nanofibers
    ZHANG Dong-dong LI Qiu-ying WANG Si-wen SUN Tong ZHONG Ke-li LI Jian-rong
    2019, 35(5):214-219. DOI: 10.13982/j.mfst.1673-9078.2019.5.030
    [Abstract](517) [HTML](232) [PDF 768.45 K](1035)
    Abstract:
    In this study, chitosan/polyvinyl alcohol nanofibers (CS/PVA) with different mass ratios were prepared using electrospinning. Morphology differences of nanofibers were analyzed by scanning electron microscopy. The CS/PVA nanofibers with good morphology was selected (mass ratio was 1/9) to prepare lysozyme/chitosan/polyvinyl alcohol nanofibers (LZ/CS/PVA) by adding different concentrations of lysozyme. Morphology and characteristics of LZ/CS/PVA nanofibers were analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and differential scanning calorimetry. The results showed that the addition of lysozyme affected the morphology uniformity of fibers and the degree of adhesion between fibers. With the addition of lysozyme, the average diameter of fibers decreased from 339.62±92.72 nm (CS/PVA) to 262.10±86.32~283.01±96.83 nm (LZ/CS/PVA series fiber). When the concentrations of lysozyme were 0.3% and 0.5%, the LZ/CS/PVA nanofibers possessed good appearance. There existed molecular interaction among the components of the nanofibers hindering the formation of crystals, resulting in an almost amorphous structure. The addition of LZ increased the thermal stability of the nanofibers, and the melting point rose from 185.60 ℃ to 189.30~191.00 ℃. LZ/CS/PVA nanofibers are prepared from safe and non-toxic materials, which have potential applications in the food industry.
    31  Efficient Extraction of Flavonoids from Rubus idaeus Residue by Ultrasonic Wave Combined with High Shear Method and Its Inhibition of α-glucosidase
    ZHAO Yun-yun YANG Xin-yi WANG Shen-meng FU Qun
    2019, 35(5):220-227. DOI: 10.13982/j.mfst.1673-9078.2019.5.031
    [Abstract](473) [HTML](238) [PDF 737.07 K](780)
    Abstract:
    In order to improve the comprehensive utilization rate of Rubus idaeus pmace and extract the hypoglycemic components of Rubus idaeus pmace efficiently, in this study, flavonoid extraction and inhibition rate of α-glucosidase were used as indexes to optimize the extraction technology of hypoglycemic components in Rubus idaeus pmace assisted by high speed shear ultrasonography. The response surface method was used to optimize the main process parameters. The results of ANOVA showed that the regression model reflected the relationship between flavonoid extraction amount and ethanol concentration ratio, extraction temperature and ultrasonic treatment time. The best process conditions: high-speed shear emulsifying machine speed of 14000 r/min, extracting temperature of 55 ℃, ultrasonic time of 26 min, shear time of 40 s, ultrasonic power of 210 w. Under this condition, the inhibition rate of α-glucosidase was (65.56±0.11)%; the content of flavonoids in Rubus idaeus pmace was (39.11±0.16) mg/g. The method has an advantage in extracting efficiency and activity retention. Comparing to the use of the ultrasound process and the high shear technique, this method increased by 117.45% and 112.17% of the flavonoids contents in Rubus idaeus pmace, respectively; and increased by 47.85% and 43.79% of α-glucosidase inhibition, respectively. The efficient extraction of flavonoids from Rubus idaeus pmace also provided a new way for the extraction of hypoglycemic substances.
    32  Study on the Changes of Material Metabolism and Antioxidant Activity of Bamboo Leaf Jiaosu during the Fermentation Process
    XUE Shu-long FAN Hao-an CHEN Xiao-wei CHENG Yong-jie SHA Ru-yi MAO Jian-wei
    2019, 35(5):228-235. DOI: 10.13982/j.mfst.1673-9078.2019.5.032
    [Abstract](641) [HTML](235) [PDF 650.57 K](776)
    Abstract:
    In this study, the ethanol, total acid, lactic acid, acetic acid, total phenolic pH value and antioxidant index (DPPH free radical scavenging ability, ABTS free radical scavenging ability and reducing power) were investigated. Principal component analysis was used to establish an evaluation method of the changes of comprehensive indexes for Bamboo Leaf Jiaosu during the fermentation process. The results showed that during the fermentation of bamboo leaf Jiaosu, the ethanol content increased from 0.55% at day 10 to 2.73% at day 180, reaching the highest level; after 100 days of fermentation, the total acid content increased to 4.78 mg/mL and gradually decreased. During the fermentation, the pH value decreased from 4.37 to 3.54 and then stabilized. Lactic acid and acetic acid content increased rapidly in the first 60 days, and then began to level off; The total phenolic content continued to rise and accumulated to 0.63 mg/mL, which showed the significant correlation between total phenolic content and DPPH radical scavenging rate, ABTS radical scavenging rate and reducing force, respectively (p<0.01). Conclusion: Bamboo leaf Jiaosu has good antioxidant activity, especially for ABTS radical scavenging ability. The total phenolic content can be used as an index to evaluate the antioxidant activity of bamboo leaf Jiaosu. The comprehensive evaluation index (CEI) reached the highest value on the 230 th day and can be used as the basis for determining the pre-fermentation end point and the reference of the fed-batch fermentation time point.
