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Table of Content

15 June 2018, Volume 39 Issue 11
Basic Research
Determination of Thermal Hysteresis Activity of Antifreeze Protein from Antarctic Krill (Euphausia superba) by Differential Scanning Calorimetry
MA Qingbao, LIU Zhidong
2018, 39(11):  1-7.  doi:10.7506/spkx1002-6630-201811001
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In this study, we investigated whether differential scanning calorimetry (DSC) can be used to detect thermal hysteresis activity (THA) of antifreeze proteins (AFPs) from Antarctic krill. Important experimental conditions, such as cooling rate, sample concentration, ice crystal content and buffer system, were optimized. The results showed that the molecular weight of AFPs was about 76 kDa and its THA was 1.76 ℃. A cooling rate of 1.00 ℃/min, a sample concentration of 1.0 mg/mL and an ice crystal content ranging from 10% to 15% were found to be the optimal conditions. THA was greatly affected by different buffer systems. This study led us to conclude that DSC can be effectively used for the evaluation of THA of AFPs.
Self-Assembly System of α-Lipoic Acid as an Antioxidant and Preparation of Molecularly Imprinted Polymers for Its Selective Adsorption
HUANG Yun’an, XU Long, YANG Bowen, ZHU Qiujin
2018, 39(11):  8-14.  doi:10.7506/spkx1002-6630-201811002
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The density functional theory was applied to simulate the self-assembly system of molecularly imprinted polymers specific for α-lipoic acid (ALA-MIPs) with N-isopropyl acrylamide (NIPAM) as a functional monomer at the B3LYP level. At the simulated optimal ALA-to-NIPAM, ALA-MIPs were prepared with ethylene glycol dimethacrylate (EGDMA) as a cross-linker and 2,2’-azodiisobutyronitrile (AIBN) as an initiator by bulk polymerization, and the morphology and structure of ALA-MIPs were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The adsorption capacity was evaluated as well. The computational simulation results indicated that the template and the functional monomer at a molar ratio of 1:2 could form stable structures. There were two kinds of binding sites found in the obtained ALA-MIPs; the corresponding dissociation constants were 6.969 7 × 10-5 and 1.558 5 × 10-5 mol/L, and the maximum adsorption capacities of ALA onto ALA-MIPs were 12.145 and 104.06 mg/g, respectively. Moreover, the ALAMIPs showed a good selectivity for ALA and its analogues compared with the non-imprinted polymers (NIPs).
Effect of Different Feeding Methods on AMP-Activated Protein Kinase Activity and Glycolysis of Postmortem Sunit Sheep
HOU Yanru, MA Xiaobing, SU Lin, ZHAO Yajuan, LUO Yulong, ZHAO Lihua, JIN Ye
2018, 39(11):  15-20.  doi:10.7506/spkx1002-6630-201811003
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The effect of different feeding methods on AMP-activated protein kinase (AMPK) and glycolysis in longissimus dorsi muscle from Sunit sheep were investigated in this study. The results showed that longissimus dorsi muscle from grazing sheep exhibited significantly higher Warner-Bratzler shear force, L* and b* values when compared with pen-reared sheep (P < 0.05). The pH1 and pH24 of longissimus dorsi were not significantly between different feeding methods (P > 0.05). PRKAA1 and PRKAG3 gene expression in pen-fed sheep were significantly higher than in grazing sheep (P < 0.05), but the opposite was found for PRKAA2 gene expression (P < 0.05). AMPK and hexokinase activity under pen-fed conditions were higher but not statistically significantly than under grazing conditions (P > 0.05). Lactic acid content under pen-fed conditions was significantly higher than under grazing conditions (P < 0.05). Correlation analysis revealed that PRKAG3 gene expression positively regulated AMPK activation, hexokinase activity and lactic acid content (P < 0.05), but had a significantly negative correlation with Warner-Bratzler shear force (P < 0.05). PRKKA1 gene expression and lactic acid content were significantly positively correlated with each other (P < 0.05), while PRKKA2 had no significant correlation with AMPK or glycolysis indicators. AMPK activity was significantly positively correlated with hexokinase activity and lactic acid content (P < 0.05). From the above results, we concluded that high levels of PRKAA1 and PRKAG3 gene expression resulted in AMPK activation and consequently an increase in hexokinase activity, thereby accelerating the process of glycolysis, increasing lactic acid content, reducing pH and consequently affecting meat quality.
Effects of Different Cooling Methods on Quality of Cooked Cured Bacon
ZHANG Pu, ZHANG Dian, ZHANG Kunsheng, REN Yunxia, ZOU Tonghua, CHEN Jinyu
2018, 39(11):  21-25.  doi:10.7506/spkx1002-6630-201811004
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The central temperature of cooked cured bacon was cooled from 60 ℃ to 25 ℃ by different cooling methods, namely vacuum cooling, natural + vacuum cooling, natural cooling and air-blast cooling before being stored at 4 ℃. Quality changes during storage were investigated. Four cooling methods were compared for their effects on cooling rate, mass loss percentage, texture, color, odor and sensory evaluation. The results showed that vacuum cooling and natural + vacuum cooling reduced microbial contamination thereby prolonging the shelf-life of cooked cured bacon. Moreover, the cooling time was shortened by natural + vacuum cooling method while improving the taste.
Effect of Sterilization Temperature on Fatty Acid Composition and Lipid Oxidation of Emulsified Sausage
ZHOU Huimin, ZHAO Yan, REN Shuang, LI Su, ZHAO Bing, PAN Xiaoqian, CHEN Wenhua, QU Chao, ZHANG Shunliang
2018, 39(11):  26-31.  doi:10.7506/spkx1002-6630-201811005
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The objective of this study was to evaluate the effect of different sterilization temperatures on the fatty acid composition and lipid oxidation of emulsified sausage. The lipids were extracted with chloroform and methanol, saponificated and methylated before being analyzed by gas chromatography-mass spectrometry. The results showed that fatty acid composition and lipid oxidation changed after emulsified sausages were sterilized at different temperatures. When sterilization temperature exceeded 100 ℃, the content of saturated fatty acids (SFA) increased significantly (P < 0.05), while the content of unsaturated fatty acids (UFA) decreased significantly (P < 0.05); the content of polyunsaturated fatty acids (PUFA) decreased highly significantly (P < 0.01), but no significant difference was noted in the content of monounsaturated fatty acids (MUFA) (P > 0.05). n-6 PUFA/n-3 PUFA ratio and PUFA/SFA ratio significantly increased and decreased, respectively. Meanwhile, sterilization at 100–110 ℃ significantly improved peroxide value (POV) and thiobarbituric acid reactive substances (TBARS) value. Sterilization at above 100 ℃ significantly increased the contents of C14:0, C16:0, C18:0 and C20:0 and decreased significantly the contents of C18:2n6, C18:3n3, C20:3n6 and C20:4n6, while C20:5n3 and C22:6n3 were undetectable in the sterilized sausages. Therefore, sterilization at below 100 ℃ could maintain the fatty acid composition of sausages to the greatest extent. Sterilization at above 100 ℃ significantly damaged the proportion of fatty acids, and promoted significantly lipid oxidation. This study can provide technical support for the application of sterilization in the production of meat products.
Effect of Processing Conditions on Quality and Microbial Population of Soft-Boiled Chicken
LI Ming, XING Tong, WANG Huhu, XU Xinglian, ZHOU Guanghong
2018, 39(11):  32-38.  doi:10.7506/spkx1002-6630-201811006
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In order to investigate the effect of processing parameters on the quality of soft-boiled chicken (SBC), three different soaking times (18, 20 and 22 min) in hot marinade at 95 ℃ and two different cold dipping times (8 and 15 min) were chosen, and totally six different combinations were designed to produce SBC. SBC was cooked at 25 ℃ for 2 h. The cooking yield, water-holding capacity, pH, color, texture profile analysis, microstructure and sensory properties were determined and aerobic plate count (APC) was measured after storage at ambient temperature for 2 h. Results showed that in the case of fixed cold dipping time, cooking yield decreased significantly while water-holding capacity increased significantly (P < 0.05); the gaps between muscle fibers became smaller and APC decreased significantly (P < 0.05) with the increase of hot soaking time. The texture properties of SBC with 15 min cold dipping were significantly better than those of SBC dipped for 8 min (P < 0.05). Sensory evaluation showed that the taste and flavor scores of SBC with 18 min soaking were significantly lower than those of other treatments (P < 0.05), and different cold dipping time had a significant influence on taste scores (P < 0.05). In conclusion, 20 min soaking in marinade at 95 ℃ followed by 15 min cold dipping in ice water gave preferable SBC with the highest sensory score. The results of this study provide a theoretical support and information for further exploration of standardized industrial production of SBC.
