Volume 31,Issue 9,2015 Table of Contents

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  • 1  PCR-DGGE Based Analysis of the Impact of Resistant Starch on Gut Microbiota in HFA Mice
    LIAO Zhen-lin ZENG Ben-hua LI Rui ZHONG Qing-ping WANG Li WEI Hong FANG Xiang
    2015, 31(9):1-6. DOI: 10.13982/j.mfst.1673-9078.2015.9.001
    [Abstract](1132) [HTML](0) [PDF 795.05 K](1476)
    Abstract:
    The effects of banana resistant starch on the alteration of gut microbiota in Human Flora-Associated (HFA) mouse model fed on a high fat diet, were investigated. Thirty HFA mice were randomly assigned into three groups (n = 10/group), which were fed a normal diet, high fat diet, and high fat diet + resistant starch, respectively. DNA was extracted from the fresh feces of all mice, which were collected prior to the beginning of the experiment (0th week) and after eight weeks (8th week). The primer-specific amplification products using the V6-V8 region of 16S rDNA were compared and differences in the profile of gut microbiota among the resistant starch, high fat diet, and normal diet groups were tested using polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE). Richness, diversity index, and evenness value of gut microbiota were not significantly different between the three groups at 0th week (p > 0.05). Flora similarity between the mice and the human feces donor was 36%, but the flora similarity between the three mice groups ranged from 60% to 93%. Principal component analysis (PCA) showed that the data points of all three groups were clustered together, indicating no difference between the three groups before intervention and that the HFA mouse model was suitable for the investigation of resistant starch on gut microbiota. Richness and diversity index values of gut microbiota between the resistant starch group and the other two groups 8 weeks after the dietary intervention were significantly different (p < 0.01). PCA of the mouse intestinal bacterial community showed that data points were distributed within different zones after the dietary interventions. In conclusion, resistant starch has a huge influence on the gut bacterial community structure of HFA mice fed on a high fat diet.
    2  Structural Characteristics and Mechanisms Involved in the Immune Activity of Jellyfish Glycoprotein JGP-III2
    REN Guo-yan SHAO Zhen GUO Jin-ying CAO Li FAN Jin-ling CUI Guo-ting XIAO Feng ZHANG Fan LIU Zhi-long LIANG Wang-chun
    2015, 31(9):7-13. DOI: 10.13982/j.mfst.1673-9078.2015.9.002
    [Abstract](828) [HTML](0) [PDF 962.65 K](1160)
    Abstract:
    A new glycoprotein JGP-III2 was obtained from jellyfish. JGP-III2 is composed of 11.87% carbohydrate and 87.74% protein, which presents a molecular weight of 39.5 kDa. JGP-III2 is composed of eight types of monosaccharides: mannose, 2-amino-D-glucose, galactosamine, lactose, glucose, galactose, xylose, and fucose in a ratio of 6.88:5.13:5.19:70.78:1.47:2.09:6.59:1.85. The total amino acid content in JGP-III2 is 85.95%. Glycine is the major amino acid, followed by valine and glutamic acid. JGP-III2 presents N- and O-glycosidic bonds and is homologous to protein (gi|156215071) from Nematostella vectensis. The immune activity and immune mechanism of JGP-III2 were investigated using an immunocompromised mouse model. Compared with the control group, JGP-III2 significantly improved the spleen index, the thymus index, the phagocytic ability of the macrophages, serum hemolysin levels, and the number of antibody producing cells and delayed the allergic reaction in immunocompromised mice. The results showed that JGP-III2 could enhance the immune ability of these mice. Furthermore, JGP-III2 could promote the mRNA expression of Th1-type cytokines, inhibit the mRNA expression of Th2-type cytokines, and restore the “Th1/Th2 shift” found in the control group. JGP-III2 is considered to enhance the immune activity by regulating the Th1/Th2 balance.
    3  Effect of Bitter Melon Saponins with Buckwheat Flavones or Pumpkin Polysaccharides on Glucose and Lipid Metabolism in Type-2 Diabetic Rats
    LI Yi-teng WANG Xiao-wen HE Qing-feng YOU Ling-ling XIAO Ping CUI Yan FENG Chao LIU Jin-fu
    2015, 31(9):14-19. DOI: 10.13982/j.mfst.1673-9078.2015.9.003
    [Abstract](955) [HTML](0) [PDF 752.71 K](1233)
    Abstract:
    Using principal component analysis (PCA), the improvement in glucose and lipid metabolism of type-2 diabetic rats was investigated with the use of bitter melon (Momordica charantia) saponins in combination with buckwheat (Fagopyrum tataricum) flavones (BSBF) or pumpkin (Cucurbita moschata) polysaccharide (BSPP). A rat model of type 2 diabetes mellitus was established and the three extracts were administered by gavage. Subsequently, body weights as well as food and water intake in all groups were compared. The results showed that individual extracts or combinations significantly ameliorated the symptoms of type 2 diabetes. Furthermore, the indicators for glucose and lipid metabolism were screened via the PCA method and single-dimensional statistics were combined in the analysis. Combined saponins (BS) and polysaccharide (PP) signi?cantly improved levels of alanine aminotransferase (ALT), adiponectin (ADPN), and creatinine (CRE) compared with that of individual extracts (p < 0.05). The effect of this combination on free fatty acids and tumor necrosis factor was improved compared with the BS group, while the effect on ALT was better than that on the PP group. The combination of BS and flavones resulted in improvement of ALT, CRE, ADPN, and insulin compared with individual extracts, BS group, as well as flavone group. In summary, the results of this study show that the combined effect of active ingredients produces more improvement of glucose and lipid metabolism in type-2 diabetic rats.
    4  Effects of Squid Lecithin on Brain Function of Mice with Scopolamine-induced Dementia
    ZHOU Miao-miao SUN Shu-hong SONG Shan-shan XU Jie WANG Yu-ming XUE Chang-hu LI Zhao-jie
    2015, 31(9):20-25. DOI: 10.13982/j.mfst.1673-9078.2015.9.004
    [Abstract](990) [HTML](0) [PDF 853.11 K](1410)
    Abstract:
    The effects of squid lecithin (SL) and egg lecithin (EL) on the brain function of mice with dementia induced by scopolamine were comparatively investigated. Male BALB/c mice were randomly divided into 4 groups: control, model, SL (3.3% squid lecithin), and EL groups (1.5% egg lecithin). Mice models were established by intraperitoneal injection of scopolamine a week after feeding, except for the control group mice, which were treated with saline, followed by the behavioral test. Acetylcholinesterase (TchE), superoxide dismutase (SOD), and monoamine oxidase (MAO) activities in the cortex, white matter, and hippocampus, as well as malondialdehyde (MDA) content in the brain were determined. In the Morris water maze test, the latency of mice fed SL significantly reduced, while the number of platform crossings and the time spent in the target quadrant increased significantly; in general, the behavioral improvement of the group fed SL was better than that of the EL group. The biochemical tests of brain tissues also showed similar trends. SL could significantly reduce the TchE activity and MDA level in various brain tissues and MAO activity in white matter, as well as significantly improve the SOD activity in the cortex, hippocampus, and white matter. The results were better than those of the EL group. In summary, SL could improve the learning and memory abilities of mice with dementia by affecting central cholinergic nervous system and antioxidant system in the brain.
    5  Microstructure and Physical Performance of Genipin Crosslinked Gelatin/Lysozyme Films with Controlled-release Behavior
    ZHANG Shou-yu HU Er-kun YIN Shou-wei
    2015, 31(9):26-30. DOI: 10.13982/j.mfst.1673-9078.2015.9.005
    [Abstract](981) [HTML](0) [PDF 757.14 K](1326)
    Abstract:
    Hydrophilic gelatin films are of weak controlled release behavior for antimicrobials, especially at high humidity. In order to solve this problem, novel gelatin films with controlled release of lysozyme were fabricated via the crosslink by a naturally biochemical crosslinker (genipin). Tensile property, water vapor permeability (WVP), swelling and thermal properties of composite antimicrobial films were evaluated, and their surface morphologies were visualized by AFM. The possible structure-function relationship of the films was discussed. Upon increasing genipin concentrations, mechanical resistance and stiffness of the films were enhanced, and the tensile strength (TS) gradually increased from 9.72 to 18.80 MPa. Both water stability and thermal stability were improved by genipin crosslinking, and the swelling decreased from 1316% (control) to ~ 200%. Surface roughness of the films depended on the genipin concentrations used, the surface of composite films were smooth at concentrations of 0~1.0%, with low Rq and Ra. In contrast, irregular projections were clearly visualized on the surface of the films crosslinked by 2.0% genipin. In brief, mild genipin crosslink facilitated to form ordered three-dimensional network structure in film matrix while agglomerate structure was observed in the case of high genipin concentrations (2.0%). Furthermore, the presence of genipin, especially at high concentrations may weaken the interaction between gelatin molecules, impairing the water vapor barrier capability of the films.
    6  Molecular Typing of Salmonella Species Isolated from Beef in a Processing Plant with Fluorescence Amplified Fragment Length Polymorphism
    DONG Peng-cheng ZHANG Yi-min MAO Yan-wei LIANG Rong-rong NIU Le-bao LI Yu-lin ZHU Li-xian LUO Xin
    2015, 31(9):31-37. DOI: 10.13982/j.mfst.1673-9078.2015.9.006
    [Abstract](902) [HTML](0) [PDF 927.13 K](1079)
    Abstract:
    Fluorescence amplified fragment length polymorphism (FAFLP) analysis was used for molecular typing of 83 Salmonella strains in seven different serotypes isolated from seven different processing points, in order to investigate the contamination of Salmonella before and during slaughtering, to specify the main steps involving the contamination of Salmonella within the processing plant, and to provide data for the control of Salmonella infection within the plant.. The results showed that the 83 strains were divided into three groups at the similarity of 0.83, and a certain correlation was observed between the FAFLP gene types and the serotypes. When source tracing was conducted at the similarity of 0.86, FAFLP exhibited a higher sensitivity than traditional serotyping, and the result was consistent with the previous data on the prevalence rate obtained from a previous epidemiological investigation. The source tracing analysis showed a serious cross-contamination of Salmonella among animals, which occurred through the feces and fur. Furthermore, some Salmonella strains isolated from the feces and fur crossed the protective barrier of the processing plants and infected the downstream carcasses. Hence, processing plants should pay more attention to standardized pre-slaughter management strategies to avoid the cross-contamination problems during in-plant interventions. Additionally, in-plant interventions should include extra critical control points to reduce the risk of Salmonella infection.
