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Table of Content

15 May 2017, Volume 38 Issue 9
Basic Research
Effect of Fish Bone Powder on Gel Properties of Nemipterus virgatus Surimi
YI Shumin, LI Huan, CHEN Si, ZHU Wenhui, LI Xuepeng, LI Jianrong, LI Yujin
2017, 38(9):  1-7.  doi:10.7506/spkx1002-6630-201709001
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In this research, Alaska pollock fish bone powder was prepared using a ball mill, and its particle size, chemical composition, surface elements and microstructure were determined. Furthermore, the effect of addition of different amounts of the fish bone powder on whiteness, gel strength, texture properties, transverse relaxation time T2, water-binding capacity and microstructure of Nemipterus virgatus surimi gel was analyzed. The results showed that the fish bone powder contained a variety of amino acids, and was rich in calcium and phosphate, with a calcium to phosphate ratio similar to that of human bones. One-factor-at-a-time experiments indicated that the surimi with 0.75% fish bone powder added had the best gel properties, and no significant difference was observed compared with addition of 1.00% fish bone powder. Addition of 1.00% fish bone powder was found to appropriate taking into account microstructure, which could effectively improve the gel properties of the surimi, and at the same time enhance the calcium content.
Molecular Interactions between Renin and Its Inhibitor Saponins from Kochia scoparia Fruit
GUANG Cui’e, ZHANG Hailing, WANG Junqing, Robert PHILLIPS
2017, 38(9):  8-13.  doi:10.7506/spkx1002-6630-201709002
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Two saponins from Kochia scoparia fruit, momordin Ic and 2′-O-β-D-glucopyranosyl momordin Ic, were found to strongly inhibit in vitro renin activity, and three different methods were used to investigate their inhibitory mechanisms. Molecular docking showed that both saponins were bound well to renin to form 9 and 4 hydrogen bonds, respectively. Amino acid residues Ser230 and Tyr231 were important for hydrogen bonds and residues Ala229, Met303, His301, Asp38, Arg82, Tyr83 and Ile137 functioned by hydrophobic interactions with both saponins. Molecular dynamics of the two complexes reached equilibration after about 1 000 ps simulation with average root-mean-square deviations of 0.224 and 0.219 nm, respectively. The two saponins also reduced the root-mean-square fluctuation of 160 amino acids in renin. The molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method yielded .44.36 and .62.46 kcal/mol total binding energy for the two complexes respectively, which were primarily contributed by electrostatic and Van der Waals interaction energies, and the binding was strongly unfavored by polar solvation energy. These results elucidated the molecular mechanisms of interaction between renin and two saponin inhibitors.
Changes in Allergenicity and Sensory Quality of Peeled Shrimp Caused by Ultra-High Pressure
JIA Ying, HU Zhihe
2017, 38(9):  14-20.  doi:10.7506/spkx1002-6630-201709003
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The aim of this investigation was to research the changes in the allergenicity and sensory quality of peeled shrimp after ultra-high pressure (UHP) treatment. Fresh peeled shrimp (Litopenaeus vannamei) were treated at different pressures (0.1–800 MPa). After that, the allergenicity of shrimp was examined by indirect enzyme-linked immunosorbent assay (ELISA) and electronic eye, electronic nose and electronic tongue were used to evaluate the changes in the color, odor and taste, respectively. Results showed that the allergenicity of peeled shrimp could be effectively decreased (by 45.66%) after treatment at 600 MPa and 40 ℃ for 30 min. In addition, UHP treatment could also change the sensory quality of peeled shrimp. Compared with the untreated shrimp, the color number and proportion of the main color increased gradually with increasing pressure, the content of the main odorant acetylpyrazine gradually decreased, and dimethyl trisulfide tended to disappear. The salty and sour taste gradually increased, and the umami taste increased by about 32–34 times. At the same time, sweet and bitter taste appeared. Moreover, at the same pressure, the intensity of sweet and bitter taste had similar values. Therefore, the allergenicity of shelled shrimp could be reduced by UHP treatment. Furthermore, UHP treatment could cause changes in the sensory quality of shelled shrimp in terms of color, odor and taste.
Effect of Phosphorylation on Actomyosin Dissociation
GAO Xing, LI Xin, LI Zheng, DING Wu, ZHANG Dequan
2017, 38(9):  21-26.  doi:10.7506/spkx1002-6630-201709004
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Objective: The objective of this study was to investigate the regulation of actomyosin dissociation and ATPase activity in crude actomyosin extract by changing the phosphorylation level of actomyosin. Methods: The crude actomyosin extract was incubated with protein kinase A and alkaline phosphatase at 4 ℃ for 48 h. Subsequently, the changes in protein phosphorylation, actomyosin dissociation and ATPase activity were measured by SDS-PAGE, Pro-Q Diamond phosphoprotein gel staining kit, Western blotting and ATPase activity assay kit. Results: The phosphorylation levels of troponin T (TnT) and myosin regulatory light chain (MRLC) were significantly higher in the protein kinase A group compared with the control group. The amount of liberated actin in the protein kinase A group was significantly higher than that in control group, and it increased significantly during the first two hours and increased slightly during the following 46 hours in both groups. In addition, the actomyosin ATPase activity decreased significantly in the protein kinase A group compared with the control group, and it increased significantly with incubation time in the two groups. However, the opposite changes were observed for the alkaline phosphatase group. Conclusion: The phosphorylation of TnT and MRLC reduces the binding force between myosin and actin and thereby promotes the dissociation of actomyosin.
Effect of Camellia Tea Oil on Properties and Structure of Surimi Gels
ZHOU Xuxia, JIANG Shan, GU Saiqi, ZHAO Dandan, DING Yuting
2017, 38(9):  27-33.  doi:10.7506/spkx1002-6630-201709005
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The objective of this study was to investigate the effect of camellia tea oil on gel strength, water distribution, lipid and protein structure of surimi gels. The results showed that added oil resulted in a significant increase in gel strength, emulsion stability and water-holding capacity of surimi gels (P < 0.05), and when the oil concentration was increased to 8%, these parameters basically kept stable. Under this condition, the gel strength was 225.1 g·cm and the percentage of total expressible fluid (TEF) was 2.60%. Raman spectroscopy analysis revealed that the addition of camellia tea oil changed the structure of lipid and protein in surimi gels, as indicted mainly by the increased width of C?H band, the decreased intensity of O?H band and the increased contents of β-sheet, β-turn and random coil accompanied by the decreased content of α-helix in surimi protein. Meanwhile, with increasing added oil, the water was distributed in a much smaller state in surimi. These findings may further explain the mechanism for the effect of exogenous oil on gel strength, emulsion stability and water-holding capacity of surimi gels.
Effect of Irradiation on the Flavor and Color of Pork Sausages
HE Lichao, LI Chengliang, MA Sumin, JIN Guofeng
2017, 38(9):  34-39.  doi:10.7506/spkx1002-6630-201709006
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In the present study, pork sausages were irradiated by 60Co γ-ray ray at doses of 1, 3, 5, 7 and 9 kGy, respectively. After that, the off-flavor intensity, lipid oxidation, volatile flavor composition and color difference of sausages were determined for the purpose of evaluating the effect of irradiation on the physicochemical and sensory quality of pork sausages. The results indicated that irradiation could significantly promote lipid oxidation and result in a decrease in the redness value (a*) of pork sausages, but the yellowness (b*) and lightness (L*) values were not affected by irradiation. The off-flavor intensity increased with increasing irradiation dose, but it did not change significantly within the dose range of 1–5 kGy; when the irradiation dose was increased to 7 kGy, pork sausages produced a significantly unacceptable off-flavor. The contents of volatile sulfur-containing compounds, 2-butene, pentane, 1-pentene, octane, hexane and aldehydes increased significantly compared to the control samples, which were positively correlated with irradiation dose. Carbon disulfide, dimethyl disulfide, 2-methyl-propanal, 3-methyl-butanal, hexanal, butene and toluene were the main volatiles that were generated after irradiation. These results suggested that the irradiation could deteriorate the flavor and color of pork sausage, especially at a dose above 5 kGy. These quality changes were closely related with lipid oxidation of pork sausages.