Effects of Different Drying Methods on Nutritional and Functional Components and Amino Acid Composition of Moringa oleifera Leaves
GUO Gangjun, HU Xiaojing, XU Rong, MA Shangxuan, LONG Jiming, LI Haiquan
2018, 39(11):  39-45.  doi:10.7506/spkx1002-6630-201811007
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The leaves of Moringa oleifera (periyakulam-1, an improved cultivar) were dried by 6 industrial drying methods: shade drying, sun drying, and mechanical (hot air at 40 and 60 ℃, microwave and far-infrared ray) drying. The major nutritional and functional components, vitamins and amino acid contents in the dried leaves were investigated. The essential amino acid composition was evaluated by score of ratio coefficient of amino acid (SRCAA) according to the World Health Organization/Food and Agriculture Organization of the United Nations (WHO/FAO) reference pattern. The results showed significant differences in the contents of protein, total phenols, vitamin E, β-carotene, vitamin B2, vitamin C, vitamin B6, nicotinic acid and pantothenic acid, while no significant difference in crude fat, flavonoid or polysaccharide contents of Moringa oleifera leaves subjected to different drying methods was observed. On the whole, hot air drying at 60 ℃ had the lowest impact on the nutritional and functional components and amino acids; L, a and b values of the dried leaves were 90.26, 5.55 and 6.35, respectively, the contents of protein, flavonoids, total phenols, total amino acids, essential amino acids, vitamin E, β-carotene, vitamin B2, vitamin B6 and pantothenic acid were 30.76%, 3.17%, 13.82%, 30.56%, 12.35%, 113.00 mg/100 g, 60.36 mg/100 g, 1.90 mg/100 g, 8.18 mg/100 g, and 89.10 mg/100 g, respectively, which were higher than those obtained using other drying methods. The proportion of essential amino acids in total amino acids was 1.17 times higher than the WHO/FAO reference pattern and SRCAA was 63.88. According to the WHO/FAO reference pattern, the first limiting amino acids were methionine and cystine. Overall, hot air drying at 60 ℃ was more suitable for drying of fresh leaves of Moringa oleifera. The results of this study can provide scientific information for industrial exploitation of Moringa oleifera leaves.
Structural Analysis and in Vitro Inhibitory Effect on α-Glucosidase Activity of Millet Bran Dietary Fiber before and after Modification
CAO Longkui, KANG Lijun, KOU Fang, SHEN Meng, GE Yunfei, WANG Weihao
2018, 39(11):  46-52.  doi:10.7506/spkx1002-6630-201811008
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Millet bran dietary fiber (MBDF) was modified by combined ultrasonic-microwave treatment in this study. The structures of the original and modified MBDF were investigated by means of scanning electron microscope (SEM), gel permeation chromatography-refractive index-multi-angle light scattering (GPC-RI-MALS), X-ray diffraction, infrared spectroscopy and ion chromatography. The inhibitory effect of the original and modified soluble dietary fiber (SDF) from millet bran on α-glucosidase activity was explored using in vitro α-glucosidase inhibitor model. SEM images showed that the surface of SDF became rough, loose and porous after modification and was composed of aggregated small particles. The results of GPC-RI-MALS indicated that the molecular mass of modified millet bran SDF was smaller than that of the original one. The crystallinity of the modified insoluble dietary fiber from millet bran was increased as indicated by X-ray diffraction analysis. Fourier transform infrared spectroscopic analysis illustrated that the chemical functional groups of the original millet bran SDF did not change after modification. Both the original and modified millet bran SDF had the characteristic absorption peaks of carbohydrates. Ion chromatography showed that both the original and modified millet bran SDF were composed of arabinose, galactose, glucose, xylose, mannose and fructose, with differences being observed in the monosaccharide contents. Both the original and modified millet bran SDF could inhibit the activity of α-glucosidase, while the inhibitory effect of modified millet bran SDF was stronger than that of the original one, with a half-maximal inhibitory concentration of 0.415 mg/mL.
Effect of MgSO4 Treatment on Bioactive Compounds and Antioxidant Activity in Broccoli Sprouts
CHU Ting, PENG Chang, GUO Liping
2018, 39(11):  53-59.  doi:10.7506/spkx1002-6630-201811009
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The growth, bioactive compound contents and antioxidant activity of broccoli sprouts sprayed with exogenous MgSO4 at 0, 25, 50 and 75 mmol/L were studied in this investigation. The results showed that MgSO4 inhibited the growth of broccoli sprouts. The contents of chlorophyll and total phenolics increased with the increase of MgSO4 concentration; however, ascorbic acid content continuously reduced. In addition, 5-day-old sprouts contained more glucosinolates and sulforaphane than 8-day-old sprouts, whereas the opposite was observed for myrosinase activity. MgSO4 treatment significantly enhanced the contents of glucosinolates and sulforaphane as well as myrosinase activity, but no significant difference was found between 50 and 75 mmol/L treatments. Antioxidant ability was significantly promoted by MgSO4 treatment. Specially, no significant difference in 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity was observed between 50 and 75 mmol/L MgSO4 groups. Nevertheless, H2O2 scavenging capacity was gradually enhanced with the increase of MgSO4 concentration. These results suggest that 50 mmol/L MgSO4 treatment could be useful to improve the nutritional value and health-promoting function of broccoli sprouts.
Effect of Different Additives on Visual Appearance, Microstructure, Cooking and Eating Quality and in Vitro Glycemic Index of Extruded Artificial Rice
WANG Xian, ZHOU Xianqing, HU Honghai, ZHANG Hong
2018, 39(11):  60-68.  doi:10.7506/spkx1002-6630-201811010
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This study investigated the influence of supplementary materials with hypoglycemic effect such as inulin, oat bran and soybean polysaccharides on the eating quality and glycemic index of extruded artificial rice. The results showed that inulin could increase the brightness of extruded artificial rice; however, the cooking loss rate was markedly increased when it was added at more than 5%. Soybean polysaccharides and oat bran could reduce the brightness of extruded artificial rice, but had no significant effect on the cooking loss rate. We found that the hardness decreased with increasing addition of supplementary materials, and inulin could significantly reduce the stickiness of artificial rice. All three supplementary materials had little impact on the springiness and cohesiveness, while they decreased the sensory quality of extruded artificial rice, with oat bran having the least effect. Electronic nose results showed that there was a significant change in the odor of extruded artificial rice when the supplementary materials were added at 50% rather than at lower than 25%. According to scanning electron microscopy analysis, the addition of inulin loosened the microstructure of the artificial rice leading to the formation of tiny voids, while tiny voids were observed only at the high addition level for soybean polysaccharides and oat bran. In vitro digestion experiments indicated that low glycemic index was obtained by adding oat bran or inulin at 50% and soybean polysaccharides at more than 35%. In conclusion, different additives have different effects on the eating quality and glycemic index of extruded artificial rice, and the appropriate additive should be chosen according to the demand.
Selection of Quality Evaluation Factors for Korla Fragrant Pear, Bud Mutants and Hybrid Varieties (Strains)
WEI Jie, JIANG Yuan, LIN Caixia
2018, 39(11):  69-74.  doi:10.7506/spkx1002-6630-201811011
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In order to simplify the quality evaluation of Korla fragrant pear and its bud mutants as well as hybrid varieties (strains), the main quality traits of 13 fruit samples from Korla fragrant pear and its bud mutants as well as hybrid varieties (strains) including single fruit weight, flesh firmness, fruit shape index, core/fruit ratio, soluble solid content, soluble sugar content, titratable acidity, stone cell content, vitamin C content, and sugar/acid ratio and juice content were analyzed by principal component analysis (PCA) and cluster analysis. The results showed significant differences in fruit quality parameters among these varieties (strains). The variation (CV) coefficients of stone cell content and single fruit weight were larger, whereas the CV of juice content was smaller than that of other quality parameters. There was a simple correlation between some quality traits. In PCA, 5 principal components were extracted and explained cumulatively 88.964 5% of the total variance. These principal components were sufficient to represent the quality characteristics of Korla fragrant pear. Five varieties (strains) were selected based on their principal component scores, including 84-1-1, 84-1-15, Xinli No. 9, Xinli No. 8 and 84-4-72. The five most important fruit quality parameters were single fruit weight, fruit shape index, stone cell content, soluble solid content and juice content according to cluster analysis. In conclusion, principal component analysis and cluster analysis are useful for the evaluation and selection of fruit quality traits of Korla fragrant pear and its bud mutations as well as hybrid varieties (strains).
Identification of Anthocyanins in Red Raspberry and Mulberry Juices and Effects of Different Sterilization Treatments on the Quality of Juices
LI Mengli, MA Jianyong, LI Chunmei
2018, 39(11):  75-82.  doi:10.7506/spkx1002-6630-201811012
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The major anthocyanins and flavonoids in red raspberry and mulberry were identified by ultraviolet-visible spectrophotometry and highperformance liquid chromatography-electrospray ionization-mass spectrometry. The effects of three different sterilization methods, including pasteurization (PS), boiling sterilization (BS) and microwave sterilization (MS), on the contents of total and individual anthocyanins, total phenols, major flavonoids and H2O2, and other physicochemical properties (pH, total soluble solid, absorbance, browning degree and transmittance) of red raspberry and mulberry juices were compared in the present study. The results indicated that major anthocyanins were cyanidin 3-sophoroside and cyanidin 3-glucoside in red raspberry, and cyanidin 3-glucoside and cyanidin 3-rutinoside in mulberry. Compared with the untreated juice, three sterilization methods reduced the contents of total and individual anthocyanins and total phenols , and MS treatment showed the weakest effect. No significant difference in the H2O2 level (P > 0.05) of sterilized juice was observed among different sterilization methods. Taken together, MS treatment could maintain the nutritional quality of red raspberry and mulberry juices.
