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Table of Content

15 April 2017, Volume 38 Issue 7
Basic Research
Impact of Microwave Extraction on Structural Characteristics and Morphology of Carrot (Daucus carota L.) Polysaccharide
WAN Yujun, YIN Junyi, NIE Shaoping, SHI Huifang, XIE Mingyong
2017, 38(7):  1-5.  doi:10.7506/spkx1002-6630-201707001
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In this paper, we investigated the effect of microwave extraction on structural characteristics and morphology of polysaccharides from carrot. Boiling water bath and microwave were used to extract carrot polysaccharide (the resulting products were denoted as WEP and MEP respectively). A comparative evaluation was made of the basic physical and chemical properties of the two polysaccharides. High size exclusion chromatography (HPSEC), monosaccharide composition analysis, and scanning electron microscope (SEM) were also used for the preliminary characterization of their morphology. The results showed that the contents of neutral sugar, uronic acid and total phenol were different in WEP and MEP. They were both composed of galacturonic acid, galactose, glucose, arabinose, and rhamnose, but the total sugar content of MEP was higher and contained more constituent monosaccharides of pectin. The HPSEC chromatogramsss of WEP and MEP had some similarity, but WEP exclusively contained a component with a relative molecular weight of up to 7.77 × 105 D. WEP displayed a more aggregated sheet structure, and its components were more dispersed and mainly present as small fragments. According to the results above, the polysaccharides obtained from two different extraction methods had significant differences.
Inhibitory Effects of Four Kinds of Food Preservatives on Biofilm Formation by Vibrio parahaemolyticus
LEI Huan, XIE Ting, WEI Yuqing, LIU Huan, ZHONG Qingping
2017, 38(7):  6-10.  doi:10.7506/spkx1002-6630-201707002
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In this study, we analyzed the minimum inhibitory concentrations (MICs) of four kinds of food preservatives (chitosan, potassium sorbate, sodium dehydroacetate and ε-polylysine) for Vibro parahaemolyticus, and we then investigated their inhibitory effects on biofilm formation by V. parahaemolyticus. The crystal violet straining method was conducted to determine the amount of biofilm, and XTT reduction assay and phenol-sufuric acid method were used to detect the changes of metabolic activities and extracellular polysaccharide of biofilm, respectively. The results showed that the MIC of chitosan was the lowest, which was 1.25 mg/mL. At both MIC and sub-MIC, these four food preservatives could not only demonstrate a remarkable inhibitory effect on biofilm formation by V. parahaemolyticus, but also reduce the metabolic activity and the secretion of extracellular polysaccharides of cells in biofilms. Among these preservatives, the inhibitory effect of chitosan was the  strongest.
Preparation and Properties of Inclusion Complexes of β-Cyclodextrin Derivatives with Phloretin
LI Shujing, ZHOU Ziruo, ZHOU Wei, WANG Xinrui, YUAN Li
2017, 38(7):  11-16.  doi:10.7506/spkx1002-6630-201707003
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The inclusion complexation behavior of phloretin with methyl-β-cyclodextrin (Me-β-CD) and (2-hydroxy) propyl-β-cyclodextrin (HP-β-CD) was investigated quantitatively by the phase solubility method. Water-soluble inclusion complexes of phloretin and two β-CD derivatives were prepared by the freeze-drying method and structurally characterized by infrared spectroscopy (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Furthermore, the antioxidant activities of phloretin and the inclusion complexes were determined by reducing power (RP) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging methods. The tyrosinase inhibitory activities of phloretin and the inclusion complexes were also investigated. The results proved that phloretin formed 1:1 stoichiometric inclusion complex with Me-β-CD and HP-β-CD, respectively. The water solubility and antioxidant activity of phloretin were greatly enhanced in the presence of CDs, providing a good way to develop water-based health food formulations. Additionally, phloretin and its inclusion complexes were observed to efficiently inhibit tyrosinase activity. The inclusion complexes could be developed as a natural, efficient and environmental friendly food preservative.
Effect of T-2 Toxin on Muscle Quality Characteristics and Autolysis in Litopenaeus vannamei
DENG Yijia, WANG Yaling, MO Bing, SUN Lijun, WANG Rundong, XU Defeng, YE Riying, LIANG Guangming, HE Wanying
2017, 38(7):  17-22.  doi:10.7506/spkx1002-6630-201707004
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Varied doses of T-2 toxin (T-2), namely 0.0 (control), 0.5, 1.2, 2.4, 4.8, 12.2 mg/kg, were orally administered to the white shrimp Litopenaeus vannamei for 20 consecutive days. The quality characteristics and autolysis of shrimp muscle were investigated by sensory evaluation, physicochemical analysis and microscopic observation. The results indicated that T-2 exposure significantly affect the color of shrimp muscle. T-2 exposure at low dose could result in a significant increase in hardness and chewiness (P < 0.05), but a significant decrease in hardness, elasticity, cohesiveness, glueyness and chewiness at high dose (P < 0.05). The cooking loss of shrimp muscle first rose and then decrease. Microscopic examination revealed loosening and fragmentation of muscle fibers and wider gaps between muscle fibers, suggesting a decline of shrimp muscle quality. Increasing T-2 exposure resulted in a decrease in amino nitrogen content and an increase in soluble solid content. Soluble protein in shrimp muscle hydrolysate increased first and then decreased (P < 0.05). Myofibril length showed a significant decline with the increase in T-2 (P < 0.05). Electron microscopy confirmed fracture and dissolution of myofibrils, suggesting increased autolysis.
Structural Features and Antioxidant Activities of Lignin Extracted from Sunflower Seed Shell
GONG Weihua, MA Yue, Lü Xia, YE Fayin, ZHAO Guohua
2017, 38(7):  23-28.  doi:10.7506/spkx1002-6630-201707005
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Lignin was extracted from sunflower seed shell using acetic acid. The structural features of the isolated lignin were characterized by gel permeation chromatography (GPC), ultraviolet spectroscopy (UV), infrared spectroscopy (FT-IR), hydrogen-1 nuclear magnetic resonance spectrocopy (1H-NMR) and thermogravimetry (TG). In addition, the antioxidant activity of the lignin was evaluated by 1,1 diphenyl-2-trinitrobenzene hydrazine (DPPH) radical scavenging activity assay. The results showed that the yield and purity of lignin extracted from sunflower seed shell were 70.12% (based on Klason lignin) and 88.54%, respectively, and the content of lignin-associated carbohydrates was 2.92%. The lignin was GS-type lignin with β-O-4 ether bond as the major inter-unit linkage, having a high proportion of guaiacyl (G) units. The weightaverage molecular (Mw), number-average molecular (Mn) and polydispersity (Mw/Mn) of the lignin were 2 977, 1 931 D and 1.54, respectively. It major decomposition temperature was 200–400 ℃ and the maximum weight loss rate was 0.32%/℃. We found that the lignin showed stronger antioxidant activity than butylated hydroxytoluene (BHT) with free radical scavenging index (RSI) of 1.54 versus 0.94. The results suggested that acetic acid extraction provides a promising way to prepare lignin from sunflower seed shell with a good potential as an antioxidant in food and other industries.
Effect of Maillard Reaction Products Derived from Arginine-Glucose Model System on the State of Acrylamide
XIANG Leiwen, WANG Hailin, CHEN Wentao, RAO Pingfan, WANG Shaoyun
2017, 38(7):  29-35.  doi:10.7506/spkx1002-6630-201707006
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Maillard reaction products (MRPs) formed in foods during heating are found in a wide range of thermally processed foods. The effect of MRPs derived from arginine-glucose model system on the state of acrylamide was investigated in this study. The changes in the spectroscopic properties of MRPs with and without the addition of acrylamide were measured. With the addition of acrylamide, the ultra violet-visible (UV-Vis) spectrum of MRPs showed no significant change, but the fluorescence spectrum of MRPs showed a significant change in excitation wavelength and emission wavelength. The absorbance of MRPs was 0.327 at 420 nm and the fluorescence intensity of MRPs at an excitation wavelength of 396 nm and an emission wavelength of 462 nm was 96.48. When acrylamide, arginine and glucose were kept in a boilingwater bath for 60 min, the absorbance was 0.159 and the fluorescence intensity was 50.75, indicating a reduction of 51.38% and 47.40%, respectively. The infrared spectroscopic results showed the characteristic absorption peaks of acrylamide at 2 356 and 2 065 cm-1, which disappeared with the addition of acrylamide. The effect of MRPs derived from arginine-glucose model system on the state of acrylamide suggests that the acrylamide may exist in a combined state in the food system, reducing the toxicity of free acrylamide molecules. This work may be helpful for evaluating the safety of acrylamide in food processing as well as providing new insight into the safety of acrylamide and similar materials.
