Volume 32,Issue 7,2016 Table of Contents

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  • 1  Preventive Effects of Lotus Seed Pod Procyanidins on Extremely Low Frequency Electromagnetic Exposure-induced Immune Function Injury
    ZHANG Hai-hui CHENG Yan-xiang LUO Xiao-ping HE Yuan-qing LI Chang-zheng QU Wen-juan DUAN Yu-qing
    2016, 32(7):1-5. DOI: 10.13982/j.mfst.1673-9078.2016.7.001
    [Abstract](840) [HTML](0) [PDF 797.51 K](1066)
    Abstract:
    To explore the effects of lotus seed pod procyanidins (LSPCs) on extremely low frequency electromagnetic field (ELF-EMF) exposure-induced immune function injury in male mice, a semi-in vitro method was used to study the effect of LSPCs on splenic lymphocyte proliferation, natural killer (NK) cell activity, interleukin 4 (IL-4), and interferon gamma (IFN-γ) in the plasma and liver. In addition, the immunomodulatory activity of LSPCs was preliminarily determined. The proliferation of T and B lymphocytes was measured by a [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] tetrazolium (MTT) reduction assay. NK cell activity was determined by a lactate dehydrogenase (LDH) release assay, and the concentrations of IL-4 and IFN-γ in plasma and liver were measured by an enzyme-linked immunosorbent assay (ELISA) kit. Our experiments indicated that after ELF-EMF radiation, the spleen and thymus indices were significantly decreased (p< 0.05, p < 0.01, respectively) compared to those of the control. MTT and LDH release assays showed that the proliferation of T and B lymphocytes and NK-cell activity decreased significantly in the ELF-EMF group (p < 0.01). The concentration of IL-4 and IFN-γ decreased significantly in the plasma and liver. However, pretreatment with LSPCs improved the above indicators compared to those of the ELF-EMF group. Especially for the ELF-EMF+LSPCs90 group, the spleen and thymus indices increased significantly (p < 0.05, p < 0.01, respectively), the proliferation of T and B lymphocytes was significantly stimulated, and NK cell activity and secretion of IL-4 and IFN-γ in the plasma and liver were promoted. In conclusion, LSPCs can effectively prevent the ELF-EMF-induced immune injury and regulate immune activity.
    2  Reduction of Bovine β-lactoglobulin Allergenicity via Bifidobacterium longum BBMN68 Modulated-dendritic Cells in Mice
    YANG Jing LUO Xu-gang REN Fa-zheng
    2016, 32(7):6-11. DOI: 10.13982/j.mfst.1673-9078.2016.7.002
    [Abstract](876) [HTML](0) [PDF 886.36 K](1196)
    Abstract:
    To clarify the mechanism of probiotics on alleviating food allergy symptoms, bovine β-lactoglobulin (BLG) was used as the allergen to construct a food-allergy mouse model. BALB/c mice were sensitized by oral administration of Bifidobacterium longum BBMN68 (BBMN68). Levels of cytokines and immunoglobulins in the serum and cell culture supernatant were determined by enzyme-linked immunosorbent assay (ELISA), and the changes in the number of CD4+CD25+Foxp3+Treg cells and different subsets of dendritic cells (DCs) were evaluated by flow cytometry. The results showed that BBMN68 alleviated the T-helper 1 (Th1)/T-helper 2 (Th2) imbalance, and reduced hypersensitivity reactions in BLG mice. Compared with the allergy group, the administration of BBMN68 significantly enhanced the expression of CD103 (p < 0.05) and reduced the expression of CD86 and MHC-II (p< 0.05) of DCs in Peyer’s patches (PP). The numbers of CD4+CD25+Foxp3+Treg cells in the lymphocytes from PP, mesenteric lymph node, and spleen were increased by 41.91%, 71.16%, and 61.25%, respectively, compared with those in BLG mice. These DCs modulated with BBMN68 and the CD4+T cells from BLG mice were isolated and cultured together. The results showed an increased proportion of Foxp3+Treg cells and an elevated secretion of regulatory cytokines TGF-β and IL-10 (p < 0.05). These data demonstrated that the mechanism of BBMN68 for reducing BLG allergenicity was associated with the regulation of DC functions and promotion of the DC-mediated immune suppression.
    3  Primary Structural Characterization and Cell Immunomodulatory Activity of a Non-agar Polysaccharide Obtained from Gracilaria Lemaneiformis
    SHI Chen-shan SUN Gui-qing WU Rui-xia GONG Zheng-si WANG Xiang-hong
    2016, 32(7):12-17. DOI: 10.13982/j.mfst.1673-9078.2016.7.003
    [Abstract](1034) [HTML](0) [PDF 933.85 K](1234)
    Abstract:
    Gracilaria lemaneiformis is an important source of agar, but its non-agar part is often ignored. A non-agar polysaccharide fraction was isolated from Gracilaria lemaneiformis, and its primary structure and in vitro biological activity were preliminarily explored. The non-agar polysaccharide fraction was isolated through the conventional process and was named GCP. The results of pre-column derivatization and high performance liquid chromatography (HPLC) suggested that GCP was composed of galactose. Periodate oxidation and Smith degradation showed that the monosaccharide group was linked by 1→3 and 1→4 glycosidic bonds. I2-KI test and a Congo red test showed that GCP had a large number of branches and long side chains, and the spatial configuration was a single helix or a coil in its free form. A main component, GCP-2 with a molecular weight of 1.05 × 104 U, was obtained after further purification using DEAE Sepharose Fast Flow (DEAE FF) column chromatography. Splenocyte damage and splenocyte proliferation assays were used to analyze the cell immunomodulatory activities of GCP and GCP-2. GCP showed a slightly higher activity than GCP-2 in the test concentration range. The highest splenocyte proliferation rate and the greatest protection rate for damaged splenocytes by GCP were 7.45% and 51.50%, respectively. This study shows that non-agar polysaccharides have good cellular immunomodulatory activity and a strong cell protective effect. In addition, they could be used as raw materials for production of new drugs and health products.
    4  Effects of Konjac Glucomannan and Banana-resistant Starch on Intestinal Secretion of Short-chain Fatty Acids and Blood Lipids in Mice
    JIA Yan WEI Xiu-xiu ZHAO Pei YAN Ya-li CHEN Qing-sen
    2016, 32(7):18-25. DOI: 10.13982/j.mfst.1673-9078.2016.7.004
    [Abstract](912) [HTML](0) [PDF 932.04 K](1015)
    Abstract:
    A type of prebiotic combining konjac glucomannan (KGM) and banana-resistant starch (BRS) was evaluated, to yield an optimized prebiotic formulation that could maintain and improve intestinal and cardiovascular health. Healthy male BALB/c mice were used as models, and one control group and six experimental groups were established. AIN93 purified diets classified into three groups with different amounts of added BRS and three groups with different proportions of BRS and KGM were designed and fed to the mice. Four weeks later, the cecal short-chain fatty acid (SCFA) levels and blood lipid indices in mice were determined. In the analysis of SCFA levels, the secretion of propionic acid in cecal contents of the mice in group BRS 1, group BRS 2, and group BRS + KGM 2 increased significantly (p < 0.05). Additionally, the secretions of acetic acid, butyric acid, and total SCFAs in group BRS 3 and group BRS + KGM 2 were also significantly increased (p < 0.01), as was butyric acid secretion in group BRS + KGM 3. In the analysis of blood lipid levels, the high-density lipoprotein-cholesterol (HDL-C) levels were significantly increased in group BRS 3 (p < 0.01). In both groups BRS + KGM 2 and BRS + KGM 3, levels of total cholesterol (TC) and triglycerides (TGs) were significantly decreased (p < 0.05 and p < 0.01, respectively), whereas HDL-C levels were significantly increased (p < 0.05). In conclusion, SCFA secretion levels and blood lipid levels were altered in a dose-dependent manner in response to BRS and KGM consumption. The comprehensive comparisons performed in this study revealed that the compound formulation (5% KGM + 23.5% BRS) of group BRS + KGM 2 was the best composite prebiotic formulation.