Food Engineering
Effect of Gamma Irradiation on the Prebiotic Functions of Konjac Glucomannan
LI Meiying, FENG Guanping, XU Zhenlin, SUN Yuanming
2018, 39(11):  83-88.  doi:10.7506/spkx1002-6630-201811013
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This work aimed to explore the effect of gamma irradiation on the fermentation characteristics and the prebiotic functions of konjac glucomannan (KGM). KGM was irradiated with 60Co gamma at doses of 0, 10, 20 and 30 kGy. The influences of different radiation doses on the changes in pH, short-chain fatty acid (SCFA) content, the numbers of harmful and beneficial bacteria, the ratio between the numbers of bifidobacteria and Escherichia coli (B/E ratio) and prebiotic index (PI) were compared during in vitro anaerobic fermentation of feces from healthy volunteers. Results showed that the pH of the fermentation broth decreased whereas B/E ratio and PI increased significantly in the irradiation groups when compared with the positive control glucose. Meanwhile, gamma irradiation could also contribute to the production of SCFA, as well as the improvement of the microbial composition of the fermentation broth. The contents of SCFA and PI value increased with increasing radiation dose ranging from 0 to 30 kGy. PI values of KGM irradiated at 0, 10, 20 and 30 kGy were 0.48, 0.61, 0.76 and 0.78, respectively. Thus, KGM exerts a good prebiotic effect in the gut and its prebiotic functions can be enhanced by gamma irradiation. Taking PI into account, 20 kGy was recommended as a suitable irradiation dose for KGM.
Effect of High Pressure Processing on Gel Properties of ChickenB reast Myofibrillar Protein Containing Magnesium Chloride
PAN Jie, ZHOU Ying, WANG Yu, DAI Xianzhuo, LI Peijun, CHEN Conggui
2018, 39(11):  89-94.  doi:10.7506/spkx1002-6630-201811014
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This research aimed to investigate the effect of high pressure processing (HPP) (at 100–400 MPa and 20–25 ℃ for 10 min) on the hardness and water-holding capacity (WHC) of chicken breast myofibrillar protein (MP) gel with 0.3% (m/m) magnesium chloride under low salt (2.3% NaCl) condition. The underlying mechanism was explored by rheological analysis, transverse relaxation time determination and microstructure observation. The results showed that the gel hardness and WHC were significantly (P < 0.05) increased with elevated pressure levels, and the appropriate pressure was 300 MPa. HPP could promote the formation of compact, porous and cross-linking gel network structures and consequently improve gel properties of chicken breast myofibrillar protein by increasing the storage modulus (G’) and shortening the water relaxation time (T22 and T23).
Inactivation of Bacillus subtilis Spores by Ultrasonic Treatment Combined with Inducer
TAO Rui, SHI Zhijia, GONG Hui, YANG Zhen, LIU Meng
2018, 39(11):  95-100.  doi:10.7506/spkx1002-6630-201811015
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In order to extend the shelf life of foods and kill spores under mesothermal conditions, ultrasound combined with heat treatment and germination inducers was used to explore the optimal conditions for killing Bacillus subtilis spores. The results showed that the germination rate of spores was up to 98.23% under the following conditions: ultrasonic power 600 W, ultrasonic frequency 25 kHz, 60 ℃,L-alanine 50 mmol/L and inosine 6 mmol/L. When other conditions were maintained same, the germination rate of spores was improved significantly by decreasing ultrasonic power (900, 600, 300 and 100 W), and inactivation of the spores could guarantee food safety and quality.
Effect of Gelatinization by Extrusion on Physicochemical Properties of Tartary Buckwheat Flour
ZHOU Xingjie, YU Shaojing, CHEN Kai, JI Mengying, TATSUMI Eizo, LUAN Guangzhong
2018, 39(11):  101-106.  doi:10.7506/spkx1002-6630-201811016
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In order to study the effect of gelatinization by extrusion on physicochemical properties of tartary buckwheat flour, four different gelatinization degree of tartary buckwheat flour, 37.7%, 56.3%, 74.3% and 94.2%, were obtained by a single-screw extruder, and the major chemical constituents, pasting properties, hydration properties, thermodynamic properties and microstructure of the extruded flours were determined. The results showed that the contents of total flavonoids and lipids in flour reduced significantly (P < 0.05) and the color of flour became darker with the increase of gelatinization degree, while the contents of starch, ash and protein showed no significant change (P > 0.05). The proportion of damaged starch, water absorption index and water retaining capacity increased significantly (P < 0.05). The rapid viscosity analyzer analysis indicated that peak viscosity, trough viscosity, trough viscosity, final viscosity, setback, and peak time declined after extrusion. Scanning electron microscope observation showed that tartary buckwheat flour appeared as round or irregular polygon starch granules with smooth surface, while the extruded flour had no definite shape and the surface became rough with cracks and holes. To conclude, the above results provide useful data for insights into the underlying mechanism and for the application of extruded tartary buckwheat flour.
Effect of Extrusion Treatment on Processing Characteristics and Microscopic Structure of Potato Flour
ZHANG Yanrong, PENG Shan, LIU Tingting, FAN Hongxiu, CHEN Bingyu, MA Ninghe
2018, 39(11):  107-112.  doi:10.7506/spkx1002-6630-201811017
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Potato flour was modified by extrusion cooking. The effects of extrusion temperature and water content on the processing characteristics of potato flour and dough elasticity were investigated. The optimum extrusion parameters were determined by one-factor-at-a-time method. Scanning electron microscopy, differential scanning calorimetry, a rapid viscosity analyzer and X-ray diffraction were used to evaluate the structure, thermodynamic properties, gelatinization characteristics and crystallinity of extruded and native potato flour. The results showed that an extrusion temperature of 150 ℃ and a water content of 35% were found to be the optimum conditions to obtain the best processing characteristics, higher solubility, the best water-holding capacity, better freeze-thaw stability and the highest dough elasticity. After extrusion, the surface microstructure of potato flour became wrinkled; the specific surface area increased, while the thermal stability, the gelation capacity and the crystallinity decreased. Extruded potato flour was difficult to retrograde.
Effect of Autoclaving Combined with Sodium Alginate on Pasting Properties and Crystal Structure of Common Corn Starch
WANG Yusheng, XU Pengcong, CHEN Haihua, CHEN Jiangang, XIA Xiaochen
2018, 39(11):  113-118.  doi:10.7506/spkx1002-6630-201811018
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The aim of this study was to investigate the effect of autoclaving combined with sodium alginate on pasting properties and crystal structure of common corn starch (CCS). The pasting properties, gel hardness and crystal structure of CCS treated by autoclaving with or without sodium alginate under different conditions (autoclaving time and starch concentration) were determined. The results showed that the combined treatment obviously decreased the pasting temperature of CCS. The best stability of starch was achieved under the following conditions: starch concentration 20%–25% and 30 min autoclaving. Compared to autoclaving alone, the combined treatment reduced the variation in gel hardness of CCS. The lowest gel hardness of starch was observed at a starch concentration of 25%. The crystal structure of CCS changed from A-type to V-type due to autoclaving treatment, independent of the presence or absence of sodium alginate. The content of A-type crystal gradually decreased with prolonged autoclaving time.
Physicochemical and Moisturizing Properties of β-Glucan from Candida utilis Extracted by Different Methods
MA Xia, LIU Lantian, SHEN Li, SHAO Li
2018, 39(11):  119-125.  doi:10.7506/spkx1002-6630-201811019
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Three different methods: high pressure microfluidization, ultrasonic, dual enzymatic hydrolysis were employed to extract β-glucan from the cell walls of the yeast Candida utilis and the obtained extracts were designated as H-YG, U-YG and E-YG, respectively. The yields, purities, molecular mass distributions, and monosaccharide compositions of these β-glucans were compared. We also evaluated the effect of three extraction methods on the antioxidant activity and moisturizing properties of β-glucans. The results showed that the purities of β-glucan extracted by three methods were all above 96% and high pressure microfluidization gave the highest yield and purity of β-glucan of 19.6% and 97.5%, respectively. UV spectra showed that none of these β-glucans contained nucleic acids, proteins or other impurities. Monosaccharide composition analysis showed that all three β-glucans were homogenous polysaccharides composed of only glucose. The molecular mass distribution and the average molecular radius were measured by high-performance size exclusion chromatography and multi-angle laser light scattering, and the results indicated that the weight average molecular masses of H-YG, U-YG and E-YG were 1.611 ×106, 4.763 × 106 and 2.661 × 105 g/mol, the polydispersity coefficients were 1.025, 1.686 and 1.362 and the average molecular radii were 67.5, 33.3 and 43.7 nm, respectively. All three β-glucans showed DPPH radical scavenging capacity, suggesting their antioxidant potential. Furthermore, they had significant moisturizing properties in vitro, and the moisturizing effect of H-YG was better than that of glycerol in 8–24 h. All these β-glucans especially H-YG significantly contributed to promoting the generation of endogenous natural moisturizing factor. These findings demonstrated that different extraction methods affected physicochemical properties and bioactivity of yeast β-glucan, and could be applied to various fields according to their characteristics.
