Volume 30,Issue 11,2014 Table of Contents

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  • 1  Polyphenolic Composition of Sphallerocarpus gracilis Seeds and Their Inhibitory Effect on Human Colon Carcinoma (Lovo) Cells
    GAO Chun-yan TIAN Cheng-rui LU Yue-hong
    2014, 30(11):1-5.
    [Abstract](1276) [HTML](0) [PDF 657.87 K](676)
    Abstract:
    The free and insoluble cell wall-bound phenolics of Sphallerocarpus gracilis seeds were characterized by ultrasound-assisted extraction. The polyphenolic contents were determined by the Folin-Ciocalteu method and high-performance liquid chromatography-mass spectrometry (HPLC-MS), and the inhibitory effects of the polyphenolic extracts on human colon carcinoma (Lovo) cells were determined by an MTT assay. The results indicated that the dominant phenolic compounds in S. gracilis seeds were chlorogenic acid, caffeic acid, paeoniflorin-diglucoside, luteolin-glucoside, dicaffeoylquinic acid glucoside, and protocatechuic acid glucoside, and that the free and insoluble cell-wall-bound phenolic content in extracts differed. The phenolic extracts from S. gracilis seeds showed significant inhibitory effects on Lovo cells. Furthermore, the inhibition rate gradually enhanced with increasing phenolic concentrations, showing a dose-dependent effect. The morphology of cells changed substantially after treatment with polyphenolic extracts; cells were smaller, shriveled, and even dried and detached, preliminarily suggesting that polyphenolic extracts from S. gracilis seeds could inhibit the growth of Lovo cells.
    2  Hepatoprotective Effect of Burdock Extracts against Carbon Tetrachloride-induced Liver Damage in Mice
    HE Ju-ping PAN Ying-jie ZHAO Yong
    2014, 30(11):6-11.
    [Abstract](1400) [HTML](0) [PDF 634.41 K](804)
    Abstract:
    The hepaprotective effects of four burdock extracts on CCl4-induced liver damage in mice, as well as the possible underlying mechanism, were studied. Ethanol and water were used to extract burdock peel and peeled burdock root to yield an ethanolic extract of burdock peel (LP), a water extract of burdock peel (PW), an ethanolic extract of peeled burdock root (MA), and a water extract of peeled burdock root (MW). Biochemical methods were used to measure aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and lactic dehydrogenase (LDH) activities, total bilirubin (TB) level in the serum, as well as malondialdehyde (MDA) level, and superoxide dismutase (SOD) and glutathione (GSH) activities in the liver in mice. The expression levels of SOD1, SOD2, and xanthine oxidase (XOD) in liver tissues were determined by western blot analysis, and the severity of hepatic lesions in mice was observed. In the LP group, the activities of ALT, AST, ALP, LDH, and the TB level in mouse serum were signi?cantly increased (up to >97%). The MDA level in the liver decreased significantly, whereas the GSH and SOD activities increased significantly (up to 45%). In the liver, SOD2 expression increased, but XOD expression decreased. Hepatic lesions were less severe in the LP group than in the CCl4 group. Serum ALT and AST activities were significantly lower in the PW, MA, and MW groups than in the CCl4 group, but no significant differences were observed in other biochemical indicators or in the severity of hepatic lesions. The hepaprotective effect of LP against CCl4-induced liver damage in mice may be achieved by in vivo scavenging of free radicals to maintain the stability of hepatocytes.
    3  Regulation of Lipid Metabolism and Oxidative Stress by Bamboo Leaf Flavonoid and Cassia Seed Compound Associated with Ascorbyl Palmitate and Vitamin E Succinate in Hyperlipidemia Rats
    LIU Lian-liang WU Cong-jun MIAO Liang LOU Qiao-ming YU Shan-kai
    2014, 30(11):12-16.
    [Abstract](1242) [HTML](0) [PDF 544.22 K](810)
    Abstract:
    This study was to investigate the in vitro oxidative stress activity of bamboo leaf flavonoid (BLF) and Cassia seed powder (CSF) compound (16:9, m/m), in combination with ascorbyl palmitate (AP) and Vitamin E succinate (α-TOS), as well as their ability to regulate lipid metabolism and anti-oxidative stress at different ratios in hyperlipidemic rats. Combination of [BLF +CSF] and AP with ratio of 5:1) had synergistic anti-oxidative activity, which was significantly higher than that of [BLF+CSF] and α-TOS with ratio of5:1. The combination of [BLF+CSF], AP, and α-TOS with ratio of 5:1:1 exhibited the most significant synergistic effect. A hyperlipidemia rat model was established, and the lipid-lowering and anti-oxidant abilities of different combinations were evaluated. The results showed that all combinations could effectively regulate lipid metabolism and reduce oxidative stress in hyperlipidemic rats. The combination of [BLF+CSF], AP, and α-TOS (5:1:1) had the strongest synergistic effect in regulating lipid metabolism and oxidative stress. The synergistic effect included a significant reduction in atherosclerosis index and regulation of blood lipids. Total cholesterol (p < 0.01), triglycerides (p < 0.01), and low density lipoprotein cholesterol (p < 0.01) were reduced, and high density lipoprotein cholesterol was increased (p < 0.01). In terms of oxidative stress, the combination significantly increased serum total antioxidant capacity (p < 0.01), superoxide dismutase activity (p < 0.01), and glutathione peroxidase activity (p < 0.01), and reduced malondialdehyde content (p < 0.01).
    4  Distribution and Antioxidant Activity of Free and Bound Phenolic Acids in Sugarcane Tissues
    FU Xiong ZHOU Hui-fang LI Chao ZHAO Zhen-gang YU Shu-juan
    2014, 30(11):17-22.
    [Abstract](1621) [HTML](0) [PDF 412.75 K](900)
    Abstract:
    In order to explore the different forms of phenolic acids in the tissues of sugarcane, qualitative and quantitative analyses of free and bound phenolic acids in the cane juice, leaves, and bagasse of sugarcane were performed using reversed-phase high-performance liquid chromatography (RP-HPLC). The results showed that phenolic acids primarily existed in the bound form in sugarcane; however, the content and form were different in the three different tissues. The leaves and bagasse had higher phenolic acid content than cane juice. The free phenolic acid content in cane juice, leaves, and bagasse was 317.18 mg/kg (dry solids), 1568.37 mg/kg (dry basis), and 1504.57 mg/kg (dry basis), respectively. The bound phenolic acid content in cane juice, leaves and bagasse was 740.32 mg/kg (dry solids), 2725.41 mg/kg (dry basis), and 2452.13 mg/kg (dry basis). In cane juice, caffeic acid and gallic acid were primarily in the free form, whereas ferulic acid and coumaric acid were primarily in the bound form. Caffeic acid, ferulic acid, and coumaric acid were primarily in the bound form in cane leaves and bagasse. In the different sugarcane tissues, free phenolic acids exhibited better free-radical removal activities towards DPPH and ABTS than bound phenolic acids. The free and bound phenolic acid content in sugarcane tissues was positively correlated with antioxidant activity.
    5  Study on the Rheology and Interactions of Casein-Carrageenan System
    LIU An-jun HU Ying-na LIU Cai-hong TENG An-guo YANG Shi-wei
    2014, 30(11):23-27.
    [Abstract](1363) [HTML](0) [PDF 612.19 K](687)
    Abstract:
    In this study, the effects of different amounts of carrageenan on the particle size and rheological properties of the casein-carrageenan system were studied. Furthermore, the intermolecular forces that contribute to the rheological and gel properties of the system were explored to reveal the gelation mechanism of the casein and carrageenan mixture. The results showed that increased concentrations of carrageenan resulted in an increased particle size of the system. When the concentration was 0.5%, the molecular size became 1096.8 nm, almost five times the molecular diameter of casein. This indicates that absorption occurred between carrageenan and casein. Rheological tests showed that the system exhibited pseudo-plastic fluid characteristics. With increasing amounts of carrageenan, the flow index, n, decreased from 0.9251 to 0.7270, and the consistency coefficient, K, increased from 0.3796 to 3.4403. Upon addition of NaCl and urea, the gelation strength of the system decreased to various extents. When the concentrations of the two components were 1.0 mol/L, the loss ratios of the system gelation strength were 100% and 32.4%, respectively. The intermolecular interactions were mainly composed of electrostatic interactions. Infrared spectroscopy analysis showed that the secondary structure of casein changed after the reaction, which further proved that a cross-linking reaction took place between carrageenan and casein.
    6  Antigenicity and Structural Properties of Soybean Protein-glucose Conjugates
    BU Guan-hao ZHU Ting-wei CHEN Fu-sheng
    2014, 30(11):28-33.