    5  Effect of the Polysaccharides from Hovenia acerba Lindl. on Immune Activity in Cyclophosphamide-Induced Immunodepressed Mice
    YE Wen-bin FAN Liang WANG Yu ZHAO Qing-fang GUO Shou-jun YUN Han-bo
    2016, 32(7):26-32. DOI: 10.13982/j.mfst.1673-9078.2016.7.005
    [Abstract](702) [HTML](0) [PDF 716.83 K](1224)
    Abstract:
    The impact of Hovenia acerba Lindl. (HAP) polysaccharides on immune activity in cyclophosphamide (CTX)-induced immunodepressed mice was studied. Except for the control group, mouse models for all other groups were constructed by intraperitoneal injection with CTX (30 mg/kg) on days 1, 3, 5, 7, and 9, respectively, and the control group was administrated normal saline (NS, 0.1 mL/10 g) by gavage.After the mouse model was established, mice with similar weight were randomly divided into five groups: normal control group, immunodepression model group, and HAP-treated groups (low-, medium-, and high-dose). The intragastric administration of HAP was performed continuously for four weeks, and the effects of HAP on the thymus and spleen indices, spleen lymphocyte proliferation, clearance index, phagocytic index, the concentration causing 50% hemolysis (HC50), the levels of serum interleukin (IL)-2, IL-4, and interferon gamma (IFN-γ), and the difference in toe thickness in CTX-induced immunodepressed mice were assessed. Compared to the CTX group, the spleen index, clearance index, phagocytic index, spleen lymphocyte proliferation, HC50, and the difference in toe thickness were enhanced significantly (p < 0.05) in the HAP groups (with all doses). Levels of serum IL-2, IL-4, and IFN-γ were significantly increased in the low-, medium- and high-dose HAP groups (p < 0.05) in CTX-induced immunodepressed mice. These results suggested that HAP could improve non-specific and specific immunological activities in immunodepressed mice.
    6  Stability of Alaska Pollock-derived Metal Chelating Peptide during In Vitro Gastrointestinal Digestion
    DU Fen HOU Hu ZHAO Yu-ran ZHAO Xue ZHANG Zhao-hui LI Ba-fang
    2016, 32(7):33-38. DOI: 10.13982/j.mfst.1673-9078.2016.7.006
    [Abstract](858) [HTML](0) [PDF 849.40 K](1242)
    Abstract:
    In order to evaluate the gastrointestinal tolerance of a new Alaska pollock skin collagen-derived metal chelating peptide (Ala-Gly-Pro-Ala-Gly-Pro-Arg, peptide M), an in vitro simulated gastrointestinal digestion (SGID) model was established, and this model included two stages: simulated human gastric digestion and simulated human intestinal digestion. The calcium-chelating activity of peptide M was 0.88 ± 0.02 μg/mg, and its iron-chelating activity was 33.67%. The calcium-chelating activity of gastric digestion product S was 0.87 ± 0.03 μg/mg, a 1.14% decrease compared to the pure peptide. The iron-chelating activity of S was 33.72%, an increase of 0.05% compared to the pure peptide. The calcium-chelating activity of intestinal digestion product D was 0.85 ± 0.01 μg/mg, a 3.40% decrease compared to the pure peptide. And the iron-chelating activity of D was 34.13%, an increase of 0.46% compared to the pure peptide. Reversed-phase high-performance liquid chromatography, full scan mass spectrometry, and circular dichroism showed that after two-stage SGID, M molecule did not show a change in molecular mass or cleavage of peptide bonds, but there were changes in the conformation, including a decrease in the proportion of random coils and increases in the proportions of β-sheets and β-turns. Therefore, during the SGID, the amino acid composition in the peptide was not changed, and the spatial conformation was changed. The calcium- and iron-chelating capabilities were not significantly changed. Peptide M showed a high gastrointestinal tolerance in SGID.
    7  Protective Effect of the Polyphenols from Osmanthus fragrans Flowers on TNF-α-induced Inflammation in HUVECs
    LI Hong-ling LI Chun-yang ZENG Xiao-xiong LIU Xiao-lin
    2016, 32(7):39-46. DOI: 10.13982/j.mfst.1673-9078.2016.7.007
    [Abstract](839) [HTML](0) [PDF 1.16 M](1165)
    Abstract:
    An in vitro human umbilical vein endothelial cell (HUVEC) model of inflammation induced by tumor necrosis factor (TNF)-α was established to study the effects of the purified fractions 1, 2, and 3 obtained from the ethanol extracts of Osmanthus fragrans flowers on cell viability (MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction assay), reactive oxygen species (ROS) content, and the activity of superoxide dismutase (SOD) and xanthine oxidase (XOD) in the inflammatory cells. The inflammatory reaction was triggered by TNF-α (10 μg/L) in HUVECs, and then the inflammatory cells were treated with fractions 1, 2, and 3 at concentrations of 6000, 3000, 300, and 30 μg/L. The protective effects of the concentrations and compositions of fractions 1, 2, and 3 on inflammatory cells were evaluated. The results showed that treatment with fractions 2 and 3 at concentrations ranging from 300–3000 μg/L and fraction 1 at a concentration of 3000 μg/L could significantly enhance HUVEC cell viability and SOD activity (p < 0.05), while significantly suppressing XOD activity and reducing ROS content (p < 0.05). The abovementioned treatment exhibited strong anti-inflammatory effects.
    8  Toxic Effects of Organic Solvents on Aspergillus niger GIM 3.25
    WANG Ya-fen ZHAO Guang-lei YUAN Kun LI Xiao-feng
    2016, 32(7):47-52. DOI: 10.13982/j.mfst.1673-9078.2016.7.008
    [Abstract](930) [HTML](0) [PDF 761.29 K](1029)
    Abstract:
    The toxic effects of 11 kinds of organic solvents on microbial cell were investigated. It was found that methanol, acetonitrile and methylbenzene had evident toxic effects on the surface morphologies of A. niger spores, forcing the spores deformation and even rupture. After incubated with t-Amyl alcohol, the morphology of the A. niger spores showed significant changes in both surface and size. Organic solvents also affected the mycelium morphology, the growth of A. niger and their catalytic abilities. Methanol, acetonitrile and chloroform had the higher toxicities than other solvents, while acetone, isopropanol and isooctane had lower cell toxicities. No evident relationship between solvent toxicity and the logP values of the solvents was found in this research.