    7  Anti-lipoperoxidation Effects of Sargassum Fucoidans in Hyperlipidemic Mice
    CHEN Su-hua WANG Wei-min CAI Lu ZHONG Si-yan ZHONG Sai-yi XIE En-yi
    2015, 31(9):38-44. DOI: 10.13982/j.mfst.1673-9078.2015.9.007
    [Abstract](973) [HTML](0) [PDF 591.45 K](1132)
    Abstract:
    The effects of four fractions of Sargassum fucoidans (SF) with medium and low molecular weights (MMWF1, MMWF2, LMWF1, and LMWF2) on lipid peroxidation indexes in hyperlipidemic mice were investigated in this study. A mouse model of hyperlipidemia was established. The lipid peroxidation indexes, malondialdehyde (MDA) content, and activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and glutathione peroxidase (GSH-PX) in the serum and liver were measured. The results showed that all four SF fractions increased the activities of CAT, GSH-PX, SOD, and POD and decreased the MDA content in the serum and liver at a significant level (p < 0.01) with the high-dose treatments. All four fractions of SF improved anti-oxidation capacity, recovered the balance of the oxidation system, decreased lipid peroxidation, maintained the activity of enzymes related to lipid metabolism, and improved and recovered normal lipid metabolism in hyperlipidemic mice. The anti-lipoperoxidation capacities of the four SF fractions were as follows: MMWF2 > MMWF1 > LMWF2 > LMWF1. The anti-lipoperoxidation capacity of MMWF was greater than that of LMWF, which indicated that among similar fucoidans, increased sulfate content resulted in higher antioxidant capacity.
    8  Protective Effect of Total Triterpenoids in Apple Pomace on CCl4-induced Liver Injury in Mice
    ZHANG Shuang REN Ya-mei LIU Chun-li MA Ting CHEN Xiang-jie REN Xiao-lin
    2015, 31(9):45-50. DOI: 10.13982/j.mfst.1673-9078.2015.9.008
    [Abstract](988) [HTML](0) [PDF 797.90 K](1190)
    Abstract:
    The in vitro antioxidant activity and in vivo protective effect of total triterpenoids in Fuji apple pomace (TTAP) on CCl4-induced acute liver injury in mice wereinvestigated. TTAP was isolated and purified by ultrasonic-assisted extraction and macroporous resin column chromatography, respectively. Using ascorbic acid (Vc) as control, the 2,2-diphenyl-1-picryl-hydrazyl (DPPH?); 2,2’-azino-di-(3- ethylbenzthiazoline-6-sulphonic acid (ABTS+?), and hydroxyl (?OH) scavenging abilities of TTAP were measured to evaluate its antioxidant activity. A CCl4-induced acute liver injury mouse model was established. Subsequently, aspartate transaminase (ALT) and aspartate transaminase (AST) activities in serum as well as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activity, malondialdehyde (MDA) content and interleukin-6 (IL-6) content in mouse liver homogenates were measured by biochemical assays. TTAP showed lesser extent of in vitro antioxidant ability compared with Vc. The in vivo study showed that ALT and AST activities in serum declined significantly and the largest decline was more than 48% when compared with the model group. Additionally, SOD and GSH-Px activities in liver homogenates significantly increased, with the highest increase of 69%. MDA and IL-6 contents declined significantly, with the largest decline of 43%. TTAP thus exhibited significant protective effect on CCl4-induced liver injury mouse model and the underlying mechanism may be related to in vivo free-radical scavenging and regulation of serum enzymes, as well as activity and content of antioxidant enzymes.
    9  Effects of Lactobacillus acidophilus S-layer Protein on Adhesion to Intestinal Cells and Macrophage Proliferation
    YIN Qiong-fang PAN Dao-dong GUO Yu-xing ZENG Xiao-qun SUN Yang-ying CAO Jin-xuan
    2015, 31(9):51-55. DOI: 10.13982/j.mfst.1673-9078.2015.9.009
    [Abstract](952) [HTML](0) [PDF 714.86 K](1213)
    Abstract:
    To investigate the autoaggregation and adherence rate to HT-29 cells of Lactobacillus acidophilus ATCC4356 with or without S-layer protein as well as the influence of S-layer protein on the proliferation and lysosomal secretion of macrophages, S-layer protein of L. acidophilus ATCC 4356 was extracted by 4 M lithium chloride, followed by further purification using centrifugation, dialysis, and microfiltration. The molecular weight was then confirmed by SDS-PAGE. Autoaggregation rate of L. acidophilus at 37°C was measured by using a microplate reader during the incubation (0 to 5.5 h). Adhesion of L. acidophilus ATCC4356 to HT-29 cells was observed by light microscopy. After incubation of S-layer proteins with RAW 264.7 macrophages for 2 h, proliferation and changes in lysosomal secretion were evaluated by MTS and Lyso-Tracker Red, respectively. The results showed that the protein extracted was S-layer protein from L. acidophilus ATCC 4356 with a molecular weight of about 46 ku. L. acidophilus ATCC4356 autoaggregation rate and adhesion to HT-29 cells were reduced when the S-layer protein was removed. L. acidophilus ATCC 4356 autoaggregation rate increased as the incubation time was extended. S-layer protein could also promote macrophage proliferation and lysosomal secretion.
    10  Effects of Astaxanthin on Caenorhabditis elegans Aging and Its Underlying Mechanisms
    LUO Qing-xin LIU Xiao-juan CAO Yong HE Li-ping ZHAO Li-chao LIU Xin
    2015, 31(9):56-60. DOI: 10.13982/j.mfst.1673-9078.2015.9.010
    [Abstract](1199) [HTML](0) [PDF 640.01 K](1585)
    Abstract:
    The effects and related mechanism of astaxanthin (Ax) on aging and normal physiological functions of Caenorhabditis elegans were studied. The nematodes were divided into normal control group and Ax groups (0.08 mM, 0.16 mM, 0.40 mM, and 0.80 mM). The lifespan and related physiological indexes (reproductive capacity, pumping rate, and locomotion assay) of N2 wild-type nematodes were observed to evaluate the impact of Ax on the aging process of nematodes and to determine the optimal dose of Ax. To explore the mechanisms underlying the effects of Ax on the insulin/insulin-like growth factor (Ins/IGF-1) signaling pathway in delaying the aging process, wild-type N2, daf-16 null, and age-1 null mutant strains, treated with the optimal dose of Ax, were tested. The results revealed that the lifespan of the Ax group was longer than that of the control group (P < 0.05) and 0.16 mM of Ax was the optimal concentration. The mean lifespan of the nematodes reached 26.03 d, with a significant increase of 31.68%. Ax treatment enhanced the mobility of the nematodes at 10 d and 15 d, but did not cause any significant effects in reproductive capacity or pharyngeal pumping rate. A concentration of 0.16 mM Ax significantly extended the lifespan of age-1 null mutant strains, but did not have a significant effect on that of daf-16 null mutants. These findings suggest that Ax led to significant lifespan extension via the Ins/IGF-1 signaling pathway during normal aging, which could be dependent on daf-16.
    11  Immunomodulatory Effects of Bacillus natto Glycopeptides on RAW264.7 Macrophages
    CAO Jing-wen HUANG Zhan-wang WU Shao-fu WU Gao-feng
    2015, 31(9):61-67. DOI: 10.13982/j.mfst.1673-9078.2015.9.011
    [Abstract](1163) [HTML](0) [PDF 1.00 M](1412)
    Abstract:
    The immunomodulatory effects of Bacillus natto glycopeptides (BNGP) on normal and lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages were investigated in the present study. After treatment with different concentrations of BNGP or combinations of LPS and BNGP in different concentrations, the proliferation of macrophages was detected by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, the phagocytic activity was detected by neutral red phagocytosis experiments, and the content of nitric oxide (NO) in the cell culture supernatants was detected by the Griess reaction. The production of cytokines (IL-1β, TNF-α) and pro-inflammatory mediator (PGE2) in culture supernatants were measured using an enzyme-linked immunosorbent assay (ELISA), and the expression levels of iNOS and COX-2 were detected using western blotting. The results showed that at concentrations of 62.5–500 μg/mL, BNGP enhanced the metabolic activity of macrophage RAW264.7 in the normal steady state, increased the secretions of NO, IL-1β, TNF-α, and PGE2, and improved the expression levels of iNOS and COX-2; at high concentrations (>125 μg/mL), it enhanced the phagocytic capacity of macrophages. For the LPS-stimulated macrophages, BNGP inhibited the secretions of IL-1β, TNF-α, and PGE2 at concentrations of 62.5–500 μg/mL, inhibited the production of NO and the expression of iNOS at concentrations of 500 μg/mL, and downregulated the expression of COX-2 at high concentrations (>125 μg/mL).
    12  Structure and Gel Characterization of Pectic Polysaccharide from Nicandra physaloides (L.) Gaertn Seeds
    NIU Qing-feng WANG Bin LI Tao JIN Xin CHEN Yin
    2015, 31(9):68-73. DOI: 10.13982/j.mfst.1673-9078.2015.9.012
    [Abstract](1764) [HTML](0) [PDF 813.99 K](1320)
    Abstract:
    A pectic polysaccharide (named NPG) was isolated from the seed of Nicandra physaloides (L.) Gaertn by hot water extraction. Its structural characteristics were investigated and elucidated by HPLC, HPGPC, IR, and 1D 13C-NMR, while gelatinization properties were studied by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The results indicated that NPG had a molecular weight of 1.6×106 u and was mainly composed of galacturonic acid, glucose, galactose, and rhamnose at a molar ratio of 12:4:1:1. 13C-NMR spectrum analysis showed that NPG had a backbone composed of 1→4 linked galacturonic acid. NPG presented a regular spherical structure. In the presence of calcium ions, the spherical molecules of NPG linked end-to-end, forming a chain structure with branching nodes. The chain structure cross-linked further with an increase in calcium ions and integrated to form a network of fibrous structures. Subsequently, the fibrous structures were accumulated and dehydrated, thereby forming the gel.