    [Abstract](1158) [HTML](0) [PDF 675.95 K](818)
    Abstract:
    Soybean is a high-quality protein source and one of eight major food allergens. Glycation is an effective way to remove protein allergens. In this paper, soy protein isolate (SPI) and glucose were used as raw materials for Maillard reactions, which were performed with various protein to carbohydrate ratios, temperatures, and experimental time, to prepare glycated conjugates. The inhibition of antigen β-conglycinin in SPI-glucose conjugates was used as an indicator, and indirect competitive enzyme-linked immunosorbent assay (ELISA) was employed to measure the antigenicity of glycated conjugates. When the mass ratio of protein to sugar was 3:1 at a temperature of 55 , the antigenicity of the prepared glycated conjugates was relatively low. When the reaction time was 72 h, the inhibition rate of antigen β-conglycinin decreased from 93.54% to 22.58%. The Maillard reaction was confirmed by the trinitrobenzene sulfonic acid (TNBS) method and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Changes in protein structure were studied by ultraviolet scans and Fourier transform infrared spectroscopy (FTIR). These basic studies might provide research methods and a theoretical basis for determining the mechanism mediating the effect of glycation on antigenicity and developing soy protein products with low allergen contents.
    7  Dissolution and Rheological Behavior of Collagen in Ionic Liquids
    WANG Zhao-mei LIAO Wei LI Lin ZHENG Cui
    2014, 30(11):34-37.
    [Abstract](1362) [HTML](0) [PDF 588.04 K](923)
    Abstract:
    The solubility and steady-state rheological behavior of collagen in the ionic liquids based on choline chloride?2ZnCl2 were studied. The collagen was regenerated using water, ethanol, and acetonitrile. The structure of regenerated collagen was characterized by Fourier transform infrared spectroscopy (FT-IR), wide angle X-ray diffraction (XRD), thermogravimetry-differential scanning calorimetry (DSC). Choline Chloride?2ZnCl2 was used as the direct solvent for collagen, and the solubility of collagen in the ionic liquid at 120 ℃ was up to 11.3 g ± 0.2 g/100 g. The FT-IR results revealed that the acetonitrile-regenerated collagen had a complete triple helical structure, while the crystallinity and thermal stability of the regenerated collagen were somewhat lower than those of the original sample. The steady-state shear rheological analysis showed that the viscosity of collagen/choline chloride?2ZnCl2 increased with increasing concentrations of solution and decreased with increasing shear rates, which are the characteristic features of a pseudoplastic fluid. When the mass fraction was 3 g/100 g, the shear-thinning phenomenon was observed in solution. Furthermore, the solution viscosity was almost disappeared when the temperature was 90 ℃ and the shear rate was 100 s-1.
    8  Correlation Analysis of the Microbial Community in Luzhou-flavor Fermented Grains and Physicochemical Indicators
    HUANG Zhi-guo LIU Yan-mei WEI Chun-hui DENG Jie WANG Yan-li ZHU Yun-fei LI Mi WAN Shi-lv
    2014, 30(11):38-42.
    [Abstract](1757) [HTML](0) [PDF 517.83 K](808)
    Abstract:
    The changing patterns of the dominant microbial community in Luzhou-flavor fermented grains during a fermentation cycle and the corresponding physiochemical indicators (starch, reducing sugar, ethanol, total acidity, and temperature) were studied, and the correlation between the two changing patterns was analyzed. The results showed that during the fermentation process, temperature and reducing sugar concentration first increased, then decreased, and finally remained constant; ethanol and total acid concentrations first increased and then remained constant; starch content continuously decreased. The bacterial diversity indices were all in the range of 2.12~2.80, and the fungal diversity indices ranged from 1.68 to 2.61. The correlation coefficients between microbial community diversity and starch, reducing sugar, ethanol, total acidity, and temperature were 0.717 (P < 0.01), 0.744 (P < 0.01), -0.704 (P < 0.01), -0.838 (P < 0.01), and 0.622 (P < 0.05), respectively. The correlation coefficient between fungal diversity and starch was 0.561 (P < 0.05), and no significant correlations were observed between fungal community diversity and other physiochemical indicators. Bacterial sample 5 and 6 were sequenced and identified as Bacillus subtilis sp. and Pseudomonas sp.
    9  Screening, Identification, and Fermentation Characteristics of High-yielding Ethanologenic Yeasts and Their Utilization of Soybean Molasses as A Raw Material
    GAO Yu-rong LI Da-peng LI Qing-chuan LI Ben-ling
    2014, 30(11):43-47.
    [Abstract](920) [HTML](0) [PDF 742.05 K](870)
    Abstract:
    A strain of yeast producing a high ethanol yield was isolated from soybean molasses, and its fermentation characteristics were studied. The strain P14, with an ethanol yield of up to 9.07% (V/V), was isolated from soybean molasses by enrichment and isolation of strains, preliminary screening using a 2,3,5-triphenyl tetrazolium chloride (TTC) assay, and determination of ethanol tolerance and fermentation capacity. Strain P14 was identified as Saccharomyces cerevisiae on the basis of morphological characteristics, colony morphology, physiological and biochemical tests, and sequence analysis of the D1/D2 region of 26S rDNA. The effects of the concentration of soybean molasses, and addition of a nitrogen source and mineral salts on ethanol fermentation by Saccharomyces cerevisiae P14, as well as the utilization of oligosaccharides in soybean molasses by Saccharomyces cerevisiae P14 were studied. The results showed that soybean molasses concentration, and addition of a nitrogen source and mineral salts significantly influenced ethanol fermentation. The following conditions were determined to be optimal: 40% soybean molasses concentration, 1.2 g/L of peptone, and 0.4 g/L of added MgSO4. After fermentation for 72 h in this medium, 90.10% of glucose, 91.23% of sucrose, 92.56% of raffinose, and 96.97% of stachyose in molasses had been utilized by the yeast. Therefore, the Saccharomyces cerevisiae strain P14 identified from soybean molasses has a relatively strong capacity to produce ethanol by fermentation, using soy oligosaccharides present in soybean molasses.
    10  Factors Influencing the Determination of Glass Transition Temperature of Penaeus vannamei Meat
    SHI Qi-long LIN Wen-wen ZHAO Ya
    2014, 30(11):48-52.
    [Abstract](1301) [HTML](0) [PDF 745.19 K](837)
    Abstract:
    In order to accurately determine the glass transition temperature (Tg) of Penaeus vannamei meat, the factors affecting the Tg determination, including the scanning mode type (single or double scan), heating rate, annealing temperature and time, and sample wet-basis moisture content during the measurement as determined by differential scanning calorimetry (DSC), were systemically investigated. The experimental results showed that single scan mode was appropriate for the DSC analysis of shrimp samples containing nonfreezable water. For the samples containing freezable water, the corresponding beginning and end temperatures for ice crystallization were between -22 ℃ and -53 ℃. When the annealing treatment was conducted in this temperature range for 30 min, the enthalpy change (ΔH) first decreased and then increased. When the ΔH value achieved the minimum value of 171.7 J/g, the corresponding temperature was -35 ℃, i.e., the suitable annealing temperature. The Tg values of the shrimp meat decreased with increasing annealing time and were gradually stabilized after 30 min. Therefore, the optimum annealing time was 30 min. The Tg values decreased with decreasing heating rate and were gradually stabilized when the heating rate was lower than 5 ℃/min. Therefore, the optimum heating rate was 5 ℃/min. The Tg values decreased with increasing moisture content in the shrimp meat. Tg had an apparent decreasing trend when the moisture content was lower than 25.88%; the reduction of Tg was very small and it gradually stabilized when the moisture content was higher than 25.88%. The results could provide a theoretical basis for determining DSC scanning protocols for Penaeus vannamei meat.
    11  Effect of Water Stress and Nutrition Stress on Premature Senescence-related Enzyme Activity in Harvested Broccoli
    YANG Shao-lan LIU Yan WANG Cheng-rong WANG Ran
    2014, 30(11):53-59.
    [Abstract](1465) [HTML](0) [PDF 758.47 K](710)
    Abstract:
    The effects of post-harvest water stress and nutrition stress during storage on broccoli (Brassica oleracea) florets were studied based on changes in color, chlorophyll content, ascorbic acid (vitamin C, Vc) content, respiratory rate, superoxide dismutase (SOD) activity, peroxidase (POD) activity, catalase (CAT) activity, malondialdehyde (MDA) content, and the total antioxidant capacity. The broccoli florets showed yellowing during storage. Water stress and nutrition stress accelerated the degradation of chlorophyll and Vc. The Vc contents of the control sample and samples subjected to water treatment, polyethylene glycol (PEG) treatment, PEG + nutrition treatment, and nutrition treatment of 12 h post-harvest were 8.84 mg/100 g, 12.16 mg/100 g, 24.44 mg/100 g, 30.68 mg/100 g, and 27.56 mg/100 g, respectively. Post-harvest water stress and nutrition stress can both result in reduced POD activity and increased CAD activity. When these two stresses occur simultaneously, the increase in the total antioxidant capacity is delayed in broccoli florets. Therefore, the total antioxidant capacity could reveal the anti-senescence capacity better than a single antioxidase in broccoli, based on comparisons of SOD, POD, and CAT activities with the total antioxidant capacity.