    9  Persister Formation in Saccharomyces cerevisiae Induced by Cinnamaldehyde
    SHEN Qing-shan ZHOU Wei WANG Miao-yan MO Hai-zhen HU Liang-bin
    2016, 32(7):53-59. DOI: 10.13982/j.mfst.1673-9078.2016.7.009
    [Abstract](755) [HTML](0) [PDF 782.71 K](1157)
    Abstract:
    The effects of cinnamaldehyde (CA) on persister formation in Saccharomyces cerevisiae were investigated in this study. CA was found to effectively inhibit the growth of S. cerevisiae in a 96-well plate with a minimum inhibitory concentration value of 0.4 mM. The formation of persister cells in S. cerevisiae cells after exposure to cinnamaldehyde was further explored by flow cytometry and serial dilution-drop plate counting methods. The results showed that CA inhibited the growth of S. cerevisiae cells, and S. cerevisiae cells were induced to form the persister state showing amphotericin B resistance. Further studies showed that CA treatment led to growth arrest of S. cerevisiae cells at any stage in the cell cycle, whereas cells undergoing autophagy induced by rapamycin stopped during the G1 phase. Therefore, persisters in S. cerevisiae differed from cells in autophagy. Previous studies of persister mainly focused on prokaryotic pathogens rather than eukaryotic cells. Additionally, the natural persister population accounted for an extremely small proportion of the overall population, creating challenges in studies of the genetic mechanisms underlying their formation. The findings of this study showed that CA treatment induced persister formation in most S. cerevisiae cells, providing a method for understanding the genetic mechanism underlying persister formation in eukaryotes. Results also confirmed that the YGL gene was significantly associated with persister formation in S. cerevisiae.
    10  Application of Colony Immunoblotting for Counting and Isolating Lactobacillus rhamnosus in Intestinal Flora
    YANG Zhen-quan GONG Xiang-lei YE Ping XIE Xin ZHANG Yu GAO Lu RAO Sheng-qi YIN Yong-qi
    2016, 32(7):60-65. DOI: 10.13982/j.mfst.1673-9078.2016.7.010
    [Abstract](842) [HTML](0) [PDF 789.49 K](959)
    Abstract:
    A specific antibody against pilus protein (FimI) of Lactobacillus rhamnosus (Lr) was prepared, to develop a colony immunoblotting (CIB) counting and isolation method for Lr. BALB/c mice were immunized with recombinant FimI (rFimI) to obtain the antiserum, and the reactivity and specificity of the antiserum were tested by western blotting and whole bacterial dot-blot analysis. The CIB counting method was developed based on the rFimI antiserum, and was used to quantitatively detect Lr in the artificial sample (mouse intestinal flora + Lr) and the fecal samples from mice fed with Lr by gavage. The titer of the obtained antiserum was 1:51,200 and this antiserum showed strong reactivity with both the lysate and whole cells of Lr, but no cross-reactivity with the intestinal flora of mouse. The optimum dilution of rFimI antiserum for CIB was 1:2000, and clear immunoblots were observed on all colony transfer membranes of samples containing Lr. The positive colony number determined using the CIB method agreed with the Lr concentration in the artificial samples, which may reflect the fluctuation tendency of Lr in fecal samples from the mouse fed with Lr by gavage. The established CIB counting method can be used to selectively count and isolate Lr in intestinal samples.
    11  Construction of Attenuated Listeria monocytogenes (actA/inlB) and Preliminary Identification of Biological Activity
    DING Cheng-chao ZENG Hai-juan ZHONG Fei-fei CHEN Guo-wei DONG Qing-li XIE Man-man WU Man LIU Wu-kang LIU Qing
    2016, 32(7):66-71. DOI: 10.13982/j.mfst.1673-9078.2016.7.011
    [Abstract](1198) [HTML](0) [PDF 860.21 K](1362)
    Abstract:
    Attenuated Listeria monocytogenes (Lm) has the potential to become a live vaccine vector. It can also produce major histocompatibility complex (MHC)Ⅰ and MHC Ⅱ antigen presentation systems, and significantly stimulate immunity in cluster of differentiation (CD)8+ and CD4+ cells. The construction of avirulent gene deletion strains and the subsequent evaluation of their biological activity are crucial for the development of live vaccine vectors. Homologous recombination technology was used to construct Lm-?actA and Lm-?actA/?inlB strains, and the biological activities of attenuated strains were explored in terms of growth, virulence gene expression, and the capacity to invade HepG2 cells. The results showed that no difference in growth was found among the attenuated strains Lm-?actA, Lm-?actA/?inlB, and wild type Lm (EGD-e). Real time quantitative polymerase chain reaction (PCR) results showed that inlA expression was enhanced two-fold after the actA gene was deleted. The expression of plcB and hly genes was significantly elevated when actA and inlB genes were simultaneously deleted. The HepG2 cell invasion assay showed that the invasive capacity was enhanced after the actA gene was deleted and was weakened after deleting actA and inlB genes. Therefore, the construction of attenuated strains and study of their biological properties is not only important for understanding the pathogenesis of food-borne Lm, but also lays a foundation for the construction of vaccine vectors for the prevention of human and animal diseases.
    12  Isolation, Purification, and Properties of Naringinase Produced from Aspergillus niger FFCC 848 by Liquid Fermentation
    WANG Wei-na LI Qian TIAN Jing FEI Xu XU Long-quan LIAN Meng
    2016, 32(7):72-78. DOI: 10.13982/j.mfst.1673-9078.2016.7.012
    [Abstract](955) [HTML](0) [PDF 847.10 K](1147)
    Abstract:
    The isolation, purification, and enzymatic properties of naringinase produced by liquid fermentation with Aspergillus niger FFCC 848 were investigated. The fermentation broth produced from liquid fermentation by A. niger FFCC 848 was purified by ammonium sulfate fractional precipitation, dialysis, and DEAE-Sepharose FF anion exchange chromatography to yield highly purified naringinase. Only one clear band was observed upon sodium dodecyl sulfate polyacrylamide gel electrophoresis, with a molecular weight of 65.10 ku. The final, purified naringinase showed 13.82-fold purification, with an enzyme activity recovery of 13.30% and specific activity of 6932.54 U/mg, and the enzyme could effectively hydrolyze naringin. Furthermore, the activity of naringinase was stable at 20–50?C and pH 3.0–6.0; optimum activity was observed at 50?C and pH 4.5. In a specific concentration range, the enzyme activity was enhanced by K+, Ca2+, and Na +, but was strongly inhibited by Fe3+, SDS, and EDTA-Na2. This study provides a basis for understanding the purification of naringinase and for further studies of the related mechanism underlying the bioconversion of bioactive natural products with naringinase.
    13  Expression of Bile Salt Hydrolase Genes in Lactobacillus plantarum KLDS1.0386
    TANG Ya-ru LI Bai-liang LI wan YU Shang-fu HUO Gui-cheng
    2016, 32(7):79-84. DOI: 10.13982/j.mfst.1673-9078.2016.7.013
    [Abstract](702) [HTML](0) [PDF 869.69 K](900)
    Abstract:
    The expression levels of four key genes encoding bile salt hydrolase in Lactobacillus plantarum KLDS1.0386 were investigated at the transcriptional level during the different growth phases. Different concentrations of taurodeoxycholate and glycodeoxycholate were used as substrates, 16s rRNA gene was used as the internal standard, and real-time quantitative polymerase chain reaction (PCR) method was used to detect the variations in the expression of the bile salt hydrolase genes (bsh1, bsh2, bsh3, and bsh4) in the presence of taurodeoxycholate and glycodeoxycholate at different concentrations. The results showed that the amplification efficiencies of the reference gene and target genes were in a range of 90~105%, indicating that the expression levels of the target genes were well reflected. The real-time quantitative PCR results showed that the expression levels of four bile salt hydrolase genes increased significantly when the incubation time was prolonged. bsh1, bsh2, bsh3, and bsh4 were expressed in two types of bile salts. The expression levels were upregulated by bile salts at different concentrations (1%, 2%, and 3%), and the increment exhibited an extremely significant upward trend with increasing bile salt concentrations. Additionally, the expression level of each gene was different in the presence of two different bile salts at the same concentration. The gene expression level was generally higher in the presence of glycodeoxycholate (GDC) than that in the presence of taurodeoxycholate (TDC).