Prokaryotic Expression of POD Gene from ‘Yali’ Pears and Effects of Maturity and Cooling Rate on the Expression of POD Gene during Storage
HAN Yanwen, LIAN Shuangqiu, HAN Yunyun, CHI Ming, YAN Shijie
2017, 38(9):  40-45.  doi:10.7506/spkx1002-6630-201709007
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In the present study, the relationships between browning development and peroxidase (POD) gene expression in both core and flesh tissues of ‘Yali’ pears subjected to different cooling methods (rapid cooling or slow cooling), as well as those collected at different harvest dates (early, mid and late) were investigated using semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). The results showed that the expression level of POD gene in pear core with slow cooling treatment was higher than that in rapidly cooled fruits at the same harvest time, indicating that POD gene was closely related to the browning of pear core. Additionally, the POD activity was the highest in mid harvested pears, followed by early harvested pears, and late harvested pears had the lowest POD activity, which suggested that maturity played an important role in ‘Yali’ pear browning. Also, the prokaryotic expression of POD gene (cDNA) in ‘Yali’ pears was investigated. A prokaryotic expression vector (pET-32a-pbPOD) for POD gene cDNA was established, and then induced successfully to be expressed in E. coli BL21(DE3). This study may provide a foundation for studying the mechanism of the browning of ‘Yali’ pears.
Effect of Tea Polyphenol, Licorice Extract, Vitamin E and Chia (Salvia hispanica L.) on the Quality of Mutton Emulsion-Type Mutton Sausage
LIU Wenying
2017, 38(9):  46-52.  doi:10.7506/spkx1002-6630-201709008
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The aim of this work was to evaluate the effect of the addition of tea polyphenol, licorice extract, vitamin E and chia on the quality of emulsion-type mutton sausage. Sausages with the addition of 0.04% tea polyphenol, 0.02% licorice extract, 1.0% vitamin E or 1.0% or 2.0% chia were evaluated for fat oxidation and color, and their major volatile flavor components were elucidated by principal component analysis (PCA). The composition of volatile esters, acids, alcohols and aldehyde was determined as well. It was demonstrated that the addition of natural active substances decreased the degree of lipid oxidation in the sausages compare with the blank control group, but there was no significant difference among the treatment groups (P > 0.05). The major volatile components of all samples were similar, which failed to be discriminated by PCA. L*, a*, b*, C* and H* values changed to different extents among different groups. Particularly, the addition of licorice extract and chia significantly influenced (P < 0.05) C* and H*values. The species and relative contents of esters, acids, alcohols and aldehydes in all treatment groups changed compared with the control group. The different additives had different effects on sausage quality. The lipid oxidation inhibitory activity of chia was not positively correlated with its concentration. Likewise, no significant concentration-response relationship was observed for the species and amounts of volatile flavor compounds.
Effect of Sugars with Different Degrees of Polymerization on Apple Hot-Air Drying Behavior and Physical Characteristics of Instant Controlled Pressure Drop Dried Apple Chips
XIAO Min, YI Jianyong, BI Jinfeng*, PENG Jian, ZHANG Biao, GAO Kun
2017, 38(9):  53-58.  doi:10.7506/spkx1002-6630-201709009
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Osmotic dehydration is a pre-treatment for drying of fruits and vegetables, which can reduce the drying time and improve food quality. The effects of different osmotic pretreatments on apple hot-air drying behavior and physical characteristics of instant controlled pressure drop dried apple chips were investigated. Samples were immersed in monosaccharide (fructose, glucose), disaccharide (sucrose, maltose), trisaccharide (raffinose), and tetrasaccharide (stachyose), respectively. Sugar gain and water loss were analyzed. The samples were further hot air-dried and the experimental data were fitted successfully using the Page model. Compared with the untreated samples, osmotic dehydration using selected sugar solutions contributed to better texture and color retention. Samples pretreated by raffinose and stachyose immersion exhibited the highest crispness. This study could provide a reference for the choice of osmotic solutions for pretreatment prior to drying of fruits and vegetables.
Physicochemical Properties of Lignin from Bamboo (Dendrocalamus latiforus) Shoot Shell
GONG Weihua, XIANG Zhuoya, YE Fayin, ZHAO Guohua
2017, 38(9):  59-65.  doi:10.7506/spkx1002-6630-201709010
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Lignin was extracted from bamboo (Dendrocalamus latiforus) shoot shell by the acetosolv process. The chemical composition, particle size, specific surface area, porosity structure, water- and oil-holding capacity, swelling power, and cation-exchange, metal ion and cholate binding capacity of the lignin were investigated. Compared with cellulose and coarse dietary fiber from the same source, the lignin had smaller particle size and significantly greater oil-holding, cation-exchange and metal ion capacity. The water-holding and swelling capacities of the samples were positively correlated with their particle size. In vitro cholate-binding studies showed that the lignin bound more significantly sodium cholate and sodium taurocholate than the other fractions, and the binding rates were 82.46% and 60.94% relative to cholestyamin (a cholesterol-lowing, bile acid-binding drug), respectively. These results indicated that lignin from bamboo shoot shell had application potential for human health.
Effect of Tartary Buckwheat Polyphenols on Physicochemical Properties of Tartary Buckwheat Starch and Wheat Starch
HE Cai’an, ZHANG Zhen, LIU Hang, LI Yunlong, WANG Min
2017, 38(9):  66-71.  doi:10.7506/spkx1002-6630-201709011
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The research was designed to investigate the interactions of tartary buckwheat starch (TBS) and wheat starch (WS) with tartary buckwheat polyphenols (TBP) at low levels (1%.4%) during gelatinization and their effect on starch paste transparency, retrogradation and pasting properties, textural properties, resistant starch content and microstructure. The results showed that adding TBP could significantly decrease the transparency and sedimentation volume of TBS and WS paste, and accelerate starch paste retrogradation. The pasting temperature and enthalpy of both starches were decreased, indicating that the starches were prone to be pasted. Compared with the control without added TBP, addition of 4% TBP led to a decrease in the hardness of TBS and WS gels by 19.74% and 54.18%, respectively, and a significant increase in resistant starch content (by 15%.30%). The scanning electronic micrographs (SEM) indicated that TBP could accelerate the aggregation and cross-linking of starch granules. The changes in physicochemical properties of starch after TBP addition can be regarded as a physical modification method to increase resistant starch. Tartary buckwheat flour can be used as a high quality ingredient of foods high in resistant starch.
Energy Metabolism and Protein Phosphorylation of Pork, Beef and Chicken during the Early Postmortem Period
ZHANG Shuang, ZHANG Nan, ZHU Liangqi, LI Chunbao
2017, 38(9):  72-78.  doi:10.7506/spkx1002-6630-201709012
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Objective: To explore the major cause for abnormal meat. Methods: At 45 min postmortem, chicken, pale soft exudative (PSE) pork, normal pork and beef were taken for the analysis of glycogen, ATP/ADP/AMP contents, lactate dehydrogenase (LDH) activity. At the same time, myofibrillar and sarcoplasmic proteins were extracted and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and the bands of interest were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The difference in band intensity was evaluated. Results: Glycogen was higher in beef than three other meats (P < 0.05). Glycogen and ATP contents were higher in PSE pork than normal pork and chicken (P < 0.05). LDH activity in PSE pork was much higher than all other groups (P < 0.05). SDS-PAGE with ProQ staining indicated that, at 45 min postmortem, the phosphorylation levels of sarcoplasmic proteins from 6 bands were lower in PSE pork than those of normal pork (P < 0.05), while sarcoplasmic proteins from other 6 bands had higher phosphorylation levels than normal pork (P < 0.05). In addition, 3 bands in beef and 1 bands in chicken had lower phsophorylation levels, whilst higher phsophorylation levels were observed for 1 bands in beef and 8 bands in chicken. For myofibrillar proteins, the majority of bands in beef had highest phosphorylation levels, the lowest phosphorylation levels were found for chicken (P < 0.05), and pork was in the middle. Similarly, 7 bands in PSE pork had lower phosphorylation levels than normal pork (P < 0.05), while 6 bands had higher phosphorylation levels than normal pork (P < 0.05). Conclusion: The rates of glycolysis and ATP depletion, and LDH activity had a great contribution to PSE pork, which is also associated with protein phosphorylation of glycolytic enzymes.