    13  Oxidative Damage and in vivo Antioxidant Responses during UV-induced Autolysis in the Sea Cucumber, Stichopus japonicus
    XI Qian DONG Xiu-fang LI Nan FU Hui ZHANG Jing-yu QI Hang
    2015, 31(9):74-80. DOI: 10.13982/j.mfst.1673-9078.2015.9.013
    [Abstract](1032) [HTML](0) [PDF 792.00 K](1294)
    Abstract:
    Live sea cucumbers (Stichopus japonicus) were irradiated under ultraviolet (UV) radiation (1.5 W/m2) for different times. Cathepsin L (CL), acetylcholinesterase (AChE), caspase-3, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), acid glutathione (GSH), protein carbonyl, and hydrogen peroxide (H2O2) contents in the intestinal tissue and body wall of the sea cucumber were analyzed. The results showed that after 6-h UV irradiation, the CL activities, H2O2 contents, and caspase-3 activities in the body wall and intestinal tissue increased by 69.27 and 52.37%, 2.44- and 3.57-fold, and 4.09- and 2.81-fold, respectively. The AChE decreased by 55.70 and 36.16%, respectively and the protein carbonyl contents in both body wall and intestinal tissue was 1.30-fold that of the control group. With increasing UV radiation time, SOD, CAT, and GPx activities in the body wall and intestinal tissue decreased by 38.79 and 24.70%, 44.27 and 36.18%, and 79.54 and 33.79%, respectively. The GSH contents increased by 75.31 and 66.71%, respectively. The results indicate that oxidative damage and apoptosis occurred with autolysis in S. japonicus under UV irradiation. ROS and related oxidation products played a fundamental role in the UV-induced autolysis pathway. This finding may improve the understanding of autolysis in S. japonicus.
    14  Multilocus Sequence Typing and Determining the Characteristics of Streptococcus thermophilus
    TIAN Hui HUO Gui-cheng LIU Fei CHEN Ling-ling GU Chun-tao
    2015, 31(9):81-86. DOI: 10.13982/j.mfst.1673-9078.2015.9.014
    [Abstract](825) [HTML](0) [PDF 729.75 K](1084)
    Abstract:
    The aim of this study was to investigate the feasibility of multilocus sequence typing for Streptococcus thermophilus. Multilocus sequence typing technology was used to genotype eight in-house S. thermophilus strains and an additional six S. thermophilus strains for which whole-genome sequences have been published. The homology of these strains was also analyzed. Phenotypic characteristics including acid production rate and protein hydrolysis were determined for the eight in-house S. thermophilus strains. The results showed that these eight strains belonged to four genotypes, whereas the other six strains belonged to five genotypes. The phylogenetic relationships among all strains varied. Among them, ND03, MN-ZLW-002, and 0#, isolated from China, had relatively high homology; 09086, 09087, and 09088, isolated from Xinjiang yogurt, had relatively high homology; 09067, 09078, and 09079, isolated from Inner Mongolia yogurt, and JIM8232, isolated from French yogurt, had relatively high homology; and s4, isolated from a French fermentation agent, and CNRZ1066, isolated from French yogurt, had relatively high homology. The acid production rates and protein hydrolysis of the eight in-house strains were strain specific, and the phenotypic properties were largely in accord with the genotypes. In summary, multilocus sequence typing is effective for the genotyping of S. thermophilus strains.
    15  Physicochemical Properties of Rose Powder
    YUE Feng-li ZHAO Yan-yan WU Xia
    2015, 31(9):87-91. DOI: 10.13982/j.mfst.1673-9078.2015.9.015
    [Abstract](1144) [HTML](0) [PDF 767.52 K](1323)
    Abstract:
    Differences between rose superfine powder (RSFP) and rose fine powder (RFP) in terms of particle size distribution, specific surface area, micro-morphology, absorption intensity of chemical functional groups, and the stability of their dispersed aqueous solution were investigated using several techniques, including laser diffraction particle size analysis, scanning electron microscopy (SEM), infrared spectroscopy (IR), Zeta potential analysis, and turbidity analysis. In addition, differences in water holding capacity (WHC), oil holding capacity (OHC), and solubility between RSFP and RFP were also studied. The results showed that most tissue structures and cell walls were broken down in RSFP. The relative absorption intensity of the functional groups in IR was higher in RSFP than in RFP. Furthermore, the dispersed aqueous solution of RSFP was more stable compared to that of RFP. As the temperature increased, the turbidity values of both dispersed aqueous solutions showed a decreasing trend followed by an increasing trend and reached the lowest value at 80 ℃. Temperature had a small effect on the stability of the RSFP dispersed aqueous solution. Moreover, although the turbidity of the dispersed aqueous solution of RSFP and RFP was affected by the ionic strength, RSFP was more resistant to intensity changes in buffer ionic strength than was RFP after being subjected to a boiling water bath. The WHC and OHC of RSFP decreased compared to those of RFP, while the solubility increased.
    16  Antioxidant Activity of in vitro Rice Protein Digest
    TONG Li-tao CHEN Qian-qian QIAN Hai-feng ZHONG Kui LIU Li-ya ZHOU Su-mei
    2015, 31(9):92-97. DOI: 10.13982/j.mfst.1673-9078.2015.9.016
    [Abstract](1318) [HTML](0) [PDF 886.49 K](1752)
    Abstract:
    The Osborne method comprising of a 2-step in vitro digestion of rice flour was used to extract albumin, globulin, prolamin, and glutelin by using pepsin and trypsin. Subsequently, the antioxidant activity of the resultant rice digest was studied in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH?), 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+?) and ?OH radical scavenging as well as Fe2+-chelating activity. The results revealed that the in vitro digests of four rice proteins exhibited better antioxidant activity than commercial soybean peptides. Among these, the digest of prolamin showed the highest antioxidant activity, where the half-maximal inhibitory concentration (IC50) values of DPPH?, ABTS+?, and ?OH radical-scavenging as well as Fe2+-chelating activities were 30.88, 27.61, 5.43, and 0.18 mg/mL, respectively. The enzymatic hydrolysates of albumin, globulin, prolamin, and glutelin showed good Fe2+-chelating activities with IC50 values < 1 mg/mL. The results indicated that the in vitro digests of the four rice proteins tested in this study showed different antioxidant activities and that the molecular weights of these small peptides were in a range of 181~1000 Da, which is similar to that od antioxidant peptides that can be absorbed easily in humans.
    17  Changes in Molecular Structure of Collagen during Gelatinization
    WANG Xue-meng YU Wei MA Liang GUO Xue-xia ZHOU Meng-rou HUANG Dan-dan ZHANG Yu-hao
    2015, 31(9):98-105. DOI: 10.13982/j.mfst.1673-9078.2015.9.017
    [Abstract](1155) [HTML](0) [PDF 882.73 K](1405)
    Abstract:
    The microstructure of collagen from pig skin was studied during gelatinization. The results showed that a relatively high degree of gelatinization of collagen was achieved after 8-h acid treatment and the yield of gelatin reached 83.98% after hot water extraction, while the yield of gelatin dropped significantly with increasing duration of acid treatment. The results from differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), and circular dichroism (CD) revealed that the triple-helical structure of collagen became progressively loose and valence bonds stabilizing the triple-helix were gradually destroyed during the process of acid treatment. The triple-helical structure was excessively destroyed after 8-h acid treatment, which could be the main reason for the decrease in gelatin yield. Moreover, the results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated that collagen peptide chains were degraded during acid treatment and the gelatin subunit content was directly influenced by the amount of subunits that remained after gelatinization. Therefore, during the gelatinization of collagen, a balance between subunit degradation and the loosening of the triple-helical structure is required, in order to obtain high yield of high-quality gelatin.
    18  Comparison of the Antioxidant Activities between 6-Gingerol Oxime and 6-Gingerol
    LU Hao-hao JIAO Rui HUANG Xue-song YAN Ri-an
    2015, 31(9):106-111. DOI: 10.13982/j.mfst.1673-9078.2015.9.018
    [Abstract](1183) [HTML](0) [PDF 615.91 K](1257)
    Abstract:
    The antioxidant activities of gingerol and gingerol oxime rom ginger oleoresin were compared. Gingerol was purified by vacuum column chromatography and gingerol oxime was prepared via oximation reaction The antioxidant activities of different concentrations of gingerol, gingerol oxime, butylated hydroxytoluene (BHT), and VE were compared through the analysis of reducing power, the scavenging capacities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals, and the oil stability index. In the concentration range of 0.2~0.8 g/L, the reducing power of gingerol oxime (absorbance value: 0.23~0.37) was lower than that of gingerol (0.52~1.11) and higher than that of VE (0.19~0.29). The DPPH and hydroxyl radical scavenging activities of gingerol oxime were 75~89% and 37~62%, respectively, which were lower than those of gingerol and BHT but similar to those of VE. In the concentration range of 50~250 mg/kg, the oxidative induction time of gingerol oxime in peanut and sunflower seed oil were 3.39~3.57 and 1.71~2.07 h, respectively, shorter than those of gingerol (3.57~3.83 and 1.90~2.16 h) but significantly longer than those of VE (3.06~3.49 and 1.53~1.93 h). In conclusion, the antioxidant activities of these four compounds were in the following order: VE ≤ gingerol oxime < gingerol ≤ BHT. Gingerol and gingerol oxime are both excellent antioxidants. However, since gingerol oxime is more chemically stable than gingerol, which has greater potential as an antioxidant for edible oil.