    33  Comparative Study on Purification Effect of Melanin in Pepper (Zanthoxylum bungeanum) Seed Coat by Different Treatment Methods
    WANG Xiao-jing FENG Li PENG Fei MA Qi LI Mei XU Huai-de
    2019, 35(5):236-243. DOI: 10.13982/j.mfst.1673-9078.2019.5.033
    [Abstract](597) [HTML](343) [PDF 839.21 K](910)
    Abstract:
    Pepper seeds was used as raw material to prepare crude melanin extract of pepper seed coat (MCEP) by alkali-soluble acid precipitation method, and the MCEP was purified by hydrochloric acid hydrolysis, enzymatic hydrolysis, organic solvent extraction and alkali-soluble acid precipitation method, respectively, to obtain melanins of pepper seed coat (MP), which were labeled as SMP, EMP, OMP and AMP, respectively. The purification effects of the four treatment methods on MP were analyzed by the color of the pigment, ultraviolet-visible spectroscopy, color value, Infrared spectroscopy and its microstructure. The results showed that the L*, a* and b* values of SMP were significantly lower than those of AMP, OMP and MCEP (p<0.05), and the SMP was black amorphous powder with metallic luster; The SMP, EMP, OMP and AMP had maximum absorption at peak 220 nm; the color values of SMP, EMP, OMP and AMP were significantly higher than the color value of MCEP (151.25 U/g) (p<0.05), and the SMP color value (341.73 U/g) was the highest; Except for AMP, the infrared spectroscopy of OMP, EMP and SMP were weakened or disappeared compared with the absorption peaks of MCEP in C-H and C-H2 characteristic absorption band; The results of scanning electron microscope showed that SMP had a random block structure, and no other structural shapes existed. Therefore, we suggest that the hydrochloric acid hydrolysis is the best treatment method for purification and preparation of MP.
    34  Response Surface Optimization Cold Fresh Donkey Meat Compound Natural Preservative Formula
    WU Dan-feng ZHOU Xiao-yan LI Xu ZHANG Hai-feng
    2019, 35(5):244-252. DOI: 10.13982/j.mfst.1673-9078.2019.5.034
    [Abstract](455) [HTML](237) [PDF 934.21 K](728)
    Abstract:
    The response surface methodology was used to obtain a natural composite preservative formulation that could be conducive to the preservation of chilled fresh donkey meat. Ginger ethanol extract, eugenol ethanol extract and Nisin Z were used as antimicrobial agents. The single factor experiments were also conducted. Response surface methodology was used to investigate the effects of three natural antimicrobial agents on TVB-N and sensory score, and to optimize the formula. The results showed that the effects of ginger ethanol extract, eugenol ethanol extract and Nisin Z on TVB-N and sensory score were significant (p<0.05). There was synergistic effect between ginger ethanoll extract, eugenol ethanol extract and Nisin Z. The composite preservative formula is: Ginger ethanol extract 41.07 mg/mL, eugenol ethanol extract 5.39 mg/mL and Nisin Z 56.28 mg/mL, vacuum storage at 4 ℃ for 15 days, the value of TVB-N is 9.48 mg/100 g, sensory evalution 87.44. The results showed that the compound natural preservatives had better preservative effect on cold donkey meat, and had little effect on sensory quality of cold donkey meat.