Effect of Interaction between Soybean Protein Isolate and Lecithin on Stability of Oil-in-Water Emulsion
BI Shuang, ZHU Ying, QI Baokun, WANG Zhongjiang, ZOU Xiaoshuang, LI Yang, JIANG Lianzhou, SUI Xiaonan
2017, 38(9):  79-84.  doi:10.7506/spkx1002-6630-201709013
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The purpose of this study was to explore the effect of the ratio and interaction between soybean protein isolate and lecithin on the stability and functional properties of emulsion systems containing them. The results showed that emulsion activity index and droplet size distribution were affected by the ratio between soybean protein isolate and lecithin. When the ratio was 10:1, a higher emulsion activity index (98.1 m2/g) and the smallest D4,3 (volume average diameter, 13.34 μm) as well as a lower level of bimodal distribution were observed. A soybean protein isolate-to-lecithin ratio of 1:1 or 100:1 was not suitable due to poor emulsion stability, as demonstrated by the measurement of ζ-potential. Phase separation and large irregular non-spherical droplets were evident under confocal laser scanning microscopy. Therefore, there was an optimal soybean protein isolate-to-lecithin ratio that provided good stability of food-grade O/W emulsion.
Interaction between β-Lactoglobulin and Black Rice Anthocyanin
ZHAO Huanjiao, Lü Xiaoling*, WANG Mengshu, WANG Luyao
2017, 38(9):  85-90.  doi:10.7506/spkx1002-6630-201709014
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In this work, we studied the interaction between black rice anthocyanin (BRA) and β-lactoglobulin (β-LG) by fluorescence spectroscopy, synchronous fluorescence spectroscopy, ultraviolet-visible spectroscopy, antioxidant capacity and molecular docking under simulated physiological conditions. The results showed that black rice anthocyanin had a strong ability to quench the fluorescence of β-lactoglobulin in a static mode. The binding constants (Ka) and site numbers (n) were obtained at different temperatures. The major interaction force was hydrophobic interaction in the binding of BRA to β-lactoglobulin based on the thermodynamic parameters. According to F.rster’s non-radiative energy transfer theory, the donor-acceptor proximity in BRA-β-LG complex was calculated as 3.14 nm. The synchronous fluorescence spectra revealed that interaction with BRA caused conformational changes in β-LG, but did not affect the microenvironment of tryptophan and tyrosine residues. Molecular docking indicated that the main driving force of the interaction between cyaniding-3-O-glucoside (the major component of black rice anthocyanin) and β-lactoglobulin was hydrophobic interaction, which was consistent with the result obtained from thermodynamic parameter analysis.
Preparation, Properties and Structural Characterization of Chitosan/Microcrystalline Sterol Composite Edible Films
CHEN Hong, LI Caiyun, LI Xia, LI Yukuo, WU Xinlei ,WANG Dawei
2017, 38(9):  91-98.  doi:10.7506/spkx1002-6630-201709015
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Chitosan/microcrystalline sterol composite edible films were prepared by flow casting method using chitosan as a film-forming material, where phytosterols were added for their antioxidant and antimicrobial properties. With increasing addition of phytosterols up to 12% (relative to the mass of chitosan), the tensile strength and elongation at break of composite films declined gradually, the solubility and swelling degree gradually increased, and the water vapour permeability coefficient remarkably reduced, indicating an improved moisture barrier property after the addition of sterol. In addition, the superoxide anion and hydroxyl radical scavenging capacities of films were improved remarkably, and the antimicrobial activity against Staphylococcus aureus and Escherichia coli were significantly enhanced. The compatibility of composite films was analyzed by infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetry (TG). The films with 9% sterol added showed good performance. Moreover, chitosan-sterol complexes were formed by strong intermolecular hydrogen bonding interactions, and the blend system had good compatibility.
Selenium Speciation Distribution, Nutritional Quality and Antioxidant Activity of Se-Enriched Agaricus bisporus
SHI Yi, HU Xingsuo, PAN Yalu, XIA Ji, HU Qiuhui, FANG Yong
2017, 38(9):  99-105.  doi:10.7506/spkx1002-6630-201709016
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The objective of this study was to determine the selenium speciation distribution, nutritional quality and antioxidant enzyme activity of Agaricus bisporus growing on mushroom beds with different amounts of selenium salt (Na2SeO3). The selenium content and speciation distribution were analyzed by atomic fluorescence spectrometry (AFS). The soluble protein, total sugar and malondialdehyde (MDA) contents as well as the activities of superoxide dismutase (SOD) and hydrogen peroxidase (CAT) were measured using non-Se-enriched A. bisporus as the control. Results showed that the addition of Na2SeO3 led to a significant (P < 0.05) increase in selenium content in the fruit bodies of A. bisporus. Protein-bound selenium accounted for 77%–87% of the total organic selenium, demonstrating protein to be the main carrier of organic selenium. The addition of 40 mg/kg selenium to the compost resulted in an increase in the contents of soluble protein and total sugar compared to the control group, whereas a significant decrease in the two parameters was observed at higher concentration of selenium. With the increase in added selenium concentration, the contents of free amino acid and MDA and SOD activity were increased while CAT activity was reduced. These results showed that the optimal range of selenium concentration could enhance the selenium content of A. bisporus, thereby improving the nutritional quality and physiological properties.
Degradation of Aflatoxin B1 by a Microbial Consortium and Its Composition and Diversity
ZHAO Chunxia, WANG Yi, CHENG Wei, Lü Yucai, GONG Dachun, GUO Peng
2017, 38(9):  106-112.  doi:10.7506/spkx1002-6630-201709017
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External elimination method was applied to obtain an efficient aflatoxin B1-degrading microbial consortium, designated FBAD-2. The degradation rates of 2 000 and 5 000 μg/L AFB1 by the microbial consortium could reach 100% and 90% within 120 h, respectively. The toxin degradation ability of FBAD-2 was kept at a high level in the range of 30–70 ℃, with an optimal temperature of 60 ℃. The results of AFB1 detoxification experiment showed that the extracellular enzymes in the supernatant played a major role in the degradation of AFB1. Furthermore, the optimal culture time for enzyme production was 24 h, and the supernatant could completely degrade 5 000 μg/L AFB1 within 48 h. 16S rRNA gene clone library analysis showed that FBAD-2 was mainly composed of bacteria from the genera Geobacillus, Symbiobacterium thermopilum, Clostridium and Tepidanaerobacter.
Isolation and Identification of Flavor Peptides from White Sufu (Fermented Tofu)
LIAO Shun, HU Xuexiao, JIN Erqing, PENG Cong, WU Jianzhong
2017, 38(9):  113-118.  doi:10.7506/spkx1002-6630-201709018
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To identify the flavor peptides from white sufu, analyze their amino acid sequences, and evaluate the taste characteristics of their synthetic counterparts. Methods: Ultra-filtration and glucose gel Sephedex G-15 filtration chromatography were applied to separate flavor fractions from white sufu extracts. The fraction with the best sensory evaluation was further purified by reversed phase high performance liquid chromatography (RP-HPLC). The subfraction with the maximum chromatographic peak area was identified by using matrix-assisted laser analytical ionization timeof-flight/time-of-flight mass spectrometry/mass spectrometry (MALDI-TOF/TOF MS/MS) with De Novo software. The potential flavor peptides were also artificially synthesized and their sensory properties were evaluated. Results: Three flavor peptides were obtained from white sufu. Their amino acid sequences were identified as Asp-Phe-Lys-Arg-Glu-Pro, Asp-Arg-Glu-Lys-Phe-Asp-Glu, and Asp-Glu-Asp-Phe-Lys-Arg-Glu-Pro. The first peptide had obvious umami taste. The third one had both umami and sour tastes. The second had less obvious taste although it could enhance the umami flavor of sodium glutamate solution. Conclusion: The umami flavor of white sufu not only cames from amino acids such as glutamate, but also was related to small peptides.