Nutrition & Hygiene
Effect of Fish Oil on Glucose Metabolism and PI3K/Akt Signaling Pathway in Diabetic KKAy Mice
HU Mingyuan, WANG Feng, MA Yongjian, SUN Guiju
2018, 39(11):  126-131.  doi:10.7506/spkx1002-6630-201811020
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Objective: To investigate the effect of fish oil on glucose metabolism and phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (Akt) signaling pathway in diabetic KKAy mice. Methods: Forty KKAy mice were randomly assigned into four groups: diabetic model group, low-dose fish oil group, medium-dose fish oil group and high-dose fish oil group. Ten male C57BL/6 mice served as a non-diabetic control group. Blood and tissue samples were collected after 12 weeks of treatment. Blood glucose, serum insulin, adiponectin, leptin, and the mRNA expressions of insulin receptor substrate-1 (IRS-1), PI3K, Akt and glucose transporter-4 (GLUT-4) were detected. Results: Compared with the model group, fasting blood glucose was reduced significantly in the low-dose fish oil group (P < 0.01), fasting insulin was increased in both the low and medium-dose groups (P < 0.05), and adiponectin level was significantly increased in all the treatment groups (P < 0.05). In addition, fish oil at all doses up-regulated the mRNA expression of IRS-1, PI3K, Akt and GLUT-4 and at low dose had more significant effect on the mRNA expression of Akt and GLUT-4. Conclusion: Fish oil at low dose may improve glucose metabolism by regulating the PI3K/Akt signaling pathway.
Effect of Dietary Methionine Supplementation on Intestinal Development and Antioxidant Function in Growing Pigs with Intrauterine Growth Retardation
SU Weipeng, ZHANG Hao, YING Zhixiong, LI Yue, ZHANG Ligen, ZHANG Lili, WANG Tian
2018, 39(11):  132-138.  doi:10.7506/spkx1002-6630-201811021
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Objective: In order to investigate the effect of dietary methionine supplementation on intestinal development and antioxidant function in growing pigs with intrauterine growth retardation (IUGR). Methods: At postnatal day 21, thirty normal birth weight (NBW) female piglets and sixty same-sex IUGR piglets were weaned. The NBW piglets were allocated to the NBW control (NBW-CON) group, and the IUGR piglets were randomly assigned to the IUGR control (IUGR-CON) and methionine supplementation (IUGR-MET) groups. The piglets were thus distributed across three groups for a 84 d of feeding trial, and each group consisted of six replicates with five piglets per replicate. Results: IUGR-CON pigs exhibited a reduction in villus height (VH) in both the jejunum and ileum, villus surface area in the jejunum, the activities of sucrase and maltase in the ileum, and OCLN mRNA expression in the jejunum when compared with NBW-CON pigs (P < 0.05). Compared with NBW-CON pigs, IUGR-CON pigs had increased malondialdehyde (MDA) content in the jejunum, decreased reduced glutathione (GSH) content and GSH/oxidized glutathione ratio in the jejunum, and superoxide dismutase activity in the ileum (P < 0.05). Dietary methionine supplementation significantly increased VH in the jejunum, maltase activity in the ileum, and OCLN mRNA expression in the jejunum of IUGR pigs (P < 0.05). A higher methionine inclusion alleviated the increased MDA content and the decreased GSH content in the jejunum of IUGR pigs (P < 0.05). Conclusion: Dietary methionine supplementation attenuates lipid peroxidation and improves antioxidant capacity in the intestine, which may be associated with the partially improved intestinal development in IUGR pigs.
Antioxidant Activity in Vitro and Protective Effect of Flavonoids from Lonicera japonica Thunb. Leaves on H2O2-Induced Toxicity in RAW264.7 Cells
LUO Lei, ZHANG Bingjie, MA Liping, FAN Jinling, ZHU Wenxue, GUAN Ningning, XUE Yihan
2018, 39(11):  139-145.  doi:10.7506/spkx1002-6630-201811022
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Objective: To evaluate the in vitro antioxidant capacity of flavonoids from Lonicera japonica Thunb. leaves and their protective effect against oxidative damage induced by H2O2 in RAW264.7 cells. Methods: Flavonoids from Lonicera japonica Thunb. leave powder were obtained by extraction and purification. Total reducing power and scavenging capacity against hydroxyl (·OH), superoxide anion (O2-·) and DPPH free radicals were determined by using ascorbic acid as a positive control. RAW264.7 cells were cultured in vitro, and the experiment was divided into blank, model, control, and low-, medium- and high-dose flavonoid groups. RAW264.7 cells were injured by H2O2. The cell viability was measured by the methyl thiazolyl tetrazolium (MTT) assay, and the contents of malondialdehyde (MDA) and glutathione (GSH) and the activities of superoxide dismutase (SOD) and lactate dehydrogenase (LDH) in cells and culture supernatant were determined using commercial kits. Results: The flavonoids at sufficient concentrations had strong total reducing power and free radical scavenging ability equivalent to that of ascorbic acid. The flavonoids from Lonicera japonica Thunb. leaves could protect against H2O2-induced toxicity in RAW 264.7 cells in a dose-dependent manner, reduce MDA content in cells and culture supernatant, improve SOD activity and GSH content and increase intracellular lactate dehydrogenase activity. Conclusion: The flavonoids from Lonicera japonica Thunb. leaves has a strong antioxidant capacity, and can repair H2O2-induced toxicity in RAW264.7 cells likely by regulating cell redox system, scavenging free radicals and enhancing the activity of intracellular antioxidant enzymes.
Effect of Ursolic Acid on Gut Microbiota in Rats with Alcohol-Induced Liver Injury
MA Haoran, JIA Hailian, ZHANG Wenlong, WANG Jing, ZHANG Nannan, LI Kexin, TAI Dapeng, GE Na
2018, 39(11):  146-151.  doi:10.7506/spkx1002-6630-201811023
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Objective: To explore the effect of ursolic acid (UA) on the gut microbiota of rats with alcoholic liver injury for the purpose of providing new insights into controlling alcoholic liver injury. Methods: A total of 30 healthy male Wistar rats at the age of 2 months were randomly divided into 3 groups with 10 animals in each group including normal control group (saline), alcohol model group and UA-treated group (alcohol + UA) throughout the 8-week experiment. The rats were weighed and anesthetized with 10% chloral hydrate at twelve hours after the last treatment. Then blood samples were collected by abdominal aorta puncture to determine biochemical parameters. Meanwhile, liver tissue and feces were also taken. Pathological changes of liver tissue were evaluated by hematoxylin-eosin (HE) staining. The activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum were determined by the method of Reitman and Frankel. The endotoxin level in serum was tested by tachypleus amebocyte lysate kit. The content of D-lactic acid (D-LA) in plasma was determined by a modified enzymatic method at an ultraviolet wavelength. The genomic DNA of the intestinal flora was used as the template through enterobacterial repetitive intergenic consensus (ERIC)-polymerase chain reaction (PCR) amplification and PCR-denaturing gradient gel electrophoresis (DGGE). At the same time, the diversity of gut microbiota was analyzed in rats. Quantitative real-time PCR was used to quantify the changes of gut microbiota following ethanol and UA treatments. Results: The pathological results obtained by HE staining showed that the hepatic lobular structure in the alcohol model group was vague, and fatty degeneration and inflammatory infiltration were increased. Compared with the alcohol model group, liver tissue damage was significantly improved and the activity of serum transaminase was significantly reduced in the UA-treated group (P < 0.05). In addition, D-LA and endotoxin levels in serum induced by alcohol were significantly suppressed after supplementing UA (P < 0.05). The results of ERIC-PCR and PCR-DGGE indicated that the alcohol-induced disorder of the gut microbiota structure was brought back to almost normal after the supplementation of UA. The results of quantitative real-time PCR indicated that the numbers of Enterococcus faecalis and Escherichia coli in the UA-treated group were significantly decreased to almost normal levels when compared with the alcohol model group (P < 0.05). Moreover, the numbers of Lactobacillus and Bifidobacterium were significantly higher in UA-treated group than in the alcohol model group (P < 0.05). Conclusion: Supplementation of UA can effectively improve alcohol liver injury in rats, likely by modulating gut microbiota distribution and improving intestinal microecology.