    19  Enzymological Characteristics of Polyphenol Oxidase from Hawthorn
    LI Li-hua LIU Jun-hai
    2015, 31(9):112-116. DOI: 10.13982/j.mfst.1673-9078.2015.9.019
    [Abstract](1087) [HTML](0) [PDF 781.57 K](1242)
    Abstract:
    The enzymatic characteirstics of Polyphenol oxidase (PPO) from hawthorn was studied The effects of substrate specificity, pH value, temperature, thermostability, substrate concentration, metal ions, and inhibitors on PPO activity were examined using spectrophotometry . The optimum substrate, pH value, temperature, and substrate concentration for PPO were found to be catechol, 6.5, 40 ℃, and 0.10 mol/L, respectively. PPO was completely inactivated by heating at 90 ℃ for 1.0 min or 85 ℃ for 1.5 min. PPO activity followed Michaelis-Menten kinetics in the enzymatic browning reaction. The Km and Vmax values were 55.83 mmol/L and 98.04 U/min, respectively. Metal ion Al3+ showed relatively strong inhibitory effect on the enzyme activity, followed by Mn2+, Ca2+, and Zn2+, where all four substances showed dose-dependent effect. The inhibitory effects of Cu2+ and Mg2+ on enzyme activity were not obvious, while activity was promoted to some degree by Fe3+. At the same concentration, inhibitory effects were in the following order: ascorbic acid > L-cysteine, NaHSO3 > citric acid, where ascorbic acid showed the most significant inhibitory effect on PPO activity.
    20  Effect of Rosemary Extract on Lipid Oxidation and Quality of Beef Meat Balls during Frozen Storage
    JIA Na CHEN Lu KONG Bao-hua
    2015, 31(9):117-123. DOI: 10.13982/j.mfst.1673-9078.2015.9.020
    [Abstract](893) [HTML](0) [PDF 861.50 K](1284)
    Abstract:
    Different concentrations of rosemary extract (0%, 0.02%, 0.04%, and 0.06%) were added to beef meat balls, and beef meat balls with 0.02% butylhydroxyanisole (BHA) were used as the control. The peroxidate value (PV), content of thiobarbituric acid reactive substances (TBARS), color, water-holding capacity, as well as textural and sensory properties were evaluated to determine any improvement brought about by rosemary extract on lipid oxidation and quality of beef meat balls. The results showed that rosemary extract significantly decreased PV and TBARS content, thus inhibiting lipid oxidation. The a* value increased and good color was maintained. The thawing and cooking losses declined with the use of rosemary extract, while water-holding capacity and textural properties, including hardness, springiness, and chewiness, improved. Beef meat balls with rosemary extract showed higher sensory values and good sensory properties. Therefore, rosemary extract have potential applications in the inhibition of lipid oxidation during frozen storage, thus improving quality of beef meat balls.
    21  Asymmetric Synthesis of (S)-3-Chloro-1-phenylpropanol with Immobilized Acetobacter sp. CCTCC M209061 Cells in a Monophasic System
    HUANG Yu-mei XU Yu ZHAO Bing-yi LOU Wen-yong
    2015, 31(9):124-131. DOI: 10.13982/j.mfst.1673-9078.2015.9.021
    [Abstract](942) [HTML](0) [PDF 952.34 K](1076)
    Abstract:
    Optically pure 3-chloro-1-phenyl-1-propanol is an important intermediate for the synthesis of drugs for treating depression. In the present study, biocatalytic asymmetric reduction of 3-chloropropiophenone to (S)-3-chloro-1-phenyl-1-propanol with immobilized Acetobacter sp. CCTCC M209061 cells was successfully conducted in a monophasic aqueous system with high efficiency and selectivity. The immobilized Acetobacter sp. CCTCC M209061 cells exhibited higher stabilities (thermal, pH, and operational stability) than the free cells. In addition, the immobilized microbial cells exhibited a relatively good recyclability; the relative activity of immobilized cells remained over 80%, while that of the free cells under the same condition was less than 20%. In the studied system, glucose was the best co-substrate at an optimum concentration of 50 mmol/L. The optimum buffer pH, reaction temperature, and substrate concentration in this reaction system were 5.5, 30°C, and 3.0 mmol/L, respectively. Under the optimized reaction conditions, the initial reaction rate, yield, and product e.e. were 1.77 mM/h, 88.9%, and above 99.0%, respectively.
    22  Preparation and Characterization of Vanillin Molecularly Imprinted Polymer Microspheres
    SUN Zhi-chun WANG Bing SHAN Juan-juan SI Hui-tong
    2015, 31(9):132-137. DOI: 10.13982/j.mfst.1673-9078.2015.9.022
    [Abstract](953) [HTML](0) [PDF 982.97 K](997)
    Abstract:
    Vanillin is an important flavoring agent that is mainly obtained from the seedpods of the tropical orchid, Vanilla planifolia. Molecularly imprinted polymer microspheres (MIPs) were synthesized by precipitation polymerization, suspension polymerization, and bulk polymerization using vanillin as the template molecule, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, and dimethyl sulfoxide as the solvent. The interaction between vanillin and MAA of vanillin in MIPs and the best molar ratios were studied using UV spectroscopy and Fourier transform infrared spectroscopy (FT-IR). In addition, their microstructure was observed by transmission electron microscopy (TEM). Equilibrium adsorption and isothermal adsorption experiments were carried out to investigate the vanillin-binding capacities of the polymers. The results indicated that MAA and vanillin interacted via hydrogen bonding. Furthermore, the MIPs synthesized by precipitation polymerization were regularly shaped and had relatively high specificity for the recognition of vanillin.
    23  Characterization of Iron Nanoparticles Prepared with Non-ionic Surfactants
    XIAO Kai-jun DAI Jia-li HE Qi ZHU Liang DONG Hao LI Shao-feng
    2015, 31(9):138-144. DOI: 10.13982/j.mfst.1673-9078.2015.9.023
    [Abstract](908) [HTML](0) [PDF 1.02 M](1370)
    Abstract:
    Polyethylene glycol 4000 (PEG-4000), PEG-20000, and polyvinyl pyrrolidone (PVP) at various concentrations were used as dispersants for the preparation of iron nanoparticles with a liquid-phase reducing method. The effects of these non-ionic surfactants as dispersants were investigated to improve product dispersibility and reactivity. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), double-beam UV-visible spectrophotometry (UV), and atomic absorption spectrophotometry (AAS) were used to characterize and investigate the product and its effectiveness in removing lead (II). SEM analysis showed that all three surfactants improved the dispersibility of iron nanoparticles. Fine, fibrous iron nanoparticles were attained after adding PEG-4000 and PEG-20000, whereas fluffy particulate iron nanoparticles were obtained after adding PVP. The FT-IR results indicated that the three surfactants did not undergo chemical reactions during iron nanoparticle formation. Instead, they attached to or coated the surface of the nanoparticles through electrostatic interaction or van der Waals forces. The results of XRD demonstrated that the surfactants had no influence on the crystal phase of iron nanoparticles, and the UV results indicated the dispersion effects of PEG-20000 and PVP were superior to that of PEG-4000. The AAS results showed that the maximum adsorption capacity of lead (II) reached 229 mg/g when iron nanoparticles were prepared by adding 3% PEG-20000.
    24  Study on the Recognition Method of Grape in Different Natural Environment
    MA Ben-xue JIA Yan-ting MEI Wei-jiang GAO Guo-gang LV Chen ZHANG Wei
    2015, 31(9):145-149. DOI: 10.13982/j.mfst.1673-9078.2015.9.024
    [Abstract](963) [HTML](0) [PDF 837.06 K](1412)
    Abstract:
    This paper is mainly about how to recognize different color grapes in nature, The grape images that taken under a fine day of front lighting, back lighting and night conditions, A novel grape image segmentation method based on different color space was proposed. The maximum classes square error method and the histogram method were used to obtain the best threshold, to get the grape bunches contours images and to cut the complex background region apart. The minimum enclosing rectangle was drawn on account of the image contour of target grapes, the feature information of grape barycenter and the plucking positions were extracted by the Harris corner test. The results showed that the identification algorithm of grapes could accurately identify the grapes in the picture and reduce impacts of illumination intensity in a large extent, among which the recognition ratio of green grapes in front lighting, back lighting and night conditions were 93.3%、86.7% and 96.7%, while the recognition ratio of purple grapes were 90%、83.3% and 96.7%.
    25  Stability of Modified Peptide Using Zinc Binding and Plastein Reaction
    ZHANG Juan-juan LIU Zun-ying DONG Shi-yuan MAO Xiang-zhao ZHAO Yuan-hui
    2015, 31(9):150-160. DOI: 10.13982/j.mfst.1673-9078.2015.9.025
    [Abstract](948) [HTML](0) [PDF 669.63 K](1279)
    Abstract:
    Modified peptide was prepared from oysters by zinc binding and plastein reaction. The effects of pH, digestive enzymes, heat treatment, storage time, and other factors on the stability of the modified peptide were studied. Additionally, the stability of the new modified peptide was compared with that of zinc-binding polypeptide and zinc-binding glutamic acid. Fourier transform infrared (FT-IR) spectroscopy indicated that new substances were generated after plastein reactions; zinc-binding complexes were easily degraded at pH = 2.0, while they were relatively stable at pH = 9.0; and the stability of zinc-binding glutamic acid was significantly lower than that of zinc-binding peptides (p < 0.05). All zinc-binding complexes exhibited resistance to digestive enzymes and the stability of zinc-binding glutamic acid was significantly lower than that of other zinc-binding peptides (P < 0.05). The modified peptide and zinc-binding polypeptides were sensitive to heat treatment and their stability was significantly lower than that of zinc-binding glutamic acid (p < 0.05). Zinc-binding complexes exhibited good stability and zinc retention rate reached up to 95.50% as storage time increased.
    26  Enzymatic Preparation, Separation, and Structural Identification of Bonito Protein Hydrolysates
    REN Jiao-yan ZHANG Rong YANG Ji-guo YIN Jia-xin LIU Jin-chuan NING Zheng-xiang ZHAO Mou-ming
    2015, 31(9):155-161. DOI: 10.13982/j.mfst.1673-9078.2015.9.026
    [Abstract](881) [HTML](0) [PDF 796.79 K](1176)
    Abstract:
    Bonito protein hydrolysates were prepared by enzymatic hydrolysis using bonito fish as the raw material. Enzymatic hydrolysis processing was optimized using antioxidant activity and protein recovery rate as indicators. The protein hydrolysates were then separated and purified by means of ion exchange chromatography and gel chromatography. Finally, matrix-assisted laser desorption/ionization-time of flight-mass spectra (MALDI-TOF-MS), in tandem with reversed-phase high-performance liquid chromatography (RP-HPLC) was applied for structural identification of fraction composition. The optimum For the hydrolysis reaction, the best hydrolytic enzyme and its concentration were papain; and 1.0%, respectively. The optimum pretreatment conditions were 100 ℃ for 5 minutes After 4-hour hydrolysis, three fractions, labeled A, B, and C, were obtained from the hydrolyzate through DEAE-52 cellulose column chromatography. Fraction A had the highest antioxidant activity, which was further separated by gel chromatography on Sephadex G-15 column to give two fractions. The fraction with the highest antioxidant activity was labeled A1 and the other was labeled A2. Using MALDI-TOF-MS, the molecular weights of A1 and A2 were found to be around 378.830 Da. Further amino acid analysis revealed that the short-chain peptide had a possible amino acid composition of Lys, Leu, and Pro.