Evoluation of Endogenous Lipase Activity, Lipolysis and Lipid Oxidation during the Processing of Traditional Dry-Salted Decapterus maruadsi
CAO Songmin, WU Yanyan, LI Laihao, LIN Wanling, CHEN Shengjun, ZHAO Yongqiang
2017, 38(7):  36-42.  doi:10.7506/spkx1002-6630-201707007
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In order to figure out the evolution of lipolysis and lipid oxidation during the processing of traditional dry-salted Decapterus maruadsi, the changes in neutral lipase (NL), acidic lipase (AL), phospholipase (PL), lipoxygenase (LOX), thiobarbituric acid reactive substance value (TBARS), peroxide value (POV), and lipid composition were measured and the correlation of endogenous lipase activity with lipid degradation and oxidation was analyzed at five processing stages, i.e., fresh fish, salting, soaking desalting, drying and final product. The results showed that neutral lipase, acid lipase, phospholipase activities markedly decreased (P < 0.05) during the whole process, and only 17%, 57%, 33% of the initial activity was retained in the final product, respectively. LOX activity increased significantly during the whole process (P < 0.05), and both POV and TBARS increase except for a significant decrease in POV during the late stage of drying. As evaluated by principal component analysis, the activities of endogenous fat hydrolases (NL, AL and PL) had a significant effect on lipid degradation, but a rather limited effect on lipid oxidation. LOX activity was positively related to lipid oxidation but it was little related to lipolysis. During both salting and drying polyunsaturated fatty acids (PUFA) revealed a significant decrease (P < 0.05), but monounsaturated fatty acids (MUFA) and saturated fatty acid (SFA) revealed a significant increase (P < 0.05). The contents of both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) exhibit a complementary relationship.
Shelling of Solenocera melantho Using Ultra High Pressure and Its Effect on the Quality of Muscle
WANG Zhiyan, YANG Wenge, ZHOU Guo, XU Dalun, LOU Qiaoming, ZHANG Jinjie, CUI Yan
2017, 38(7):  43-48.  doi:10.7506/spkx1002-6630-201707008
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With the aim to study the effect of ultra high pressure (UHP) on the shelling and quality of shrimp meat, Solenocera melantho was subjected to UHP treatment (100?500 MPa), and evaluated for salt-soluble protein content, total sulfhydryl content and Ca2+-ATPase activity of myofibrillar protein, as well as the color, texture and ultrastructure of shrimp muscle. The results indicated that UHP at 200 and 300 MPa could improve the shelling efficiency while maintaining the integrity and quality of shrimp meat, but shrimp meat showed some degree of curing at 400 and 500 MPa. Compared with the control group, the hardness, springiness and chewiness of shrimp meat increased by 35.37%, 7.46% and 24.93% respectively, the surface hydrophobicity rose, but the salt-soluble proteins content, total sulfhydryl content and Ca2+-ATPase activity of myofibrillar protein had no significant differences at 200 MPa. After treated with 300, 400 and 500 MPa, the saltsoluble protein content, total sulfhydryl content and Ca2+-ATPase activity of myofibrillar protein decreased. Taking into account both shelling efficiency and the influence of UHP on the biochemical characteristics of shrimp protein, a pressure of 200 MPa was suitable to treat S. melantho. These results can provide a full support for the industrial application of UHP in the shucking of S. melantho in the production of frozen shrimp.
The Alcoholic Extract of Capparis zeylanica Linn Protects against Oxidative Damage in Saccharomyces cerevisiae: An Investigation into the Mechanism
ZHANG Peng, WANG Xiangxing, YANG Yaping, LI Shiming, ZHAO Hui, LUO Yanping
2017, 38(7):  49-54.  doi:10.7506/spkx1002-6630-201707009
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The crude alcoholic extract of Capparis zeylanica Linn (AECZ) was purified through AB-8 macroporous resin. The in vitro tests indicated that AECZ had potent hydroxyl radical and (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activities. The cytoprotection of AECZ in Saccharomyces cerevisiae BY4741 and its homogenous strains deficient in antioxidant enzyme genes under oxidative stress induced by H2O2, CCl4 and CdSO4 was explored. Interestingly, AECZ could dramatically protect yeasts against oxidative stresses induced by H2O2, CCl4 and CdSO4. Adaptive treatment with AECZ could reduce the level of intracellular lipid peroxidation and reactive oxygen species in yeasts under stress conditions. Moreover, the GTT1 gene played an important role in alleviating oxidative damage in yeast cells. This study for the first time demonstrated the intracellular antioxidant activity of AECZ, which will provide theoretical evidence for further exploitation and utilization of Capparis zeylanica Linn.
Moisture Adsorption Isotherms and Thermodynamic Properties of Peanut Shell and Kernel
ZHAO Ya, ZHANG Pingping, SHI Qilong
2017, 38(7):  55-62.  doi:10.7506/spkx1002-6630-201707010
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In order to reveal the relationships between temperature and moisture content and water activity (aw) of peanut shell (PS) and peanut kernel (PK) and thus to improve the storage stability of peanut, the moisture adsorption isotherms of PS and PK were investigated at 10, 20 and 30 ℃ by the static weighing method. Thermodynamic properties such as net isosteric heat of sorption (qst), differential entropy (Sd), spreading pressure, integral entropy, integral enthalpy, enthalpyentropy compensation, and glass transition temperature (Tg) of PS and PK were also discussed. The results showed that the water adsorption of PK and PS followed a typical type Ⅲ isotherm behavior, and the water contents of PK and PS increased with increasing aw. The GAB model showed the best fit with the experimental data. The qst and Sd of PS and PK decreased with increasing moisture content. The spreading pressure increased with increasing aw, and decreased with increasing temperature. The integral enthalpy decreased with increasing moisture content, whereas reverse trend was observed for the integral entropy. Both qst and Sd of PS were higher than those of PK, while the spreading pressure of PK at the same temperature was higher than that of PS. At the same moisture content, the integral enthalpy of PK was lower than that of PS, whereas integral entropy of PK was higher than that of PS. The water adsorption processes of PS and PK were both a spontaneous process driven by enthalpy and Tg of PS and PK decreased with increasing water content, with the former being higher than the latter at the same water content. According to the state diagram, at 10 ℃, critical water activity and critical water content were 0.80 and 0.175 4 g/g for PS and 0.68 and 0.095 5 g/g for PK, respectively. These results can provide a theoretical basis for peanut drying and improved storage stability of dehydrated peanut.
Effect of Glycosylated Soybean Protein Isolate on Functional Properties of Myofibrillar Protein
WANG Bo, YI Dong, XIE Mengying, PAN Nan, ZHANG Lili*, XIA Xiufang
2017, 38(7):  63-69.  doi:10.7506/spkx1002-6630-201707011
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Glycosylated soybean protein isolate (SPI) was prepared by reaction between SPI and glucose at a ratio of 1:1 (m/m) at 70 ℃ for 4 h, and its blends with myofibrillar protein (MP) at different ratios of 9:1, 8:2, 7:3, 6:4 and 5:5 (m/m) were determined for emulsifying properties, turbidity, surface hydrophobicity and gel properties (texture properties, whiteness and microstructure) in order to elucidate the effect and mechanism of glycosylated SPI on the functional properties of MP. The results showed that the emulsifying properties and surface hydrophobicity of glycosylated SPI and MP blends were significantly improved compared with MP (P < 0.05). The turbidity of the blended proteins rose with increasing temperature (30?80 ℃), but it decreased with higher proportion of glycosylated SPI. The gel hardness and springiness of MP and glycosylated SPI blends were significantly better than those of MP and native SPI blends (P < 0.05), and the gel microstructure was more compact and uniform than that of MP and native SPI blends. Compared with MP, the gel whiteness of the mixed proteins significantly decreased, except for no significant difference at a mixing ratio of 9:1 (P > 0.05).
Effect of Drying Methods on Eating and Nutritional Qualities of Chinese Jujube Fruits (Ziziphus jujuba Mill. cv. Dongzao)
SHEN Jing, WEI Ting, JI Xiaolong, WANG Min
2017, 38(7):  70-76.  doi:10.7506/spkx1002-6630-201707012
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The effects of microwave vacuum freeze drying (MVFD), microwave vacuum puffing (MVP), short- and medium-wave infrared drying (ID) and vacuum freeze drying (VFD) on the eating and nutritional qualities of Chinese jujube were determined. The results showed that the contents of total sugar and reducing sugar increased after drying. The total acid content declined after all drying treatments except short- and medium-wave ID. No significant changes in the color and browning degree occurred after MVFD and MVP. MVFD resulted in the highest retention rate of VC (98.62%), whereas jujube fruits dried by short- and medium-wave ID showed the lowest VC contents. The total phenolic content in jujubes after MVP and MVFD significantly increased to 4 721.30 and 4 516.25 mg/100 g md, respectively. The total flavonoid content after VFD was significantly higher than that in samples dried by other drying methods (P < 0.05). The eating and nutritional qualities of Chinese jujube after ID were more seriously damaged. Microscopic observation demonstrated that VFD fruits had a highly porous honeycomb structure. In addition, MVFD fruits displayed large and uniform pores, while the structure of MVP fruits was more loose, showing a large number of small granules. ID fruits exhibited a dense structure without cavities. In summary, dried jujube obtained after MVFD and MVP had better eating and nutritional qualities in terms of color, aroma, taste and appearance, which were similar to those of VFD samples. Due to their low cost and high efficiency, both MVFD and MVP are significantly advantageous for producing high quality jujube products in the future with broad application prospects.