Antioxidant Properties of Anthocyanins Extract from Habenaria ciliolaris Kranzl
GOU Anna, PAN Xinyu, BAI Dingding, ZHONG Kai, RAN Yun, HUANG Yina, GAO Hong
2018, 39(11):  152-158.  doi:10.7506/spkx1002-6630-201811024
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Objective: The aim of this study is to investigate the antioxidant activity in vitro of anthocyanins extracted from the fruits of Habenaria ciliolaris Kranzl and the protective effect of the extract on H2O2-induced oxidative stress in V79-4 cells. Methods: The anthocyanin composition was detected by high performance liquid chromatography-mass spectrometry, and the antioxidant activity was evaluated by using 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assays. Moreover, the protective effect of the extract on H2O2-induced oxidative damage in V79-4 cells was measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl- 2-H-tetrazolium bromide, thiobarbituric acid reactive substances and 2’,7’-dichlorofluorescein diacetate assays. Results: The anthocyanins in the extract were identified as cyanidin 3-galactoside, cyanidin 3-(6”-coumaroyl) glucoside, peonidin 3-galactoside and peonidin 3-(6”-coumaroyl) glucoside by retention time and mass spectral data. The anthocyanins extract exhibited strong ABTS and DPPH free radical scavenging capacity with half maximal inhibitory concentrations of (1.72 ± 0.26) and (0.74 ± 0.24) μg/mL, respectively, which was superior to that of soluble VE. The pretreatment of V79-4 cells with the extract in the ranges of 50-200 μg/mL significantly reduced H2O2-induced cytotoxictiy, potentially inhibited lipid peroxidation and reduced the level of intracellular reactive oxygen species. Conclusion: These findings confirm the in vitro free radical scavenging activity of anthocyanins extracted from H. ciliolaris Kranzl and their cytoprotective effect on H2O2-induced oxidative stress in V79-4 cells.
Antioxidant and Antiproliferative Activity of Carotenoids and Isoprenoid Quinones from Rhodococcus sp. B7740
MU Qing, CHEN Yashu, XIE Bijun, YANG Jifang, CHEN Jigang, SUN Zhida
2018, 39(11):  159-164.  doi:10.7506/spkx1002-6630-201811025
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In this paper, the antioxidant and antiproliferative activity of a carotenoid and isoprenoid quinone-rich extract (B7CIQE) from Rhodococcus sp. B7740 were determined. The in vitro antioxidant activity was evaluated by β-carotene bleaching, lipid peroxidation inhibition, protein oxidation inhibition and oxidative DNA cleavage inhibition assays, and the antiproliferative activity against HepG2 human liver cancer and KB human oral cancer cells and the cellular antioxidant activity were investigated as well. Three common carotenoids from higher plants, β-carotene, lutein and lycoypene, were used as controls. The inhibition rate of β-carotene oxidation by different antioxidants was in the decreasing order of B7CIQE (70.20%) > butylated hydroxytoluene (66.70%) > epigallocatechin gallate (17.80%) > lycopene (1.90%). Peanut oil with the addition of B7CIQE had the lowest initial oxidation temperature (175 ℃) followed by β-carotene (165 ℃), lutein (162 ℃) and lycopene (160 ℃). The inhibition rate of protein oxidation was in the decreasing order of B7CIQE (25.75%) > β-carotene (24.97%) > lutein (17.94%) > lycopene (10.40%). The median effective concentration (EC50) against HepG2 cells was in the decreasing order of lutein (20.86 μg/mL) < β-carotene (124.88 μg/mL) < B7CIQE (126.34 μg/mL) < lycopene (139.24 μg/mL), whereas the EC50 against KB cells decreased in the following order: B7CIQE (25.14 μg/mL) < lutein (64.29 μg/mL) < lycopene (69.87 μg/mL) < β -carotene (149.16 μg/mL). These results demonstrated that B7CIQE had superior antioxidant activity and antiproliferative effect when compared with plant-derived carotenoids.
Effect of Prodelphinidins from Chinese Bayberry Leaves on Pancreatic Lipase and Phospholipase A1
ZHOU Xiaozhou, CHEN Shiguo, YE Xingqian
2018, 39(11):  165-170.  doi:10.7506/spkx1002-6630-201811026
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The effect of prodelphinidin extracts from Chinese bayberry leaves at different processing stages (leaf powder, non-desugarized prodelphinidin extract, and desugarized prodelphinidin extract) on pancreatic lipase and phospholipase A1 was evaluated in vitro and in the small intestine of SD rats in comparison with Orlistat. The results indicated that Orlistat had the highest inhibition percentage against pancreatic lipase in vitro and in the small intestine of SD rats, which were 99.0% and 96.5%, respectively, followed by the purified prodelphinidins (90.9% and 91.4%, respectively). Also, Orlistat had the highest inhibition percentage against phospholipase A1 in vitro and in the small intestine of SD rats, which were 97.1% and 97.2%, respectively, followed by the purified prodelphinidins (96.7% and 87.7%, respectively). The half maximal inhibitory concentration of the purified prodelphinidins against pancreatic lipase and phospholipase A1 were 0.01 and 0.06 mg/mL, respectively. The type of inhibition was competitive + uncompetitive for pancreatic lipase and was competitive for phospholipase A1. The purified prodelphinidins from Chinese bayberry leaves are potentially an efficient and controllable anti-obesity agent.
Effect of Genistein on Expression of Key Enzymes StAR, P450scc and CYP19 Involved in Androgen Synthesis in Ovarian Tissues of Young Female Rats
ZHEN Jinglong, CHU Xiaoli, CONG Sha, ZHANG Tao, CHI Xiaoxing
2018, 39(11):  171-176.  doi:10.7506/spkx1002-6630-201811027
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The objective of this investigation was to study the effect of genistein (GEN) on the gene expression of steroidogenic acute regulatory protein (StAR), cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc) and cytochrome P450 aromatase (CYP19) involved in steroid synthesis in ovarian tissue of young female rats. Forty female SD rats were selected and divided according to their body mass into control, low-, middle- and high- dose GEN, (15, 30 and 60 mg/(kg·d)), and negative control (NC, administered with diethylstilbestrol at 0.5 mg/(kg·d)) groups. The whole experiment was lasted for 30 d. The gene expression of StAR, P450scc and CYP19 mRNA was detected by real-time polymerase chain reaction. The protein expression of StAR and P450scc was detected by Western blot analysis. Compared with the NC group, the body mass of rats in the GEN groups showed no significant difference (P > 0.05); the expression levels of StAR, P450scc, CYP19 mRNA increased, especially in the middle- and high-dose groups (P < 0.05); the protein expression of StAR significantly increased in the high-dose group (P < 0.05); the protein expression of P450scc significantly increased in the middle- and high-dose groups (P < 0.05). Conclusively, GEN at a dose of 30–60 mg/kg can increase the expression of key enzymes involved in androgen synthesis in the ovaries of young female rats, and consequently affect the development and maturation of follicles.
Quantitative Microbiological Risk Assessment of Salmonella Cross-Contamination from Fresh Pork to Ready-to-Eat Food in Domestic Kitchen
ZHANG Li, YIN Defeng, ZHANG Dawen, LUO Linguang
2018, 39(11):  177-184.  doi:10.7506/spkx1002-6630-201811028
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In this study, the cross-contamination of Salmonella from raw pork to ready-to-eat (RTE) foods in the domestic kitchen was evaluated by using a quantitative risk assessment model, and the key factors involved were examined. Risk management strategies were put forward. Relevant data were collected from published literature to analyze the possibility and level of Salmonella contamination in fresh pork. Based on these data combined with resident consumption habit survey data from the statistical yearbook of China, a predictive model was developed for describing the growth of Salmonella in fresh pork at room temperature. The model was run through Monte Carlo simulations using the @Risk software. In order to quantitatively estimate the risk of Salmonella positioning in Chinese consumers caused by cross-contamination from fresh pork to RTE foods in the kitchen, hazard recognition, exposure estimation, description of hazard characteristics and risk analysis were carried out. According to the data we collected, the highest probability of Salmonella prevalence in fresh pork from the market was 15.5%. After being stored at room temperature initially and then refrigerated temperature for several hours, the number of Salmonella in fresh pork was ?1.95 (lg(CFU/g)) with a 90% confidence interval of ?5.32 to 0.67 (lg(CFU/g)). Cross-contamination from fresh pork to RTE foods occurred through contact with the cutting boards, hands and knives. The daily per capita intake of Salmonella in the consumers was ?4.77 (lg(CFU/g)) with a 90% confidence interval of ?8.73 to ?1.24 (lg(CFU/g)) as calculated from the predictive models for Salmonella growth and cross-contamination. The results of quantitative risk assessment showed that the probability of Salmonella poisoning due to Salmonella contamination of fresh pork in the kitchen was 4.15 × 10-6. The annual number of infections predicted from the dose-response relationship of Salmonella was consistent with the observed number of salmonellosis cases (about 95 299). The initial contamination level of Salmonella in fresh pork was the primary cause of cross-contamination of RTE foods; meanwhile, contact of raw and cooked foods with the same chopping boards was another important factor. The risk of cross-contamination could be reduced by controlling refrigerator temperature and storage time. It is concluded that the probability of Salmonella poisoning from fresh pork in our domestic kitchen depends on the initial level of Salmonella in fresh pork and consumers’ habit of separate usage of chopping boards and choppers for raw and cooked foods as well as refrigerator usage habit. All these factors are closely related to the seasons, the standard of living and the level of socio-economic development.