Antioxidant Activities of Phloridzin Myristate
HUO Yanxiong, REN Yamei, YUAN Chunlong, WANG Tao, REN Xiaolin, YANG Junlin
2017, 38(9):  119-125.  doi:10.7506/spkx1002-6630-201709019
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The antioxidant activities of phlorizin myristate, a new compound synthesized enzymatically, were assessed by measuring its capacity to inhibit xanthine oxidase (XOD) and lipid perioxidation and scavenge hydrogen peroxide (H2O2), hypochlorous acid (HClO), and nitrite radical. Results showed that phlorizin myristate and phlorizin were a reversible competitive inhibitor of XOD and their effects on XOD were in a dosage-dependent manner. The half inhibitory concentrations (IC50) of phlorizin myristate and phlorizin were 131.17 and 172.18 μg/mL, and the inhibitory constants (Ki) were 58.50 and 104.80 μg/mL, respectively. Phlorizin myristate inhibited lipid oxidation with IC50 of 126.18 μg/mL, which was significantly higher than that of vitamin C (78.10 μg/mL) and lower than that of phlorizin (149.86 μg/mL). Phlorizin myristate scavenged H2O2 and HClO with IC50 of 58.16 and 157.11 μg/mL, respectively, which was significantly higher than those of vitamin C (32.33 and 116.23 μg/mL) and lower than those of phlorizin (83.36 and 213.50 μg/mL). Nitrite radical scavenging activity of phlorizin myristate was weaker than that of phlorizin and vitamin C. Phlorizin myristate, phlorizin and vitamin C scavenged nitrite radical with IC50 of 232.22, 210.86 and 134.58 μg/mL, respectively. Conclusively, the antioxidant capacity of phlorizin was improved after modification with myristate. These results will provide a new method and theoretical basis for improving the biological activity of phlorizin.
Fixation and Drying of Green Tea Using Sequential Catalytic Infrared Heating and Hot Air Drying
WU Bengang, XIAO Mengchao, LIU Meijuan, PAN Zhongli, MA Haile
2017, 38(9):  126-132.  doi:10.7506/spkx1002-6630-201709020
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The fixation and drying characteristics of green tea processed with sequential catalytic infrared (CIR) heating and hot-air (HA) drying were investigated. The effect of CIR fixation on product quality was compared with that of steaming at 100 ℃. The quality characteristics of green tea were evaluated using polyphenoloxidase (PPO) activity, vitamin C and tea polyphenol contents and sensory evaluation. The best processing conditions were found to be fixation by CIR heating for 150 s at a distance of 20 cm, followed by sequential rolling and HA drying for 40 min at 70 ℃. A Page model was developed for describing the drying behavior as well as a first-order kinetic model fit well for describing the PPO inactivation during the process.
Inactivation Mechanism of Salmonella by Atmospheric Gliding Arc Discharge and Its Application in the Preservation of Eggs
ZHU Lihua, LI Yan, TONG Qigen, SUN Yunjin, MA Tingjun
2017, 38(9):  133-137.  doi:10.7506/spkx1002-6630-201709021
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In order to retain the freshness and prolong the shelf-life of fresh eggs, a new type of cold sterilization technology was put forward, namely gliding arc discharge, which can be worked in air environment at room temperature. Firstly, egg surface was coated with Salmonella suspension and transported through plasma discharge plume at a certain speed of self-spinning to inactivate the surface bacteria, part of which was sampled to investigate its inactivated mechanism and the remaining treated eggs were stored in a sealed environment at 37 ℃ to assess the impact of this air discharge plasma on egg quality by measuring the mass loss rate and Haugh unit (HU). The results of scanning electron microscopy (SEM) and extracellular protein concentration analysis indicate that atmospheric gliding arc discharge technique could have an effective etching effect on Salmonella, leading to cell membrane disruption and leakage of intracellular proteins of Salmonella. Meanwhile, the egg quality measurements showed that the atmospheric gliding arc discharge could maintain the freshness of eggs to a certain extent.
Nutritional and Functional Components of Chinese Wolfberry Dried by Different Drying Methods
EBEYDULLA Rahman, WANG Xuan, ZHAO Liang, XU Duoyuan, SUN Huiqin, JI Baoping, ZHOU Feng
2017, 38(9):  138-142.  doi:10.7506/spkx1002-6630-201709022
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The color, major nutrient contents, amino acid composition, and bioactive composition of Chinese wolfberry dried by two different drying methods, i.e., natural air drying and hot-air drying after removal of the wax layer were analyzed. The results indicated that there was a significant difference in color crude fat and carotenoid contents and amino acid composition between both dried samples. Natural air-dried Chinese wolfberry had a brighter color, a greater loss in crude fat content and a smaller loss in carotenoid and amino acid contents compared with the other drying method. Furthermore, the former showed better retention of the major nutrients and functional components. Although requiring a longer time, natural air drying had less impacts on the color, nutritional and functional components of Chinese wolfberry.
Structural Modification of Oat Bran Globulin by Glycosylation and Change in Its Functional Properties
WANG Changyuan, QUAN Yue, LI Yuqiong, FENG Yuchao, CAO Longkui, ZHANG Dongjie
2017, 38(9):  143-148.  doi:10.7506/spkx1002-6630-201709023
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In the presence of glucosamine, oat bran globulin was subjected to glycosylation using transglutaminase (TG) for analyzing and correlating the structural and functional characteristics of the modified protein. The results showed that some properties of the glycosylated protein were improved when compared to the unmodified one, such as solubility, emulsion stability, foaming ability and foam stability. However, the surface hydrophobicity was significantly decreased. Additionally, the denaturation temperature and enthalpy change of the protein declined after glycosylation. The secondary structure contents changed, as indicated by an increase in α-helix, a decrease in β-sheet and β-turn and almost no change in random coil. The tyrosine residues of the glycosylated globulin were exposed, whereas the tryptophan residues were buried. Moreover, the disulfide stretching vibration mode was t-g-t. A comparison of functional properties and spatial conformation between the modified and unmodified globulin demonstrated that TG catalyzed the binding of glucose to oat bran globulin, further confirming the relationship between its functional characteristics and spatial conformation. The findings of this study may provide a theoretical basis for extending the minor grain industry chain, and offer basic data to study molecular design and intermolecular recombination for the production of special products based on oat bran protein.
Effect of Moisture on Texture and Gluten Protein Secondary Structure in Frozen Wheat Dough
WANG Shixin, YANG Qiang, LI Xinhua
2017, 38(9):  149-155.  doi:10.7506/spkx1002-6630-201709024
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The texture and microstructure (gluten protein secondary structure) of wheat dough were determined by texture analyzer and Fourier transform infrared spectrometer (FTIR) to analyze the effect of adding different amounts of water on the quality of frozen wheat dough. The results showed the significant impact of water addition and freezing on texture characteristics of wheat dough and the secondary structure of gluten proteins. With increasing water addition, the hardness, and viscosity of frozen wheat dough increased, cohesion and the elasticity decreased when compared with the nonfrozen one. However, water addition had little effect on the resilience of frozen wheat dough. After freezing, the contents of β-sheet and α-helix of gluten proteins increased, and the content of β-turn decreased, resulting in a stable network structure of gluten proteins. These results indicated that water is an important factor affecting the quality of frozen wheat dough. This study can provide a theoretical basis for further studies aimed at revealing the mechanism of the effect of water addition on the quality of frozen wheat dough.