    35  Study on Quality Change Model of Kiwifruit during Storage
    MA Ya-hong CAI Jin-fan FAN Xiao-jiao XING Zhuo
    2019, 35(5):253-258. DOI: 10.13982/j.mfst.1673-9078.2019.5.035
    [Abstract](582) [HTML](270) [PDF 521.32 K](778)
    Abstract:
    In order to prolong the storage time of kiwifruit and ensure its freshness, it is necessary to analyze the quality changes of kiwifruit during storage. The quality changes of kiwifruit during storage are simulated and predicted in this work. A quality change analysis model based on infrared spectroscopy was constructed. According to the model, the quality change prediction data of kiwifruit were obtained. Tthe storage period prediction model of weight loss rate of kiwifruit was also established. According to the model, the weight loss rate and the best shelf life of kiwifruit during storage were obtained. Furthermore, the change rule of quality of kiwifruit during storage was finally obtained. The results showed that there was a small gap between the quality change value and the actual value of kiwifruit during storage by using the designed prediction model. Among them, the predicted correlation coefficient of kiwifruit sample hardness is 0.806, and the predicted root mean square error is 1.112. The predicted results met the validity criteria, which showed that the proposed model can achieve the validity of the quality change of kiwifruit during storage. The model has potential practical application.
    36  Nutritional Analysis and Evaluation on Skin and Scales of Spinibarbus caldwelli
    CHENG Xiao-fei HONG Bo SU Dong-xu LI Cheng SONG Rui YUAN Xi-ping PENG Zhi-tao WU Yuan-an LI Hong
    2019, 35(5):259-267. DOI: 10.13982/j.mfst.1673-9078.2019.5.036
    [Abstract](819) [HTML](243) [PDF 818.58 K](1203)
    Abstract:
    The nutritional components of skin and scales of Spinibarbus caldwelli cultured in Zhijiang river reservoir cage in Hunan province were determined. The results showed that the contents of crude protein, crude fat, moisture, and crude ash in fresh skin of Spinibarbus caldwelli were 23.80%, 13.24%, 49.21% and 0.38%, respectively, while those in fresh scales were 40.77%, 2.70%, 53.53% and 9.05%, respectively. Both skin and scales contained 16 kinds of amino acids, in which the total amino acids (TAA) accounted for 11.91% and 50.64%, respectively. Although, the ratios of EAA/TAA and EAA/NEAA in skin were only 20.91% and 26.43%, respectively, as well as those in scales were only 16.71% and 20.06%, respectively, but the ratios of delicious amino acids (DAA)/TAA in skin and scales were up to 46.23% and 48.42%, respectively. Both skin and scales contained 11 kinds of fatty acids, in which the saturated fatty acids accounted for 23.20% and 25.01%, respectively, the monounsaturated fatty acids accounted for 53.59% and 53.95%, respectively, and the polyunsaturated fatty acids accounted for 23.21% and 21.04%, respectively. Cu, Zn, Fe, Mn and Se were detected in the skin and scales of Spinibarbus caldwelli. In skin, the content of Zn was the highest, and Se was the lowest, which were 64.62 and 0.03 mg/kg, respectively. In scales, Zn was the most abundant and Se the least abundant trace element, and their contents were 32.96 and 0.27 mg/kg, respectively. In conclusion, both skin and scales were rich in minerals and unsaturated fatty acids, with huge potential for development and utilization.
    37  QuEChERS-GC/MS Analysis of the Residues of Chlorpyrifos Degraded by Bacillus subtilis on the Phyllosphere of Brassica chinensis
    CHEN Lin LI Zu-ming BAI Zhi-hui
    2019, 35(5):268-273. DOI: 10.13982/j.mfst.1673-9078.2019.5.037
    [Abstract](548) [HTML](198) [PDF 15.79 M](1060)
    Abstract:
    In China, chlorpyrifos, as one of the most suitable pesticides to replace the highly toxic organophosphorus pesticides, has been widely used to control pests and diseases in vegetable production. However, the food safety problems brought by chlorpyrifos have attracted more and more attention. Therefore, it is very important to establish new methods for rapid detection of chlorpyrifos residues. In this study, an improved method, QuEChERS sample pretreatment coupled to gas chromatography-mass spectrometry (GC-MS) has been developed for rapid detection of the residual amount of chlorpyrifos on the phyllosphere of Brassica chinensis. The sample was extracted with acetonitrile containing 1% acetic acid, and purified with an appropriate amount of N-propyl Ethylenediamine(PSA), anhydrous magnesium sulfate, graphitized carbon black(GCB) and C18 filler, before analysis by gas chromatography-mass spectrometry and quantification with external standards. The obtained results showed a good linear relationship in the concentration range of 0.20~1.00 mg/L with correlation coefficients greater than 0.999. When the spiked level was 0.10~0.50 mg/kg, the average recoveries of chlorpryrifos were 72.00%~111.00%, with the relative standard deviations as 1.30%~1.60%, limit of detection (LOD) as 0.005 mg/kg, and limit of quantitation (LOQ) as 0.01 mg/kg. The established method is simple, rapid, accurate and sensitive, and can meet the requirements for qualitative and quantitative analysis of the residues of chlorpyrifos on the phyllosphere of Brassica chinensis. Bacillus subtilis 3374 could degrade effectively the chlorpyrifos residues on the phyllosphere of Chinese cabbage.