    27  Effect of Deamination on the in vitro Digestibility of Grain Proteins
    LONG Pei ZHANG Hui WANG Li QIAN Hai-feng QI Xi-guang
    2015, 31(9):162-168. DOI: 10.13982/j.mfst.1673-9078.2015.9.027
    [Abstract](843) [HTML](0) [PDF 945.60 K](1262)
    Abstract:
    Deamination is a method used to modify the physicochemical and nutritional properties of proteins. Here the effect of deamination using an acid method on the in vitro digestibility of rice, wheat, and corn proteins was studied. Additionally, the mechanism underlying the effects of the deamination on the in vitro digestibility of proteins in three types of grains was explored in terms of physicochemical properties including solubility, surface hydrophobicity, sulfhydryl and disulfide content, and ultrastructure. The results showed that with an increasing degree of deamination, the difference in the inter-conversion between sulfhydryl and disulfides in the proteins of the three types of grains (rice, wheat, and corn) was not significant (p < 0.05), and the sulfhydryl and disulfide contents were generally unchanged. Protein solubility in the three types of grains at the optimum pH for pepsin (pH = 1.5) and trypsin (pH = 7.5) was slightly increased; however, surface hydrophobicity slightly decreased with an increasing degree of deamination. The in vitro digestibility of rice, wheat, and corn proteins increased from 66.5% to 79.5%, 79.5% to 89.0%, and 78.5% to 89.2%, respectively. Meanwhile, the protein ultrastructure, which was originally dense and compact, became porous and loose, which was more conducive to digestion.
    28  Color Satisfaction Model of Roast Chicken Based on the Level Set
    JI Bin WANG Jun
    2015, 31(9):169-174. DOI: 10.13982/j.mfst.1673-9078.2015.9.028
    [Abstract](1616) [HTML](0) [PDF 781.16 K](1193)
    Abstract:
    A new sampling method and model for quantitative measurement of color quality of oven-roasted chicken was investigated. An adaptive-balance energy model (ABEM), based on the level set was used for sampling. Based on the mean value and the contrast information from images of the roast chicken, the level set was employed for sampling images of the oven chamber, and rapid extraction of the color area in the roast chicken was achieved. In order to verify this, ABEM and distance-regularized level set evolution method (DRLSE) were adapted for sampling images of the oven chamber. The experimental results showed that the foreground image of the roast chicken in the oven could be obtained using ABEM without compromising the sampling. Using the model for quantitative determination of color quality, the color index of the roast chicken image was computed via a color satisfaction-based relative index model (CSIM) and the core frequency domain of S component in the hue-saturation-value (HSV) color space. Subsequently, the color index was converted to the relative color satisfaction index for roast chicken, directly reflecting the chicken color quality. The results indicated that a combination of ABEM and CSIM is effective in monitoring the color quality index for roast chicken, thus providing an important reference for the core algorithm in food quality control systems.
    29  Isolation, Purification, Identification, and Sensory Evaluation of Umami Peptide in Wheat Gluten Fermentation Broth
    CUI Chun QIAN Yang-peng PENG Huan-huan WANG Hai-ping ZHAO Hai-feng
    2015, 31(9):175-179. DOI: 10.13982/j.mfst.1673-9078.2015.9.029
    [Abstract](1100) [HTML](0) [PDF 717.74 K](1358)
    Abstract:
    Umami is one of five basic tastes, which has been playing an increasingly important role in the selection of food products. Peptides are primary tastants composed of amino acids with several tastes. Peptides with significant umami taste could be produced through proteolysis. An umami peptide was isolated and purified from wheat gluten fermentation broth by ultra-filtration (UF), gel filtration chromatography (GPC), reverse phase high-performance liquid chromatography (RP-HPLC), and sensory evaluation. The sequence and molecular weight of the umami peptide were identified by matrix-assisted laser desorption/ionization- time-of-flight - mass spectrometry (MALDI-TOF-MS). The identified peptide was synthesized and taste dilution analysis (TDA) was conducted to evaluate taste characteristics of the peptide. The umami peptide was identified to be Asp-Cys-Gly (DCG) and the molecular weight was 293.15 Da. TDA results showed that the umami taste threshold of the peptide was 100 mg/mL, which was one third of MSG. DCG can enhance the umami taste of I+G at a concentration of 200 mg/L, but no similar effect was found with MSG.
    30  Effect of Dry Heat Treatment on the Properties of Glutinous Rice Mixed Flour and Rice Proteins
    QIN Yang QIU Chao CAO Jin-miao XIONG Liu SUN Qing-jie
    2015, 31(9):180-184. DOI: 10.13982/j.mfst.1673-9078.2015.9.030
    [Abstract](919) [HTML](0) [PDF 730.02 K](1135)
    Abstract:
    Glutinous rice mixed flour (GRF) was modified by dry heat treatment and the effects of the dry heat treatment on the properties of GRF and glutinous rice proteins (GRP) were investigated. The results showed that GRF peak viscosity decreased after adding GRP, which indicated that GRP reduced the content of glutinous rice starch (GRS) and had a diluting effect. However, the viscosity of GRF increased significantly after dry heat treatment, which indicated that dry heat treatment prompted the interaction between GRS and GRS or GRP via non-covalent or hydrogen bonding. The analysis of color differences showed that the yellowness of GRP significantly increased after dry heat treatment. Results of thermogravimetric analysis (TGA) showed that the temperature at the onset of mass loss for GRF increased from 238 ℃ to 291 ℃ after dry heat treatment at 130 ℃ for 4 h, indicating that the thermal stability was significantly enhanced. Fourier transform infrared spectroscopy (FT-IR) indicated that GRP dry-heated for 4 h produced a new small peak at 1250 cm-1, which indicated that there were structural changes in the β-pleated sheets. In addition, amide bond vibration was enhanced and protein secondary structure modified at 1600~1700 cm-1, suggesting that dry heat treatment promoted molecular interactions.
    31  Effects of Various Hot-air Drying Methods on the Composition and Antioxidant Activity of Polyphenols in Mushrooms (Lentinus edodes)
    LU Ke-ke GUO Xiao-hui LI Fu-hua MING Jian
    2015, 31(9):185-190. DOI: 10.13982/j.mfst.1673-9078.2015.9.031
    [Abstract](946) [HTML](0) [PDF 877.15 K](1318)
    Abstract:
    The effects of six hot-air drying methods on the content, composition, and antioxidant activity of polyphenols in mushrooms (Lentinus edodes) were studied. Phenols were analyzed qualitatively and quantitatively with the Folin-Ciocalteu method and HPLC, and their antioxidant activities were evaluated with chemical methods. The results showed that isothermal drying (ID) resulted in the highest free phenol content (2.69 mg GAE/g DW) and the lowest bound phenol content (0.19 mg GAE/g DW), whereas uniform intermittent drying resulted in the lowest free phenol content and relatively high bound phenol content. The free phenols mainly consisted of gallic acid, chlorogenic acid, caffeic acid, and quercetin, and the bound phenols mainly consisted of gallic acid and quercetin. Polyphenol content in mushrooms after drying with all methods had measurable levels of antioxidant activity. The ID group had the strongest DPPH? radical scavenging capacity, with IC50 values for free and bound phenols as 0.53 μg/mL and 0.06 μg/mL, respectively. The ID group free phenols also had the strongest ABTS+? radical scavenging capacity, with an IC50 value of 3.32 μg/mL. No differences in ABTS+? radical scavenging capacities by bound phenols were found among the groups. The reducing powers of the groups also showed no significant differences. In conclusion, the polyphenol content in mushrooms dried with various methods showed differences in content, composition, and antioxidant activity. Additionally, ID is a relatively ideal drying method for mushrooms.
    32  Impact of the Conditions of the Drying Medium on the Dehydration of Fine-dried Noodle
    WU Liang LIU Rui ZHANG Bo ZHANG Ying-quan WEI Yi-min
    2015, 31(9):191-197. DOI: 10.13982/j.mfst.1673-9078.2015.9.032
    [Abstract](856) [HTML](0) [PDF 755.54 K](1435)
    Abstract:
    The effects of the conditions of the drying medium such as temperature, relative humidity, and air velocity as well as varying width (1, 2, and 3 mm, with same thickness) on the drying rate of fine-dried noodle was studied using a 60-m, five-row production line in a tunnel drying room. A multifunctional, pocket weather meter (Kestrel NK-4500) was used for real-time monitoring of temperature, relative humidity, and air velocity of the medium during the drying process. Data were collected 12 times for each type of fine-dried noodle strip. While the conditions of the drying medium were monitored dynamically, the moisture content of the noodle was measured at five different drying distances (1, 15, 30, 45, and 59 m) in the tunnel drying room, and the effect of each parameter on the drying rate of the noodle was analyzed. The results showed no significant differences in the drying rates of noodle strips with different widths (1, 2, or 3 mm) and the same thickness when a similar drying process was employed. The most important factor affecting the drying rate was relative humidity, followed by temperature and air velocity. The effects of the conditions of the drying medium on noodle drying was more significant than that of the width of the noodle strip (with the same thickness).