Preparation and Properties of Starch from Chinese Yam (Dioscorea opposita Thunb. cv. Changshan)
WANG Lixia, WANG Jingzhen, ZHANG Jinling, HOU Huihui
2017, 38(9):  156-161.  doi:10.7506/spkx1002-6630-201709025
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Changshan yam starch (CYS) was successfully isolated from the rhizomes of Dioscorea opposita Thumb. cv. Changshan by sodium hydroxide solution immersion and its granular characteristics, physicochemical properties, pasting kinetics and crystalline properties were determined and analyzed. The scanning electron microscope (SEM) examination indicated that the shape of the starch granules was approximately oval or round with a smooth surface. The size distribution of starch granules showed a single peak curve at 48.57 μm, with a median diameter of 22.72 μm. Examination with a polarizing microscope revealed that the starch granules had significant cross-polarization. At 95 ℃, the solubility and swelling power of the starch were 16.78% and 33.55%, respectively. The transparency of the starch paste was 23.2% and the retrogradation stability was 6 h. The syneresis rate was 48.20%. Differential scanning calorimetric (DSC) analysis showed that the gelatinization onset and conclusion temperatures were 72.50 and 85.40 ℃, respectively. The gelatinization kinetics of Chinese yam starch belonged to a first-order reaction. Rapid viscosity analysis indicated that the peak viscosity, holdthrough, final viscosity, breakdown and setback were 6 220, 3 902, 5 702, 2 318 and 1 800 cP, respectively. X-ray diffraction revealed the starch was typical C-type crystalline starch.
Nutrition & Hygiene
Effect of Caffeine and Chlorogenic Acid on Body Weight, Lipid Accumulation and the Expression of Lipid Metabolism-Related Genes in High-Fat Diet-Fed Mice
ZHU Yanping, YANG Licong, LIN Lezhen, GAN Shuxiang, ZHENG Guodong
2017, 38(9):  162-167.  doi:10.7506/spkx1002-6630-201709026
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This study was undertaken to investigate the effects of caffeine and chlorogenic acid (CGA), two major components in coffee, on body weight, lipid accumulation and the expression of lipid metabolism-related genes in obese mice fed a high-fat diet. With this aim, 50 female ICR mice were randomly divided into five groups: control, high-fat diet (HFD), caffeine, CGA, and caffeine + CGA groups. The animals in the experimental groups were given drinking water supplemented with 0.05% caffeine, 0.2% CGA and 0.05% caffeine + 0.2% CGA, respectively for 14 consecutive weeks. Body weight was measured daily during the experimental period. Visceral organs and intraperitoneal adipose tissues (IPAT) were harvested and weighed at the end of the experimental period, and blood samples from the heart were collected for measurement of serum glucose and lipid concentrations and liver lipid levels. The mRNA expression levels of lipid metabolism-related genes in liver (AMPK, HMG-CoAr, FASN, and ACO) were determined by real time-quantitative PCR (RT-qPCR). Compared with the HFD group, caffeine + CGA remarkably reduced body weight gain and IPAT weight. The serum glucose and TC levels were decreased significantly by caffeine, and caffeine + CGA. The serum low-density lipoprotein cholesterol (LDL-C) concentration was remarkably lower in mice administrated with CGA, while CGA could result in an increase in serum free fatty acid concentration. Caffeine alone and in combination with CGA remarkably reduced the liver total cholesterols (TC) and triglyceride (TG) levels, significantly increased the mRNA expression of AMPK and significantly reduced the mRNA expression of FASN in liver. A significant up-regulation in the mRNA expression of ACO and a significant down-regulation in the mRNA expression of HMG-CoAr in liver were observed for all three experimental groups. Conclusions: The anti-obesity effects of caffeine + CGA may be achieved through regulating the mRNA expression of lipid metabolism-related genes in liver, modulating serum and liver lipid levels in, and inhibiting body weight gain and fat accumulation in mice in a synergistic manner.
Distribution of Procyanidin B2 Metabolites in Mice
XIAO Ying, YIN Zhiting, HU Zhongzhi, LIU Taiyi, ZHOU Yiming, ZHOU Xiaoli
2017, 38(9):  168-172.  doi:10.7506/spkx1002-6630-201709027
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In the present study, the metabolite profiles of procyanidin B2 in the plasma, liver, heart, spleen, lung, kidney, brain and small intestine of mice were qualitatively evaluated by high performance liquid chromatography with diode array detector coupled with electrospray ionization ion trap time-of-flight multistage mass spectrometry (HPLC-DAD-ESI-ITTOF-MSn). The results showed that the major conjugated metabolites included methylation metabolites (8), sulfonation metabolites (7), hydration metabolites (5) and hydroxylation metabolites (1), glucuronidation metabolite (1). Procyanidin B2 was metabolized into 6, 8, 8, 6, 3, 6, 2 and 2 forms in plasma, liver, small intestine, kidney, lung, heart, brain and spleen, respectively; three forms of identified metabolites were found with cleavage of interflavanic bond. The conjugated metabolites of procyanidin B2 were diverse and distributed widely in various tissues of mice. Methylation metabolites, sulfonation metabolites and hydration metabolites were dominant, and the liver was the main organ for the conjugated metabolites of procyanidin B2 according to product formation (Mr>577.13). The cleavage of interflavanic bond reaction was an important way that procyanidin B2 is absorbed.
Protective Effect of Chinese Red Jujube Pigment on Vascular Endothelial Cell Injury Induced by Hydrogen Peroxide
SHAO Peilan, XU Ming, GUO Xiaodan, ZHENG Anran, ZHOU Huapei, LI Wantao
2017, 38(9):  173-178.  doi:10.7506/spkx1002-6630-201709028
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This research was designed to explore the protective effect of Chinese red jujube pigment (CRJP) on human vascular endothelial cell injury induced by oxidative hydrogen in vitro. For this purpose, human vascular endothelial cells were cultured in vitro and randomly divided into 6 groups: control group, oxidative hydrogen injury group, CRJP low-,medium- and high-dose groups (50, 150, 250 mg/L), and positive control group (50 μmol/L VE). Cellular morphology, proliferation viability, LDH activity, apoptosis rate, mitochondrial membrane potential and ultrastructure of all groups were determined by inverted microscope, MTT assay, kit assay, flow cytometry and transmission electron microscope, respectively. The results showed that CRJP treatment at various doses had a protective effect on vascular endothelial cell injury induced by oxidative hydrogen. Cellular morphology and ultrastructure of the CRJP intervention groups were improved obviously along with a significant decrease in proliferation inhibition rate, LDH activity and apoptosis rate and a significant increase in mitochondrial membrane potential (P < 0.05) in a dose-dependent manner. These results indicate that Chinese red jujube pigment has a protective effect on human vascular endothelial cell injury induced by oxidative hydrogen in vitro and the underlying mechanism may be related to its antioxidant capacity, and its ability to inhibit apoptosis and maintain mitochondrial membrane potential.
Cytotoxicity Evaluation of Total Flavonoids and Recognition of Hydroxyl Radical Scavenging Components from Cichorium endivia L. Seeds
ZHAO Yue, LI Rong, JIANG Zitao
2017, 38(9):  179-184.  doi:10.7506/spkx1002-6630-201709029
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The cytotoxicity of total flavonoids from Cichorium endivia L. seeds towards RAW264.7 cells was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and the antioxidant activities were investigated based on total antioxidant activity, 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt cation radical (ABTS+·) scavenging capacity, superoxide anion radical scavenging capacity and inhibition on Fe2+-induced lipid peroxidation in egg yolk. These activities were compared with those of the common antioxidants vitamin C (VC) and tert-butylhydroquinone (TBHQ). Furthermore, the total flavonoids extracted from C. endivia seeds were screened for those scavenging hydroxyl radical by a high-performance liquid chromatography (HPLC) method. MTT assay showed that the total flavonoids were toxic towards RAW264.7 cells at a concentration of 1 mg/mL, but they were hardly toxic at a certain lower temperature. Antioxidant assays revealed that the total antioxidant activity and ABTS+· scavenging activity of these compounds were lower than those of VC and TBHQ. However, at low concentration, the total antioxidant activity was similar to that of TBHQ. The superoxide anion scavenging capacity of these samples was in the decreasing order of VC > total flavonoids from C. endivia seeds > TBHQ. The lipid peroxidation inhibitory activity of the total flavonoids was higher than that of VC, but lower than that of TBHQ. The HPLC analysis indicated that hydroxyl radical scavenging capacity of chlorogenic acid was higher than that of cynarin, which showed a scavenging percentage of 66.42% and 46.00%, respectively.