Changes in Structural Properties of Myofibrillarlar Proteins during the Processing of Fish Bone Paste
LI Xuepeng, ZHOU Mingyan, LI Cong, ZHU Wenhui, YI Shumin, LI Jianrong, LI Yujin, ZHAO Wei, XU Jiayi, JIAO Xueqing
2017, 38(7):  77-81.  doi:10.7506/spkx1002-6630-201707013
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Superfine fish bone paste was prepared by sequentially using colloid mill grinding and wet superfine grinding. Myofibrillarlar proteins from fish bone paste were extracted to investigate the changes in structural properties during the processing of bone paste through the determination of solubility, particle size, turbidity, active sulfhydryl content, surface hydrophobicity, and secondary structures. The results showed that processing methods significantly affected myofibrillar proteins in fish bone paste, and wet superfine grinding showed a bigger impact on structural properties of myofibrillar proteins than colloid mill grinding. The solubility of myofibrillar proteins was enhanced after sequential grinding. The particle size reduced under the shear stress of colloid mill grinding, and then increased obviously from 299.4 to 464.5 nm after wet superfine grinding, accompanied with an increase in turbidity. The active sulfhydryl content and surface hydrophobicity were decreased after colloid mill grinding, but both of them firstly rosed then declined with the increase of wet superfine grinding time. The proportion of α-spiral in secondary structure increased from 64.21% to 79.99%, while β structure proportion decreased after colloid mill grinding, and wet superfine grinding could degrade part of the α-spiral structure and turned it into β structure.
Basic Research
Characteristics and Identification of Woody Breast Fillets
SUN Xiao, CHEN Cairong, ZHOU Manjing, CHEN Kunjie
2017, 38(7):  82-87.  doi:10.7506/spkx1002-6630-201707014
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Woody breast (WB) has recently been characterized by a distinct hardness of breast fillets. The objective of this study was to determine the basic performance parameters of WB and to identify different grades of WB by microstructural examination and different measures. A total of 147 and 175 Cobb 500 broilers were slaughtered at 42 and 63 days of age following the same procedure, respectively and breast samples were collected for WB classification. The weight, dimensions namely length (L), width (W), top height (H1) and bottom height (H2), and compression force (CF) of all these samples were measured and statistically correlated with WB grades by analysis of variance. Furthermore, a predictive model for WB classification was developed based on the parameters highly significantly correlated with WB grades. The results showed that the microstructure of WB was related to muscle cells with nonuniform size and shape because of muscle degeneration and muscle tissue was replaced by connective tissue when compared to normal breast fillet. For WB samples from carcasses of broilers of the same age, H1, H2 and CF significantly increased as the severity of WB increased (P < 0.05). These three parameters had highly significant correlations with each other, and they were important factors that affected and were correlated with WB categories (P < 0.001). The overall recognition rate of the developed model was 92.30%, suggesting that H1, H2 and CF enables to objectively identify WB and can potentially replace the artificial scoring system.
Water Desorption Isotherm and Pore Characteristics of Glutinous Rice Flour
ZHANG Hua, ZHAO Xuewei, BAI Yanhong, DUAN Ruiqian
2017, 38(7):  88-95.  doi:10.7506/spkx1002-6630-201707015
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Water desorption isotherm of glutinous rice flour is necessary for understanding water transfer from it to environment. On the other hand, the isotherm data can be used to explore pore characteristics a solid matrix, which will allow a deeper understanding of water adsorption mechanism. Equilibrium water contents of glutinous rice flour were determined after conditioning to 10 different water activity levels at 10, 20 and 30 ℃ using a static gravimetric method. The obtained desorption data were fitted with four selected isotherm models, and were further mined to estimate pore properties of glutinous rice flour. Glutinous rice flour exhibited a typical type-Ⅱ adsorption isotherm. The Lewicki model performed best in predicting water desorption of glutinous rice flour at a constant temperature, while the GDW model could predict the moisture content as a function of water activity and temperature. The pores in glutinous rice flour included micropore and mesopore. Pore size distribution posed a single peak located in micropore zone whose value increased with the decrease in temperature. Consequently, micropore volume also increased as temperature decreased. The pore surface in glutinous rice flour was fractal in nature. The more porous surface structure and the larger specific surface area at lower temperature contributed to the increased adsorption capacity.
Effect of Ultra-High Pressure Processing on the Formation and Stability of Emulsions Containing Soy Protein and Soluble Polysaccharide Complexes
DING Jian, MA Wenjun, BI Shuang, QI Baokun, WANG Zhongjiang, SUI Xiaonan, JIANG Lianzhou
2017, 38(7):  96-101.  doi:10.7506/spkx1002-6630-201707016
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The present study was undertaken to explore the effect of ultra-high pressure (UHP) processing the formation of emulsions containing soy protein and soluble polysaccharide complexes and to reveal the relationship between the structural change and emulsion stability of the complexes. For this purpose, the changes in the microstructure, particle size distribution, interfacial adsorption properties and spatial structure of soy protein after UHP modification were studied using confocal laser technology, dynamic laser light scattering, contact angle measurement and circular dichroism. The experimental data showed that the droplet size of the emulsion became smaller, more regular in shape and more evenly distributed with increased pressure and the negative surface charge increased. UHP treatment at 400 MPa provided the maximum emulsifying activity and emulsion stability, which were 18.33 m2/g and 30.2 min, respectively. The secondary structure of soy protein changed after UHP treatments, thereby influencing its bonding with soluble polysaccharides and the adsorption properties of protein at the oil-water interface and the interface pressure of the emulsion. These results uncovered that the stability mechanism of emulsions containing ultra-high pressure-modified soy protein and soluble polysaccharides may related to the change in the molecular structure of the interfacial layer in emulsions.
Effect of Different Modes of Magnesium Chloride Addition on Tofu Quality Properties
LIU Lingfei, CHEN Yinghui, XU Jingting, CHEN Zhenjia, GUO Shuntang
2017, 38(7):  102-108.  doi:10.7506/spkx1002-6630-201707017
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This study was executed to investigate the effect of different methods of magnesium chloride addition on tofu yield and quality. Tofu was produced using four different stirring speeds (60, 120, 180 and 240 r/min) and three different stirring times (10, 20 and 30 s), and compared for differences in quality properties. Furthermore, a comparative evaluation was made of the quality of tofu produced by one-time and portionwise addition of magnesium chloride (in two, three and four portions) under optimum stirring conditions. The results indicated that one-time addition of tofu coagulant with a stirring speed of 120 r/min and a stirring time of 30 s provided the highest tofu yield of 282.0 g/100 g whereas the lowest value of 183.9 g/100 g was obtained with a stirring speed of 240 r/min and a stirring time of 30 s. Tofu prepared by coagulant addition in batches had higher water-retaining capacity and better quality than that prepared by one-time addition. Addition in three portions was found to be optimal for the maximum increase in hardness, cohesiveness and gumminess by 19.9%, 6.9% and 30.0%, respectively.
Quality and Behavior Characteristics of Apple Micropowder Processed from Five Cultivars
XUE Yujie, CHEN Qinqin, BI Jinfeng, ZHOU Mo, NING Xibin, WANG Shuzhen
2017, 38(7):  109-114.  doi:10.7506/spkx1002-6630-201707018
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To select the appropriate cultivar for processing pure apple micropowder, physicochemical and behavior characteristics of different pure apple micropowder processed from five apple cultivars including Changfu No. 2, Hanfu, Golden Delicious, Guoguang and Qinguan were evaluated. Apple micropowder was prepared by using short- and mediumwave infrared radiation drying combined with coarse grinding technology. All above parameters were further analyzed by principal component analysis (PCA). Among these cultivars, the lightness L value of Hanfu apple micropowder was the highest, whereas Qinguan apple micropowder presented the lowest L value. The contents of total phenol and total sugar in Fuji apple micropowder were the highest. The cohesiveness of Changfu No. 2 apple micropowder and Hanfu apple micropowder was lower than that of other cultivars under the condition of high stress. Furthermore, three principal factors were selected through PCA, which could account for 90.38% of the total variability. In summary, Fuji apple is the most appropriate cultivar for processing apple micropowder.
Effects of Domestic Cooking Methods on Phenol Contents and Antioxidant Activity in Purple-Fleshed Potatoes
WANG Yaohong, WANG Lei, ZHAO Peng, ZHANG Chao, YANG Le, YAN Xiaoyang, WANG Dongdong, CHEN Qin
2017, 38(7):  115-121.  doi:10.7506/spkx1002-6630-201707019
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Purple-fleshed potato, rich in phenolic compounds such as anthocyanin, chlorogenic acid, is a good source of natural antioxidants due to its extensive availability and cheapness. This research was performed to investigate the impacts of domestic cooking methods on the contents of anthocyanins, free polyphenols, bound polyphenols and chlorogenic acid and antioxidant activity in purple-fleshed potato for the purpose of achieving maximum retention of the antioxidant bioactives. Three purple-fleshed potato breeding lines and the white potato cultivar ‘Shepody’ were tested in this study. The results showed that all cooking methods significantly reduced anthocyanin contents in purple-fleshed potato varieties; compared with ‘Shepody’, free polyphenols, bound polyphenols and chlorogenic acid contents and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity in purple-fleshed potatoes increased after steam and microwave treatments, whereas all components except for bound polyphenols decreased after boiling treatment. In conclusion, phenolics could be retained maximally after microwave irradiation and steaming and thus exert their antioxidant activities.