    33  Effect of Different Starters on Microbial Flora and Physicochemical Properties of Fermented Sausages
    ZHU Ying-chun DU Zhi-hui MA Li-zhen XIAO Yan DANG Xiao-yan
    2015, 31(9):198-204. DOI: 10.13982/j.mfst.1673-9078.2015.9.033
    [Abstract](861) [HTML](0) [PDF 942.32 K](1247)
    Abstract:
    The physicochemical properties and microbial flora of fermented sausages were investigated when three composite starters (VBL-9, VBM-60, and SHI-59) and a single-organism starter (BOM-13) were used during production. The results showed that lactic acid bacteria (LAB) were the dominant species during fermentation and maturation processes using all four starters. In all mature sausages, LAB counts reached 7.21 to 8.13 log cfu/g and the Staphylococcus count (except with BOM-13) was >5.50 log cfu/g, while the Enterobacteriaceae count was <3 log cfu/g. In case of the starter BOM-13, composed of Lactobacillus sakei, sausage fermentation and ripening took longer and therefore, the values of thiobarbituric acid reactive substances (TBARS, 0.84 mg/100 g) and non-protein nitrogen (NPN, 0.46%) were higher than those of the other three groups. Thus, fermenting conditions (temperature and time) and ripening time for the sausages depended on the composition of the starter used. All starters tested in this study produced high-quality sausages (pH < 5.3; water activity (Aw) < 0.82; TBARS < 1.0 mg/kg; high NPN value; LAB (dominant bacteria) count > 7.0 log cfu/g, and Enterobacteriaceae count < 3.0 log cfu/g). The starter VBL-97 showed strong acidification capabilities and antioxidant capacity, whereas the highest degree of protein decomposition occurred with starter BOM-13.
    34  Effect of Slaughter Stress on Post-slaughter Pork Water-holding Capacity
    WU Xiao-wei LI Xia ZHANG Chun-hui TANG Chun-hong WEI Xiu-li JING Xiao-liang
    2015, 31(9):205-211. DOI: 10.13982/j.mfst.1673-9078.2015.9.034
    [Abstract](909) [HTML](0) [PDF 736.82 K](1271)
    Abstract:
    The influences of electric and carbon dioxide stunning methods on ante-mortem stress and its effect on water-holding capacity of post-slaughter muscle in Duroc-Landrace-Yorkshire (with halothane genotype NN) and Sanmenxia black pigs (without halothane gene) were studied. The results showed that, compared with electric stunning, carbon dioxide stunning could significantly lower lactate (LAC), lactate dehydrogenase (LDH), creatine kinase (CK), creatinine (CRE), and cortisol (COR) content (P < 0.05) in the blood of both Duroc-Landrace-Yorkshire and Sanmenxia black pigs. The pH value measured at 45 min post-mortem (pH45min) in the longissimus muscle of pigs stunned by carbon dioxide was significantly higher (P < 0.05) than that of pigs stunned electrically. Carbon dioxide stunning significantly reduced values of muscle drip loss rate (reduced by 1.17% and 0.59%), cooking loss rate (reduced by 3.09% and 3.56%), and thawing loss rate (reduced by 0.55% and 0.29%) at 24 h post-mortem as well as shear forces (reduced by 0.71 and 0.66 kg) in the longissimus muscle of Duroc-Landrace-Yorkshire and Sanmenxia black pigs, respectively (P < 0.05). The results of low-field nuclear magnetic resonance technique (LF-NMR) indicated that carbon dioxide stunning significantly reduced the free water content (reduced by 32.24% and 28.92% for Duroc-Landrace-Yorkshire and Sanmenxia black pigs, respectively), and inhibited the transformation from immobilized to free water (state change). Thus, carbon dioxide stunning reduces the stress effect of live pigs and improves muscle water-holding capacity during pig slaughter.
    35  Effects of Carrageenan and Transglutaminase on the Gel Properties of Tilapia Sausage
    CHEN Bin ZHU Zhi-wei RUAN Zheng LI Bian-sheng LIU Tong-xun DAI Bing-hu ZENG Guang-xing
    2015, 31(9):212-217. DOI: 10.13982/j.mfst.1673-9078.2015.9.035
    [Abstract](831) [HTML](0) [PDF 758.71 K](1143)
    Abstract:
    The influence of carrageenan and transglutaminase (TGase) addition on the gel strength, texture profile analysis (TPA) indicators (hardness, cohesion, and resilience), water holding capacity, and chemical bonding indicators, to maintain the gel structure of tilapia sausage under thermal sterilization (121.1 ℃ for 14 min, 17 min, and 20 min) was investigated. Results showed that tilapia sausage, under heat sterilization with the additives (carrageenan and TGase), had significantly higher gel strength and water holding capacity (P < 0.05) than that of the control samples. The hardness, cohesion, and resilience of the samples with the compound additives decreased as the sterilization intensity increased, but were all higher than that of the control samples. Among them, hardness and resilience were significantly higher (P < 0.05), but the effect on cohesion was not significant (P > 0.05). Furthermore, compared to control samples, the extent of damage to hydrophobic interactions and ε- (γ-glutamyl) lysine bond under heat sterilization decreased significantly (P < 0.05), while the extent of damage to disulfide bonds did not change significantly (P > 0.05).
    36  Effect of Slaughter Methods on Quality of Frozen Channel Catfish Fillets
    CHEN Ang-hong XU Yan-shun JIANG Qi-xing XIA Wen-shui
    2015, 31(9):218-222. DOI: 10.13982/j.mfst.1673-9078.2015.9.036
    [Abstract](864) [HTML](0) [PDF 664.32 K](1203)
    Abstract:
    To improve the quality of frozen fish fillet, different slaughter methods were evaluated to determine their effect on the quality of frozen channel catfish. Fresh channel catfish were slaughtered by four methods (carbon dioxide stunning, electrical stunning, percussive stunning, and bleeding in ice slurry) and fillets were stored in a refrigerator at -18 ℃. The pH value, color, hemoglobin content, drip loss, total volatile base nitrogen (TVB-N), and bacterial counts in each group were evaluated. Muscle pH values showed an upward trend after an initial decline at 45-h post-mortem; the change in pH value for bleeding-in-ice-slurry group was the smallest, followed by percussive-stunning group; whereas the largest pH change was found in CO2-stunning group. The a* and L* values for the bleeding-in-ice-slurry group were significantly different from those for other groups (p < 0.05), whereas less blood was retained in the bleeding-in-ice-slurry group (p < 0.05). During the 60-day storage period, highest drip loss (5.53%) was observed for the CO2-stunning group (p < 0.05), while the lowest (3.25%) was found for the percussive-stunning group. The lowest TVB-N value was found for the bleeding-in-ice-slurry group (p < 0.05), with no significant differences among other three groups (p < 0.05). The bacterial count exhibited a declining trend during storage and the lowest count was found for the bleeding-in-ice-slurry group, followed by percussive-stunning, CO2-stunning, and electric-stunning groups. Thus, fish slaughter by bleeding in ice slurry and percussive stunning produce good-quality fillets of frozen channel catfish.
    37  Effect of Crude Extract of Endophytic Strain 011 on Fresh-keeping of Tomatoes after Harvest
    ZHOU Jin-wei ZHOU Hong-li YI You-jin BO Lian-yang LI Gao-yang LONG Li-lin CHENG Yuan-du XIA Bo
    2015, 31(9):223-229. DOI: 10.13982/j.mfst.1673-9078.2015.9.037
    [Abstract](843) [HTML](0) [PDF 905.46 K](1110)
    Abstract:
    The effect of post-harvest treatment of Xiangfenyihao tomatos with endophytic strain 011 crude extract in comparison to sterile water on the fresh-keeping of tomatoes was investigated in this study. The results indicated that after 25-d storage, the decay rate of the tomatoes treated with crude extract significantly decreased by 52.17% compared to that with sterile water. The results also showed that crude extract treatment slowed the mass-loss rate, significantly delayed the decline in Vitamin c, reducing sugar, soluble protein and the titratable acid content, and satisfactorily maintained the flavor of tomato fruits during storage. The accumulation of malonic dialdehyde and increase of superoxide anion radical (?O2-) were significantly inhibited, integrity of the cell membrane was maintained, and activities of peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), and phenylalanine ammonia-lyase (PAL) were significantly enhanced. Therefore, the crude extract satisfactorily maintained the nutritional and commercial value as well as significantly improved the preservation of tomatoes. These results provide a theoretical basis for biological control and fresh-keeping of fruits and vegetables after harvest.
    38  Preparation of Koji Using Aspergillus oryzae and a Halophilic Aromatic Yeast
    LIU Jing-jing HU Yong CHEN Meng CHEN Shi-gui FU Cai-xia WANG Chao CHEN Xiong XU Ning LI Dong-sheng
    2015, 31(9):230-237. DOI: 10.13982/j.mfst.1673-9078.2015.9.038
    [Abstract](1140) [HTML](0) [PDF 1.16 M](1393)
    Abstract:
    A halophilic aromatic yeast (Zygosaccharomyces rouxii) was added to Aspergillus oryzae and their synergistic effect on the preparation of koji was explored in terms of the metabolic regulation of yeast with enzymatic systems, physicochemical indices, and volatile compounds. Changes in the numbers of the yeast colonies and Aspergillus oryzae spores, the activity of the enzymatic systems, and physicochemical indicators during the preparation of koji were dynamically monitored, while the volatile components of the finished product were analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that when the amount of yeast added was approximately 1.5 × 106 yeast/g koji and the inoculum size of Aspergillus oryzae was 0.15% (m/m), the number of Aspergillus oryzae spores did not significantly change and the neutral protease activity was 3100 U/g at 36 h, which was comparable to the results obtained for the control group. However, α-amylase activity decreased by 22% and saccharifying enzyme activity increased by 7% in the yeast-inoculated group, while aminopeptidase and acidic carboxypeptidase activities did not exhibit significant difference compared to the results obtained in the control group. After the preparation of koji was complete, the concentrations of amino nitrogen and reducing sugar were almost the same for the yeast-inoculated and control groups, while the organic acid content of the yeast-inoculated sample was lower than that of control. There were 32 and 23 volatile components identified by GC-MS in the yeast-inoculated and control groups, respectively. Comprehensive analysis showed that inoculation of a halophilic aromatic yeast during the preparation of koji did not show a significant effect on the enzymatic system and growth of Aspergillus oryzae; however, it improved the flavor and quality of the finished koji.