Genetic Toxicity Evaluation of Electron Beam Irradiated Rice
CHEN Xiaoping, WANG Huan, XIE Jing
2017, 38(9):  185-188.  doi:10.7506/spkx1002-6630-201709030
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Electron beams of 0, 1, 3 and 5 kGy were used to irradiate rice. The Ames test, bone marrow cell micronucleus test and mouse sperm abnormality test were conducted to evaluate the genetic toxicity of irradiated rice. The results indicated that in the Ames test, the number of revertant colonies in each dose group was not more than twice as high as the number of spontaneous colonies both with and without S9 metabolic activation system, and no dose-response relationship was seen for chromosome aberration. In the mouse bone marrow micronucleus test, there was no significant increase in the incidence of micronucleus (P > 0.05), suggesting that the cell chromosome was not significantly damaged. In the sperm deformity test, no significant difference (P > 0.05) in sperm abnormality rate existed between each dose group and the negative control group, and no dose response relationship was observed, indicating that the germ cells in mice were not damaged. Conclusion: The above negative genetic test results demonstrate that electron beam irradiated rice does not display genetic toxicity under the experimental condition of this study.
Effect of Wood Pulp-Derived Sterols on Intestinal Cholesterol Regulation and Microbiota in Hamsters Fed High-Fat and High-Cholesterol Diet
WANG Yifei, CHEN Jianrong, WANG Xiaobin, HUA Erbing, ZHAO Jiang, WANG Hao
2017, 38(9):  189-195.  doi:10.7506/spkx1002-6630-201709031
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The aim of this research was to investigate the effects of wood pulp-derived sterols on cholesterol regulation and the intestinal microbiota in Golden Syrian hamsters fed a high-fat and high-cholesterol diet. Totally 45 hamsters were randomly divided into normal group, high-fat and high-cholesterol (HFHC) group and three experimental groups given 1‰, 5‰ and 10‰ of wood pulp-derived sterols, respectively. Serum total cholesterol (TC), triglyceride (TG) and high-densitylipoprotein-cholesterol (HDL-C) were detected in all animals. The contents of cholesterol in liver, fecal neutral and acidic sterols were determined by gas chromatography (GC). The expression of cholesterol-regulating genes in the liver and small intestine was assayed by quantitative real-time polymerase chain reaction (qRT-PCR). The change of intestinal microbiota was assayed by denaturing gradient gel electrophoresis (DGGE). TC, TG and non HDL-C in the experimental groups were significantly decreased compared with the HFHC group (P < 0.05), and hepatic cholesterol level was significantly decreased with increasing dose of wood pulp-derived sterol (P < 0.01). The weight of liver in the 5‰ and 10‰ groups was significantly decreased compared with the HFHC group (P < 0.01). The mRNA expression levels of acyl-coenzyme A: cholesterol acyltransferase-2 (ACAT-2) and microsomal triglyceride transfer protein (MTP) in the 5‰ and 10‰ groups were significantly decreased (P < 0.05), and the RNA expression levels of 3-hydroxy-3-methylglutaryl-coenzyme A reductase the ATP-binding cassette (ABC) transporters ABCG5 and ABCG8 in the 10‰ group was significantly increased (P < 0.05) compared with the HFHC group. Significantly higher fecal excretion of total fecal neutral sterols and total fecal acidic sterols were observed in the 10‰ group compared with the HFHC group (P < 0.01). Wood pulp-derived sterols at doses of 1‰ and 5‰ significantly decreased intestinal bacterial overgrowth induced by HFHC diet (P < 0.05). Oscillibacter sp. and Desulfovibrio sp. were significantly decreased, while Akkermansia sp., Anaerostipes sp. and Roseburia sp. were significantly increased in the experimental groups (P < 0.05). Therefore, wood pulp-derived sterol resulted in increasing intestinal cholesterol excretion and inhibition of cholesterol absorption and synthesis, and improved the intestinal microbiota in hamsters.
Immunoenhancing and Anti-Athletic Fatigue Effect of Ashitaba Chalcone
ZHANG Jianwei
2017, 38(9):  196-201.  doi:10.7506/spkx1002-6630-201709032
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Objective: To investigate the effect of ashitaba chalcone on enhancing immune function and relieving fatigue in overtrained mice. Methods: A mouse model of overtraining was established using male ICR mice subjected to 8-week treadmill training. The overtrained mice were divided into four groups with five small groups of 10 animals each: low-dose (160 mg/kg), middle-dose (320 mg/kg), high-dose (800 mg/kg), model control and positive control (200 mg/kg of Herba Rhodiolae-American ginseng capsule) groups. Ashaba chalcone was gavaged to the animals. The anti-fatigue effect of ashaba chalcone in overtrained mice was investigated by measuring related parameters, and we also evaluated the effect on immune function in terms of humoral immune parameters, cellular immune parameters, monocyte/macrophage functions and natural killer cell activity. Results: Compared with the overtraining group, the contents of muscle glycogen and hepatic glycogen significantly increased in the middle- and high-dose groups (P < 0.05), and serum lactate dehydrogenase, creatine kinase and blood urea nitrogen decreased (P < 0.05). Ashitaba chalcone at the middle and high doses could promote the proliferation of antibody-producing cells, the activity of natural killer cells, and the proliferation and transformation of mouse spleen lymphocytes. Conclusion: Ashitaba chalcone effectively ameliorates exercise-induced fatigue and enhances immune function.
Effect of Sacha Inchi Oil on Improving Memory in Mice
SI Ru, ZHENG Mengsi, ZOU Libo
2017, 38(9):  202-206.  doi:10.7506/spkx1002-6630-201709033
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Objective: To investigate the effect of sacha inchi oil on improving memory in mice. Methods: Totally 72 SPF male KM mice were randomly divided into control group, model group, sacha inchi oil low- medium-, high-dose groups (375.1, 750.2 and 1 500.0 mg/(kg·d)) and deep-sea fish oil group (1 500.0 mg/(kg·d)) . The animals were intragastrically administered for 30 days. After the experimental period, step-through test, step-down test and Morris water maze test were carried out. Results: In the medium- and high-dose groups, sacha inchi oil could prolong the latency time and reduce the number of errors in step-through test and step-down test (P < 0.05), but had no significant effect on the latency time or the percentage of swimming distance in Morris water maze. Conclusion: Sacha inchi oil may play an important role in memory improvement in mice at a dose from 375.1 to 1 500.0 mg/(kg·d).
Packaging & Storage
Effect of Cold Storage on the Activities and Protein Expression of Key Enzymes Involved in the Biosynthesis of Aroma-Related Esters in ‘Nanguo’ Pears
WANG Long, ZHOU Xin, SHENG Lei, ZHOU Qian, WANG Junwei, BAI Lijuan, JI Shujuan
2017, 38(9):  207-212.  doi:10.7506/spkx1002-6630-201709034
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In order to explore the mechanism of the effect of low temperature storage on the metabolism of aroma-related esters in ‘Nanguo’ pears, the changes in the composition of aroma-related esters, and the activities and protein expression of lipoxygenase (LOX) and alcohol acyltransferase (AAT), the key enzymes for the metabolism of aroma-related esters, in Nanguo pears during cold storage and subsequent shelf life at ambient temperature were investigated. Results showed that compared with storage for 90 days, the number of aroma-related esters, the content of the major aroma components and total ester content after 180 days of storage and after subsequent ripening at ambient temperature until the optimal consumption date significantly decreased. There was no significant difference in the activities and protein expression of LOX and AAT during cold storage. However, during the shelf life at room temperature after cold storage, the activities and protein expression of LOX and AAT reached the maximum levels three days earlier in the 180-days stored fruits than the 90-day stored ones. Moreover, the former showed a significant reduction in AAT activity and the protein expression levels of LOX and AAT. These results indicated that long-term refrigeration could inhibit the activities and protein expression of the key enzymes for the biosynthesis of aroma-related esters to a certain extent, thus affecting the generation of aroma-related esters and reducing the aroma quality of Nanguo pears.