Porcine Blood Hydrolysate Protect against Acute Alcoholic Liver Injury in Mice
HU Bin, LI Kanglin, WU Qiao, KE Qin, DENG Yuchan, CHEN Yizi
2018, 39(11):  185-190.  doi:10.7506/spkx1002-6630-201811029
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Objective: The protective effect of porcine blood hydrolysate (PBH) on acute alcoholic hepatic injury in mice was investigated. Methods: The mice were randomly divided into blank control, model control, reduced glutathione (20 mg/kg mb) and PBH (0.83, 1.70 and 3.33 g/kg mb) groups. All mice except those in the blank control group were administered for 30 days. On day 31, 50% alcohol was given at a dose of 12 mL/kg mb to establish the animal model of acute liver damage. At 16 h post-administration, sera were collected to determine the activities of alanine aminotransferase (ALT) and aspartate transaminase (AST). All mice were killed by cervical dislocation for the assay of antioxidant enzyme activities in liver, and the degree of hepatic injury was analyzed by histological examination. Results: The levels of AST and ALT in serum and malondialdehyde, tumor necrosis factor alpha and interleukin-6 in liver obviously decreased in the PBH treatment groups when compared with the model control group, while the content of glutathione, and the activities of superoxide dismutase and glutathione peroxidase in liver remarkably increased. The pathological changes such as fatty degeneration in liver were significantly alleviated in the PBH groups. Conclusion: PBH can protect the mouse liver from alcohol-induced injury, and the underlying mechanism may be related to anti-inflammatory and antioxidant activities.
Protective Effects of Betulinic Acid and Total Triterpenic Acids from Red Jujubes on Alcoholic Liver Injury in Mice
CAI Tianjiao, WANG Ruizhen, WEI Junhui, XUE Yuan, LEI Hongjie, XU Huaide
2018, 39(11):  191-195.  doi:10.7506/spkx1002-6630-201811030
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The protective effects of betulinic acid (BA) and total triterpenic acids from red jujube (JTTA) on alcoholic liver injury in mice were investigated. A mouse model of alcoholic liver injury was established by intragastrically treating mice with alcohol. Body weight, liver index and relevant biochemical indicators were determined. Histopathological changes in the liver were detected by staining liver sections with hematoxylin and eosin. The results showed that BA and JTTA could reduce liver index, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) levels in serum, increase high-density lipoprotein cholesterol (HDL-C) levels in serum and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities, and decrease malondialdehyde (MDA) levels in liver tissue significantly (P < 0.05). Furthermore, BA and JTTA could repair pathological liver injury. The results demonstrated that BA and JTTA could protect the liver from alcohol-induced injury.
Protective Effect of an Endophytic Fungus from Dalbergia odorifera T. Chen against H2O2-Induced Oxidative Damage in HepG2 Cells
GAO Yuan, WANG Fuling, JIA Qi, LIU Wei, ZHOU Yanyan, ZHANG Xiaomeng, XIAN Yuetong
2018, 39(11):  196-200.  doi:10.7506/spkx1002-6630-201811031
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In this study, a strain of endophytic fungus JXP21 with good antioxidant activity was isolated from the barks of Dalbergia odorifera T. Chen, and was identified as Alternaria alternata through ITS-rDNA sequence alignment and phylogenetic analysis, whose ITS-rDNA sequence was 100% similar with GenBank accession number KP979753.1. The compound genistein was detected as one of its metabolites by high performance liquid chromatography tandem mass spectrometry. The protective effect of the metabolites of JXP21 at different concentrations (0, 10, 20, 40 and 80 μg/mL) on oxidative damage induced by 200 μmol/L H2O2 in HepG2 cells was investigated by measuring malondialdehyde (MDA) content, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities. The results showed that the fungal metabolites decreased the increase in MDA content from 4.65 to 3.68 nmol/mg protein, increased SOD activity from 6.88 to 8.64 U/mg pro and GSH-Px activity from 8.45 to 9.68 U/mg pro. In conclusion, the results of this study indicated that the endophytic fungal metabolites can protect against oxidative damage induced by H2O2.
Protective Effects of Selenium-Enriched Corn Peptides on Liver Injury Induced by Acetaminophen in Mice
ZHAO Juanjuan, XIONG Huizhu, LIU Weiwei, SHI Wen, HE Hui
2018, 39(11):  201-206.  doi:10.7506/spkx1002-6630-201811032
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Objective: To investigate the effect of selenium-enriched corn peptides (SeCPs) on the enzyme activities related to the metabolism of acetaminophen and its protective effect on liver injury. Methods: Se-enriched corn proteins were extracted with a aqueous solution NaOH and alcohol, and then hydrolyzed by alcalase. SeCPs with a molecular weight less than 5 kDa were prepared by ultrafiltration. Liver injury was induced by intraperitoneal injection of acetaminophen in mice. Liver index, aspartate aminotransferase (AST) activity in serum, and the contents of cytochrome P4502E1 (CYP2E1), cytochrome P4501A2 (CYP1A2), glutathione S-transferase (GST), uridine diphosphate-dependent glycosyltransferase (UGT) and glutathione (GSH), the activities of sulfotransferase (SULT) and glutathione peroxidase (GSH-Px) in mice liver were determined. Hematoxylin-eosin staining was used to observe pathological liver changes. Results: Compared with the model group, the contents of CYP2E1, CYP1A2, UGT and SULT in the liver of mice treated with SeCPs were significantly decreased (P < 0.05), while the contents of GSH and GST and the activity of GSH-Px were significantly increased. In addition, liver index and serum AST activity were significantly lowered and liver pathology was significantly improved. Conclusion: The protective effect of SeCPs on liver injury induced by excessive acetaminophen was better than that of combined sodium selenite and corn peptides (CPs + Na2SeO3). Therefore, the combined use of organic selenium and corn peptides had a good synergistic effect on liver protection.
Protective Effect of Konjac Flour on Acute Alcohol-Induced Brain Injury in Mice
SHUAI Tiangang, WANG Min, ZHONG Geng
2018, 39(11):  207-213.  doi:10.7506/spkx1002-6630-201811033
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In order to evaluate the protective effect of konjac flour on acute alcohol-induced central nervous system damage in the brain of mice, 70 mice were randomly divided into 5 groups including blank group, model group, low, medium and high-dose konjac flour groups. Each group consisted of 14 mice. The mice were gavaged with 56% Chinese liquor (alcohol, V/V) at a dose of 14 mL/kg to establish a mouse model of acute alcoholism. The low, medium and high doses were 166, 332 and 500 mg/kg, which were 5, 10 and 15 times higher than recommended intake of konjac flour for humans, respectively. The aldehyde (AcH) content in the serum and brain of mice with acute alcoholic brain injury, and the activity of superoxide dismutase (SOD), and the contents of malondialdehyde (MDA), glutathione (GSH), nitric oxide (NO), β -endorplhin (β-EP), dopamine (DA) and 5-hydroxytryptamine (5-HT) in brain homogenate were determined. Results showed a significant increase in SOD, GSH and NO levels in mice from the high-dose konjac flour group and a significant reduction in MDA level in mice from the medium- and high-dose groups compared with the model group (P < 0.05). Meanwhile, konjac flour at all doses could reduce the content of AcH in serum and brain, and significantly decrease the content of β-EP (P < 0.05). In addition, konjac flour at the medium and high doses could reduce the content of DA and 5-HT significantly in brain homogenate (P < 0.05). Therefore, konjac flour can regulate free radical metabolism in brain tissue after drinking, thus avoiding oxidative damage, and protect brain tissue against acute alcoholic injury in mice by reducing AcH content in serum and brain and regulating neurotransmitter content in brain tissue.
Packaging & Storage
Comparison of Quality Changes of Prepared Beer Bass Fillet under Different Storage Conditions
WU Yanyan, ZHU Xiaojing, LI Laihao, YANG Xianqing, HU Xiao, LIN Wanling, RONG Hui
2018, 39(11):  214-220.  doi:10.7506/spkx1002-6630-201811034
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In order to extend the storage life of prepared fish products, prepared beer fillets of largemouth bass (Micropterus salmoides) were stored in normal air (control group), vacuum packaging (VP) and modified atmosphere packaging (MAP) at 4 and ?3 ℃, respectively and changes in total bacterial count, total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA), pH, electric conductivity, drip loss and sensory evaluation were measured. The results showed that drip loss, TVB-N, TBA, electric conductivity and total bacterial count were increased in each packaging group during storage at both temperatures, but the rate of increase was slower at ?3 ℃ than at 4 ℃. pH declined at the early stage of storage period but rose at the late stage. Sensory scores continuously declined during storage. In general, VP and MAP could prolong the shelf-life of prepared fillets compared with the control group; the shelf-life of MAP packaged fillets was up to 12 d at 4 ℃ and 50 d at ?3 ℃, which was extended by 8 and 4 d, and 35 and 15 d compared with the control and VP packaged fillets, respectively. MAP packaged fillets maintained better quality and had a longer shelf-life when stored at ?3 ℃ than at 4 ℃ and could meet the current demands of consumers for ice stored fish products. The results of this work can provide a technical basis for the development of prepared beer bass fillets.