    14  Effect of Pretreatments on Release of Collagen-derived Angiotensin-converting-enzyme Inhibitory Peptide in Enzymatic Hydrolysis
    HUANG Dan-dan MA Liang CAI Lu-yun LIU Yi YANG Hui HAN Shuang ZHANG Yu-hao
    2016, 32(7):85-90. DOI: 10.13982/j.mfst.1673-9078.2016.7.014
    [Abstract](730) [HTML](0) [PDF 794.03 K](926)
    Abstract:
    The effects of five pretreatments (acid, alkali, heat, ultrasound, and high pressure) on the production of angiotensin-converting-enzyme (ACE) inhibitory peptide from collagen were explored. After pretreatment, collagen was hydrolyzed by Alcalase, and the degree of hydrolysis (DH), ACE inhibitory activity, and the molecular weight distribution of the hydrolysate were measured. Results showed that alkali- and ultrasound-treated groups had higher DH and ACE inhibition rate than the untreated group, which indicated that these two pretreatments can favor exposure of sites in the triple-helical region of collagen. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the structure of collagen, and the results showed that alkali treatment changed the configuration of collagen, affected the balance of non-covalent bonds, and exposed the hydrophobic site completely in the triple-helical region of collagen. However, the integrity of the subunits was maintained. Ultrasound treatment damaged the covalent bonds in the helical region of collagen and exposed more hydrophobic sites, which was helpful for alcalase hydrolysis. In contrast, acid, heat, and high-pressure treatments mostly affected the non-helical region of collagen, and could not promote the release of ACE inhibitory peptide from collagen during enzymatic hydrolysis.
    15  Isolation, Identification, and Screening of Dominant Yeast Strains in Fried Cake Made from Natural Fermented Glutinous Rice
    SHAO Bing-jie TAO Yong-qing WANG Su-ying BI Lian-ke ZHU Xiao-hao CHEN Jin
    2016, 32(7):91-96. DOI: 10.13982/j.mfst.1673-9078.2016.7.015
    [Abstract](1218) [HTML](0) [PDF 895.26 K](962)
    Abstract:
    To explore the dominant yeast strain in industrial pure or mixed fermentation during the preparation of Tianjin erduoyan fried cake, the rice slurry and fermented dough were used as experiment material, and six yeast strains were separated and purified by the streak plate method using slurry solid culture medium.Based on observations of colony morphology in Wallerstein Laboratory (WL) medium and individual cell morphology, determination of physiological and biochemical characteristics, and 18S rRNA gene sequence analysis, strains Y2 and Y3 were identified as Saccharomyces cerevisiae and strain Y4 was identified as Pichia occidentalis. Besides, Y7-1 and Y7-2 were identified as Candida humilis, and Y8 was identified as Galactomyces geotrichum. Gas production, carbon source utilization rate, and cell growth rate of each strain were determined. Results showed that Y2 had a fast gas production rate and the highest gas production. At the end of fermentation, the content of residual sugar in the fermentation broth was the lowest (16.33 mg), and the optical density at 600 nm (OD600) during exponential growth phase was 0.149. Thus, strain Y2 is the dominant yeast in the production of fried fermented glutinous rice cake, and has the potential to be a pure fermentation agent. This study provides a theoretical basis for the quality control and industrial production of erduoyan fried cake.
    16  Protein Fractions on Pasting Properties of Non-waxy Rice Flour
    YI Cui-ping YANG You-wang GAO Wen-ming
    2016, 32(7):97-102. DOI: 10.13982/j.mfst.1673-9078.2016.7.016
    [Abstract](713) [HTML](0) [PDF 807.02 K](871)
    Abstract:
    Protein fractions on pasting properties of non-waxy rice flour were investigated through the fraction removed method, as well as the protein structures were analyzed. The results of RVA and DSC indicated that the peak viscosity, hot paste viscosity and final viscosity increased in different degree after the treatment, while the breakdown, setback and paste temperature decreased. The results of SDS-PAGE and microstructure analysis demonstrated that the mechanisms of pasting property affected by protein fractions were distinct: because binding to cellulose tightly glutelin lead to repel the swelling of starch granule, prolamin absorb water to swell and interact with starch, albumin and globulin hydrolyze or synthetize the rice component through bioactive constituents such as enzyme, starch granule associated protein affect the intrinsic pasting property of non-waxy rice flour. Compared with isolate and reconstitute method, the fraction removed method have more protein interaction, which lead to the diversity of the pasting value.
    17  Prediction of the Influencing Factors of Protein Thermal Stability using Random Forest and Feature Selection Techniques
    ZHANG Li AI Hai-xin ZHANG Ji-kuan HU Huan LIU Hong-sheng MA Shu-cai
    2016, 32(7):103-108. DOI: 10.13982/j.mfst.1673-9078.2016.7.017
    [Abstract](1005) [HTML](0) [PDF 705.36 K](939)
    Abstract:
    Thermal stability is crucial for implementation of an enzyme in the food industry. The thermostability of enzymes were predicted through protein sequences, using a random forest algorithm and the important influencing factors on protein thermal stability were analyzed. Four hundred and thirty protein features were calculated for 1600 enzymes extracted from the Swiss-Prot database that contained thermal stability information. The data imbalance was solved by using repeated under-sampling methods, and the 30 most-important features were selected by backward recursive feature elimination (RFE). The classification performances of different random forest models built by different feature subsets were evaluated by cross-validation and independent testing. The results indicated that the model built by amino acid composition exhibited the best performance (accuracy = 85.83%, sensitivity = 89.16%, specificity = 73.33%, precision = 77.00%, and F-measure = 74.87%), suggesting that amino acid composition had the most significant impact on the thermal stability of an enzyme. Further, it was found that thermophilic enzymes contained relatively high contents of glutamic acid, isoleucine, and lysine, whereas mesophilic enzymes contained high contents of glutamine, serine, and threonine. The results in this study provided a theory and method for engineering proteins to improve enzyme thermostability for the food industry.
    18  Effects of the Hydrophile-Lipophile Balance Value of Surfactants on the Characteristics of Enzymatic Hydrolysis in Walnut Kernels
    ZHAO Mou-ming XU Ju-cai LIU Lei ZHAO Rong-zhong DING Liu-gang ZHAO Yue Nurmemet OBUI SU Guo-wan
    2016, 32(7):109-114. DOI: 10.13982/j.mfst.1673-9078.2016.7.018
    [Abstract](933) [HTML](0) [PDF 813.65 K](1160)
    Abstract:
    The effects of the hydrophile-lipophile balance (HLB) value of surfactants on the oil extraction rate, enzymatic hydrolysate supernatant yield, emulsified layer formation rate, protein recovery, and protein reducing power of walnut hydrolysates were examined in this research. And the molecular weight distribution of the peptides in the enzymatic hydrolysate, the droplet size distributions in the emulsified layer, and the composition of the emulsified layer were determined to further investigate the underlying mechanisms. The results showed that the oil extraction rate decreased gradually as the HLB value increased. The emulsified layer formation rate and the contents of proteins or peptides with molecular weights higher than 5000 or 3000 Da increased gradually as the HLB value increased. In addition, the yields of enzymatic hydrolysate supernatants and proteins initially tended to decrease, then increased, and finally decreased. Compared with the blank control, the oil extraction rate was increased by five percent at an HLB value of one. When the HLB value was 13.5, the contents of surface proteins and peptides in the emulsified layer decreased significantly, the particle sizes of the fat globules in the emulsified layer increased, and protein recovery in the enzymatic hydrolysate supernatant improved significantly. However, the antioxidant activity of the walnut hydrolysate was not significantly altered.