Effect of Enzymatic Hydrolysis of Lactose Combined with Heat Treatments on Maillard Reaction of Milk
LI Sining, TANG Shanhu, HU Yang, MAO Menglan, LIU Yuan
2017, 38(7):  122-128.  doi:10.7506/spkx1002-6630-201707020
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The objective of this study was to investigate the relationship between the hydrolysis degree of lactose combined with heat treatments and Maillard reaction in milk. Fresh milk was hydrolyzed with neutral lactase to obtain low-lactose milk with different hydrolysis degrees. Then, the products were treated by various heating methods and the degree of Maillard reaction was assessed. The glucose concentration and the hydrolysis degree of lactose in milk at different hydrolysis times were measured by the glucose oxidase method. Furosine and 5-hydroxymethylfurfural (5-HMF) contents and browning degree (OD values) were determined by using high-performance liquid phase chromatography (HPLC) and ultraviolet spectrophotometry, respectively. The results showed that the glucose content in milk was increased with prolonged time of lactose hydrolysis, and glucose concentration slowly increased from 0.00 to 1 721.33 mg /100 mL. Similarly, lactose hydrolysis percentage increased from 0% to 70.33%, reaching a level higher than 50% after 2.0 h heat treatment. Furosine content in milk showed a rising trend with extended heat treatment (P < 0.05). Milk subjected to hydrolysis for more than 3.0 h and then heat treatment at 75 ℃ for 30 min had a furosine content exceeding 190 mg/100 g protein, while hydrolysis for 0.5 h and longer followed by heat treatment at 75 ℃ for 15 s resulted in a furosine content more than 12 mg/100 g protein. 5-HMF was not detected in fresh milk or in milk hydrolyzed and heat treated at 75 ℃ for 30 min. The content of 5-HMF in hydrolyzed milk increased with the extension of hydrolysis time followed by heat treatment at 75 ℃ for 15 s (P < 0.05). Likewise, the browning degree significantly increased with the extension of hydrolysis time (P < 0.05). Browning reaction in milk treated at 75 ℃ for 30 min was significantly higher than that at 75 ℃ for 15 s. Therefore, enzymatic hydrolysis of lactose coupled with heat treatment can promote Maillard reaction and thus affect protein quality in milk.
Drying Characteristics and Process Simulation of Ultrasound-Assisted Hot Air Drying of Purple-Fleshed Sweet Potato Based on Weibull Distribution Model
SUN Yue, LIU Yunhong, YU Huichun, LI Xiaofang
2017, 38(7):  129-135.  doi:10.7506/spkx1002-6630-201707021
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In order to explore the enhancing effect of ultrasound on hot air drying process, the drying characteristics and quality changes of purple-fleshed sweet potato in an ultrasound-assisted hot air dryer were investigated at different drying temperatures (40, 50, 60 and 70 ℃) and ultrasound powers (0, 30 and 60 W). The Weibull distribution model was applied in the dynamic simulation of the drying process. The results showed that the increase in drying temperature and ultrasound power resulted in a significant reduction in drying time. The Weibull distribution model could fit the drying curves accurately under different drying conditions. Scale parameter (α) decreased in the range of 92.317 to 345.764 min with the increase in drying temperature and ultrasound power. Shape parameter (β) ranged from 0.817 to 1.032, indicating that the hot air drying of purple-fleshed sweet potato was controlled by internal diffusion resistance. The effective moisture diffusivity coefficient (Dcal) values increased in the range of 1.205 × 10-10 to 4.513 × 10-10 m2/s with the increase in drying temperature and ultrasound power. The activation energy decreased as ultrasound power increased. At the same ultrasound power, the contents of total phenolics and total flavonoids increased at first and then decreased with the increase in drying temperature. Both classes of compounds increased with the increase in ultrasound power at lower drying temperature, whereas the reverse trend was observed at higher drying temperature. Therefore, ultrasound-assisted hot air drying is an effective method to accelerate drying rate and simultaneously achieve better quality.
Demethylation Kinetics of Citrus Pectin in Alkaline Solution
LI Meng, HUANG Xuesong, WANG Chao, DUAN Hanying
2017, 38(7):  136-141.  doi:10.7506/spkx1002-6630-201707022
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For a better understanding of the mechanism of alkali demethylation of pectin and the effect of temperature and pH on the degree of esterification (DE) and demethylation rate of pectin, high methoxyl citrus pectin (DE = 77.8%) was investigate for demethylation kinetics and thermodynamic characteristics at different temperatures (10, 20, 25 and 30 ℃) and pH (10.0-11.3). The pH was accurately controlled by sodium hydroxide in sodium bicarbonate/sodium carbonate buffer. DE and methoxyl group concentration were studied during the demethylation process. The results showed that the alkali demethylation followed a first-order kinetic reaction model. Temperature, pH and their interaction had remarkable effects on the demethylation process, while the effect of pH was more notable. The demethylation reaction rate constant (k) and pH showed an exponential relationship and k sharply increased when pH varied lightly from 11.0 to 11.3. At pH 10.7, 11.0 and 11.3, the activation energy (Ea) were 136.97, 122.37 and 104.20 kJ/mol, the activation enthalpy (ΔH) were 134.52, 119.92 and 101.75 kJ/mol, the activation entropy (ΔS) were 141.86, 100.28 and 44.81 J/(mol·K), and the free energy of activation (ΔG) were 92.76, 90.40 and 88.56 kJ/mol, respectively.
Quality Characteristics, Phenolics Content and Antioxidant Activity of Chinese Wild Grapes
JIANG Yu, MENG Jiangfei, LIU Chonghuai, JIANG Jianfu, FAN Xiucai, YAN Jing, ZHANG Zhenwen
2017, 38(7):  142-148.  doi:10.7506/spkx1002-6630-201707023
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Wild grape resources are abundant in China, but their utilization is limited. In order to reveal the quality differences among different Chinese wild grape species and lay the theoretial foundation for further utilization, 10 Chinese wild grape species (46 lines) and four different control populations were investigated with regard to their quality characteristics, phenolics content and antioxidant activity. The results showed that: 1) the single berry mass of Cabernet Sauvignon was higher than that of all wild grape species except V. davidii, but the mass ratio of skin to whole berry of Cabernet Sauvignon was lower; 2) the sugar composition of Chinese wild grapes was similar to that of the controls without significant differences observed in the contents of fructose and glucose, but total sugar content was significantly lower in Chinese wild grapes than in Cabernet Sauvignon and Hutai No. 8. Total acid contents in all Chinese wild grape species except V. davidii were significantly higher than those in Cabernet Sauvignon and Hutai No. 8. The ratio of tartaric acid to malic acid in Chinese wild grapes was lower than that in Cabernet Sauvignon, indicating that Chinese wild grapes belonged to the type of high malic acid. The contents of sugar and acid in Chinese wild grape were relatively closer to those in V. riparia and V. rotundifolia. Compared with Cabernet Sauvignon and Hutai No. 8, with high sugars and low acids, Chinese wild grapes belonged to the species with low sugars and low acids; 3) the phenolics contents and antioxidant activity of Chinese wild grapes had a wide range, with most species being similar to Cabernet Sauvignon. The content of anthocyanins in Chinese wild grapes was higher than that in the controls. In conclusion, the wild grapes of V. yanshanensis, V. bryoniaefolia and V. davidii have good quality based on their similarity to Sauvignon and Hutai No. 8 in terms of sugar and acid compositions, phenol contents and antioxidant activity.
Effects of Different Thawing Methods on Drip Loss, Physicochemical Quality and Antioxidant Activity of Quick-Frozen Mulberry Fruits
WANG Yixiu, CHEN Qinqin, BI Jinfeng, ZHOU Mo, LI Bin
2017, 38(7):  149-154.  doi:10.7506/spkx1002-6630-201707024
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Different thawing methods, microwave radiation at 500 and 550 W, ultrasonic radiation, and thawing at refrigerated and room temperatures were compared to find the best one to reduce the negative effect of thawing on drip loss, color, functional components and antioxidant activities of quick-frozen mulberry fruits and to shorten the thawing time. The results showed that the time required for microwave thawing was the shortest, which was respectively 0.58 and 0.35 min at 500 and 550 W, while the thawing process took the longest time (305 min) under refrigerated condition. Significant differences were presented in drip loss among different thawing methods; the drip loss after microwave thawing at 500 W was the lowest (1.34%), whereas the highest values was obtained after ultrasonic thawing (9.24%). The content of total phenols (151.66 mg/100 g) and anthocyanins (2.27 mg/g cyanidin-3-O-glucoside, 0.69 mg/g cyanidin-3-O-rutinoside, and 0.047 mg/g pelargonidin-3-glucoside) as well as antioxidant activity in terms of 2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate (ABTS) free radical scavenging activity (21.87 μmol Trolox/g), 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity (35.70 μmol Trolox/g) and ferric reducing antioxidant power (FRAP) (27.85 μmol Trolox/g) of mulberry fruits after microwave thawing at 500 W were significantly higher than those of four other thawing methods. In summary, microwave thawing at power 500 W was the most appropriate method for quick-frozen mulberry fruits.