    12  Study on the Physiochemical Properties and Structural Characteristics of the Dietary Fiber in Tomato Pomace
    WANG Qing-ling ZHU Li MENG Chun-mian LU Shi-ling
    2014, 30(11):60-64.
    [Abstract](1359) [HTML](0) [PDF 521.42 K](898)
    Abstract:
    Tomato pomace is a byproduct in the tomato processing industry, and is rich in dietary fiber (DF) which is beneficial to humans. However, the degree of comprehensive utilization of tomato pomace is very low. The objective of this study was to evaluate the physiochemical properties of the DF in tomato pomace by measuring the water holding capacity (WHC), swelling capacity (SC), oil holding capacity (OHC), and glucose adsorption capacity (GAC). In addition, the structures of functional groups, microstructure, and monosaccharide composition were characterized by infrared spectroscopy (IR), scanning electron microscopy (SEM), and GC-MS, respectively. The WHC, SC, OHC, and GAC of the DF in tomato pomace were 9.33 g/g, 9.29 mL/g, 9.84 g/g, and 19.206 mmol/g, respectively. The glucose retardation index (GRI) reached 36.78 mmol/g after 30 min of dialysis. The analysis of the structure of soluble DF (SDF) in tomato pomace showed the characteristic absorption peak of glycolipids. The major monosaccharide in SDF was galactose, followed by arabinose and xylose. According to SEM results, SDF had an irregular sheet-like structure, with honeycomb-like holes. The DF in tomato pomace is a kind of raw or auxiliary material for high-quality functional foods.
    13  Fatty Aacid Typing Analysis of Food-borne Listeria monocytogenes in Hebei Area
    DI Hui-ling ZHANG Yao-qi SHAN Xiao-xiao YAN He SHI Lei
    2014, 30(11):65-70.
    [Abstract](1151) [HTML](0) [PDF 552.41 K](672)
    Abstract:
    In this study, the usefulness of fatty acid typing to identify and evaluate strain similarity among Listeria monocytogenes (LM) strains was evaluated. Ninety LM strains isolated from six types of food in Hebei area from 2005 to 2007 were selected for this study. The fatty acids were extracted, and their components were analyzed using the MIDI Sherlock system. SPSS 19. 0 statistical software was used for data and cluster analyses. The fatty acid typing was compared with traditional serotyping and pulsed-field gel electrophoresis (PFGE), which is the gold standard for typing. The results showed that the fatty acid analysis method successfully identified 96.67% of LM strains, 20 fatty acid components were detected from all of the tested strains, and the three main fatty acid components were 15:0 anteiso, 17:0 anteiso, and 15:0 iso. The fatty acid components differed among the different serotypes, and the differences in two main fatty acid components between serotype 1/2c isolates and serotype 1/2a, 1/2b, and 4b isolates were statistically significant (P < 0. 01). Compared with PFGE typing, fatty acid typing was a more efficient method for identifying genetic relationships between strains in small samples with simple structures. The combination of fatty acid typing along with serotyping and PFGE typing could better identify correlations among LM strains.
    14  Effect of Protein Hydrolysate-Fe2+ Complex on the Growth Performance and Non-specific Immune Parameters of Procambarus clarkii
    WANG Xiao-ling ZHANG Bin MA Lu-kai WANG Qiang DENG Shang-gui WANG Bin
    2014, 30(11):71-78.
    [Abstract](1385) [HTML](0) [PDF 653.75 K](784)
    Abstract:
    The purpose of this study was to investigate the effects of addition of protein hydrolysate-Fe2+ complex (TPH-Fe2+) to feed on the growth performance and non-specific immune parameters of Procambarus clarkii. After 60 days of consumption of the basal feed supplemented with 400~1000 mg/kg TPH-Fe2+, the survival rate, weight, specific growth rate, and meat yield were increased by 9.94%~10.10%, 8.55%~8.72%, 0.24%~0.29%/d and 2.39%~3.05%, respectively (P < 0.05), compared to the control group. When 800 and 1000 mg/kg TPH-Fe2+ were added to the feed, the crude protein and fat contents of P. clarkii increased significantly. After 30 days of consumption of the basal feed supplemented with 200 and 400 mg/kg TPH-Fe2+, superoxide dismutase (SOD), phenoloxidase (PO), lysozyme (LSZ), and acid phosphatase (ACP) activities in the serum and hepatopancreas did not differ significantly from those in the control group (P > 0.05). However, feed supplementation with 800 and 1000 mg/kg TPH-Fe2+ significantly increased the SOD, LSZ, and ACP activities (P < 0.05). After 60 days of feeding with 400 and 600 mg/kg TPH-Fe2+, the activities of SOD and LSZ were significantly enhanced, but the activities of PO and ACP were not significantly affected. When 800 and 1000 mg/kg TPH-Fe2+ were added to the feed, the SOD, PO, LSZ, and ACP activities were all significantly increased (P < 0.05). In conclusion, the addition of 800~1000 mg/kg TPH-Fe2+ to the basal feed could improve the growth performance of and activities of non-specific immune enzymes in P. clarkii .
    15  Effects of Allicin and Organic Solvents on the Alliinase Activity and Composition of Garlic Oil
    LI Wen-qing ZHOU Hua HU Xing-peng YAN Ri-an HUANG Xue-song OU Shi-yi QIU Rui-xia
    2014, 30(11):79-83.
    [Abstract](1533) [HTML](0) [PDF 508.44 K](894)
    Abstract:
    Garlic oil has important biological activities and flavoring functions. In this study, garlic oil was prepared by using alliinase as catalyzer and allicin which was chemically synthesized as a raw material; meanwhile, how the intermediate product, allicin, and extraction solvents affect alliinase activity were investigated and the effect of solvents on the composition of garlic oil was explored. The results indicated that allicin partially inhibited alliinase activity, but did not lead to complete inactivation of alliinase. Further, organic solvents had a complicated effect on alliinase activity. Chloroform and methylene chloride caused complete inactivation of alliinase, whereas no obvious effects were observed with n-hexane and n-pentane. Gas chromatography-mass spectrometry and two-dimensional nuclear magnetic resonance spectroscopy were employed to characterize the components of garlic oil in different solvents. Extracting allicin with non-polar solvents, such as chloroform and hexane, resulted in garlic oil that primarily contained 3-vinyl-1,2-disulfide cyclohex-4-ene (4×) and 3-vinyl-1,2-disulfide cyclohex-5-ene (5×), whereas extracting allicin using polar solvents, such as acetic acid, resulted in garlic oil composed primarily of diallyl sulfide (DATS) and diallyl disulfide (DADS).
    16  Isolation and Identification of Yarrowia lipolytica Strains From Chicken Feet With Pickled Peppers and Analysis of Their Growth Characteristics
    WU Hai-hong WANG Xin-xin LIU Fang ZHU Yong-zhi BIAN Huan WANG Dao-ying GENG Zhi-ming ZHANG Mu-han XU Wei-min
    2014, 30(11):84-88.
    [Abstract](1981) [HTML](0) [PDF 554.91 K](967)
    Abstract:
    This study analyzed the dominant spoilage bacteria present in chicken feet with pickled peppers packed in inflated bags and analyzed their growth characteristics. Traditional isolation and culture methods were employed to screen the dominant spoilage bacteria; cell morphology was observed by microscopy after methylene blue staining, and the isolated strains were identified by phylogenetic analysis of the D1/D2 region of 26S rDNA sequences. Enterobacterial repetitive intergenic consensus-random amplified polymorphic DNA (ERIC-RAPD) analysis was used to characterize the genetic variation of the isolated strains. The growth characteristics of the dominant strains were also studied. Forty strains of yeast, numbered PJ1-PJ40 were isolated from the chicken feet product, and microscopic images showed that all strains had the same morphological characteristics; all were oval in shape. Molecular identification showed that all strains belonged to two genotypes of Yarrowia lipolytica, indicating that Y. lipolytica was the dominant spoilage bacteria in this product, originating from several sources of contamination. The optimal pH and temperature for growth of Y. lipolytica were found to be 4.5 and 25 ℃, respectively; increasing the NaCl concentration had an inhibitory effect on the growth of these bacteria.
    17  Inhibitory Effect of Xanthoceras sorbifolia Nutshell Saponin on Pancreatic Lipase
    GENG Jie ZHANG Hong-mei ZHOU Quan-cheng
    2014, 30(11):89-92.