    19  Effects of Extraction Method on the Physicochemical Profiles and Colloidal Properties of Green Tea Cream
    LI Bin LUO Wei CHEN Zhong-zheng ZHANG Yuan-yuan GAO Xiong LI Xiao-ling LIN Xiao-rong
    2016, 32(7):115-123. DOI: 10.13982/j.mfst.1673-9078.2016.7.019
    [Abstract](839) [HTML](0) [PDF 795.97 K](990)
    Abstract:
    To explore the effects of extraction method on the formation of green tea cream and the potential underlying mechanisms, Yunnan “large-leaf” green tea samples were extracted using a water bath, a microwave, and ultrasonography. The colloidal properties of the particles in original infusions and the green tea cream were analyzed using dynamic light scattering and other techniques, and corresponding physicochemical profiles were determined with high-performance liquid chromatography. The linearity between the cream concentration and infusion concentration in each fraction was analyzed by stepwise regression analysis. The results showed that the number of the infusion particles extracted by ultrasonography was only 53% that of the infusion particles extracted by the water bath. However, the ultrasound-assisted extraction gave higher total cream amount and total creaming rate compared with those by water bath extraction. The amount of total cream in green tea extracted with the microwave was linearly correlated with the ratios of gallated catechins to nongallated catechins and of gallated catechins to methylxanthine alkaloids in the original infusions (R2 = 0.972). In contrast, the amount of total cream in green tea extracted using the water bath was significantly correlated with the original concentration of methylxanthine alkaloids (R2 = 0.969) in infusions. Ultrasound-assisted extraction significantly reduced the diameters of colloidal particles in infusions and cream particles, but did not alter the total cream amounts or total creaming rates relative to those of water bath extraction. Additionally, the amount of total cream in the ultrasound-assisted extract exhibited a weak linear correlation (R2 = 0.632) with the concentrations of protein and methylxanthine alkaloids in the infusion. In conclusion, extraction methods can not only affect the colloidal properties and physicochemical profiles of green tea cream, but also alter the concentration-dependent mechanisms of cream formation.
    20  Application of Genome De novo Assembly and Reference-based Transcriptome Assembly Strategy for Studying Lactobacilli in the VBNC State
    XU ZHEN-bo HOU YU-chao LIU JUN-yan DENG Yang ZHANG Xia LI Bing LI Lin
    2016, 32(7):124-129. DOI: 10.13982/j.mfst.1673-9078.2016.7.020
    [Abstract](932) [HTML](0) [PDF 974.92 K](997)
    Abstract:
    A new reference-based assembly strategy was applied for the transcriptome analysis of a Lactobacillus strain in two physiological states, isolated from beer. First, the genomic information was collected using the Illumina HiSeq 2500 sequencing system and de novo assembly. Next, this Lactobacillus strain was induced into the viable but nonculturable (VBNC) state and total RNA were extracted in the normal and VBNC states. The quality of total RNA was evaluated and RNA with acceptable quality was reverse-transcribed into cDNA. A library was constructed and Solexa sequencing was performed. Based on five relevant indices, the sequencing quality was evaluated. Subsequently, the whole genome sequence obtained previously was used as a control for sequence alignment between the transcriptome and genome, as well as to analyze differences in gene expression. The results showed that the total mapping ratio was greater than 95% after sequence comparison, and 21 significantly up-regulated and seven down-regulated genes were detected. Compared to conventional de novo RNA-Seq technology, this application of genome de novo assembly and reference-based transcriptome assembly strategy can help avoid the tedious steps required in de novo assembly, shows high accuracy, and provides an important foundation for studying the molecular regulation mechanisms of food microorganisms in different physiological states.
    21  Comparative Study of the Thermodynamic Properties of Penaeus vannamei Shell and Meat
    SHI Qi-long ZHANG Ping-ping WANG Rui-ying LI Lin
    2016, 32(7):130-138. DOI: 10.13982/j.mfst.1673-9078.2016.7.021
    [Abstract](768) [HTML](0) [PDF 1.19 M](935)
    Abstract:
    To determine the relationships among water activity (aw), moisture content, and temperature of Penaeus vannamei shell (PV-S) and P. vannamei meat (PV), the moisture adsorption isotherms and thermodynamic properties of PV-S and PV were investigated. The moisture adsorption isotherms of PV-S and PV followed typical type Ⅱ and III behaviors, respectively. The optimum models for describing the adsorption properties of PV-S and PV were the Blahovec-Yanniotis model and GAB model, respectively. For both PV-S and PV, the net isosteric heat of adsorption (differential enthalpy) and differential entropy decreased with increasing moisture content. The spreading pressure increased with increasing aw, but decreased with increasing temperature. The integral enthalpy of PV decreased with increasing moisture content, whereas that of PV-S first increased and then decreased with increasing moisture content. The integral entropy of PV increased with increasing moisture content, whereas that of PV-S first decreased and then increased with increasing moisture content. The adsorption behaviors of PV-S and PV were enthalpy-driven and satisfied the entropy-enthalpy compensation theory. When moisture content was lower than 0.20 g/g, the net isosteric heat of adsorption and differential entropy of PV-S were higher than those of PV. The spreading pressure and integral entropy of PV were lower than those of PV-S, whereas the integral enthalpy of PV was higher than that of PV-S. At a moisture content of 0.07 g/g, the integral enthalpy and integral entropy of PV-S reached a maximum value (1.91 kJ/mol) and minimum value (–14.34 kJ/(mol K)), respectively. The results obtained in the present study will provided a scientific basis for the drying process and storage stability of dehydrated P. vannamei.
    22  Thermal Loss Patterns of Antioxidant BHT in Oil and Frying Systems
    MA Su-min BI Yan-lan LIU Wei TAN Dan-dan
    2016, 32(7):139-144. DOI: 10.13982/j.mfst.1673-9078.2016.7.022
    [Abstract](691) [HTML](0) [PDF 967.26 K](1092)
    Abstract:
    Oil samples added with BHT (2,6-di-tert-butyl-4-methylphenol) was processed by deep frying at 180?C (potato and bean curd) or oven heating. The thermal loss and conversion of BHT were investigated by high-performance liquid chromatography (HPLC) and HPLC-mass spectrometry, and the possible conversion products of BHT in the oil were hypothesized. The results showed that losses of BHT upon deep frying were significantly higher than that in the oven heating system; during high-temperature frying, as frying time increased, the loss of BHT in the oil system were significantly increased. During high-temperature frying, the different ingredients in fried food led to loss of BHT to different extents; BHT was not absorbed by food components, and the enrichment loss of BHT was close to zero. BHT loss occurred mainly through volatilization, followed by conversion. The volatilization loss of BHT primarily yielded its parent form, and the main conversion products were 1,2-di-(3,5-di-tert-butyl-4-hydroxyphenyl) ethane (II) and 2,6-di-tert-butyl-4-methyl anisole (IV). The yield of the conversion products was low. Therefore, BHT loss can occur via volatilization and conversion in heating oil and frying systems.