Effect of Short-Term Storage on Raw Meat Quality Traits of Woody Breast Fillets
SUN Xiao, ZHANG Dacheng, JI Fangfang, CHEN Kunjie
2017, 38(9):  213-219.  doi:10.7506/spkx1002-6630-201709035
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In order to investigate the changes in meat quality parameters of woody/wooden breast (WB) during short-term storage, 68 42-day-old Cobb 500 broilers were classified into normal (NORM) and severe (SEV) categories (n = 34/category). Weight, compression force (CF), drip loss (DL), sarcomere length (SL) and gravimetric fragmentation index (GFI) were measured in all samples at different times of storage (1, 3, 8 days). We determined if there was a significant difference in any of the parameters between different WB categories and between different storage times, and the correlation analysis was conducted between each of the parameters and WB. The results showed that SEV were significantly higher than NORM in weight, CF, SL and GFI at all storage times (P < 0.05), and DL was not significantly different between SEV and NORM on day 1 of storage, but it was significantly different from day 3 to 8 (P < 0.05). There was a significant decrease in CF, SL and GFI from day 1 to 3 (P < 0.05), but there was no significant difference in CF between days 3 and 8 (P > 0.05). SL and GFI did differ in NORM, but continued to reduce in SEV from day 3 to 8 (P < 0.05). Correlation analysis showed that CF and total DL were significantly correlated with WB (P < 0.01), and there was a link between changes in SL and GFI and WB hardness reduction over time. These results indicated that SEV breast fillet was negatively related to raw meat quality. WB hardness decreased during short-term storage, which, however, did not result in any changes in meat quality. Therefore, WB test should be carried out on-line on the day of slaughter, and WB hardness was determined by a variety of factors.
Effects of Gas Packaging Combined with High Hydrostatic Pressure on Storage Quality and Microbiology of Dry Pot Lotus Root Slices, a Chinese Dish
XIONG Xinxing, ZHOU Bing, ZHANG Luyao, OU Yawen, LIU Qi, ZHANG Yan, LIAO Xiaojun
2017, 38(9):  220-224.  doi:10.7506/spkx1002-6630-201709036
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Dry pot lotus root slices is a popular Chinese dish with rich nutrients and good taste. This study was done to analysis the effects of gas packaging combined with high hydrostatic pressure (HHP) on the shelf life and storage quality of dry pot lotus root slices. For this purpose, changes in total colony count, texture, color difference, lipid peroxidation and sensory evaluation of dry pot lotus root slices during storage after sequential gas packaging combined with HHP treatment were measured. The results showed that compared with N2 packaging, CO2 packaging, vacuum packaging combined with HHP, and N2 packaging combined with HHP, the shelf life of dry pot lotus root slices treated by CO2 packaging combined with HHP was longer, the hardness during the first cycle was maintained at about 14 000 g, and the decrease in b* value was less than 2 during storage. Sensory evaluation of the product subjected to CO2 packaging combined with HHP was also good. Thus, the results provide new ideas and methods for the preservation of low acid foods.
Effect of Bayberry Polyphenols on the Quality of Tuna (Thunnus albacores) Meat Used for Raw Consumption during Refrigerated Storage
BU Tingting, JIN Yang, XU Dalun*, ZHANG Jinjie, YANG Wenge, LOU Qiaoming
2017, 38(9):  225-231.  doi:10.7506/spkx1002-6630-201709037
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The effects of bayberry polyphenols (BP) as a natural antioxidant and color fixative on the quality of tuna (Thunnus albacores) meat used for raw consumption during refrigerated storage were studied. Raw tuna meat was soaked in ultra-pure water (control group), 0.3 g/100 mL BP solution (BP-0.3 group), 0.7 g/100 mL BP solution (BP-0.7 group) or 0.9 g/100 mL BP solution (BP-0.9 group) for 5 min and stored at (4 ± 0.5) ℃. The freshness, color and lipid oxidation were assessed daily during storage. The results showed that BP could maintain the quality of tuna meat during refrigerated storage, significantly inhibit the increase in total volatile basic nitrogen (TVB-N) value, K value, total viable count (TVC) value, 2-thiobarbituric acid (TBA) value and metmyoglobin content (P < 0.05), and significantly retard myoglobin loss, freshness breakdown and sensory quality decrease (P < 0.05). At (4 ± 0.5) ℃, the shelf life of the control group for raw consumption was 3 days, which was extended to 5 days for the BP-0.3 group and to 6.7 days for the BP-0.7 and BP-0.9 groups. No significant difference between the BP-0.7 and BP-0.9 groups was observed as far as the preservation of tuna quality was concerned (P > 0.05). Taken together, 0.3.0.7 g/100 mL BP as a natural antioxidant and color fixative could be applied on tuna meat used for raw consumption before refrigerated storage.
Mechanism by Which Blueberry Skin Turns Red during Chilling Storage and Control of This Phenomenon
WANG Siyao, ZHOU Qian, BU Fengya, JI Shujuan
2017, 38(9):  232-238.  doi:10.7506/spkx1002-6630-201709038
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‘Lanfeng’ blueberries were used to explore the mechanism by which blueberry skin turns red during chilling storage. Meanwhile, the effect of programmed chilling treatment on controlling this phenomenon was also investigated. The results showed that the skin of only a minority of blueberries turned red during chilling storage. During the shelf life at room temperature after 30 days of chilling storage, there were significantly more blueberries whose skin turned red. At this time, the brightness of fruits decreased, and the a* value increased rapidly. These changes became more pronounced with extended storage time. Polyphenol oxidase (PPO) activity was significantly enhanced after long-term refrigeration, leading to a considerable reduction of anthocyanin and total phenols in the skin of blueberries. Programmed chilling treatment could effectively hinder blueberries from turning red and significantly inhibit the increase in a* value and the reduction in anthocyanin. Thus, the degradation of the pigments anthocyanins may explain why blueberry skin turned red under cold stress, and programmed chilling treatment can control this phenomenon effectively.
Reviews
Progress in Research on Natural Products in MicroRNA Regulation for Metabolic Syndrome Improvement
GUO Qin, BAI Jie, HE Yuxuan, TANG Chuanhui, CAO Qingguo, DONG Ying
2017, 38(9):  239-247.  doi:10.7506/spkx1002-6630-201709039
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The metabolic syndrome has become a global health problem. microRNA (miRNA), a short single-stranded endogenously expressed RNA (approximately 22 nt), regulates gene expression at the post-transcriptional level. A lot of researches have shown that miRNA plays an important role in metabolic syndromes. Additionally, natural products which can be used as both food and medicine can modulate the activities and functions of miRNA to improve glucose and lipid metabolism disorders. Recent evidence described in this review highlights the significant role of miRNA in metabolic syndromes and how dietary factors may influence metabolic syndromes by modulating the activities and functions of miRNA.
Application and Prospects of Molecular Biology Techniques in Predictive Microbiology: A Review
ZHANG Zhaohuan, LOU Yang, DU Suping, PAN Yingjie, ZHAO Yong
2017, 38(9):  248-257.  doi:10.7506/spkx1002-6630-201709040
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Predictive microbiology is an important area of food microbiology, and its essence lies in the application of mathematical model to describe the growth and inactivation of microbiology under specific environmental conditions. Predictive microbiology model could not only predict the shelf life of foods to control spoilage organisms, but also contribute to food microbial risk assessment system to reduce the risk of pathogen infection. Therefore, it is of great importance for guaranteeing food safety and improving public health. This review overviews the history of predictive microbiology and analyzes the current research hotspots in predictive microbiology. The emphasis of this review is placed on the state of the art in the application of molecular biology techniques in predictive microbiology, and it also expounds the concept and methodological development of molecular predictive model. The feasibility of the application of other molecular biology techniques in predictive microbiology and the future prospects for the application of molecular predictive model are also discussed. This review is expected to provide a firm theoretical basis for promoting the advancement of predictive microbiology.