    [Abstract](1196) [HTML](0) [PDF 509.56 K](731)
    Abstract:
    In this study, the influence of saponin from Xanthoceras sorbifolia nutshell (SXS) which was considered as a weight-reducing agent on pancreatic lipase activity was studied. The effects of SXS purified by AB-8 macroporous resin on pancreatic lipase were investigated by evaluating various experimental conditions (pH, reaction time, and order of adding reagents). The mechanism of SXS-mediated inhibition of pancreatic lipase was studied using ultraviolet absorption spectrometry (200~340 nm) and fluorescence spectrometry (excitation wavelength 290 nm, scanning wavelength 300~450 nm). The results indicated that the inhibition rate of SXS to pancreatic lipase activity could reach 87.5% using the optimal reaction system of pH 7.4, reaction time 15 min, and preheating the substrate and SXS together prior to adding the pancreatic lipase solution. Following the reaction of SXS and pancreatic lipase, the microenvironment of luminous amino acids (Trp, Tyr), the molecular structure, and the conformation of pancreatic lipase were changed. This resulted in a red-shift in the maximum absorption wavelength in the ultraviolet absorption spectrum of pancreatic lipase, and a reduction in fluorescence intensity. Further, pancreatic lipase activity was inhibited. Thus, SXS can act as a weight-reducing agent through the inhibition of pancreatic lipase.
    18  Comparative Study on Theabrownins in Pu-erh Tea and Its Powder Fermented in Liquid State
    LI Tao DU Li-ping XIAO Dong-guang LI Chang-wen XU Yong-quan
    2014, 30(11):93-97.
    [Abstract](1371) [HTML](0) [PDF 599.49 K](785)
    Abstract:
    To study the spectroscopic and physicochemical properties of theabrownins in ripened Pu-erh tea “7572” produced by solid-state fermentation and the Pu-erh powder produced by natural liquid-state fermentation, two types of theabrownins were extracted with an organic solvent. The UV-visible results showed that liquid theabrownin had an additional absorption peak at ?380 nm compared to solid theabrownin. The IR results indicated that the two theabrownins had similar functional groups. Both of them were composed of phenolic and carboxylic compounds, along with proteins and polysaccharides. The quantitative analysis of the acidic functional groups in theabrownins showed that both types of theabrownins contained carboxyl and phenolic hydroxyl groups, and the number of the two functional groups in liquid theabrownin was more than that in solid theabrownin. Theabrownins were isolated and graded based on membranes. The results showed that the contents of the oligomer fraction (M <10 ku) in solid and liquid theabrownins were 26.74% and 18.84%, respectively. The contents of the high-polymer fraction (M >100 ku) in solid and liquid theabrownins were 56.98% and 70.72%, respectively. The reducing powers of two theabrownins were dose-dependent and had similar activities. The measurement of the reducing power of each fraction after the grading by membranes indicated that the reducing powers of the middle- (10 ku < M < 100 ku) and high- (M > 100 ku) polymer fractions in both the theabrownins were significantly higher than that of the oligomeric fraction.
    19  Dietary and Nutritional Properties of Lingwu Long Jujube at Various Stages of Maturation
    GOU Qian WANG Min JI Xiao-long SHEN Jing WANG You-ke DUAN Xu-chang
    2014, 30(11):98-104.
    [Abstract](1398) [HTML](0) [PDF 671.75 K](864)
    Abstract:
    Variation in the dietary and nutrient qualities of Lingwu Long Jujube during four ripening stages (white-green, reddish, over half red, and fully red) was investigated to clarify the nutrient characteristics of the fruit, and to provide a scientific basis for its timely harvest. The results showed that during the ripening of Lingwu Long Jujube, the cyclic adenosine monophosphate content was significantly positively correlated with sucrose content (p < 0.01), glucose content and citric acid were significantly positively correlated (p < 0.01), and quinic acid content was significantly negatively correlated with oxalic acid content (p < 0.05). The sugar to acid ratio in mature (fully red), Lingwu Long Jujube fruits was 104.59, with a relatively high quinic acid content (up to 0.26%), which is an important substance for the flavor of fresh jujube. In addition to large amounts of crude fiber (8.26%) and cyclic nucleotides, mature (fully red) Lingwu Long Jujube fruits also contained potassium at a level as high as 9.90 mg/g, indicating it is a potassium-rich fruit. Lingwu Long Jujube fruits had the best taste at the fully red stage. They had good dietary and nutritional qualities. At the over half red stage, these qualities were similar to those at the fully red stage. Thus, the over half red stage is the optimal harvesting time for the storage of fresh fruits.
    20  Effect of Secondary Heat Sterilization on Volatile Flavor Compounds in Stewed Pork
    SUN Cheng-feng YU Qian-qian ZHU Liang LIU Cai-xia XU Shi-ming
    2014, 30(11):105-111.
    [Abstract](1052) [HTML](0) [PDF 647.51 K](859)
    Abstract:
    In order to explore the effects of different secondary heat sterilization methods on volatile compounds in stewed pork, the volatile flavor compounds in different samples treated by secondary heat sterilization were extracted by headspace-solid phase micro-extraction (HS-SPME) and identified by gas chromatography mass spectrometry (GC-MS). The samples treated with different sterilization methods and the types of volatile compounds in these samples were further analyzed by principal component analysis (PCA) and cluster analysis (CA) using SPSS software. Sixty volatile compounds were identified from stewed pork samples treated with different sterilization methods, and the total peak areas of the volatile compounds after secondary sterilization were significantly decreased compared to those of the control group. The PCA results showed that the highest comprehensive score was in the control group; ketones, heterocyclic compounds, and hydrocarbons made dominant contributions, and the lowest comprehensive score was found in 110 ℃ sterilization group. CA revealed that the five different sterilization methods could be classified into three clusters: a cluster containing 85 ℃ and 95 ℃ sterilization groups, a cluster containing the control and 121 ℃ sterilization groups, and another cluster containing the 110 ℃ sterilization group. Eight volatile flavor compounds could be classified into two clusters: ketones, heterocyclic compounds, hydrocarbons, phenols, aldehydes, and ethers in one cluster, and alcohols and esters in another cluster.
    21  Study on the Preparation of Starch Glutaric Acid Ester
    ZHANG Ben-shan ZHENG Yan-na
    2014, 30(11):112-118.
    [Abstract](1324) [HTML](0) [PDF 701.00 K](699)
    Abstract:
    In this study, corn starch and glutaric anhydride (GA) were used as the raw material and esterifying agent, respectively, to explore the effects of the initial starch slurry concentration, reaction time, reaction temperature, and pH value (during the preparation of starch glutaric acid ester in ethanol) on the degree of substitution. The conditions used to prepare GA starch were as follows: starch slurry concentration: 35% (m/m); reaction period: 3 h; reaction temperature: 35 ℃; and pH value of the reaction system: 8.5. The product was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). New absorption peaks corresponding to a C=O stretching vibration at 1733 cm-1 and -COO- antisymmetric stretching vibration at 1555 cm-1 were found in starch glutaric acid ester, indicating the successful esterification of starch molecules. Varying degrees of dents and ruptures were found on the granule surface of the modified starch. The XRD results revealed that the modified starch GA exhibited an A-type diffraction pattern, which confirmed that the reaction mainly occurred in the amorphous region. DSC revealed that the gelatinization temperature and enthalpy of the modified starch were decreased. Analysis by the Brabender viscosity method indicated that the peak viscosity of the modified starch was significantly increased.
    22  Influence of Protease Activity on the Preparation of Chitin and Comparison of the Properties of Different Chitins
    DUAN Shan LI Ting MAO Ying-chao XIAO Yin-jin WANG Xiang-jun
    2014, 30(11):119-124.
    [Abstract](1126) [HTML](0) [PDF 552.78 K](740)
    Abstract:
    In this study, the influence of protease activity on the removal of ash during chitin extraction by acetic acid in combination with protease (enzymatic method) and fermentation methods was investigated. The characteristics of the chitins extracted by chemical, enzymatic, and fermentation methods were further compared. The results indicated that protease activity could facilitate the removal of ash. The chitins extracted using the enzymatic and fermentation methods were very similar in all indices but showed obvious difference from the chitin extracted by the chemical method. The protein content, ash content, degree of crystallinity, and solution viscosity of the chemically extracted chitin were 1.24%, 0.23%, 79.8%, and 48 mPa?s, respectively. In contrast, the corresponding data for the chitins obtained using enzymatic and fermentation methods were 5.80% and 5.91%, 1.08% and 1.02%, 85.8% and 86.4%, and 57 and 59 mPa?s, respectively. The parameters for the enzymatic and fermentation methods were obviously higher than those of the chemically extracted chitin. However, the deacetylation degree of the chemically extracted chitin was higher than that of the other two types of chitin. These facts indicate that the enzymatic and fermentation processes cause less degradation, deacetylation, and damage to crystallinity of chitin molecules than the chemical process.
    23  Effect of Lysozyme Coatings on the Storage and Preservation of Fresh-cut “Hanfu” Apples
    FENG Xu-qiao FAN Lin-lin HAN Peng-xiang ZHAO Hong-xia LI Meng-meng DUAN Xiao-ming
    2014, 30(11):125-132.