Chemical Modification and Immunoregulatory Activity of Polysaccharides from Dendrobium officinale
TONG Wei, YU Qiang, LI Hu, CUI Wuwei, NIE Shaoping
2017, 38(7):  155-160.  doi:10.7506/spkx1002-6630-201707025
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Highly pure polysaccharides from the dried stems of Dendrobium officinale were obtained by water extraction and alcohol precipitation combined with freeze-thawing, and they were further subjected to chemical modification by sulfation, deacetylation and carboxymethylation, respectively, with the aim of investigating the effects of these different modifications on the immunomodulatory activity of Dendrobium officinale polysaccharides in RAW264.7 macrophages. The results showed that Dendrobium officinale polysaccharides had high neutral sugar contents along with low contents of uronic acids and proteins, which were 87.37%, 3.19% and 0.51%, respectively. The neutral sugar content of Dendrobium officinale polysaccharides was significantly reduced by sulfation and carboxymethylation. The Fourier transform infrared spectroscopic (FTIR) analysis indicated that sulfation, deacetylation and carboxymethylation derivatives were successfully prepared. The molecular weight of Dendrobium officinale polysaccharides measured by high-performance gel permeation chromatography (GPGPC) was 960 kD, while it was significantly increased by sulfation and carboxymethylation. It was found that sulfation and deacetylation could enhance the immunomodulatory activity of Dendrobium officinale polysaccharides in vitro, while carboxymethylation had a significant opposite effect, indicating that grafted modification cannot necessarily improve the immunomodulatory activity of Dendrobium officinale polysaccharides.
Effects of Different Proteases on Antioxidant Activities of Wheat Gluten Hydrolysates
ZHENG Zhiqiang, LI Baolin, HAO Limin, GUO Shuntang
2017, 38(7):  161-166.  doi:10.7506/spkx1002-6630-201707026
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Wheat gluten is a main by-product of wheat starch processing. Enzymatic hydrolysis is an effective way of improving the solubility and functionality of wheat gluten; however, protease type may influence the functionalities of wheat gluten hydrolysates such as antioxidant activities. Six frequently used proteases including Alcalase, Neutrase, Pepsin, Flavourzyme, Pancreatin and Papain were used for the hydrolysis of wheat gluten, and the degree of hydrolysis and antioxidant capacity of four-hour hydrolysates were evaluated in terms of polypeptide yield, molecular weight distribution, 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical scavenging activity, superoxide radical anion (O2- ·) scavenging activity, and hydroxyl radical (·OH) scavenging activity. The results showed that Flavourzyme hydrolysate exhibited the highest polypeptide yield (91.44%), containing up to 76.9% polypeptide with a molecular weight of less than 3 000 D. Papain hydrolysate at a concentration of 3 mg/mL exhibited the best DPPH radical scavenging activity (65.12% scavenging percentage, P < 0.01), followed by Flavourzyme hydrolysate (58.43%) and Alcalase hydrolysate (55.29%). Alcalase hydrolysate exhibited the best superoxide anion radical scavenging activity (58.68% scavenging percentage, P < 0.01), followed by Flavourzyme hydrolysis (49.25%). Alcalase and Papain hydrolysates exhibited the best hydroxyl radical scavenging activity (scavenging percentages of 59.23% and 58.16%, respectively). Therefore, protease type had a notable effect on antioxidant activities of wheat gluten hydrolysates. In addition, Flavourzyme hydrolysis gave a significant improvement in the degree of hydrolysis and the formation of small polypeptides; moreover, Alcalase, Papain and Flavourzyme resulted in improved antioxidant activities of hydrolysates.
Changes in Endogenous Hormones during the Development of Vitis vinifera L. cv. Cabernet Sauvignon and Their Relationship with Berry Ripening
GAO Jiangman, MENG Ying, LIU Qing, WANG Tongmeng, LIU Meiying, LI Wenbing, XI Zhumei, ZHANG Zhenwen
2017, 38(7):  167-175.  doi:10.7506/spkx1002-6630-201707027
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To investigate the changes in endogenous hormone contents of various berry tissues during the development of Vitis vinifera L. cv. Cabernet Sauvignon and further to examine their relationship with berry ripening, abscisic acid (ABA), indole acetic acid (IAA), gibberellin A3 (GA3), jasmonic acid (JA) and salicylic acid (SA) in grape seeds, skin and pulp were determined by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The results indicated that the variation of ABA in grape pulp and skin showed a double S-shaped trend during the development of grape berries. At 20 days after anthesis (20 DAA), the ABA level was relatively high, and the ABA levels in pulp and skin decreased before veraison, and then increased until the middle of veraison, followed by a slow decrease until ripening. GA3 and JA were changed in a similar pattern. Both of them first increased rapidly followed by a decrease at the fruit expansion stage and then showed a bell-shaped trend during veraison. IAA contents in grape pulp and skin first decreased slightly followed by a rapid increase until reaching a peak during the rapid developmental stage of grape berries, and then gradually decreased and remained stable during the subsequent veraison. IAA contents in grape seeds were high before the beginning of the fruit expansion stage, and then declined and remained at a low level after entering the fruit expansion stage. Similar changes were observed for SA. Conclusion: ABA, GA3 and JA were related to the ripening of Cabernet Sauvignon, while IAA, GA3, SA and JA were related to the development of Cabernet Sauvignon.
Effect of Extraction Temperature on Physicochemical Properties and Intestinal Mucosal Immunomodulating Activity of Polysaccharides from Dendrobium huoshanense
JIANG Xianmin, WANG Zhengming, PAN Lihua, ZHA Xueqiang, LUO Jianping
2017, 38(7):  176-181.  doi:10.7506/spkx1002-6630-201707028
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Objective: To investigate the effect of extraction temperature on the yield, physicochemical properties and intestinal mucosal immunomodulating activity of polysaccharides extracted from Dendrobium huoshanense. Methods: Four different extraction temperatures including 40, 60, 80 and 100 ℃ were used to investigate the changes in the yield and intrinsic viscosity of Dendrobium huoshanense polysaccharides (DHP) extracted by the water extraction-ethanol precipitation method. High performance liquid chromatography (HPLC), gas chromatography (GC) and Fourier transform infrared spectrometry (FTIR) were used to analyze the molecular weight distribution, monosaccharide compositions and characteristic groups of DHP and its fractions eluted with water and salt solution from DEAE-cellulose anion exchange column. The conditioned medium from Peyer’s patch cells from the small intestine of mice was used to determine the intestinal mucosal immunomodulating activity of DHP and its fractions by observing the proliferation of bone marrow cells of mice. Results: With increasing extraction temperature, the yield of DHP rose and its intrinsic viscosity dropped. HPLC analysis showed that DHP extracted at different temperatures were mainly composed of higher molecular weight fraction (HMW) and lower molecular weight fraction (LMW). LMW, which had better thermal stability, mainly existed in the water-eluted fraction (DHPW) from DEAE-cellulose anion exchange column and HMW, which had weaker thermal stability, mainly existed in the salt-eluted fraction (DHPS). GC and FTIR analysis displayed that DHPW mainly consisted of Glc in α-configuration and DHPS mainly consisted of Glc, Gal, Ara and Man in β-configuration with some uronic acids. All DHPs from different extraction temperatures and the corresponding DHPW and DHPS fractions possessed intestinal mucosal immunomodulating activity and the activity of DHPS was higher than that of DHPW, but their activities decreased significantly with increasing extraction temperature. Conclusion: Extraction temperatures not only influenced the yield of DHP, but also markedly changed its intrinsic viscosity, molecular weight distribution, monosaccharide compositions and immunomodulating activity. Although higher temperature increased the extraction yield of DHP, it significantly decreased the intestinal mucosal immunomodulating activity of DHP because of the reduction in the proportion of HMW in DHP.
Effects of Different Tenderization Treatments on the Quality of Goose Meat
GAO Haiyan, ZHANG Ruiyao, JIA Tian, HU Yajie, MA Hanjun, ZENG Jie
2017, 38(7):  182-186.  doi:10.7506/spkx1002-6630-201707029
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Natural aging, papain and phosphate solution treatments were used on goose meat and then the quality of goose meat was assayed in terms of water-holding capacity, shear force, pH, oxidation degree and the diameter of muscle fiber. The results showed that there was no apparent difference in water-holding capacity or shear force of goose meat with different natural aging times ranging from 12 to 60 h, while papain and phosphate solution treatments could significantly improve the water-holding capacity of goose meat with the largest water-holding capacity being obtained in the samples treated by compound phosphate solution. The shear force of goose meat treated with papain and different phosphate tenderizers was lower than with natural aging. The minimal shear force was obtained in the samples tenderized by 15 U/mL papain. The pH values of goose meat treated by papain, sodium pyrophosphate and compound phosphate solution were obviously higher than that of goose meat treated by natural aging. The degree of lipid oxidation in goose meat gradually increased with the extension of natural aging time, while papain and different phosphate solutions could inhibit lipid oxidation. The lowest degree of oxidation was observed in goose meat treated with 6 U/mL papain. Muscle fiber diameter of goose meat changed only a little during natural aging; however, it decreased with the increase in the concentrations of papain and phosphate. Taken together, these results will hopefully provide a theoretical basis for the development and application of tenderizers for goose meat products.