Preparation of PLA/SA Composite Coating and Its Application in Quality Preservation of Sweet Cherries
ZHAO Shan, GONG Hansheng, TIAN Yachen, KONG Yanhui, LIU Yanzhao, WANG Yaqi
2018, 39(11):  221-226.  doi:10.7506/spkx1002-6630-201811035
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Penyllactic acid (PLA) as a natural antifungal agent and sodium alginate (SA) as a carrier were blended to develop a composite preservative for the control of postharvest decay in sweet cherries. The appropriate concentration of sodium alginate was determined by measuring film-forming properties. The efficacy of the preservative coating in maintaining the quality of sweet cherries during cold storage was evaluated by monitoring physiological and quality changes. Addition of 12 g/L sodium alginate to the preservative exhibited good film-forming property in the presence of 6 g/L phenyllactic acid, 5 g/L glycerol and 5 g/L xanthan gum. The preservative significantly inhibited fruit decay, reduced water loss, decreased respiratory intensity, maintained the color and firmness of sweet cherries during storage, and delayed the decrease in soluble solids and titrable acidity content, thereby helping attenuate metabolism intensity, maintain fruit quality and prolong the storage life of sweet cherries.
Effect of Lysozyme Liposomes on Trachinotus ovatus Preservation
WANG Zhe, GUAN Rongfa, LIU Zhenfeng, WANG Wei, XIAO Chaogeng, ZHANG Xiaojun, Lü Fei
2018, 39(11):  227-232.  doi:10.7506/spkx1002-6630-201811036
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In order to improve the stability and lipid solubility of lysozyme, lysozyme liposomes were prepared by reverse phase evaporation method. The solubility of lysozyme liposomes in rapeseed salad oil was investigated as well as the stability in simulated intestinal environment of Trachinotus ovatus. The effects of lysozyme liposomes and lysozyme at different concentrations on preserving the quality of Trachinotus ovatus during storage at 4 ℃ were evaluated using sterile phosphate buffer as negative control. Changes in the quality of Trachinotus ovatus were examined by sensory evaluation, pH, thiobarbituric acid (TBA) value, total bacterial count, and total volatile basic nitrogen content. The results indicated that lysozyme liposomes had good stability and lipid solubility during cold storage. Lysozyme liposomes could better maintain the fish quality after the same storage period, slowed the rate of decrease in sensory score, inhibit the increase in TBA value and pH and prolong the shelf-life by 2–3 and 5–6 d, respectively, compared with lysozyme and the control group.
Effects of 1-Methylcyclopropene Treatment and Self-Developed Modified Atmosphere on Quality and Reactive Oxygen Species Metabolism of Kiwifruits during Storage
QIAN Chunlu, YIN Jiandong, WANG Libin, LIN Chen, WANG Jingye, XIAO Lixia, JIN Changhai, CHEN Xuehao, QI Xiaohua
2018, 39(11):  233-240.  doi:10.7506/spkx1002-6630-201811037
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In order to explore the effect of 1-methylcyclopropene (1-MCP) treatment and self-developed modified atmosphere (MA) on the storage quality and reactive oxygen species metabolism of kiwifruits, kiwifruits were treated with 1 μL/L 1-MCP and MA separately and in combination and then stored at (20 ± 1) ℃ for 28 days. The results indicated that both 1-MCP treatment and MA storage could maintain fruit firmness, restrain the decrease of titratable acid and the increase of total sugar content, and also reduce ethylene production. 1-MCP treatment was more effective than MA, and the fruits stored under MA condition after 1-MCP treatment could maintain the best quality. Both 1-MCP treatment and MA could increase superoxide dismutase, catalase (CAT) and ascorbate peroxidase (APX) activity in kiwifruits during storage, and increase ascorbate (ASC) content during the early and middle stages, thereby decreasing oxidative stress and restrain membrane lipid peroxidation. 1-MCP treatment was more effective during the early and middle stages but less effective than MA during the late stage. The fruits stored under MA condition after 1-MCP treatment had the highest CAT and APX activity and ASC content during the early and middle stages. In conclusion, both 1-MCP treatment and MA could maintain fruit quality and increase key antioxidant enzyme activities and antioxidant substance content of kiwifruits during room temperature storage, and 1-MCP treatment had better preservative effect than MA. MA storage after 1-MCP treatment was the most efficient way to preserve kiwifruits at room temperature.
Effect of Incorporation of Spearmint Extract Microencapsulated with β-Cyclodextrin on Properties of Polypropylene Packaging Films and Emulsion Sausage Shelf Life
JIA Xiaoyun, ZHANG Shunliang, LIU Wenying, LI Yingnan, ZHAO Yan, YANG Kai, WANG Le, LI Xiang, WANG Shouwei, CHENG Xiaoyu
2018, 39(11):  241-246.  doi:10.7506/spkx1002-6630-201811038
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In this paper, we prepared polypropylene (PP) films as the membrane material and PP films incorporated with spearmint extract as an antibacterial agent (S/PP) and spearmint extract microencapsulated with β-cyclodextrin (β-CD) as a sustained-release layer (S-β-CD/PP) by extrusion blow molding. The thickness, mechanical properties, light transmittance, water vapor transmittance and antimicrobial properties of these films were compared and their effects on preserving the quality and extending the shelf life of emulsion sausage were evaluated by monitoring changes in the color, pH, thiobarbituric acid value and total bacterial count of sausages during storage at 25 ℃. The results indicated that β-CD as an embedding medium could greatly protect the active ingredients of spearmint extract from being damaged during film processing. The 1% S-β-CD/PP film had sustainable and stable antibacterial effect, extending the shelf life of emulsion sausage to 50 days. The results of this study can provide new ideas for the development of meat packaging material.
Effect of Precooling Treatment with Slurry Ice on the Quality Change of Japanese Seabass (Lateolabrax japonicus) during Circulation
LAN Weiqing, ZHANG Wanjun, WU Qiyue, XIAO Lei, XIE Jing
2018, 39(11):  247-254.  doi:10.7506/spkx1002-6630-201811039
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Objective: The effect of precooling treatment with slurry ice on the quality change of fresh Japanese seabass was investigated during simulated circulation (precooling, transportation and storage). Methods: The fish were randomly divided into three groups: 1) precooling with slurry ice, transportation and storage (SI), 2) slurry ice precooling, transportation without ice and storage in crushed ice (SNI) and 3) precooling with crushed ice, transportation and storage (control). During storage, sensory attributes and physiological properties such as pH, salinity, texture profile analysis (TPA) and thiobarbituric acid (TBA) as well as total viable count (TVC) were measured at regular intervals. Scanning electron microscopic and sodium dodecyl sulfate polyacrylamide gel electrophoresis were performed. Furthermore, the quality change of Japanese seabass was evaluated. Results: The internal temperature of seabass was reduced to 0 ℃ by precooling with slurry ice for 1.0–1.5 h and the final temperature was ?1.1 ℃; the rate of temperature decrease was significantly higher than that of crushed ice treatment. Compared with the control group, SI maintained better sensory quality and texture properties, inhibited the increase in TBA, pH and TVC, and delayed the degradation of protein and muscle tissue during the mid-late storage period. The shelf-life of SI was about 18 d, which was 6 d longer than that of the control group. The fish in the SNI group were kept at a temperature below 0.8 ℃ during transportation without ice and no significant differences in texture properties, microbial quality or protein degradation were found compared with the control group. The shelf-life of both groups was 12 d. These findings suggested that slurry ice precooling could control temperature, thereby maintaining the quality of seabass. Conclusion: Slurry ice provides a rapid and efficient way to preserve aquatic products. SNI treatment can increase the loading amount of fish, thus cutting down the cost of transportation. The results of this study can provide valuable information for short-distance transportation of aquatic products during circulation.
Effect of High-Oxygen Dynamic Controlled Atmosphere on Cell Wall Metabolism and Lignification Process ofA garicus bisporus
SUN Han, WANG Xiangyou, LI Ling
2018, 39(11):  255-262.  doi:10.7506/spkx1002-6630-201811040
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In this paper, changes in the contents of chitin, cellulose and lignin in Agaricus bisporus during high-oxygen dynamic controlled atmosphere (HO-DCA) storage were examined as well as changes in cell wall metabolism and enzyme activities related to lignin synthesis. The results showed that the chitin content of HO-DCA treated Agaricus bisporus was significantly higher than that of the static-controlled atmosphere and control groups at the end of storage (P < 0.05), and chitinase activity was significantly lower than the control group (P < 0.05), indicating that HO-DCA treatment effectively inhibited the degradation of chitin in the cell wall. Meanwhile, HO-DCA treatment significantly inhibited cellulase activity (P < 0.05) and maintained a higher content of cellulose, thus maintaining a higher tissue compressive resistance. At the late stage of storage, the lignin content of the stipe increased dramatically, and the degree of lignification was improved; the degree of lignification was greater in the stipe than in the pileus. The activities of 4-coumarate: coenzyme A ligase (4CL) and cinnamyl alcohol dehydrogenase (CAD) were positively correlated with lignin content, while there was no significant correlation between phenylalnine ammonialyase and lignin content. The lignin content of HO-DCA treated Agaricus bisporus was significantly lower than that of the control (P < 0.05), indicating that HO-DCA treatment inhibited lignin accumulation by inhibiting the activity of 4CL and CAD in Agaricus bisporus and delayed its lignification. The results of this study can provide a theoretical basis for effectively controlling texture deterioration of Agaricus bisporus.