    23  Effect of Soybean Cultivars on the Processing Characteristics of Brine Tofu and Lactone Tofu
    YANG Jian-ting LI Meng-liang XU Qing HU Xiang-fang ZHANG Dong-dong
    2016, 32(7):145-150. DOI: 10.13982/j.mfst.1673-9078.2016.7.023
    [Abstract](773) [HTML](0) [PDF 717.17 K](1014)
    Abstract:
    Zhonghuang 13, Xiaojinhuang, Black soybean 1, Dongnong 53, and Wuhe wild soybean (new and old) were used as raw materials, and brine and glucono-δ-lactone were used as coagulants to prepare brine tofu and lactone tofu following basic procedures. Texture property analysis (TPA), sensory evaluation, yield, and nutrients of tofu were determined to analyze the effect of soybean cultivars on the processing characteristics of the two types of tofu. The results showed extremely significant differences (p< 0.01) in the sensory score and TPA results of the two types of tofu prepared from different soybean cultivars. Among them, Zhonghuang 13, Xiaojinhuang, and Black bean 1 showed higher sensory scores and better TPA results. Brine tofu prepared from Wuhe wild soybeans had a loose texture, and curd could not be formed from Wuhe wild soybean (old). In comprehensive analysis based on yield as well as protein and fat content, Xiaojinhuang, Zhonghuang 13, and Black soybean 1 were suitable for the preparation of brine tofu; Xiaojinhuang and Black soybean 1 were also suitable for the preparation of lactone tofu.
    24  Comparison of the Antioxidant Activities of Ethanol Extracts from Shuidouchi Samples Fermented using Different Vessels
    FENG Xia ZHAO Xin
    2016, 32(7):151-156. DOI: 10.13982/j.mfst.1673-9078.2016.7.024
    [Abstract](720) [HTML](0) [PDF 785.29 K](983)
    Abstract:
    The antioxidant activities of Shuidouchi samples fermented in different vessels were determined in this study. First, the physicochemical properties of Shuidouchi samples fermented in different vessels were compared, and glass vessel-fermented Shuidouchi (GVFS) showed lower temperature and acidity and higher moisture contents and total bacteria counts than plastic vessel-fermented Shuidouchi (PVFS) and ceramic vessel-fermented Shuidouchi (CVFS). The active isoflavone contents in Shuidouchi samples fermented in different vessels were measured, and the daidzein and genistein contents in GVFS were higher than those in PVFS and CVFS. The in vitro antioxidant experiments showed that the 2,2-diphenyl-1-picrylhydrazyl (DPPH?) free radical and hydroxyl (?OH) radical scavenging capacities of GVFS were also higher than those of PVFS and CVFS. Animal experiments showed that GVFS increased the levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decreased the levels of nitric oxide (NO) and malondialdehyde (MDA) in serum and liver of mice with D-galactose induced oxidative stress, and these effects of GVFS were better than those of PVFS and CVFS. Reverse transcription polymerase chain reaction (RT-PCR) showed that GVFS upregulated the expression of nNOS, eNOS, Mn-SOD, Gu/Zn-SOD, and CAT mRNA and downregulated iNOS expression in the liver of mice subjected to oxidative stress, indicating that these expression levels were close to those in normal mice. Based on these results, GVFS had higher antioxidant activity than PVFS and CVFS, and a glass vessel is suitable for Shuidouchi production.
    25  Effect of Nitrite on the Quality of Roasted Chicken Wings during Processing
    LI Bian-sheng LIN Jun-hong GU Miao-qing RUAN Zheng GUO Wei-bo LIN Guang-ming YANG Huan-bin
    2016, 32(7):157-163. DOI: 10.13982/j.mfst.1673-9078.2016.7.025
    [Abstract](640) [HTML](0) [PDF 1.01 M](1267)
    Abstract:
    The effects of different amounts of nitrite (0, 50, 100, and 150 mg/kg) on color attributes, thiobarbituric acid value (TBA) value, total number of colonies, and organoleptic properties of chicken wing drumettes during curing, drying, roasting, and sterilization were investigated. The results showed that the outside and inside surface color of chicken wing drumettes changed dramatically during processing. Increasing the amount of added nitrite resulted in increased L* and a* values, but the amount of added nitrite did not significantly affect the b* value (P > 0.05). Nitrite can inhibit lipid oxidation during the processing of chicken wing drumettes; during curing, drying, and roasting, higher nitrite levels led to lower TBA values. The sterilized product with added nitrite had lower TBA values (0.961–0.990 mg/kg) than the control sample (1.223 mg/kg) (P < 0.05), but no significant differences were found among the samples to which various amounts of nitrite were added (50, 100, and 150 mg/kg). Nitrite-free roasted chicken wing drumettes had dark and yellow surfaces, lower scores in color and sensory evaluation, and overall acceptability (P < 0.05). The samples with added nitrite had a cured red color, but no significant differences were observed in the sensory scores in terms of mouthfeel, taste, and flavor among samples with various amounts of added nitrite (P < 0.05). Nitrite had no effect on the total number of colonies on the roasted chicken wings during processing.
    26  Synthesis of Schiff Base Metal Derivatives of Apigenin and Their Antioxidant Activity
    LI Hai-xia WEN Li-jun CHEN Li-zhen ZHAI Rui-rui AI Zhao-hui LI Juan CAI Lan-jie
    2016, 32(7):164-169. DOI: 10.13982/j.mfst.1673-9078.2016.7.026
    [Abstract](750) [HTML](0) [PDF 1.00 M](1100)
    Abstract:
    Apigenin (AP) is a natural antioxidant possessing multiple biological activities, but has some limitations such as low efficacy and low utilization. To better develop and utilize AP, its structure was modified. The Schiff-base derivatives of AP ([Co(C22H16O4N)2(H2O)2]?8H2O and [Zn(C22H16O4N)2(H2O)2]?4H2O) were synthesized, and characterized by ultraviolet (UV), infrared (IR), differential scanning calorimetry (DSC)-derivative thermograms (DTG), and other spectroscopic methods. Through the salicylic acid method and the pyrogallic acid-nitroblue tetrazolium (NBT) method, the in vitro superoxide radical and hydroxyl radical scavenging activities of AP and its Schiff-base derivatives were evaluated. Structural characterization showed that two Schiff-base derivatives of AP, [Co(C22H16O4N)2(H2O)2]?8H2O and [Zn(C22H16O4N)2(H2O)2]?4H2O, were successfully prepared. The half-maximal inhibitory concentration (IC50) values of AP, [CoL2], and [ZnL2] on scavenging hydroxyl radical were 880.65 ± 46.52 μg/mL, 517.12 ± 16.36 μg/mL, and 633.62 ± 18.95 μg/mL, respectively. The IC50 values of AP, [CoL2], and [ZnL2] on scavenging superoxide radical were 116.30 ± 3.94 μg/mL, 61.13 ± 0.05 μg/mL, and 48.56 ± 0.32 μg/mL, respectively. Two novel Schiff-base complexes of AP, [Co(C22H16O4N)2(H2O)2]?8H2O and [Zn(C22H16O4N)2(H2O)2]?4H2O, possessed stronger antioxidant activity than AP, which might be a new antioxidant food additive. This research provided a theoretical basis for AP development during future studies on antioxidants.