Nutrition & Hygiene
Effects of Green Tea Polysaccharides on Intestinal Health and Immune Regulation in Mice
LI Haishan, LIU Liqiao, NIE Shaoping
2017, 38(7):  187-192.  doi:10.7506/spkx1002-6630-201707030
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The objective of this work was to evaluate the effect of tea polysaccharides (TPS, from Wuyuan green tea) on intestinal health and immune regulation in mice. Healthy C57/BL6 mice were randomly divided into four groups, and they were administrated by gavage with different concentrations of tea polysaccharides. After adaptive feeding for one week, the animals in these groups were given high, mediumand low doses of TPS and normal saline as blank control for 21 days, respectively. At the end of the experimental period, the mice were sacrificed, and spleen and thymus were harvested and weighted to calculate immune organ indexes. Peritoneal macrophages were used to examine phagocytosis activity by using neutral red phagocytosis assay. Short chain fatty acids (SCFAs) in colonic contents were analyzed by gas chromatography (GC) and ammonia by the indophenol blue colorimetric method. Meanwhile, the pH and water content of colonic contents were also measured. Results showed that immune organ indexes were increased significantly after TPS administration. The phagocytosis of peritoneal macrophages was improved in a dose-dependent manner. Some SCFAs (acetic acid, propionic acid and butyric acid) were increased while no difference in isobutyrate, pentanoic acid and delphinic acid was detected. A significant decline in the ammonia content and pH of colonic contents of mice was observed, while water content increased. Therefore, TPS can regulate immune function and promote intestinal health in mice.
Oridonin-Induced Quinone Reductase Activity and Its Mechanism in Mouse Hepatoma Hepa1c1c7 Cells
WANG Zuo, WANG Lu, CHEN Zhongzheng, LAO Yang, LIU Xingyi, GAO Xiong, YAN Ni, LIN Xiaorong, ZHANG Yuanguan, LI Bin
2017, 38(7):  193-200.  doi:10.7506/spkx1002-6630-201707031
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To screen and identify the anticancer components of Rabdosia serra (Maxim) Hara, the effects of the crude ethyl acetate extract of Rabdosia serra (Maxim) Hara and its purified fractions obtained by silica gel column chromatography and semi-preparative chromatography on cell viability and quinone reductase (QR/NQO1) activity were evaluated using mouse hepatoma Hepa1c1c7 cells. The purified fractions were identified by mass spectrometry (MS), 1H-nuclear magnetic renonsance (1H-NMR) and 13C-NMR. Furthermore, mouse hepatoma cells were pretreated with specific protein kinase inhibitors including phosphatidylinositol 3-kinase (PI3K) inhibitor, extracellular signal-regulated kinase (ERK) inhibitor, mitogen activated protein kinases(MAPK) p38 inhibitor, protein kinase C (PKC) inhibitor and c-Jun N-terminal kinase (JNK) inhibitor to determine the signal transduction pathways leading to the induction of QR activity. The mRNA and protein expression levels of NQO1 were measured by quantitative PCR and Western blot, respectively. Our results suggested as follows: 1) oridonin was identified as a potential anticancer component of this extract; 2) oridonin at a concentration of 0.94 μg/mL exhibited a remarkable potency in inducing QR; 3)PI3K inhibitor significantly inhibited the induction of QR activity by oridonin, while ERK inhibitor showed an opposite effect. Moreover, p38, PKC and JNK inhibitors did not significantly affect the induction effect of oridonin on QR; 4)oridonin markedly increased the expression of both mRNA and protein of NQO1. In conclusion, oridonin from Rabdosia serra (Maxim) Hara can induce QR activity in cultured Hepa1c1c7 cells by activating the PI3K signal transduction pathway and inhibiting the ERK signal transduction pathway, and it also can significantly induce the transcription and translation of NQO1. These results would provid a preliminary theoretical basis for cancer chemoprevention with Rabdosia serra (Maxim) Hara and oridonin.
Basic Research
Effect of Polyphenols Extracted from Tieguanyin Tea on the mRNA and Protein Expression Levels of Hepatic Cytochromes P450 (Cyp450s) in Mice
REN Hong, LIU Dong, ZHENG Shaojie, YAN Yijing, SUN Haiyan, MING Jian
2017, 38(7):  201-206.  doi:10.7506/spkx1002-6630-201707032
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In this paper, the effect of polyphenols extracted from Tieguanyin tea on the mRNA and protein expression levels of cytochromes P450 3a11 (Cyp3a11), 2d22 (Cyp2d22) and 2c37 (Cyp2c37) in the liver of mice was explored by real-time reverse transcription polymerase chain reaction(real-time RT-PCR) and Western blot. The results showedthat the polyphenol extract at low dose (150 mg/(kg·d)) significantly induced the mRNA expression of Cyp3a11, Cyp2d22, and Cyp2c37 (P < 0.05) in comparison with the control group, while it significantly induced the protein expression of Cyp2d22 but had no significant effect on the protein expression of Cyp3a11 and exhibited a significant inhibitory effect on the protein expression of Cyp2c37. The polyphenols at middle dose (300 mg/(kg·d)) significantly inhibited the mRNA and protein expression of Cyp3a11 and Cyp2c37 (P < 0.05) but had no significant effect the mRNA and protein expression of Cyp2d22. The polyphenols at high dose (600 mg/(kg·d)), although having no significant effect on the mRNA expression of three enzymes, significantly inhibited their protein expression levels (P < 0.05). Therefore, Tieguanyin tea polyphenols can affect both the mRNA and protein expression levels of Cyp3a11, Cyp2d22 and Cyp2c37 in the liver of mice, suggesting that metabolism-based interactions can occur when they are used in combination with medicines.
Nutrition & Hygiene
Internalization and Colonization Capacity of Salmonella typhimurium in Artificially Contaminated Mung Bean Sprouts and Its Disinfection
MA Wenjuan, SHI Jianchun, FENG Qiushi, LI Jinquan, WANG Xiaohong
2017, 38(7):  207-212.  doi:10.7506/spkx1002-6630-201707033
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In this investigation, the internalization and colonization capacity of Salmonella typhimurium ATCC14028 in artificially contaminated mung bean sprouts during different germination stages was studied. Furthermore, two different disinfection methods of ultraviolet irradiation and chemical disinfectant treatment were developed to eliminate internalized Salmonella typhimurium effectively. During four different stages (0?48 h) of pre-germination of mung bean namely expansion (G1, 0 h), budding (G2, 0?12 h), early germination (G3, 12?24 h) and germination (G4, 24?48 h), Salmonella typhimurium had different internalization and colonization capacities at different inoculation concentrations (102, 104, 106 and 108 CFU/mL), which, however, tended to be identical at the end of the growth cycle (about 144 h). In addition, our results showed that ultraviolet radiation could effectively eliminate internalized Salmonella typhimurium while dipping in a mixed solution of sodium hypochlorite and silver nitrate solution had no such effect.
Effect of Oligomeric Proanthocyanidins from Grape Seeds Combined with Cisplatin on A549 Cell Proliferation and Cell Cycle
WANG Hai, LIAN Yanna, GAO Liping
2017, 38(7):  213-218.  doi:10.7506/spkx1002-6630-201707034
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Objective: To investigate the effect of oligomeric proanthocyanidins from grape seeds (O-GSP) combined with cisplatin (DDP) on the proliferation, cell cycle and cell cycle-related protein expression of A549 cells. Methods: A549 cells were cultured in vitro. The effects of DDP and O-GSP alone and in combination on the survival rate of A549 cells were observed by MTT assay; the combined effect of O-GSP and DDP on the cell cycle of A549 cells was detected by flow cytometry and the expression levels of the cell cycle-related proteins CDK 4, Cyclin D1 and p-Rb were detected by Western blot. Results: DDP (≥ 5 mg/L) and O-GSP (≥16 mg/L) treatments alone could inhibit A549 cell proliferation. The combined treatment had a synergistic effect on the inhibition of cell proliferation. DDP treatment alone at 5 mg/L arrested A549 cells at S phase and O-GSP at 4 mg/L arrested the cells at G0/G1 phase. The combination of DDP at 5 mg/L and O-GSP at 4 mg/L significantly reduced the expression levels of the cell cycle regulatory proteins CDK 4, Cyclin D1 and p-Rb. Conclusion: DDP can inhibit the proliferation of A549 cells in combination with O-GSP through a mechanism related to the regulation of cell cycle progression mediated by the Cyclin D1-CDK 4-Rb pathway.
Effect of Lactobacillus paracasei KL1, Isolated from Tibetan Kefir, on Lipid Peroxidation in Laying Hens
NIE Yanfen, DONG Muqun, ZHANG Ce, XIONG Lixia, XIE Yuanhong, ZHANG Hongxing, LIU Hui, LIAN Zhengxing
2017, 38(7):  219-223.  doi:10.7506/spkx1002-6630-201707035
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This work aimed to evaluate the effect of lyophilized cells of Lactobacillus paracasei KL1, a strain with good fermentation performance and bile salt hydrolase activity isolated from Tibetan kefir, on lipid peroxidation in laying hens. A total of 120 laying hens were divided into experimental groups with dietary supplementation of low, medium and high doses (105, 106 and 107 CFU per animal per day) of the freeze-dried culture and control group fed a basal diet alone for 11 weeks. Serum antioxidant parameters were measured during the experimental period, and all the animals were slaughtered for the measurement of liver fat content and liver histological examination by biopsy. Our experimental data demonstrated that liver fat contents in the medium- and high-dose groups were significantly reduced by 32.4% and 48.2% (P < 0.01), respectively, while a reduction of only 9.4% was observed for the low-dose group as compared with the control group. Oil red O staining of liver slices showed that Lactobacillus paracasei KL1 reduced the deposition of fat droplets in the liver in a dose-dependent manner. The results of antioxidant assays indicated that serum total antioxidant capacity was significantly higher by 16.3%, 13.9% and 14.8% in the three treatment groups than in the control group, respectively. Serum superoxide dismutase (SOD) activity levels in the medium-dose group were increased significantly by 19.4%, and by 11.3% and 16.4% in the low- and high-dose groups, respectively in comparison with the control group. However, malondialdehyde (MDA) content and glutathione peroxidase (GSH-Px) activity had no significant change (P > 0.05). The above results suggested that Lactobacillus paracasei KL1 has the ability to strongly inhibit lipid peroxidation in the liver of laying hens.