    38  Study on Antibiotics Resistance of Escherichia coli in Milk Samples from Cows with Mastitis in North China
    SHI Run-jia HAN Rong-wei WANG Jun TIAN Xiao-ying DENG Fang YU Zhong-na
    2019, 35(5):274-280. DOI: 10.13982/j.mfst.1673-9078.2019.5.038
    [Abstract](616) [HTML](214) [PDF 21.78 M](995)
    Abstract:
    In order to investigate the drug resistance of E. coli in the breast milk samples in North China, 240 batches of mastitis milk samples from North China were collected. E. coli was isolated and identified by EMB medium and bacterial suspension method. Susceptibility tests were performed on eight commonly used antibiotics. The results showed that 17 strains (7.08%) of Escherichia coli were isolated. The results of drug susceptibility tests showed that isolated strains of E. coli showed high resistance and multi-drug resistance. The isolated strains were resistant to 4 antibiotics at least, with the most resistant 19 species, and more than 5 resistant strains (58.82%). For single antibiotics, the resistance rate to penicillin, oxacillin, and lincomycin of isolated strains was 100%. For different types of antibiotics, the resistance rates of isolated strains of E. coli to β-lactams and lincosamides were 55.15% and 61.76%, respectively. The objective of this work was to find out the drug resistance of E. coli in milk samples from mastitis. It was helpful to prevent and control cow mastitis according to the data and reduce the residue of veterinary drugs in milk, which would improve the quality of milk.
    39  Analysis of Volatile Compounds in Sweet Corn Beverage with Different Sterilizations
    CHENG Yuan WU Ji-jun LIU Zhong-yi YU Yuan-shan XU Yu-juan XIAO Geng-sheng
    2019, 35(5):281-288. DOI: 10.13982/j.mfst.1673-9078.2019.5.039
    [Abstract](553) [HTML](187) [PDF 3.00 M](876)
    Abstract:
    A combination of solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) was used to study the effects of different sterilizations [fresh corn beverage, treated atmospheric pressure sterilization, medium temperature sterilization, high temperature sterilization, ultra high pressure (UHP) and ultra-high temperature instantaneous sterilization (UHT)] on the aroma substances in sweet corn beverage. In this experiment, D-limonene and myrcene were the main flavor components in fresh sweet corn beverage. D-limonene had a delicate, flower like fragrance, and myrcene was provided with fruit aroma. The contents of D-limonene and myrcene in fresh corn beverage were 14.18 mg/L and 2.71 mg/L, respectively. After sterilization, the content of D-limonene and myrcene decreased. Dimethyl sulfide is an essential hallmark component of heat-sterilized corn beverage, which was not detected in fresh corn beverage and UHP group. Dimethyl sulfide has “sweet corn fragrance” and dimethyl sulfide only appeared in heat sterilization. Among the treated sweet corn beverages, the content of dimethyl sulfide in the high temperature sterilization treatment group was up to 32.48 mg/L, and the contents were 15.07 mg/L, 11.43 mg/L and 9.16 mg/L in the medium temperature sterilization group, UHT group and atmospheric pressure sterilization group, respectively. The results also showed that the sweet corn flavor components such as terpenes, alcohols and ethers for different sterilization methods were significantly different. Non-thermal sterilization and low-intensity heat sterilization can better maintain the original flavor of sweet corn, and heat sterilization beverage produced a flavoring substance such as dimethyl sulfide to impart a unique fragrance to the heat-sterilized sweet corn beverage.