    [Abstract](1223) [HTML](0) [PDF 828.90 K](854)
    Abstract:
    To study the effect of lysozyme coatings on the quality of fresh-cut “Hanfu” apples, the fresh-cut apples were soaked in 0.01%, 0.05%, and 0.08% lysozyme solution for 2 min and drained. They were then packaged in a polyethylene (PE) film with a thickness of 0.11 mm and stored in a refrigerator at 4 ℃. Physiochemical indicators related to maturity and aging were measured every two days during the storage period. The results showed that in a comparison with control, the lysozyme coating treatment more effectively maintained the quality of fresh-cut apples, partially inhibited increases in relative conductivity, malondialdehyde (MDA) content, polyphenol oxidase (PPO) activity, and total bacterial count, and significantly maintained the peroxidase activity. After cold storage at 4 ℃ for 8 d, the quality of lysozyme-treated fresh-cut apples was effectively maintained in terms of sensory evaluation, hardness, color, soluble solids, and ascorbic acid content. Of the three concentrations of lysozyme coatings examined, the 0.08% lysozyme solution showed the best preservation, followed by the 0.05% lysozyme solution, and the 0.01% lysozyme solution did not show apparent effects on the preservation of freshness.
    24  Menthol Adsorption and Desorption Performance of Aluminum Silicates Modified by Different Metal Ions
    CHEN Sen-lin YAO Jing-jing KONG Hao-hui XIAO Jing LI Zhong
    2014, 30(11):133-138.
    [Abstract](1114) [HTML](0) [PDF 569.73 K](735)
    Abstract:
    In this study, three types of aluminum silicate (AS), Fe3+/AS, Cu2+/AS, and Ag+/AS, were prepared using the immersion method to measure the adsorption of menthol by modified AS using a static adsorption method. Temperature programmed desorption (TPD) experiments were conducted to measure the desorption activation energy, Ed, of menthol by modified AS. The variation in menthol Ed was analyzed and discussed using hard and soft acid and base (HSAB) theory. The results indicated that the surface area of the modified AS was significantly increased compared with that of the original AS. The differences were 105.83%, 44.41%, and 32.69% for Fe3+/AS, Cu2+/AS, and Ag+/AS, respectively. The modified materials also had increased menthol adsorption, which followed the order: Fe3+/AS > Cu2+/AS > Ag+/AS > AS. In addition, these modifications changed the binding force between menthol and the AS surface. The Ed of menthol by modified AS was as follows: Ag+/AS > Cu2+/AS > Fe3+/AS. Compared to the original AS, the loading of Ag+ and Cu2+ enhanced the binding force between menthol and AS, whereas the loading of Fe3+ weakened it, which were consistent with the results predicted by HSAB.
    25  Construction of a Microemulsion System and the Antibacterial Performance of Peppermint Essential Oil
    CHEN Shuo XUMA Jun-kun ZHANG Yun-bin YANG Xiao-bo CHEN Lian-lian WANG Yi-fei
    2014, 30(11):139-144.
    [Abstract](1358) [HTML](0) [PDF 775.65 K](812)
    Abstract:
    The composition of peppermint essential oil was analyzed by gas chromatography-mass spectrometry (GC-MS). Using pseudo-ternary phase diagrams, the effect of various cosurfactants (ethanol, n-propanol, and n-butanol) on the phase behavior of the food-grade microemulsion system for peppermint essential oil using Tween 80-water was studied. In this study, the density, particle size, and pH value of the microemulsion, as well as its antimicrobial activity against Saccharomyces cerevisiae in NYDB medium and various drinks, were determined. The mechanism of the antimicrobial action of the microemulsion against Escherichia coli was primarily evaluated based on a cell membrane permeability assay. The results showed that the major components of peppermint essential oil were menthol (30.67%), and menthone (26.89%). Ethanol had the best solubilizing effect as a cosurfactant. The average particle sizes for two formulations (ME1, oil/ethanol = 1:1 and ME2, oil/ethanol = 1:3) were 66.57 nm and 55.63 nm, respectively. ME1 had higher antimicrobial activity and a better suppression effect against S. cerevisiae in clear apple juice. The minimum bactericidal concentration (MBC) was 64 μL/mL after cultures were grown at 28 ℃ for 48 h. When culturing with 5-fold diluted ME1 at 37 ℃ for 75 min, the leakage of E. coli nucleic acids was 51.68%. The microemulsion solution could kill E. coli by releasing nucleic acids and increasing the permeability of the E. coli cell membrane.
    26  Improvement of Enzymatic Hydrolysis of Polysaccharides in Rice Straw by Cholinium Alkanoate Ionic Liquid Pretreatment
    XU Jie REN Huan LI Ning ZONG Min-hua
    2014, 30(11):145-150.
    [Abstract](1423) [HTML](0) [PDF 524.46 K](822)
    Abstract:
    Pretreatment of lignocellulosic biomass is a key step in the production of biofuels by biorefinement. Recently, ionic liquid (IL) pretreatment of lignocellulosic biomass has attracted increasing interest. In this study, seven cholinium alkanoate ([Ch][Alk]) ILs were synthesized via a neutralization reaction, and were used for the pretreatment of rice straw. At 25 ℃, the viscosities of these ILs ranged from 74 to 488 cP. After the pretreatment of rice straw by these ILs, the efficiency of the enzymatic hydrolysis of polysaccharides in rice straw was improved significantly. In addition, the pretreatment performance of ILs depended on the chain length of the anion. Among the tested ILs, cholinium butyrate ([Ch][But]) proved to be the optimal solvent for the pretreatment of rice straw. Following the enzymatic hydrolysis of rice straw pretreated by [Ch][But] at 90 ℃ for 6 h, the yields of glucose and xylose reached 70.62% and 41.47%, respectively. This type of IL could selectively remove lignin and xylan from rice straw, while retaining the cellulose crystalline structure, which significantly improved the efficiency of the subsequent enzymatic hydrolysis.
    27  Optimization of Microwave Thawing of Pork Loin
    GAO Wen-hong LUO Man TANG Xiang-wei ZHANG Bin LI Yan ZENG Xin-an YU Xu-cong HAN Zhong SUN Da-wen
    2014, 30(11):151-155.
    [Abstract](1621) [HTML](0) [PDF 481.29 K](749)
    Abstract:
    Pork is an important meat in China, and storage via freezing is commonly used for long storage periods. Thus, thawing is required prior to processing; however, traditional thawing methods are time consuming and severely limit the production efficiency. Compared to traditional thawing methods, microwave thawing has outstanding advantages such as fast heating speeds as well as decreased time and energy consumption. In this paper, a household variable frequency microwave oven was used to thaw pork loin. Several thawing procedures were optimized and compared with the existing defrost mode of a microwave oven, and the gravy leakage rate, color, and texture characteristics were analyzed. Two optimized thawing procedures were found to provide a better thawing effect than the existing defrost mode of the microwave oven. The samples were completely thawed, exhibited a low gravy leakage rate, and maintained the color of fresh meat. The pork loin thawed using the optimized microwave thawing method exhibited a smaller temperature difference, better textural properties, and a shorter cooking time.
    28  Factors Influencing Microbial Oil Production from Food Waste Hydrolysates by Fermentation Using Saccharomyces cerevisiae As2.516
    SUN Shi-quan JIANG Chang-bo ZHOU Qian LIU Qing-zhi ZHAO Gang TAN Wan-chun NIE Xiao-bao WAN Jun-li YU Guan-long
    2014, 30(11):156-162.
    [Abstract](1063) [HTML](0) [PDF 742.85 K](805)
    Abstract:
    To increase microbial oil production by fermentation from food waste hydrolysates and to study the characteristics of fermentation production and the factors that influence it, Saccharomyces cerevisiae As2.516 was used as a test strain. Fermentation was conducted in a 1-L fermentor, and the fermentation conditions were as follows: initial amount of food waste hydrolysates, 90% (V/V); agitation speed, 180 r/min; aeration rate, 2.5 L/min; fermentation cycle, 10 d. The fermentation process was affected by the initial pH value, temperature, inoculation biomass, content of reducing sugar, and concentrations of inorganic salts and metal ions. The optimal culture conditions were as follows: pH value, 6; temperature, 30 ℃; inoculum size, 10%. Under these conditions, the maximum biomass, oil production, and product conversion rate were observed. On day 7 of the fermentation by S. cerevisiae, the highest oil yield was attained (4.26 g/L), and the biomass and oil production rate were 12.95 g/L and 32.9%, respectively. The gas chromatography analysis showed that C16 and C18 fatty acids were the main components of the fatty acids produced by fermentation, and unsaturated fatty acids accounted for 72.09%. Inorganic salts were abundant in the food waste hydrolysates; additional potassium, magnesium, manganese, and other ions could inhibit bacterial growth and affect oil production. Therefore, except for a trace amount of CuSO4?5H2O (1 × 10-4 g/L), it was not necessary to add additional inorganic salts. S. cerevisiae , which used food waste hydrolysates, was characterized as broad-spectrum and stress tolerant.