    39  Effects of Ginger, Onion, and Garlic Mixtures on the Sensory Quality, Lipid Oxidation, and Fatty Acid Composition of Stewed Pork
    WANG Rui-hua JIANG Wan-zhou WANG Qian CHEN Jian-chu YE Xing-qian LIU Dong-hong
    2015, 31(9):238-243. DOI: 10.13982/j.mfst.1673-9078.2015.9.039
    [Abstract](826) [HTML](0) [PDF 781.47 K](1392)
    Abstract:
    The effects of the addition of a ginger, onion, and garlic (OGG) mixture on the sensory quality, basic physical and chemical characteristics, level of lipid oxidation and fatty acid composition of stewed pork were evaluated. The results suggested that the addition of OGG improves the sensory quality of stewed pork and the water-holding capacity of the meat, which significantly increased with further addition of OGG (P < 0.05). OGG suppressed the formation of peroxides and TBARS in stewed pork, and 15% OGG achieved the most significant effect (P < 0.05). The addition of OGG significantly suppressed the oxidation of fatty acids, especially that of unsaturated fatty acids, in stewed pork. The suppressive effect increased significantly as OGG addition increased. Furthermore, OGG affected the fatty acid content of stewed pork. The mono- and polyunsaturated fatty acid contents significantly increased with the addition of OGG (P < 0.05), as did the ratio of unsaturated fatty acid to saturated fatty acid (P < 0.05), thus improving the nutritional value of pork.
    40  Composition Analysis and Nutritional Evaluation of Wild and Farmed Channa argus
    ZHAO Li CHEN Jun ZHAO Chun-gang BAI Qing-yun BI Yan-hong WANG Hui
    2015, 31(9):244-249. DOI: 10.13982/j.mfst.1673-9078.2015.9.040
    [Abstract](1081) [HTML](0) [PDF 635.68 K](1266)
    Abstract:
    Abstract: Analysis of the nutrient content of wild and farmed Channa argus muscle tissue showed that crude fat content in wild Channa argus was significantly lower than that in the farmed variety (p < 0.05). However, the content of n-3 polyunsaturated fatty acids (PUFA) and c22:6 (DHA) in the muscle of wild Channa argus was higher than that in the farmed Channa argus, where the ratio of n-3/n-6 of the two samples was 1.21 and 0.65, respectively. A total of 17 amino acids were detected in the muscles of wild and farmed Channa argus, where the content of total amino acids, delicious amino acids, and essential amino acids in the farmed Channa argus was higher than that in the wild variety. The ratio of essential to total amino acids (EAA/TAA) in the muscles of wild and farmed Channa argus was 42.66% and 42.28%, respectively. The ratios of essential to non-essential amino acids were 74.40% and 73.26%, respectively, which were higher than the ideal protein patterns recommended by Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO). The essential amino acid index of wild and farmed Channa argus muscles was 63.48 and 70.82, respectively. In both samples, potassium showed the highest mineral content, whereas trace elements were significantly higher in muscles of the farmed variety than wild Channa argus (p < 0.05). In conclusion, the farmed Channa argus fed with low-value, wild trash-fish shows good development prospects for .
    41  Origin of Pigments in Eggs Traced by Stable Isotope Ratio Mass Spectrometry
    SUN Feng-mei WANG Hui-wen SHI Guang-yu
    2015, 31(9):250-255. DOI: 10.13982/j.mfst.1673-9078.2015.9.041
    [Abstract](1066) [HTML](0) [PDF 778.96 K](1132)
    Abstract:
    Abstract: The δ13C and δ15N values of eggs was measured using an isotope ratio mass spectrometer to trace the origin of pigments in eggs. A total of 320 layer chickens were randomly divided into four groups that were fed diets containing different corn content and an additional four groups that were fed diets containing different amounts of added artificial pigment. The values of Roche color fan (RCF), δ13C, and δ15N of yolks were measured on Day 28 (early stage) and Day 56 (late stage). The results indicated that the RCF and δ13C values of egg yolk in each group increased with an increasing corn content, and significant differences were observed between groups fed diets with different corn content (P < 0.01). In the late stage, when the feeds of the 10% corn and 70% corn groups were swapped, the RCF values and δ13C values of egg yolk in both groups were significantly different compared with their previous results (P < 0.01), while no significant differences were found in these values for the two groups without feed swapping (P > 0.05). For the varying pigment groups, the RCF values increased significantly with an increase in amount of added artificial pigment (P < 0.05) in the early stage, whereas after the removal of pigment, the RCF values showed no significant differences (P > 0.05). Additionally, no significant differences were found in δ13C values before and after pigment removal (P > 0.05). In the varying corn content groups, a strong positive correlation (P < 0.01) was found between RCF and δ13C values, but no correlation was found in the varying pigment groups. When the RCF values were the same in two groups, δ13C values showed significant differences. Thus, analysis of carbon stable isotope ratio (δ13C) in egg yolk can be used to trace the origin of pigment in eggs.
    42  Proteomic Analysis of Juglans mandshurica Maxim from Changbai Mountain Using Shotgun Sequencing
    LI Jing-jing LIU Chun-lei MIN Wei-hong LIU Jing-sheng LI Hong-mei ZHENG Hong-yan
    2015, 31(9):256-262. DOI: 10.13982/j.mfst.1673-9078.2015.9.042
    [Abstract](1289) [HTML](0) [PDF 862.66 K](1418)
    Abstract:
    Juglans mandshurica Maxim kernel protein isolates, prepared by alkaline solubilization and acid precipitatio, were hydrolyzed with trypsin, isolated through column chromatography, and identified using shotgun proteomics. From the hydrolyzate, 61 proteins were identified. Gene Ontology classification showed that these proteins were mainly distributed in a range of 1~100 kDa. Among them, 21 proteins were in a range of 10~20 kDa and the isoelectronic points (pI) of 19 proteins (31.15%) were between 6.00~7.00. The number of residues ranged from 100~300 in 28 proteins. The 49 proteins had GRAVY values <0.00, being of hydrophilic proteins. 10 proteins had transmembrane domains. Walnut proteins could be divided into 13 categories by biological processes, and 42 proteins were related to metabolic processes. Regarding the cellular components, 24 proteins were from cells and 16 were from organelles. Regarding molecular function, the proteins could be classified into six types; 34 proteins (55.74%) exhibited catalytic activities, and 26 proteins (42.62%) possessed binding activities. Through mass spectrometry, the present study provided a theoretical basis and experimental data for the functions of walnut kernel proteins in the body.
    43  Measurement of Triterpenic Acid Content and Its Distribution in Loquat Leaves Based on the Hyperspectral Imaging Technique
    ZOU Xiao-bo XU Yi-wei CHEN Wu SHI Ji-yong ZHU Yao-di SHEN Ting-ting
    2015, 31(9):263-267. DOI: 10.13982/j.mfst.1673-9078.2015.9.043
    [Abstract](848) [HTML](0) [PDF 819.42 K](1257)
    Abstract:
    Triterpenic acids are abundant in Loquat leaves, which present a relatively high medicinal value. The relative relationship between hyperspectral signal and triterpenic acid content was established and the distribution of triterpenic acids in loquat leaves was measured using hyperspectral images, as they contain the spectral signal for each pixel. Synergy interval partial least squares (siPLS) was used to establish an analytical model of triterpenic acid content in loquat leaves. The results showed that the optimal model was obtained by the siPLS spectral region screening method, which separated the whole spectrum into 11 intervals and combined four intervals, including intervals 1, 5, 6, and 7, and had a factor number of 4. The model achieved a correlation coefficient of 0.8449 and root mean square error of cross validation (RMSECV) of 3.392 mg/g in the calibration set and a correlation coefficient of 0.8223 and root mean square error of prediction (RMSEP) of 3.73 mg/g in the prediction set. Every pixel in the hyperspectral image was computed and the triterpenic acid content of each pixel was obtained according to the siPLS model, followed by the creation of a pseudo-color map to describe the distribution of triterpenic acids in loquat leaves. Overall, the results sufficiently demonstrate that it is feasible to employ hyperspectral imaging technology to measure the content of triterpenic acid and its distribution in loquat leaves.
    44  Comparison of Aroma Components in Eleven Medium- and Late-maturing Yantai Apple Cultivars by Multivariate Statistical Analysis
    SUN Cheng-feng ZHU Liang ZHOU Nan YANG Jian-rong LI Yan-shen JIANG Zhong-wu
    2015, 31(9):268-277. DOI: 10.13982/j.mfst.1673-9078.2015.9.044
    [Abstract](1027) [HTML](0) [PDF 852.50 K](1214)
    Abstract:
    To investigate the differences in the major aroma components between medium- and late-maturing Yantai apple cultivars, headspace solid phase microextraction (HS-SPME) combined with gas chromatography mass spectrometry (GC-MS) was employed . The apple cultivars and their aroma components were analyzed using principal component analysis (PCA) and cluster analysis (CA). The results showed that 59 aroma compounds were identified from 11 apple cultivars, and 21 of these were common to all apple cultivars. Among the common aroma components, acetate esters, butyrate esters, hexanoate esters, hexanal (including 2-hexenal), and some higher alcohols showed higher concentrations. The PCA results indicated that the comprehensive scores of Yang Guang and Dan Xia apples were the highest, while that of the Extremely Precocious Fuji apple was the lowest. The comprehensive score ranking reflected the differences of the major aroma components between the apple cultivars. The CA results showed that 11 apple cultivars could be classified into four clusters. Yantai Fuji 3, Dou Nan, Gan Hong, Extremely Precocious Fuji, Pinova, Yantai Fuji 1, and Best Short Fuji were classified into a cluster; Dan Xia and Yang Guang were classified into a cluster; and Liang Xiang and Hua Shuai were classified into two clusters. Through an effective combination of PCA and CA, the aroma characteristics of four apple cultivars (Dan Xia, Yang Guang, Liang Xiang, and Hua Shuai) were more prominent, providing a basis for parent selection in future apple breeding.