Packaging & Storage
Effect of Composite Preservatives Consisting of Tea Polyphenols and Lysozyme on the Quality of Silver Carp Meatballs during Storage
WANG Dangfeng, LI Tingting, GUO Jingwen, LIU Nan, LI Jianrong
2017, 38(7):  224-229.  doi:10.7506/spkx1002-6630-20170707036
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This work aimed to evaluate the effect of composite preservatives consisting of tea polyphenols (TPs) and lysozyme (Lys) on the eating quality of silver carp meatballs during storage at 4 ℃. Fish meatballs added with 0.1 g/kg of TPs + 0.3 g/kg of Lys (group A), 0.2 g/kg of TPs + 0.2 g/kg of Lys (group B), and 0.3 g/kg of TPs + 0.1 g/kg of sample (group C) were determined for total colony count, pH, TVB-N value, whiteness, springiness, hardness, gel strength and water distribution in order to evaluate the efficiency of preservative combinations in fish meatballs. The results showed that whiteness, springiness, and TVB-N value were not significantly changed in the treatment groups compared with the control group, whereas total colony count, pH, hardness, gel strength and water distribution were better in the treatment groups; group A had the most significant effect. These findings showed that composite preservatives could significantly inhibit microbial growth and the oxidative degradation of proteins and improve the storage quality of fish meatballs, extending the shelf life, while having little impacts on the appearance.

Isolation and Identification of Sour Rot Pathogen of Satsuma Mandarin and Inhibitory Effects of Three Antifungal Substances on It
ZHAO Yijie, TANG Yi, WANG Weihao, YAO Shixiang, DENG Lili, ZENG Kaifang
2017, 38(7):  230-237.  doi:10.7506/spkx1002-6630-201707037
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This investigation aimed to identify the sour rot pathogen of satsuma mandarin and to test the effect of Pichia membranaefaciens, salicylic acid and chitosan oligosaccharide in controlling this pathogen. We isolated a fungal pathogen from naturally infected citrus fruits and identified it as Geotrichum candidum on the basis of morphological characteristics, rDNA-ITS sequence analysis and pathogenicity. In addition, 2.5 mmol/L salicylic acid and 1.5% chitosan oligosaccharide could significantly inhibit the germination and mycelial growth of G. candidum under detached conditions. The volatile substances of P. membranaefaciens could inhibit the mycelial growth of G. candidum. Similarly, 1 × 108 CFU/mL P. membranaefaciens, 2.5 mmol/L salicylic acid and 1.5% chitosan oligosaccharide treatment of the same and different wounds could control sour rot incidence and lesion diameter, especially P. membranaefaciens and salicylic acid through inoculation on the same wounds and different wounds, respectively.
Effect of Biological Preservative Paper on Shelf Quality and Flavor Substances of Suffolk Red Seedless Grapes at Different Cold Storage Periods
LIU Zhentong, ZHANG Peng, LI Jiangkuo, YAN Tingcai, LI Chunyuan
2017, 38(7):  238-246.  doi:10.7506/spkx1002-6630-201707038
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In order to improve the quality of grapes during storage and transportation, headspace solid phase microextraction coupled with gas chromatography mass spectrometry (HS-SPME-GC-MS) and E-nose were used to evaluate the quality and flavor compounds of Suffolk Red seedless grapes wrapped with natamycin and epsilon-polylysine preservative paper during cold storage and subsequent shelf life. The results showed that both natamycin and epsilon-polylysine preservative paper, which were obtained by soaking in 500 mg/L natamycin and 500 mg/L ε-polylysine, respectively could obviously inhibit the decay and abscission of Suffolk Red seedless grapes, delay the decrease in grape hardness as well as titratable acid and VC contents, and maintain soluble solid content at a certain level, thereby improving the quality preservation of grapes. These effects were significant compared to the control without any preservative (P < 0.05), whereas natamycin preservative paper was better than ε-polylysine preservative paper. The flavor substances of Suffolk Red seedless grapes were composed of three major classes: esters, aldehydes and alcohols with ethyl acetate, n-hexyl aldehyde, cis-3-hexenal, trans-2-hexenal, 1-hexanol and cis-3-hexen-1-ol being predominant. The relative contents of the major flavor-active esters and alcohols decreased, while the relative content of the major flavor-active aldehydes increased with extended cold storage. During shelf storage, the relative contents of the major flavor-active alcohols and aldehydes decreased, whereas the relative content of the major flavor-active esters increased. The control group showed the largest changes in the relative contents of flavor compounds. The application of biological preservative paper had a positive effect on maintaining the flavor stability of Suffolk Red seedless grapes. Furthermore, natamycin was more effective in maintaining the flavor-active aldehydes and alcohols, whereas ε-polylysine was more effective in retarding the reduction of the flavor-active esters. In addition, principal component analysis (PCA) and linear discriminant analysis (LDA) of electronic nose data enabled to distinguish the flavor of grapes stored cold for different periods during shelf life.
Dynamic Response of Physiological Metabolism in Postharvest Citrus to Crude Toxin from Colletotrichum gloeosporioides
HUANG Xiaolan, WANG Rikui, HAN Leng, HE Mingyang, ZHOU Lian
2017, 38(7):  247-252.  doi:10.7506/spkx1002-6630-201707039
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Objective: The dynamic response of physiological metabolism in postharvest citrus to toxin from Colletotrichum gloeosporioides was studied to obtain a better understanding of the interaction between citrus and C. gloeosporioides. Methods: The crude toxin was isolated by organic solvent extraction, and its bioassay was performed by the acupuncture method in postharvest citrus. Moreover, the dynamic effects of the crude toxin and pathogenic bacteria on physiological metabolism of citrus fruits in terms of the contents of phenols, flavonoids, and malondialdehyde (MDA), cell wall components in citrus peel and the activities of polyphenol oxidase (PPO), peroxidase (POD), superoxide dismutase (SOD), phenylalanine ammonialyase (PAL), and β-1,3-glucanase (GLU) were analyzed. Results: Typical lesion caused by the toxin was observed, and the content of MDA was significantly increased, while the content of cell wall compounds was decreased. Upon treatment with the crude toixn at a low concentration, there was a positive correlation of lesion diameter with the content of flavonoids, lignin and the activities of PPO and POD, whereas a negative correlation existed between cell wall compounds and lesion diameter. However, the defense enzyme system and citrus fruits were damaged by the crude toxin at a high concentration, causing a dramatic decrease in the enzyme activities. Conclusion: Physiological metabolism of citrus fruits can be influenced by the crude toxin of C. gloeosporioides , and thus it plays an important role in the pathogenicity of C. gloeosporioides.
Effect of Natural Preservatives on Inhibition of Biogenic Amine Formation during Superchilled Storage of Pork
DANG Xiaoyan, WANG Kaili, WANG Wei, ZHU Yingchun
2017, 38(7):  253-259.  doi:10.7506/spkx1002-6630-201707040
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We performed this study to explore the effect of four kinds of natural preservatives, chitosan, clove oil, cinnamon oil and garlic oil on pork quality during superchilled storage at (−3 ± 1) ℃ for the purpose of screening the most suitable preservative for controlling biogenic amines. After treatment with each preservative at a mass fraction of 2%, pork longissimus dorsi muscle was packaged in vacuum and stored at superchilled temperatures. During a 40-day storage period, sensory evaluation, total viable counts (TVC), total volatile basic nitrogen (TVB-N) and biogenic amine content in pork were periodically determined to investigate the efficiency of four kinds of natural preservatives. The results showed that chitosan could observably inhibit the formation of histamine, putrescine, tyramine and cadaverine, and maintain total biogenic amines within a safe range (61.92 mg/kg after 40 days of storage), which was much lower than the standard limit. The inhibitory effect of cinnamon essential oil on the formation of biogenic amines was better, and the total biogenic amine content of pork treated with this preservative and stored for 40 days was 68.93 mg/kg. Marked inhibition of the formation of biogenic amines was observed using clove essential oil for histamine and putrescine and using garlic essential oil for tyramine. The efficiencies of these preservatives were in the order: chitosan > cinnamon essential oil > clove essential oil > garlic essential oil. Meanwhile, it turned out that chitosan and cinnamon essential oil treatment showed higher effectiveness in inhibiting the increase in TVC and TVB-N and sensory quality deterioration. These natural preservatives can reduce the formation of biogenic amines due to their powerful antimicrobial activity and ability to inhibit the formation of total volatile basic nitrogen. There results may provide evidence for the inhibition of the formation of biogenic amines.