    29  Effect of pH on the Preparation and Gelation Characteristics of Tilapia Surimi in Alkaline Solubilization/Isoelectric Precipitation
    TIAN Jin-he WANG Yan-jie ZHU Zhi-wei ZENG Qing-xiao
    2014, 30(11):163-169.
    [Abstract](1027) [HTML](0) [PDF 579.88 K](706)
    Abstract:
    Tilapia surimi (TS) was prepared by alkaline solubilization/isoelectric precipitation (pH-shift) in the pH range 10.5~12.5. On increasing the pH values, the protein recovery from TS significantly increased. However, when the pH value was increased from 11.5 to 12.5, the protein recovery only increased by 11.56%, while the alkali consumption increased by 77.65%. The increased pH values sharply decreased the ATPase activity of solubilized proteins (51.80→0%), but increased the surface hydrophobicity, indicating that increasing the pH values promoted the unfolding of myosin. The electrophoresis results showed that increasing the pH values did not cause significant differences in the composition of soluble protein at the isoelectric point (pI). As the pH value increased, the whiteness of TS first increased from 75.40 to 80.50, and then decreased to 76.20; the breaking force of the TS gel also decreased after an initial increase (290.00 → 335.20 → 278.80 g). Both the aforementioned results suggested that treatment under extreme alkaline conditions (pH >12.0) produced a negative effect on the quality of the TS gel. The electrophoresis results of the TS gel suggested that no significant differences were found in the protein compositions of gel proteins prepared at different pH values. In addition, no significant cross-linking occurred in myosin during the formation of the TS gel, indicating that the activity of endogenous transglutaminase (TGase) was very low compared to that in traditional surimi. This was probably due to the separation between TGase and TS at the pI during the second centrifugation.
    30  Preparation and Characterization of Dietary Fiber-rich Powder from Pomelo Peel
    WANG Si-yuan LIU Xue-ming CHEN Zhi-yi YANG Chun-ying LIN Yao-sheng TANG Qiu-shi
    2014, 30(11):170-174.
    [Abstract](1405) [HTML](0) [PDF 535.10 K](1094)
    Abstract:
    To comprehensively use the resources of pomelos, a dietary fiber-rich powder from pomelo peel was prepared and evaluated for its physicochemical properties and aromatic compounds. The result showed that the powder from pomelo peels was rich in dietary fibers, where the percentages of soluble, insoluble, and total dietary fiber were 9.88%, 59.49%, and 70.38%, respectively. The water-holding capacity, oil-holding capacity, and swelling capacity increased with particle size reduction. The water-holding capacity, oil-holding capacity, and swelling capacity of the superfine powder were found to be 12.41 g/g, 4.47 g/g, and 21.0 mL/g, respectively. All of these values were better than those of commercial cellulose. The naringin content of the powder was approximately 1.64 mg/g. This ensured the powder was not bitter and had certain bio-active properties. In addition, the powder preserved the unique aroma and flavor of pomelo. These characteristics indicated that pomelo peel powder is a rich source of dietary fiber and has physicochemical properties that make it suitable as an additive in various food products, especially to enhance the quality of high-fiber and low-calorie foods.
    31  Effect of Heat-pressure Treatments on Mussel Quality and Shucking Efficiency
    LV Fei SHEN Jun-liang DING Yu-ting
    2014, 30(11):175-181.
    [Abstract](1015) [HTML](0) [PDF 730.37 K](706)
    Abstract:
    Heat-pressure steam treatments at various temperatures were used for short periods to shuck mussels, and the optimal shucking mechanism using heat-pressure treatment was determined. The results showed that mussel meat treated at 145 ℃ for 1 min had the highest quality among all of the treated meats. The results of SDS-PAGE showed that bands of actomyosin light chain and heavy chain disappeared after the heat-pressure treatment. Based on the infrared spectrum, the non-covalent bond of its protein tertiary structure ruptured, and the proteins of the adductor muscle in mussels showed gelation. Collagen in the connective tissue changed to gelatin at the glass transition temperature. The results of differential scanning calorimetry showed that the glass transition temperature was approximately 134 ℃. An electron microscope was used to observe the appearance of adductor muscles, and after heat-pressure treatment, there was clear breakage in the fibers of adductor muscles. The adductor protein was spherically scattered before the treatment, but when it was treated by the heat-pressure method, it displayed stronger gel combination than the adductor protein treated by boiling in water, and the functional proteins in the adductor muscle degenerated to a larger degree after treatment. Therefore, the heat-pressure treatments made the adductor muscle system of mussels lose micelle intensity, and achieved the purpose of separating the adductor muscle from the shell. In conclusion, heat-pressure treatment was more effective than the traditional method of boiling in reducing damage to the meat and improving the efficiency of shucking.
    32  Characterization of Fenghua Taro Starch
    QIAO Xing XU Feng TANG Yue-chang RONG Qun-jie SHAO Xing-feng WANG Hong-fei
    2014, 30(11):182-187.
    [Abstract](1399) [HTML](0) [PDF 747.50 K](854)
    Abstract:
    In this paper, the properties of Fenghua taro starch were examined. The starch was extracted by ammonia, and its composition, morphology, pasting temperature, thermal stability, and the molecular structure of its granules were investigated. An iodometric analysis showed that the amylose and amylopectin contents in taro starch were 10.23% and 89.77%, respectively. The amylose content was lower in Fenghua taro than in other starches. Scanning electron microscopy revealed that Fenghua taro starch granules had an irregular shape and angular morphology with a smooth surface. The laser particle size distribution analyzer showed that the average particle size of Fenghua taro starch was only 4.113 μm; this was relatively small compared with other starch particles. X-ray diffraction indicated that Fenghua taro starch had an A-type starch-crystal form. An infrared spectroscopy analysis indicated that Fenghua taro had primary and secondary alcoholic hydroxyl groups in an α-D-pyran ring. The gelatinization temperature of taro starch was 80~85 ℃, and it demonstrated a high thermal stability.
    33  Antioxidant Activities of Five Wild Edible Mushrooms Extracts From Qinghai
    LI Hong-ji JIAO Ying-chun FAN Lin-lin DONG Ya-chen CHEN Qi-he
    2014, 30(11):188-193.
    [Abstract](1348) [HTML](0) [PDF 545.30 K](808)
    Abstract:
    The aim of the present study was to comprehensively analyze the antioxidant activities and relevant components of five wild edible mushrooms: Agaricus bisporus (Lange) Sing., Coprinus comatus (Muell: Fr.) S. F. Gray., Coprinus atramentarius (Bull.) Fr., Collybia radicata (Relh. ex Fr.) Quel., and Inocybe calamistrata (Fr.) Gill. from Qinghai province. The two extracts of I. calamistrata showed the strongest 2,2-diphenyl-1-picryhydrazyl (DPPH) scavenging capacity, and the EC50 values of its methanolic crude extract (MCE) and ethanolic crude extract (ECE) were 0.90 ± 0.06 mg/mL and 0.85 ± 0.14 mg/mL, respectively. The MCE (0.45 ± 0.01 mg/mL) and ECE (0.78 ± 0.01 mg/mL) of C. radicata showed the strongest metal chelating capacity. Both the MCE (0.26 ± 0.002 mmol Trolox equivalents/g) and ECE (0.24 ± 0.003 mmol Trolox equivalents/g) of I. calamistrata possessed the highest micromolar Trolox equivalent per gram. The total content of phenols (active antioxidant components) was significantly higher in the MCE of C. atramentarius (19.04 ± 0.30 mg gallic acid equivalents/g) than of the other four extracts (P < 0.05). Similarly, the total phenolic content was significantly higher in the ECE of I. calamistrata than of the other four extracts (P < 0.05). All five edible mushrooms showed marked antioxidant capacities; I. calamistrata showed the strongest antioxidant activity.
    34  Chemical Composition Antioxidant and Antimicrobial Activities of Essential Oil from Cleome gynandra L. Seeds
    GENG Hong-mei ZHANG Yan MIAO Qing-feng QI Jin-long GUO Chun-hai
    2014, 30(11):194-199.
    [Abstract](1408) [HTML](0) [PDF 733.60 K](815)
    Abstract:
    In this study, the chemical composition, antioxidant and antimicrobial activities of the essential oil from Cleome gynandra L. seeds were investigated. The essential oil was extracted by hydrodistillation, and gas chromatography–mass spectrometry (GC-MS) was employed to analyze the chemical composition of the essential oil. Based on a comparison with the NIST 05 mass spectral library, 61 compounds were identified, and the main components were trans-9-octadecenoic acid (17.14%), n-hexadecanoic acid (9.91%), n-decanoic acid (8.62%), 1,13-tetradecadiene (7.89%), linoleic acid (5.32%), and heptanoic acid (4.21%). The essential oil from Cleome gynandra L. seeds had a good 2,2-diphenyl-1-picryhydrazyl (DPPH?) radical scavenging capacity. The antimicrobial activity of the oil was tested by the zone of inhibition test method. The essential oil showed very strong antimicrobial activity against Bacillus Megaterium, Bacillus subtilis, and Staphylococcus aureus, as well as a relatively strong antimicrobial activity against Escherichia coli. The study indicated that the essential oil from Cleome gynandra L. seeds had certain antioxidant and antimicrobial effects, which may be attributed to the chemical composition.