Reviews
Analysis and Suggestions on Food Safety Strategy in China
LUO Jie, MI Zhongxiang, GONG Dianrong, YAN Zhigang
2018, 39(11):  263-268.  doi:10.7506/spkx1002-6630-201811041
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The food safety strategy generally includes starting point, goals, tasks and measures. The strategic starting point has a good foundation but faces many challenges, such as serious pollution of the sources, weak industrial foundation, and low food safety standards. The strategic objectives can be formulated according to the short, medium and long term plans under the framework of China’s overall development strategy. The strategic task mainly includes eight aspects, such as taking basic measures to address both the symptoms and root causes of food safety problems. The implementation of food safety strategy should be considered from three aspects including orientation value, governance structure and concrete implementation. We should adhere to the idea of innovation, coordination, green, openness and sharing to build a unified and authoritative food safety governance system, and implement “the four most stringent” requirements.
Improving the Stability of Anthocyanins during Processing and Storage: A Review
ZENG Xixi, LEI Lin, ZHAO Guohua, YE Fayin
2018, 39(11):  269-275.  doi:10.7506/spkx1002-6630-201811042
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Anthocyanins are a group of water-soluble flavonoid pigments, which are widely distributed in plant foods such as fruits and vegetables. They confer various colors on foods. Additionally, anthocyanins are the research focus of functional foods due to their biological activities including antioxidant, anti-inflammatory and anti-tumor activities. However, because of their instability, the application of anthocyanins in foods, beverages and dietary supplements is limited. Following an extensive review of the literature, this article outlines the methods and techniques used for improving the stability of anthocyanins during processing and storage with special emphasis on copigmentation, complexation, and encapsulation. The aim of this review is to provide useful information for further research and industrialization of anthocyanins.
Application of Hyperspectral Imaging Technology in Meat Quality Evaluation
LIU Hai, ZHENG Fuping, XIONG Zhenhai, LIU Yuan
2018, 39(11):  276-283.  doi:10.7506/spkx1002-6630-201811043
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Hyperspectral imaging technology integrates the advantages of both image technology and spectroscopy, and it can capture the spatial and spectral information on food materials for rapid, non-destructive and accurate detection. The main objectives of this review are to describe the basic principle of hyperspectral imaging technology and analyze hyperspectral data processing methods. In addition, we review recent progress in the application of hyperspectral imaging technology in the detection of various meat quality attributes, and conduct a classification review in accordance with detection indicators of meat products. This review is expected to provide valuable information for future studies on meat quality evaluation.
Progress in Research on Fine Microstructure of Starch Granules
ZHAO Mixue, BAO Yali, LIU Peiling
2018, 39(11):  284-294.  doi:10.7506/spkx1002-6630-201811044
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Starch, a natural polymer material, is increasingly used in the field of food processing. As an industrial raw material, starch has been also widely used in the fields of pharmaceutics, textile, paper and materials. There is a long history of more than 4 000 years since humans began to use starch, but it is only 100 years since its large-scale production and application occurred. This is because the large-scale application of starch in different fields is restricted by some fine microstructural characteristics of natural starch. Elucidating starch structure is a rather lengthy process. This article reviews the current state of the art of the fine microstructure of starch granules. The molecular composition of starch is described and a systematic review of how starch structure is organized at 6 increasing orders of magnitude is presented with special emphasis on double helix structure, super helix structure, sealing plug structure, and particle structure. Finally, the fine microstructural features of starch granules are summarized. This review is expected to provide a theoretical basis for future research on the fine microstructure of starch granules to facilitate the application of starch to the food industry.
A Review of the Effect of Lipid and Protein Oxidation on Meat Quality and Their Interrelationship
WANG Zhaoming, HE Zhifei, LI Hongjun
2018, 39(11):  295-301.  doi:10.7506/spkx1002-6630-201811045
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Due to its high amounts of fat and protein, meat is characterized by high nutritional value. Lipid and protein oxidation can cause deterioration of meat quality. In fact, there is an interrelationship between lipid and protein oxidation in the complex system of meat. A comprehensive understanding of the effect of lipid and protein oxidation on the quality of meat and the interrelationship between these chemical reactions is of great importance to explain the reasons for meat quality deterioration and to select appropriate antioxidants. In this paper, the changes of meat quality caused by lipid and protein oxidation are reviewed together with the interrelationships between lipid and myoglobin oxidation, lipid and nonheme protein oxidation, and myoglobin and nonheme protein oxidation.
Suggestions on Key Research Areas of Technical Support System for Food Safety Supervision during the 13th Five-Year Plan
MAO Ting, JIANG Jie, LU Yong
2018, 39(11):  302-308.  doi:10.7506/spkx1002-6630-201811046
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This article reviews the development of supporting technologies for food safety supervision worldwide with respect to food analysis, evaluation, supervision and emergency disposal. Some suggestions on the key research areas of technical support system for food safety supervision during the 13th five-year plan are proposed taking into account the weaknesses of relevant technologies and recent progress in food safety technical innovation planning.
Recent Progress in Research on Enantiomers of Volatile Compounds in Tea
MU Bing, Lü Haipeng, ZHU Yin, LIN Zhi
2018, 39(11):  309-315.  doi:10.7506/spkx1002-6630-201811047
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Tea aroma is a mixture of various volatile compounds at different concentrations, which is an important factor to evaluate tea quality. Most volatile compounds in tea have one or more stereocenters, and there are enantiomers with different aroma characteristics and thresholds. The enantiomer composition has an important influence on the formation of tea aroma. By reviewing recent studies on enantiomers of volatile compounds in tea and other plants as well as foods in China and abroad, this paper compares the enantiomers of different volatile components with aroma characteristics, and describes the state of the art of chiral volatile compounds and the analytical methods used to detect these compounds. Future research and development trends are also discussed. We hope this review can provide new insights into the chemical nature of tea aroma quality with respect to enantiomers.
Progress in the Synthesis of Catechin and Its Derivatives
LU Changqi, MAO Shihong, TONG Huarong, DING Yangping
2018, 39(11):  316-326.  doi:10.7506/spkx1002-6630-201811048
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Catechins not only have antitumor, antioxidant, antibacterial and antiviral functions, but also can protect the heart and brain and execute other pharmacological effects. These pharmacological effects are principally dependent on the polyhydroxyl structure of catechins, which, however, makes catechins unstable under neutral and alkaline conditions. Catechins are rapidly methylated or glycosylated by enzymes when ingested into the human body. Researchers have found that introducing new chemical groups into the structure of catechins can significantly improve their stability and bioavailability and specifically enhance their pharmacological effects. Notably, methylated catechins can suppress allergic reaction and tumor cell resistance; glycosylation can increase the water solubility of catechins and effectively prevent browning, while acylated catechins show significantly improved antioxidant and antitumor activity due to their high fat solubility. Moreover, the effects of substitution at different locations are different. Studying the synthesis routes and pharmacological effects of catechin derivatives will help discover new pharmacological effects of catechins and promote the clinical application of catechins. The aim of this article is to outline the the biosynthesis and chemical synthesis pathways of catechins with focus on the synthesis pathways and pharmacological effects of catechin derivatives.
Isolation and Cultivation of Akkermansia muciniphila and Comparison of Its Colonization in Different Populations: A Review
WANG Lei, YAO Hong, PENG Yongzheng, LI Jiawen, WU Xiyang
2018, 39(11):  327-333.  doi:10.7506/spkx1002-6630-201811049
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Akkermansia muciniphila is a strictly anaerobic gram-negative bacterium that can specifically degrade mucin in the mucus layer of the gastrointestinal tract. It was first isolated from human feces. A. muciniphila plays an important role in promoting host health at the mucosal interface, which has recently become a hot spot in the field of intestinal microecology and probiotics. This paper is focused on summarizing the current state of the art in the genomics, molecular biological identification and typing, and isolation and purification of A. muciniphila. The merits and drawbacks of the existing culture conditions as well as the existing methods for the isolation and purification of A. muciniphila. In addition, we compare the colonization characteristics in different populations of A. muciniphila. The aim of this review is to analyze the possibility of microbiota transplantation, extend the study of the molecular mechanism of action of A. muciniphila and thereby develop new probiotic products.