Cryoprotective Effects of Carrageenan Oligosaccharides on Pacific White Shrimp (Litopenaeus vannamei) during Frozen Storage
WU Haixiao, ZHANG Bin, SHI Zhourong, FANG Chuandong, ZOU Junjie, LI Haibo
2017, 38(7):  260-265.  doi:10.7506/spkx1002-6630-201707041
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Objective: To evaluate the cryoprotective effects of carrageenan oligosaccharides on peeled shrimp (Litopenaeus vannamei). Methods: The thawing loss, color, texture, myofibrillar protein content, Ca2+-ATPase activity, and microscopic structure of shrimp muscle were investigated during frozen storage with sodium pyrophosphate as a positive control. Results: Both sodium pyrophosphate and carrageenan oligosaccharide treatments significantly decreased the thawing loss, inhibited the degradation of myofibrillar proteins and Ca2+-ATPase activity, and maintained the pH and textural and color properties of shrimp muscle, when compared with the control during frozen storage. In addition, each treatment at a concentration of 3 g/100 mL showed better cryoprotective effect on shrimp muscle than at 1 g/100 mL. Importantly, carrageenan oligosaccharides were significantly more effective than sodium pyrophosphate (P < 0.05) at the same concentration of 3 g/100 mL. The microstructural analysis revealed that the texture of shrimps treated with 3 g/100 mL carrageenan oligosaccharide after six weeks of frozen storage was compact and showed good integrity, which was not significantly different from that of fresh shrimps after frozen storage. Conclusion: Carrageenan oligosaccharide treatment at 3 g/100 mL is more beneficial for maintaining the quality of white shrimp during frozen storage. This study can lay the foundation for developing a low-sweetness and low-calorie cryoprotective additive for frozen shrimp.
Reviews
Progress in Research on Dietary Polyphenols Metabolism Based on a Mechanism Involving Intestinal Absorption
ZUO Dan, LIAO Xia, LI Yao, SHI Fang, WANG Liying, MING Jian
2017, 38(7):  266-271.  doi:10.7506/spkx1002-6630-201707042
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Dietary polyphenols, an important class of components in plant-derived foods, is not only directly related to the flavor and color of foods, but also is helpful for maintaining human health. Since they are easily changed during release from the matrix, digestion, absorption, metabolism and distribution to various tissues in the body, the bioavailability of different dietary polyphenols is different. The most abundant dietary polyphenols do not necessarily represent the highest bioavailability. The absorption and biotransformation of plant polyphenols as well as their bioavailability are one of the current hot research topics. In this article, the gastrointestinal digestion, absorption and metabolism of dietary polyphenols are reviewed based on a mechanism involving intestinal absorption, with the aim to provide valuable information for the research and development of polyphenolics-rich health foods.
Progress in the Application of Aptamer Sensors in Milk Detection
LI Wenqing, LIU Huimin, ZHANG Guozhi, SU Lijuan, LI Wanli
2017, 38(7):  272-277.  doi:10.7506/spkx1002-6630-201707043
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In recent years, with the frequent occurrence of food safety issues, the public have been highly concerned about milk adulteration, quality and safety. Aptamer sensor is a new detection method with the characteristics of high specificity and sensitivity and easy operation. The application of aptamer sensors for detecting milk is a future direction. In this paper, the recent applications of aptamer sensors for detecting pathogenic bacteria, antibiotics, biological toxins, heavy metals and other harmful trace substances in milk are reviewed. The current problems regarding the application of this detection method and its future prospects are analyzed, with the aim to provide some references for better utilization of this new technology in milk detection.
Dietary Polyphenols Modulate Lipid Metabolism by Regulating Farnesoid X Receptor: A Review
XIAO Juan, ZHANG Ruifen, WEN Yejie, HUANG Fei, ZHANG Mingwei, SUN Yuanming
2017, 38(7):  278-283.  doi:10.7506/spkx1002-6630-201707044
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Hyperlipidemia is an underlying cause of many chronic diseases, and the cardiovascular diseases and other chronic diseases partially caused by hyperlipidemia has become a worldwide public health problem. Farnesoid X receptor (FXR) plays a key role in the regulation of cholesterol and triglycerides metabolism. FXR might be a pharmacological target for the treatment of hyperlipidemia and related diseases. Dietary polyphenols can exert hypolipidemic activity by regulating FXR and its targeted genes. This paper reviews the advances in understanding the mechanism of action of FXR in modulating lipid metabolism and the possible effect of dietary polyphenols in such a bioprocess.
A Review of the Current Research on the Mechanism of PSE-like Poultry Meat Quality Defect
KANG Zhuangli, ZHAO Yingying, LI Ke, WANG Huhu, ZHU Xueshen, XU Xinglian, BAI Yanhong
2017, 38(7):  284-289.  doi:10.7506/spkx1002-6630-201707045
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Pale, soft, exudative-like (PSE-like) poultry meat continues to a major quality defect that adversely affects the poultry industry worldwide, resulting in a great economic loss. This review describes the history of understanding PSE-like poultry meat and reviews recent research focused on the typical characteristics of PSE-like poultry meat (color, pH, texture and water holding capacity) and the criteria for its identification. The deterioration mechanism of functional properties of PSE-like poultry meat protein such as solubility and gel properties is discussed as well as the future direction in the development of strategies to improve functional properties of PSE-like poultry meat protein. The review is expected to provide a theoretical reference and technical support for improving functional properties of PSE-like poultry meat protein in the poultry industry.
Progress in Understanding Degradation of Nitrite by Lactic Acid Bacteria
LIU Nian, CHEN Pei, GAO Bing, WANG Chao, XU Ning, HU Yong, SHI Wenbo, LI Dongsheng, ZHOU Mengzhou
2017, 38(7):  290-295.  doi:10.7506/spkx1002-6630-201707046
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The safety of nitrite and nitrate is currently a research hotspot in the field of food safety. Most fermented foods contain nitrites that results from microbial growth and metabolism. Intake of large doses of nitrite can initiate a series of adverse reactions in the body, increasing the risk of cancerogenesis. In this paper, the dietary sources of nitrite and nitrate and their impacts on human health are reviewed in detail along with a summary of studies on nitrite degradation by lactic acid bacteria, with the aim of providing a solution for safe and effective degradation of nitrite.
Plant Polyphenols Exert Antitumor Effect through MAPK Signaling Pathways: A Review
LI Yao, LIAO Xia, ZHENG Shaojie, WANG Liying, SHI Fang, ZUO Dan, WU Surui, MING Jian
2017, 38(7):  296-301.  doi:10.7506/spkx1002-6630-201707047
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The biological processes of tumor cells such as proliferation, differentiation, invasion and migration are the signs of cancer. The mitogen-activated protein kinase (MAPK) signaling pathway has been proved to be an essential pathway that can adjust the biological processes of tumor cells. A number of studies indicate that natural plant polyphenols, such as tea polyphenols, resveratrol and anthocyanins, have a significant regulatory effect on tumor cells. Plant polyphenols can adjust tumor cells through the MAPK signaling pathway, which has attracted widespread research interest worldwide. This article reviews the regulating effect of plant polyphenols on tumor cells through the MAPK signaling pathway and elucidates the response mechanisms of different polyphenols to the four MAPK signaling pathways (p38, ERK-1/2, ERK5 and JNK pathways), aiming to further clarify the antitumor activity of plant polyphenols and the underlying molecular mechanisms and provide a reference for developing anticancer health foods or drugs.
Effect of Heat Treatment on Milk Components and Changes in Heat-Sensitive Components: A Review
YANG Jinhui, LI Songli, ZHENG Nan, WEN Fang, WANG Jiaqi
2017, 38(7):  302-308.  doi:10.7506/spkx1002-6630-201707048
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Heat processing is necessary to effectively inactivate pathogenic bacteria in raw milk but simultaneously affect milk components. Whey protein denaturation and aggregation, lactose isomerization and degradation, and Maillard reaction occur successively in milk subjected to heat treatment at increasing temperatures. The reduced activity of active components (e.g. enzyme and whey protein) or the formation of reaction products (e.g. lactulose and furosine) indicates the heat load during thermal processing. Heat treatment conditions for milk as well as physiochemical changes and changes in the corresponding sensitive components during the process are discussed in this paper.
Progress in Functional Properties and Applications of Animal Plasma Protein Hydrolysates
WANG Wenting, HOU Chengli, SONG Xuan, WU Liguo, ZHU Jie, ZHANG Dequan
2017, 38(7):  309-314.  doi:10.7506/spkx1002-6630-201707049
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Animal blood, one of the major animal by-products from slaughterhouses, is rich in protein and has high nutritional value. Animal plasma protein can be used in animal feed and food processing as an important protein resource. It has been shown that enzymatic hydrolysates of animal plasma protein, consisting of small peptides and amino acids, can be used as potential food additives, nutritional supplements and health products because of its ease of digestion and absorption in the body and functional properties such as antioxidant activity, angiotensin-converting enzyme inhibitory activity and toxicity reduction. This review summarizes the enzymatic hydrolysis conditions, characteristics and applications of plasma protein hydrolysates, with the hope of offering some references for further researches and applications of plasma protein hydrolysates.