    35  Development and Optimization of the Brand Traceability Model of Vinegar Based on Near-infrared Spectroscopy
    GUAN Xiao GU Fang-qing LIU Jing YANG Yong-jian
    2014, 30(11):200-203.
    [Abstract](1077) [HTML](0) [PDF 448.23 K](705)
    Abstract:
    In this paper, near-infrared spectroscopy (NIRS) and pattern recognition technology were used to establish a brand traceability model for vinegar. NIR diffuse reflectance spectra of 160 vinegar samples from four different brands (SICHUAN BAONING vinegar, SHANXI EASTLAKE vinegar, HENGSHUN CHINKIANG vinegar, and CHINKIANG vinegar), were collected. After the spectral variables were compressed and eight abnormal sample data were removed using principal component analysis (PCA), 114 samples were randomly selected to form a training set for the construction of a traceability model, and the remaining 38 samples were used to form a test set for model validation. The effects of different pretreatment methods of the NIR spectra including multiplication signal correction (MSC), second derivative (SD), standard normal variate (SNV) etc., and different combinations of these methods on the traceability model were compared, and the effects of two modeling methods, partial least squares-discriminant analysis (PLS-DA) and soft independent modeling by class analogy (SIMCA)were examined. The results demonstrated that the correct recognition rates of the four different brands of vinegars could reach 100%, 100%, 91.7%, and 90%, respectively, when the spectral data were pretreated by MSC combined with SD and the model was developed using SIMCA. Therefore, the brand traceability of vinegar could be effectively achieved using NIR and a pattern recognition technique.
    36  Identification of Aroma-active Compounds in Soy Sauce by HS-SPME-GC-MS/O
    ZHAO Mou-ming CAI Yu FENG Yun-zi CUI Chun ZHAO Hai-feng
    2014, 30(11):204-212.
    [Abstract](1749) [HTML](0) [PDF 574.38 K](1005)
    Abstract:
    The aroma compositions of soy sauce were analyzed using headspace–solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry/olfactometry (GC-MS/O). A total of 109 volatile compounds were isolated and identified by GC-MS. Among them, alcohols were dominant (75.82%), followed by aldehydes, esters, acids, and furanones. Thirty-nine aroma-active compounds were identified by GC-MS/O. The key aroma-active compounds were 3-methylbutanal, 2-methylbutanal, 2-methylpropanal, 3-(methylthio) propanal, ethanol, 4-hydroxy-2-ethyl-5-methyl-3(2H)-furanone (HEMF), phenylacetaldehyde, 1-octen-3-ol, ethyl isobutyrate, 2-methylbutanol, 3-methylbutanol, dimethyl trisulfide, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), acetic acid, and 2-methoxyphenol. Their odor activity values (OAVs) were above 20, and their aroma intensity scores were more than 2.0. They contribute malty, baked potato-like, alcoholic, caramel-like, floral, mushroom-like, fruity, onion-like, and smoky flavors to the overall flavor of soy sauce, constituting the unique aroma of fermented soy sauce.
    37  Method to Determine the Triple-Helical β-glucan Content in Yeast
    WANG Zhi XIE Ting LI Dong-zhi PAN Ya-fang CHEN Xiong ZENG Yu-lei LI Biao
    2014, 30(11):213-217.
    [Abstract](1174) [HTML](0) [PDF 896.12 K](1063)
    Abstract:
    A quick method to determine the triple-helical β-glucan content in yeast using Congo red was established. The final concentration of dimethyl sulfoxide, which was the cosolvent for the yeast triple-helical β-glucan in the measuring system, was 2%, and the maximum absorption wavelength of the Cogon red system was 523 nm. The regression equation for the β-glucan mass (Y) and ΔOD523 value (x) was Y = 923.0x - 5.641, with a coefficient of determination (R2) of 0.996. The β-glucan mass and ΔOD demonstrated a strong linear relationship in the mass range of 35~199 μg of β-glucan. High accuracy was achieved using the Congo red method to measure yeast triple-helical β-glucan, with a relative standard deviation (RSD) of 2.21%. Using this method, the content of triple-helical β-glucan in yeast cell wall samples was 18.33%. The recovery rate varied from 97.68% to 103.90% (average, 99.60%), and the RSD of the recovery rate was 2.32%. The results indicated that the Congo red method used to determine the triple-helical β-glucan content had a high recovery rate and was suitable to measure yeast triple-helical β-glucan. It was a rapid, simple, and efficient determination method that could meet the demands of the industrial production process.
    38  Scavenging of DPPH Free Radicals by Plant Essential Oils in Gas and Liquid Phases
    CHAI Xiang-hua LIU Zhi-zhen WU Ke-gang
    2014, 30(11):218-222.
    [Abstract](1455) [HTML](0) [PDF 499.88 K](789)
    Abstract:
    The 2,2-diphenylpicrylhydrazyl (DPPH) free radical scavenging capacities of 14 types of essential oils in the gas and liquid phases were studied via spectrophotometry. The essential oils exhibited different DPPH free radical scavenging capacities. Under liquid and gas phase conditions, cinnamon, thyme, and clove essential oils exhibited the best scavenging capacities. Furthermore, cinnamon, thyme, and clove essential oils were used to prepare compounded essential oils, and the clove essential oil produced synergistic effects with the cinnamon and thyme oils. In particular, the compounded essential oil prepared from thyme and clove essential oils had good DPPH scavenging capacities in both the liquid and gas phases. When clove essential oil was compounded with thyme oil, the rate of DPPH radical scavenging in the gas phase at 28 ℃ was obviously higher than that at 19 ℃. Synergistic effects in the gas phase at 19 ℃ and 28 ℃, as well as in the liquid phase were appeared when clove essential oil accounted for 60% to 80%, 20% to 60%, and 40% to 80%, respectively. With different compounding ratios, the different anti-free radical active ingredients of the compound could produce synergistic effects.
    39  Analysis of Nε-(carboxymethyl) lysine Content in Oriental Foods
    BIAN Hua-wei LI Yu-ting LI Bing FU Quan-yi LI Lin
    2014, 30(11):223-228.
    [Abstract](1230) [HTML](0) [PDF 641.85 K](902)
    Abstract:
    In this study, high performance liquid chromatography-mass spectrometry (HPLC-MS) was used to establish a simple and stable method in detecting Nε-(carboxymethyl) lysine (CML) in foods; a quantitative determination of the CML content in four common -types of food in China (liquid foods, instant powders, seasonings, solid or semi-solid foods) was carried out. The optimal mobile phase composition for HPLC-MS was 30% methanol, and the analysis time and retention time for CML were 6 min and 3.7 ± 0.1 min, respectively. The CML levels in the foods were as follows: –bound form and free form in liquid foods were 2.72 ~ 5.18 ?g /mL food and 0.05 ~ 1.78 ?g /mL food; bound form and free form in instant powders were 0.84~63.00 ?g /g food and 0.73 ~ 14.37 ?g /g food; bound form and free form in seasonings–were 0.86 ~ 42.80 ?g /mL(g) food and 7.69 ~ 821.02 ?g /mL(g) food; bound form and free form in solid or semi-solid foods–were 0.63 ~ 61.22 ?g /g food and 0.24 ~ 9.29 ?g /g food. The highest CML content was found in dark soy sauce (bound form: 0.97 ± 0.11 ?g /mL food; free form: 796.35 ± 24.67 ?g /mL food), and the lowest CML content was observed in quick-frozen steamed buns (bound form: 0.66 ± 0.03 ?g/g food, free form: 0.42 ± 0.02 ?g /g food).
    40  Rapid Detection of Listeria monocytogenes Using a Fluorescence Immunochromatographic Assay Combined with Immunomagnetic Bead Separation
    ZHANG Sai HE Xiao-wei LIU Xiao-yun PENG Yun-ping LI Wen-mei
    2014, 30(11):229-234.