    40  Antibiotic Resistance of Aeromonas veronii and Streptococcus agalactiae in Aquatic Animals from Guangdong
    LYU Guan SHI Lei XU Li-wen YAN Yuan-yi CHANG Yan-lei XIAO Ya-wen
    2019, 35(5):289-295. DOI: 10.13982/j.mfst.1673-9078.2019.5.040
    [Abstract](702) [HTML](345) [PDF 9.04 M](909)
    Abstract:
    To evaluate the antibiotic sensitivity of Aeromonas veronii and Streptococcus agalactiae from aquatic animals in Guangdong Province, Aeromonas veronii and Streptococcus agalactiae were isolated from aquatic animals cultured in 9 areas of Guangdong Province. Among them, 32 strains of Aeromonas veronii and 16 strains of Streptococcus agalactiae were isolated. The sensitivity of these strains to 14 different antibiotics was determined using drug-sensitive disk method. It was found that the two strains of bacteria were sensitive to 7 kinds of antibiotics. Based on the detection of drug resistance of isolated strains to 7 sensitive antibiotics by minimum inhibitory concentration(MIC) method. 32 strains of Aeromonas veronii were found to be resistant to thiamphenicol (29%), sensitive to oxytetracycline hydrochloride (41%) and josamycin (38%), ciprofloxacin hydrochloride (82%), doxycycline hydrochloride (82%), florfenicol (75%) and sulfamethazine (100%). All of 16 Streptococcus agalactiae strains were found to be resistant to thiamphenicol (100%), but sensitive to josamycin (25%), and ciprofloxacin hydrochloride (100%), doxycycline hydrochloride (100%), oxytetracycline hydrochloride (100%), florfenicol (100%) and sulfamethazine (100%). This study provides some reference for the future use of antibiotics in Aeromonas veronii and Streptococcus agalactiae, and promotes the rational use of antibiotics.
    41  Screening of Sulfonamide-sensitive Strains by UV Mutagenesis and Their Applications in Detection of Sulfonamide Residue in Milk
    KOU Ling-yun QUE Fei NIU De-jun WANG Ying
    2019, 35(5):296-303. DOI: 10.13982/j.mfst.1673-9078.2019.5.041
    [Abstract](699) [HTML](185) [PDF 27.82 M](811)
    Abstract:
    In this study, two strains with sulfonamide-sensitive strains H1 and H2 were screened by UV mutagenesis. After DNA identification, the two strains were of the genus Bacillus, a species of Geobacillus stearothermophilus. Using H1 and H2 as the indicator bacteria, the total amount of sulfonamide residues in milk was detected, and the obtained results showed that these two strains exhibited different sensitivities to different kinds of sulfa drugs. When the total colony ratio of spore suspension for H1 and H2 was 3:4, the test kit had good sensitivity: sulfonamide, 30 μg/L; sulfadiazine, 30 μg/L; sulfamethazine, 30 μg/L; sulfamethazine, 30 μg/L; sulfonamide, 60 μg/L; sulfathiazole, 45 μg/L; sulfachloropyridazine, 80 μg/L; sulfamethoxazole, 75 μg/L; sulfazone, 75 μg/L. Under these conditions, the two strains were simultaneously passaged, and the effect of strain passage on the sensitivity of the test kit was investigated. The results showed that the test kit lost sensitivities to sulfonamide and sulfaguanidine when the fourth generation bacteria was used as the indicator. The sensitivity to sulfachloropurazine or sulfamethoxazole also lost when the sixth generation was used. Whereas, the sensitivity to sulfonamides, sulfadiazine, sulfamethazine or sulfathiazole remained constant till the seventh generation. Compared with domestic and overseas commercial kits, this kit had a higher sensitivity than the domestic kits, and showed advantage in detection time over the overeas kits.
    42  Recognition of Beef Deterioration Areas Based on Adaptive Optimal Genetic Algorithms
    ZHANG Zhan-zhao XU Mo ZHOU Hong-fei
    2019, 35(5):304-309. DOI: 10.13982/j.mfst.1673-9078.2019.5.042
    [Abstract](506) [HTML](285) [PDF 16.94 M](720)
    Abstract:
    To solve the problem of low accuracy and long time of traditional methods for beef deterioration area identification, a method based on adaptive optimization genetic algorithm was investigated. The subset of beef detection spectrum data was used as chromosome, and binary coding was used to calculate individual coding and population initialization. The fitness function was used to optimize crossover and mutation operation, and the individual crossover probability and mutation probability were calculated for different individuals of the population. The final detection spectrum data of beef deterioration area was output. The resultas showed that 40 iterations could conduct beef deterioration area recognition the proposed method. The average recognition accuracy was 95.8%, and the recognition time was 1.7 s. Compared to two traditional methods, the recognition accuracy in this work was improved by 28.72% and 20.34%, respectively, and the recognition time was shortened by 2.09 s and 4.13 s, respectively. The proposed method had the advantages of high recognition rate, short time, high reliability, scientificity and feasibility in identifying beef spoilage areas.

    Editor in chief:李琳

    Inauguration:现代食品科技

    International standard number:ISSN 1673-9078

    Unified domestic issue:CN 44-1620/TS

    Domestic postal code:46-349

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