Effect of High-Fat Diet on Cognitive Functions
ZHAO Meiqi, ZHANG Peng, GUO Yanmin, ZHAO Hui
2017, 38(9):  258-264.  doi:10.7506/spkx1002-6630-201709041
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The association of high-fat diet (HFD) intake or western diet with obesity, diabetes, cardiovascular and other metabolic diseases has been demonstrated, and accumulating evidence has shown that HFD also has an important influence on the brain, behavior and cognitive functions. However, the mechanism for the effect of HFD on cognitive functions is not yet fully understood. In addition to insulin resistance, oxidative stress and inflammation, blood-brain barrier, brain-derived neurotrophic factor and serotonin pathway also play important roles in the mechanisms underlying cognitive impairment induced by HFD. In this article, we review recent research on the influence of diet (especially HFD) on cognitive functions and its possible mechanism of action in the brain, and we also summarize the site of action of HFD, with the aim to provide a good basis for targeted prevention and therapy of diet-related diseases and provide a useful guidance for future studies aimed to make our diet more reasonable.
A Review of the Effect of Dietary Maillard Reaction Products on Gut Microbiota
HAN Kaining, DONG Shiyuan, YAO Ye, YANG Yuhong, JIN Weiya
2017, 38(9):  265-270.  doi:10.7506/spkx1002-6630-201709042
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The Maillard reaction is one of the most widespread and important reactions during food processing, storage and cooking. However, this reaction causes a decrease in the gastrointestinal digestibility of proteins or amino acids, thus making it more possible for the gut microbiota to utilize and ferment these nutirents. This article reviews recent progress in understanding the effect of Maillard reaction products on the gut microbiota and the formation of fermentation products, which will provide some guidance for future studies on the relationship of Maillard reaction products, gut microbiota and human health.
Recent Advances in Understanding Changes in Antioxidants during in Vitro Digestion
TAO Wenyang, SUN Peilong, SUN Yujing
2017, 38(9):  271-279.  doi:10.7506/spkx1002-6630-201709043
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There is evidence that dietary antioxidants play a crucial role in promoting health and reducing the risks of chronic diseases, which has recently attracted a great amount of attention in both academic and industrial fields. However, most current studies are limited to activity evaluation of extracts and far away from application in the human body. Both pH and various digestive enzymes are potential factors that influence the stability of antioxidants in food during digestion. This article reviews the latest studies on the structural changes of polyphenols, flavonoids and carotenoids in food as well as changes in their antioxidant capacity during digestion, which will provide a theoretical reference for the evaluation of the antioxidant capacity of food components.
Recent Progress in Technologies for the Improvement of Protein-Based Film Performance Based on Molecular Cross-Linking
GAO Guixian, WANG Wenhang
2017, 38(9):  280-286.  doi:10.7506/spkx1002-6630-201709044
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Protein-based film has an important role in the field of edible film due to its characteristics of non-toxicity, biodegradability, green environmental protection, shelf life extension of foods, and nutrient supply. How to improve its relatively weak mechanical strength and insufficient barrier performance has always been and will be a problem of great concern for researchers. This article first reviews the formation mechanism and properties of protein-based film with emphasis on the existing technologies for the improvement of protein-based film properties based on molecular cross-linking including physical cross-linking, chemical cross-linking, enzymatic cross-linking and physical energy-induced cross-linking. Finally, the significance and development trend of cross-linking in protein-based film are also proposed.
Current Status and Future Prospects of Food Biological Manufacturing
WANG Shouwei, CHEN Xi, QU Chao
2017, 38(9):  287-292.  doi:10.7506/spkx1002-6630-201709045
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Recently, biotechnologies such as genetic engineering, cell engineering, fermentation engineering and enzyme engineering have propelled the development of new materials and technologies in food manufacturing. They can improve the efficiency of biomass utilization, food product quality and nutrition structure as well as overall performance, thus providing a good foundation for the rapid development of food industry. The food biological manufacturing has become an important way for sustainable social development in the future. In this article, the concept, research contents and directions of food biological manufacturing, as well as the current research trends and existing problems are reviewed. The future prospects of food biological manufacturing are also addressed in order to provide a reference and guidance for future research and industrial development.
Botanical Characteristics, Chemical and Nutritional Composition and Pharmacological and Toxicological Effects of Medicinal and Edible Plant Millettia speciosa Champ.
ZHAO Zhenyu, LIU Pinghuai, MA Shasha, WANG Shenglin, LI Ang, LIU Jiguang, WANG Meng
2017, 38(9):  293-306.  doi:10.7506/spkx1002-6630-201709046
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Millettia speciosa Champ. is a plant of the Millettia genus belonging to the Leguminosae family. This plant is widely cultivated in the south of China as a source of both food and medicine. Millettia speciosa has antibacterial and antioxidant effects. In addition, it is clinically confirmed to have therapeutic effects on lumber muscle strain, rheummatic arthritis, pulmonary tuberculosis, chronic bronchitis, chronic hepatitis, spermatorrhea, leukorrhagia, nephritis and other chronic ailments. The typical bioactive components of Millettia speciosa are formononetin and maackiain. Up to date, more than 50 compounds including alkaloids, terpenoids, flavones, phenylpropanoids, volatile oil and phytosterol have been isolated from Millettia speciosa. However, there is currently little published information on the toxicology of Millettia speciosa. With this in mind, this article presents an elaborate review of the traditional medicinal applications, chemical and nutritional constituents, pharmacological and toxicological activities of Millettia speciosa with the aim to provide a theoretic guideline for further studies on this plant.
Effect of Thermal Treatment on Whey Proteins in Liquid Milk
QU Xueyin, ZHENG Nan, LI Songli, WEN Fang, MENG Lu, YANG Jinhui, WANG Jiaqi
2017, 38(9):  307-313.  doi:10.7506/spkx1002-6630-201709047
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β-Lactoglobulin, α-lactalbumin, bovine serum albumin and immunoglobulin constitute the major whey proteins in milk. Thermal treatment of milk causes denaturation of whey proteins, thereby affecting the structure and activity of whey proteins and reducing the nutritional value of milk. In this article, we review the major processing technologies for liquid milk used in different countries and the effects of thermal treatment of milk on the major whey proteins.
Progress in Protein Oxidation during Meat Processing and Preservation and Its Adverse Health Effects
WEI Cheng, ZHU Lijuan, XIE Yueying, YUAN Min, ZHOU Caiqiong
2017, 38(9):  314-321.  doi:10.7506/spkx1002-6630-201709048
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Different processing steps may influence physicochemical properties and nutritional value of meat products, and even produce some compounds that are detrimental to human health. Thermal treatment, for instance, has been observed to increase free radical contents and reduce antioxidant capacity in meat systems, both of which contribute to protein oxidation. Some meat processing and preservation methods may promote protein oxidation and then affect the sensory quality of meat products, and even accelerate the quality deterioration. Thus, this article discusses the impact of common meat processing and preservation methods and related new technologies on protein oxidation as well as the adverse effects of protein oxidation on human health, with the aim to provide a reference for further studies on protein oxidation during meat processing and preservation and the development of reasonable food processing technologies.
Causes and Control Measures of the Fading of Edible Roses
ZHANG Zhiguo, JIANG Shan
2017, 38(9):  322-328.  doi:10.7506/spkx1002-6630-201709049
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Edible roses are the flowers of the genus Rosa in the family Rosaceae, which have bright colors and are commonlyred or pink. Edible roses are not only edible but also ornamental. During storage, the color of edible roses may be changed,which is related to the stability of anthocyanins in edible roses. In this article, the factors such as anthocyanin structure, pH,temperature, endogenous enzymes and water content affecting the stability of anthocyanins are reviewed. The causes of thefading of edible roses are analyzed and some countermeasures are proposed to delay the fading of roses.