    [Abstract](1624) [HTML](0) [PDF 669.32 K](1053)
    Abstract:
    In order to establish a simple, rapid, sensitive, and specific method to detect Listeria monocytogenes, in this study, immunomagnetic beads were prepared by coupling anti-L. monocytogenes monoclonal antibody with magnetic beads. The fluorescence immunochromatographic strips were composed of anti-L. monocytogenes polyclonal antibody and mouse IgG marked by fluorescent microspheres as the detection antibody, anti-L. monocytogenes polyclonal antibody as the test line, and the goat anti-mouse IgG secondary antibody as the control line. Immunomagnetic separation was combined with a fluorescence immunochromatographic assay, and this method was applied to rapidly detect L. monocytogenes. The results showed that the detection limit of fluorescence immunochromatographic strips for pure cultures was 4 × 105 CFU/mL. For the joint detection method using samples concentrated 10- and 100-fold, the detection limits of pure culture samples were 4 × 104 CFU/mL and 1 × 104 CFU/mL, respectively. The joint detection method showed good specificity, and no cross-reactivity of the 10 strains kept in the laboratory was observed. The detection limit of artificially contaminated samples was also 1 × 104 CFU/mL and was not reduced compared with pure cultures. This method is of great value for rapid on-site detection of L. monocytogenes in food products.
    41  Determination of Four Sudan Dyes in Chili Products Using Ultra-high Performance Liquid Chromatography-tandem Quadrupole Mass Spectrometry
    HAO Jia- yong CHEN Xia LI Hong-min FANG Ting-ting
    2014, 30(11):235-239.
    [Abstract](1332) [HTML](0) [PDF 508.53 K](710)
    Abstract:
    Using a basic alumina column, which has stronger reaction with sudan dye, as a solid phase extraction (SPE) column, an ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry (UPLC-MS) method was developed for the determination of four sudan dyes in chili products. The extraction solvent, washing liquid for the SPE column, eluent solvent, and liquid chromatography conditions were optimized separately. The sudans were extracted by using 10 mL mixed acetonitrile and dichloromethane solution (3:2, V/V) was used to extract the Ten milliliters of n-hexane and 4 mL mixed ethyl acetate and n-hexane (1:1, V/V) were used as washing liquids. Twelve milliliters of a mixed 5% acidified methanol and ethyl acetate solution (1:1, V/V) was used for elution. An ACQUITY BEH C18 chromatography column (2.1 × 100 mm, 1.7 μm) was used with mobile phases composed of 0.3% formic acid acetonitrile solution and 0.3 % formic acid water solution. The substrate spiked standard curves of the four sudan dyes had good linear correlations in the range 10~500 μg/L, with all correlation coefficients above 0.995. The limits of detection (LOD) of the four sudan dyes were 5.0, 5.0, 4.0, and 4.0 μg/kg. The recovery experiment, performed by adding samples, was carried out with blank samples at concentrations between 10-150 μg/kg. The average recovery ratio was 71.4%~104.2%, and the relative standard deviation (RSD, n = 6) was 4.6%~8.9%. Three hundred and eighty samples were examined using this method, and 36 samples were positive for sudans, and the component was primarily sudan IV.
    42  Analysis of the Fatty Acids and Volatile Flavor Compounds in Oxidized Sheep Bone Oil
    LIU Jin-kai GAO Yuan WANG Zhen-yu NI Na ZHANG De-quan AI Qi-jun
    2014, 30(11):240-245.
    [Abstract](1249) [HTML](0) [PDF 809.69 K](788)
    Abstract:
    The fatty acid composition and volatile flavor compounds in oxidized and non-oxidized sheep bone oil were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The relative odor activity value (ROAV) was used to evaluate the contributions of volatile flavor compounds to the overall flavor of sheep bone oil. In addition, the cluster analysis (CA) method was also employed to identify the characteristic volatile flavor compounds in oxidized sheep bone oil. Seven fatty acids were identified in sheep bone oil, including three saturated fatty acids and four unsaturated fatty acids, and oxidation led to a significantly lower linoleic acid content in oxidized sheep bone oil (P < 0.05) than in non-oxidized sheep bone oil. Trans-2-enal and trans ,trans-2,4-dienal were the major volatile flavor compounds in sheep bone oil. There were 22 additional volatile flavor compounds found in sheep bone oil after oxidation. The total peak area of the flavor compounds in oxidized sheep bone oil was more than four times larger than that of non-oxidized sheep bone oil. The linoleic acid oxidation product trans-2-nonenal was the most critical volatile flavor compound in oxidized sheep bone oil. The oxidization process could increase the content of numerous flavor compounds in sheep bone oil and improve the fat flavor.
    43  Simultaneous Determination of Sildenafil, Vardenafil, and Tadalafil in Health Foods by Ultra-performance Liquid Chromatography Tandem Mass Spectrometry
    LI Jin-qing QI Yan LI Ming-hao LONG Shun-rong QIU Qi-dong
    2014, 30(11):246-250.
    [Abstract](1247) [HTML](0) [PDF 582.00 K](825)
    Abstract:
    A method was established for the determination of vardenafil, sildenafil, and tadalafil in health foods using solid-phase extraction–ultra-performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS). The sample was extracted by methanol or hydrochloric acid, and then purified by a hydrophilic/lipophilic balanced (HLB) SPE column. The target compounds were separated on a reversed phase column using a solution of acetonitrile and 0.1 % formic acid in water as the mobile phase, and then detected by positive electrospray ionization under multiple reaction monitoring (MRM) mode. Good linearity of the calibration curves was achieved for three target compounds in the range of 10 ~200 μg/L, with correlation coefficients (r2) greater than 0.99. The average recoveries of the blank matrix sample were all more than 75%, and the relative standard deviations (RSDs) were less than 8%. The limits of detection (LOD) for vardenafil, sildenafil, and tadalafil in the capsule form were 10 μg/kg, 10 μg/kg, and 20 μg/kg, respectively. The limits of quantitation (LOQs) for vardenafil, sildenafil, and tadalafil in the capsule form were 40 μg/kg, 40 μg/kg, and 80 μg/kg, respectively. For oral samples, the LODs were 3 μg/L, 3 μg/L, and 6 μg/L, respectively; the LOQs were 10 μg/L, 10 μg/L, and 20 μg/L, respectively. The sample matrix effects were also studied, which had a suppressive effect on the response of vardenafil, sildenafil, and tadalafil, and the most significant suppressive effect was found on vardenafil.
    44  An Improved Method for Natamycin Titer Measurement and the Rapid Determination of Its Content
    LEI De-zhu LI Qing-rong HUANG Yong-jian
    2014, 30(11):251-255.
    [Abstract](1433) [HTML](0) [PDF 598.08 K](831)
    Abstract:
    To find an effective method for the rapid detection of natamycin and an accurate analysis of biological potency during solid-phase fermentation, three methods including high-performance liquid chromatography (HPLC), ultraviolet spectroscopy, and the cylinder-plate method were used to determine the natamycin content in the product of a batch of Streptomyces glvosporue during solid-state fermentation. The natamycin content in the solid fermentation product determined by HPLC and ultraviolet spectroscopy was 2351.52 mg/L and 2280.16 mg/L, respectively. The former showed good accuracy and reproducibility, while the accuracy of latter was 96.97% of the former (assigning the accuracy of HPLC method as 100%) and proved to be applicable for the rapid determination of natamycin content during solid fermentation. The average potency of natamycin determined by the cylinder-plate method was 1979.87 mg/L, and using an improved cylinder-plate method was 1990.29 mg/L when n-hexane was used in combination with methanol as the solvent. The accuracy of HPLC determined result increased from 84.20% to 84.64% using the cylinder-plate method (assigning the accuracy of HPLC method as 100%). The results indicated that n-hexane could effectively control the volatility of methanol, and improved the accuracy and concentration range for measurements using the cylinder-plate method, without having an antimicrobial effect.
    45  Research Progress on Arsenic Species in Seafood and Their Metabolic Mechanisms
    WANG Ying CHEN Miao-miao TAN Ting-ting LI Yi TENG Jiu-wei
    2014, 30(11):256-265.
    [Abstract](2077) [HTML](0) [PDF 640.89 K](1071)
    Abstract:
    Arsenic in seafood enters the human body by a process of food chain enrichment. The arsenic species detected in seafood include arsenide (As(III)), arsenate (As(V)), arsenocholine (AsC), arsenobetaine (AsB), arsenosugars, and arsenolipids. Arsenic species are metabolized through various pathways and result in different metabolites and toxicities. High-performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS) was used to analyze arsenic species in seafood. The metabolites of AsC, a type of organic arsenic, were mainly AsB and arsenolipids. AsB could be excreted through urine. Each arsenolipid has different metabolites. More than 12 arsenic species were found as metabolites of arsenosugars, of which dimethylarsinic acid (DMA(V)) was the most common. The pentavalent methylated DMA(V), and trivalent methylated DMA(III) were the final metabolites of inorganic arsenic species. Cooking methods affect the concentration of total arsenic and the form of arsenic. Some methods can result in increased toxicity. Therefore, to prevent excessive intake of toxic forms of arsenic, effective measures including reducing seafood intake, increasing intervals between seafood meals, daily intake of specific nutrients, and choosing optimal cooking methods, should be recommended to consumers.

    Editor in chief:李琳

    Inauguration:现代食品科技

    International standard number:ISSN 1673-9078

    Unified domestic issue:CN 44-1620/TS

    Domestic postal code:46-349

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