    45  Detection of Virulent Vibrio parahaemolyticus Strains from Commercial Shellfish in Shanghai by Loop-mediated Isothermal Amplification
    HAN Xiao-long ZHANG Hai-yan CAO Ming-xiu SHEN Xiao-sheng
    2015, 31(9):278-283. DOI: 10.13982/j.mfst.1673-9078.2015.9.045
    [Abstract](845) [HTML](0) [PDF 574.21 K](1150)
    Abstract:
    Loop-mediated isothermal amplification (LAMP) was used to detect and analyze virulence-associated genes, thermostable direct hemolysin (tdh) and thermostable-related hemolysin (trh), in Vibrio parahaemolyticus strains isolated from commercial shellfish in Shanghai from August to October, 2014. A total of 180 samples of six common species of shellfish were studied and results were compared between LAMP and polymerase chain reaction (PCR) assays. The detection rates of tdh and trh genes in Vibrio parahaemolyticus strains from commercial shellfish were 12.77% and 11.66% using LAMP as compared to 10.55% and 7.77% by PCR, respectively. Serotyping the isolated virulent strains revealed two O3: K6 serotype Vibrio parahaemolyticus strains, including one carrying double-positive virulence genes (tdh+/trh+). Additionally, high similarity was observed between pulsed-field gel electrophoresis (PFGE) bands of two O3: K6 serotype Vibrio parahaemolyticus strains (similarity > 90%). The results indicate contamination of commercial shellfish in Shanghai by virulent strains of Vibrio parahaemolyticus, where the emergence of tdh+/trh+ O3:K6 serotype Vibrio parahaemolyticus is a cause for concern. Surveillance needs to be strengthened, for Vibrio parahaemolyticus strains of different serotypes, especially the O3: K6 serotype. Results from the comparison with PCR assay indicated that LAMP method was suitable for the detection of virulent strains of Vibrio parahaemolyticus in shellfish.
    46  Interference of Sulfate Esterification in the Detection of Polysaccharide Molecular Weight
    CHEN Hai-xiu WU Yong-pei LIU Yi-xiang CAI Hui-nong LIU Meng LING Shao-mei LI bin
    2015, 31(9):284-287. DOI: 10.13982/j.mfst.1673-9078.2015.9.046
    [Abstract](977) [HTML](0) [PDF 775.69 K](1342)
    Abstract:
    Sulfate esterification facilitates a number of biological activities, such as antiviral and anticoagulant effects, that are unique to polysaccharides. Its activity is strictly controlled by molecular weight. However, dextran is widely used as the standard substance in the determination of the molecular weights of sulfated polysaccharides and its use inevitably leads to the misjudgment of active sulfated polysaccharide molecular weight. The rheological mechanic differences between standard dextran and dextran sulfate were observed by comparing the characteristic viscous parameters of the two substances. An improved Mark-Houwink-Sakurada (MHS) model and conventional column chromatography were used to analyze the interference of sulfate esterification in the detection of polysaccharide molecular weight. The results showed that dextran and dextran sulfate have different fluid mechanics. The gradient of the correlation equation for dextran concentration and its reduced viscosity was positive, whereas that for dextran sulfate was negative. Improved MHS model also demonstrated significant differences in the specific coefficients in the DB equations of the two polysaccharides. The results of column chromatography showed that the molecular weight detected with dextran sulfate was far greater than the true value if dextran was used as the standard substance. In summary, sulfate esterification may change the rheological behavior of polysaccharides and is thus a fundamental cause for the misjudgment of polysaccharide molecular weight measured using normal detection methods.
    47  Texture, Free Amino Acid Content, and Volatile Compounds of Chicken Meat Fermented by Penicillium nalgiovense
    LIU Gong-ming SUN Jing-xin LI Peng YU Lin-hong HUANG Ming XU Xing-lian YU Bing
    2015, 31(9):289-295. DOI: 10.13982/j.mfst.1673-9078.2015.9.047
    [Abstract](1068) [HTML](0) [PDF 964.58 K](1257)
    Abstract:
    Abstract: Changes in the edible quality of chicken meat fermented by Penicillium nalgiovense were studied using a texture analyzer (TA-XT plus), gas chromatograph-mass spectrometer (GC-MS), and high-speed amino acid analyzer (Agilent 1100). Chicken meat paste was sterilized by autoclaving, inoculated with Penicillium nalgiovense, pre-fermented for 3 days at 27 ± 1 ℃, and ripened for 7 days at 4 ℃, to produce a fermented chicken meat product. Changes in certain aspects of the edible quality such as texture, free amino acid (FAA) content, and volatile compounds were compared among meat samples during fermentation, including the final fermented chicken meat products and unfermented meat samples (control). The results showed that, for the meat samples, during fermentation, hardness first increased and then decreased. Springiness decreased gradually, while gumminess increased gradually. The FAA content, essential FAA and flavor FAA, in the fermented chicken meat product ripened for 7 days increased significantly (P < 0.05). The volatile compounds in the final fermented chicken meat products were mainly alcohols, aldehydes, ketones, and esters, of which guajacolum and γ-butyrolactone were newly formed when compared to those in unfermented chicken meat samples. Hence, sterilized chicken meat fermented by fungi presents an acceptable edible quality and represents a creative way to develop a new type of fermented meat product.
    48  Relationship between Amino Acids and Ethyl Carbamate in Wine
    ZHANG Ying LIU Guo-xin ZHU Liu-yang ZHANG Jian
    2015, 31(9):296-300. DOI: 10.13982/j.mfst.1673-9078.2015.9.048
    [Abstract](915) [HTML](0) [PDF 745.35 K](1200)
    Abstract:
    Ethyl carbamate, a type 2A carcinogen, widely exists in fermented foods and is generated by the reaction of carbamyl compounds and ethanol. The amino acids in grape juice are transformed to carbamyl compounds via the nitrogen metabolism of Saccharomyces cerevisiae and in turn form ethyl carbamate. To examine the relationship between amino acids and ethyl carbamate in wines, this study used a simulated grape juice lacking amino acids and compared its ethyl carbamate and urea content with that in normal simulative grape juice after fermentation. In addition, an N15 isotope tracer was used to confirm the contribution of amino acids in the formation of ethyl carbamate. The results showed that as the sole nitrogen fermentation source, diammonium phosphate could not generate ethyl carbamate and did not affect the normal fermentation process when it replaced the missing amino acids. Furthermore, urea and ethyl carbamate contents decreased significantly in the arginine-lacking simulated grape juice after fermentation, whereas the lack of other amino acids had no significant effect on this measure. N15 isotope tracing proved that the guanidine nitrogen atoms of arginine were involved in ethyl carbamate synthesis. The results of this study provide a new direction for mining the precursor of hazardous substances in fermented foods.
    49  Relationship between Freshness and Volatile Organic Components of Goat Meat
    LI Zhi-cheng FU Mang-juan YUE Tian-li BAI Lian-she LI Meng HU Hai-mei
    2015, 31(9):301-308. DOI: 10.13982/j.mfst.1673-9078.2015.9.049
    [Abstract](874) [HTML](0) [PDF 875.63 K](1365)
    Abstract:
    To develop intelligent refrigerators that can evaluate the freshness of chilled meat based on the content of volatile organic compounds, changes in the content of volatile organic compounds of goat meat stored at 4 ℃ ± 2 ℃ were analyzed using headspace solid-phase microextraction–gas chromatography-mass spectrometry (HS-SPME- GC-MS). Indicators of goat meat freshness, including total volatile basic nitrogen (TVB-N), total bacterial count, and pH, were measured to explore the relationship between freshness and volatile organic compounds in goat meat. The results showed that after a 5-day cold storage of fresh goat meat, there were no obvious patterns in the components contributing to the characteristic odor of fresh goat meat (except for butanoic acid ethyl ester). The characteristic volatile organic compounds that were generated when the fresh meat turned stale included 2-butanone, 2-methyl-butanal, 3-methyl-butanal, trichloromethane, 3-methyl-1-butanol, and 3-hydroxy-2-butanone, at concentrations of 92.87, 5.81, 27.39, 30.53, 175.76, and 159.96 μg/L, respectively. Components causing the characteristic odor showed a moderate to high correlation with the freshness of goat meat (p < 0.001 to p < 0.05) (except for 3-hydroxy-2-butanone on Day 7). The results provide a theoretical basis for the evaluation of goat meat freshness based on the content of volatile organic compounds.
    50  Determination of L-Se-methylselenocysteine Content by Chiral Chromatography
    HUANG Xiao-wan WANG Shan JIE Qin-feng QIU Wei-hua HE Yue-ming DENG Ze-yuan
    2015, 31(9):309-313. DOI: 10.13982/j.mfst.1673-9078.2015.9.050
    [Abstract](1060) [HTML](0) [PDF 716.95 K](1447)
    Abstract:
    L-Se-methylselenocysteine is a new selenium-containing food supplement; however, no studies regarding the safety of D-Se-methylselenocysteine have been reported. Current methods for the determination of L-Se-methylselenocysteine content mainly focus on the measurement of total Se-methylselenocysteine content and cannot differentiate it from the content of L-Se-methylselenocysteine. High-pressure liquid chromatography (HPLC) was used in this study to estimate L-Se-methylselenocysteine content using chiral separation, and a standard curve was established. Reliable chromatographic separation was achieved on an EC250/4 NUCLEOSIL Chiral-1 column (4 mm × 250 mm, 5 μm) when the mobile phase was 0.4 mmol/L CuSO4?5H2O, column temperature was 35 ℃, flow rate was 1.0 mL/min, sample size was 20 μL, and detection wavelength was 240 nm. Under these conditions, the calibration curves established showed good linearity across the concentration range of 0.541~1.352 mg/ml, with a correlation coefficient of 0.9999 and an average recovery of 97.73%. The method is simple, accurate, and can be used to monitor the quality of L-Se-methylselenocysteine and its related products.
    51  Anti-obesity and Anti-diabetic Effects of Fucoxanthin
    PENG Juan DENG Xia-qing AO Yu-su YUAN Jian-ping
    2015, 31(9):314-325. DOI: 10.13982/j.mfst.1673-9078.2015.9.051
    [Abstract](1094) [HTML](0) [PDF 853.43 K](1546)
    Abstract:
    Obesity and type II diabetes are rapidly taking a form of global epidemics. Fucoxanthin, a characteristic carotenoid found in brown seaweeds, has potential anti-obesity and anti-diabetic properties and may be effective for the treatment of these two conditions. The polyene chromophore tail of fucoxanthin, which contains an allenic bond and two hydroxyl groups, is believed to be a key factor for the bioactivities of the compound. Fucoxanthin induces mitochondria uncoupling protein 1 in white adipose tissue (WAT), which leads to increased heat production. In addition, fucoxanthin improves insulin resistance and decreases blood glucose levels through the regulation of cytokine secretion in WAT. This article provides a comprehensive review of the anti-obesity and anti-diabetes effects of fucoxanthin.

    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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