    27  Formation and Exploration of Maillard Reaction Products during Jinhua Ham Production
    ZHOU Yi-ming HE Li-qing HAO Ting-feng WANG Hong ZHOU Xiao-li
    2016, 32(7):170-175. DOI: 10.13982/j.mfst.1673-9078.2016.7.027
    [Abstract](785) [HTML](0) [PDF 864.88 K](935)
    Abstract:
    Jinhua ham was chosen as the study object to analyze the formation of Maillard reaction products during the processes in Jinhua ham production (salting, sun-drying, ripening), and to study the effects of the Maillard reaction products on the unique flavor and antioxidant activity of Jinhua ham by high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). The results showed that Maillard reactions occurred during the production of Jinhua ham, in particular during fermentation, in which the contents of protein and sugar decreased by 1.17% and 0.65%, respectively. Meat became darker in color, and the degree of browning continuously increased. In addition, during Jinhua ham production, the contents of aldehydes (40%), ketones (20%), and the Maillard reaction products (pyridine, pyrazine, and furans) are increased. Additionally, 5-(hydroxymethyl)furfural (HMF), acrylamide, pyrazine, and other typical Maillard reaction products were produced; the corresponding contents in the end product were 0.16 mg/g, 0.09 μg/g, and 0.025 μg/g, respectively, and they made important contributions to the unique flavor of Jinhua ham. In vitro antioxidant activity assays and Caco-2 cell tests indicated that Jinhua ham can promote the growth of Caco-2 cells and has a high antioxidant activity.
    28  A Primary Study on the Factors Affecting Yeast Growth in a Mixed Culture
    LIU Qian WU Zu-fang FAN San-wei WENG Pei-fang
    2016, 32(7):176-181. DOI: 10.13982/j.mfst.1673-9078.2016.7.028
    [Abstract](855) [HTML](0) [PDF 843.00 K](928)
    Abstract:
    To investigate the factors affecting the growth of different yeast strains in a mixed culture, the effects of initial glucose concentration and pH value on the growth of Saccharomyces cerevisiae (Sc) and Issatchenkia orientalis (Io) were investigated. The differences in organic acid metabolism of the two types of yeasts in a mixed culture were compared using pure cultures as controls. The results showed that low initial glucose concentration, low pH, and differences in organic acid metabolism were the main factors inhibiting the growth of Sc. The glucose consumption rate of Io was faster than that of Sc; in the mixed culture with an initial glucose concentration of 1%, Io consumed glucose preferentially, and the Io/Sc (the ratio of colony numbers) value was 70. Io was more acid tolerant than Sc, and the Io/Sc was 56 in pH 3.5. Regarding organic acid metabolism, Io produced 2.52 g/L lactic acid specifically, and Sc produced 1.14 g/L acetic acid specifically. In a mixed culture, Io could absorb the acetic acid produced by Sc, whereas the lactic acid produced by Io could inhibit the growth of Sc. The factors influencing cell behavior of wine yeasts in a mixed culture were analyzed in terms of cell growth and organic acid metabolism, and this study provides a theoretical basis for the application of multi-strain mixed fermentation in the wine industry.
    29  Effect of Evacuation Rates on Vacuum Precooling of Iceberg Lettuce and Its Post-storage Quality
    LIAO Cai-hu SHAN Bin ZHONG Rui-min XIE Si-yun HUANG Mei-feng
    2016, 32(7):182-187. DOI: 10.13982/j.mfst.1673-9078.2016.7.029
    [Abstract](717) [HTML](0) [PDF 1.02 M](915)
    Abstract:
    The techniques of slow air precooling and vacuum precooling with different evacuation rates (pressure reduction rates at A-0.126 min-1, B-0.185 min-1, and C-0.315 min-1) were applied to precool iceberg lettuce, and all samples were packaged after precooling and stored in a cold room (5 ± 2 ℃). The effects of different precooling methods on iceberg lettuce were evaluated by measuring related indices for precooling and storage processes. The experimental results showed that vacuum precooling at any evacuation rate was more effective in removing heat than in slow air cooling. However, the precooling times of groups B (65 min) and C (70 min) were equivalent, showing no significant difference (p > 0.05). Nearly the same amount of time was required to remove the heat in different parts of the iceberg lettuce when the evacuation rate was the same. After six days of storage, group B showed a significantly lower respiration rate 183.9 mg/(kg?h) and CO2 concentration (7.2%), and significantly higher vitamin C (46 mg/kg) and O2 (2.1%) concentrations at the top of the packaging bag than groups A and C. All differences were significant (p < 0.05). In conclusion, an evacuation rate of 0.185 min-1 is suitable for precooling of iceberg lettuce.
    30  The Antioxidant Activity of Grape Seeds with Different Pulverized Treatments and their Corresponding Fortified Bread
    YANG Jiu-fang MAN Yuan LI Shu-yan NI Yuan-ying LIU Xing-zhi LI Jing-ming
    2016, 32(7):188-194. DOI: 10.13982/j.mfst.1673-9078.2016.7.030
    [Abstract](978) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Three groups of grape seeds powder were obtained by mechanical crushing method, ultrafine pulverization technology and ultrafine pulverization combined with upercritical fluid extraction technology. Specifically, they were abbreviated as GSP, UPGS, SUPGS to represent grape seeds powder, ultrafine powder of grape seeds and the ultrafine powder of skimmed grape seeds. Diameters of each sample were determined and their inside structure was evaluated under the scanning electron microscope. Then a proper bakery process was established to produce bread added with UPGS and SUPGS. The antioxidant activity of fortified bread enriched with UPGS and SUPGS before and after the process of in-vitro-digest were analysed. The results showed that fortified bread added with SUPGS still had strong antioxidant capacity after in-vitro-digest process and increased 62.4%, 43.93%, 53.2% in ABTS, DPPH scavenging activity as well as FRAP assays compared with common ones. Therefore, SUPGS-fortified bread can be applied in industrial production to enhance its antioxidant capability.
    31  Effect of Raw-meat Properties on Quality of Hunan Dry-cured Meat
    CHEN Xin-xin ZHOU Hui LI Na HE Xiang-li LIU Cheng-guo
    2016, 32(7):195-204. DOI: 10.13982/j.mfst.1673-9078.2016.7.031
    [Abstract](824) [HTML](0) [PDF 999.52 K](1949)
    Abstract:
    To compare the results of using commercial pork from crossbred pigs versus meat from local pigs on the quality of Hunan dry-cured meat, the longissimus dorsi muscle and pork belly from ternary crossbred commercial pigs (A and B, respectively) and local Ning-Xiang pigs (C and D, respectively) were used as the raw materials in this experiment to prepare Hunan dry-cured meat. The changes in the physicochemical indicators, meat color, and volatile components of the meat samples during the processing were measured. The results indicated that for the final dry-cured meat samples prepared from the two types of pig, the dry-cured meat samples prepared from crossbred commercial pork had a significantly higher water content than those prepared from local Ning-Xiang pork (A > C, B > D). However, an opposite trend was observed in nitrate and salt contents. Lower nitrate and salt contents were observed in the dry-cured meat samples prepared from crossbred commercial pork (A < C, B < D) than those in the samples prepared from local Ning-Xiang pork. The L* value decreased in all samples during drying, and the a* values of the dry-cured meat samples prepared from the longissimus dorsi muscles of both types of pork decreased in the beginning and then increased, whereas no significant change was observed in the a* values of the dry-cured meat samples prepared from pork belly. From samples A, B, C, and D, 40, 24, 54, and 23 volatile components were identified, respectively. These results revealed that the raw materials from different breeds of pig and different parts of the meat can affect the quality of Hunan dry-cured meat.
    32  Development of Loop-mediated Isothermal Amplification (LAMP) Assay Based on Propidium Monoazide (PMA) for Detecting Vibrio parahaemolyticus
    MA Biao WU Ying-ying DAI Ming-yan FANG Jie-hong ZHANG Ming-zhou
    2016, 32(7):205-213. DOI: 10.13982/j.mfst.1673-9078.2016.7.032
    [Abstract](874) [HTML](0) [PDF 1.14 M](1337)
    Abstract:
    Vibrio parahaemolyticus is a common foodborne pathogen frequently detected in seafood, and consumption of raw, pickled, or uncooked food contaminated with V. parahaemolyticus can cause food poisoning. Nearly all current methods for rapidly detecting V. parahaemolyticus can not distinguish live cells from dead cells, resulting in false-positive results. In this study, a real-time visual loop-mediated isothermal amplification (LAMP) method was developed based on the characteristics of the DNA binding dye propidium monoazide (PMA) and fluorescent dye calcein to detect viable V. parahaemolyticus strains. This method was compared to quantitative polymerase chain reaction (qPCR). The results of real-time visual PMA-LAMP assay could be observed by the naked eye and monitored in real-time using fluorescence analysis instruments. A preliminary semi-quantitative analysis was conducted, providing a basis for in-depth quantitative analysis. The results indicated that the sensitivities of the real-time visual PMA-LAMP assay in the sensitivity experiment and artificial contamination experiment were 5.0 × 102 CFU/mL and 1.9 × 102 CFU/mL, respectively, which were consistent with the values from PMA-qPCR. The entire detection process required only 2 h, excluding the pre-enrichment step. Furthermore, the method showed high accuracy and may be an effective technical method for rapid detection of V. parahaemolyticus.
    33  Establishment of a Method for Measuring the Brittleness of Mustard Based on the Bionic Technique
    SUN Zhong-lei XU Yi PENG Yi-mei ZHANG Chang-ping PAN Ning HUA Liu-ci LI Yu
    2016, 32(7):214-219. DOI: 10.13982/j.mfst.1673-9078.2016.7.033
    [Abstract](796) [HTML](0) [PDF 777.54 K](869)
    Abstract:
    A method was established for the determination of brittleness of mustard, based on the bionic technique. The process by which human experts conduct sensory evaluations of the brittleness of mustard was simulated, and a bionic system consisting of a bionic chewing device, a bionic periodontal ligament pressure sensor, a bionic eardrum sound sensor, and test software to measure the brittleness was designed and manufactured. This system was used to test the brittleness of five different mustard samples, and the characteristic values of the embrittling force signals and embrittling sound signals were determined and used for correlation analysis and multiple regression analysis of the scores of sensory evaluation on brittleness, to establish a prediction model for the brittleness of mustard. The results showed significant correlations between sensory evaluation scores and the values measured by the bionic technique, including the maximum value, peak-trough difference, mean difference, and amplitude difference, with correlation coefficients of 0.997, 0.993, 0.975, and 0.968, respectively. The average relative error between the prediction equation and sensory evaluation was less than 10%, and the relative standard deviation was less than 2%. Besiseds, the significance level was greater than 0.05 by t-tests. There were no significant differences between the predicted values and measured values. This method was accurate, objective, and rapid, might be used for replacing human experts in the analysis of mustard brittleness.
    34  Analysis of Volatile Flavor s in Smoked Abalone Using Electronic Nose and Solid Phase Micro-extraction Coupled with GC-MS
    WU Jing-na LU Hai-xia CAI Shui-lin SU Jie PAN Nan LIAO Deng-yuan LIU Zhi-yu
    2016, 32(7):220-230. DOI: 10.13982/j.mfst.1673-9078.2016.7.034
    [Abstract](862) [HTML](0) [PDF 928.33 K](1165)
    Abstract:
    Differences in volatile flavors of abalone processed using different fumeols were analyzed by electronic nose, and solid phase micro-extraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was employed to investigate changes in volatile flavor components, allowing for identification of factors affecting flavor formation in response to different fumeol treatments. The results indicated that changes in the volatile flavors of abalone samples generated by different fumeol treatments could be sensitively detected using the electronic nose method. The results of GC-MS demonstrated that there were significant changes in the types and relative contents of volatile flavor compounds in fumeol-treated abalone, and 72 and 98 volatile compounds were detected in the liquid smoked abalone I processed with super fumeol II-2001 and liquid smoked abalone II processed with super fumeol II-2008A, respectively. Additionally, phenolic compounds were characteristic substances related to the smoked flavor, and 19 and 22 volatile phenolic compounds (contents: 47.52% and 55.94%, respectively) were found in liquid smoked abalone samples I and II, respectively. Principal component analysis (PCA) of GC-MS data suggested that GC-MS could effectively distinguish the abalone samples processed using different fumeols, and GC-MS results of the differences in flavor substances were consistent with those from the electronic nose.
    35  Acute Toxicity of T-2 Toxin in Shrimp at Different Growth Stages and Comparison of Corresponding Analytical Methods
    SHI Qi WANG Xiao-Bo WANG Ya-ling MO Bing QIU Mei SUN Li-Jun XU De-Feng LI Jian-Rong
    2016, 32(7):231-236. DOI: 10.13982/j.mfst.1673-9078.2016.7.035
    [Abstract](739) [HTML](0) [PDF 666.00 K](959)
    Abstract:
    The acute toxicity of T-2 toxin on Litopenaeus vannamei at different growth periods and corresponding analytical methods were compared. Additionally, the optimal period to use shrimps as a biomarker for evaluation of the toxicity of T-2 toxin was determined, and a complementary method for evaluation of the acute toxicity of T-2 toxin on shrimps was established. Acute toxicity tests were performed on L. vannamei at different growth stages. The Spearman-Karber and probability unit methods were used to calculate the lethal dose 50% (LD50) values for T-2 toxin in L. vannamei at different growth stages. The obtained LD50 values were compared by u-tests. The LD50 values for T-2 toxin in shrimp eggs, juvenile shrimps, and adult shrimps were 2.33, 1.79, and 3.34 mg/kg of body weight, respectively, and no significant differences were observed between the LD50 values obtained using the two methods. These findings suggested that T-2 toxin exhibited the lowest toxic effect on adult shrimps and the highest toxic effect on juvenile shrimps. Thus, juvenile L. vannamei were more suitable for biomarker analysis when evaluating the acute toxicity of T-2 toxin, and a relatively accurate LD50 value could be obtained using a method combining the Spearman-Karber method and the probability unit method.
    36  Identification of Milk Flavoring Essences Based on the Odor Fingerprint Technique
    JIANG Jin-jin YAO Zheng-xiao HAN Ming LIU Hui-juan ZHANG Ting LU Yu-xia
    2016, 32(7):237-242. DOI: 10.13982/j.mfst.1673-9078.2016.7.036
    [Abstract](991) [HTML](0) [PDF 1004.36 K](1314)
    Abstract:
    Milk flavoring essence is one of the essential additives, which has been widely used in the modern food industry. The difference in odor between various types of milk flavoring essences is difficult to identify by using chromatographic techniques and human sensory evaluation. In order to establish the method for odor fingerprint identification of milk flavoring essences, the natural milk flavoring essence, compound milk flavoring essence, flavoring essence from the enzymatic hydrolysis of butter, and laboratory-prepared milk flavoring essence were used as samples to analyze the composition of the volatile components and to determine the odor fingerprint of the samples. The odor of several commercially available milk flavoring essences was compared, and the method to identify the milk flavoring essence based on odor fingerprint technique was developed. The results showed that the odor fingerprint technique could accurately distinguish between and identify the difference in the odor among the milk flavoring essences, showing an effective recognition performance. A high similarity in the main characteristic flavor components was detected between natural milk flavoring essence and laboratory prepared milk flavoring essence, while the overall odor of compound milk flavoring essence was significantly different from those of other samples. The analysis data indicated that the flavor of the natural milk flavoring essence may be produced by further processing and modifying the product obtained from the enzymatic hydrolysis of butter.
    37  Analysis of Sulfite Content in Mung Bean Sprouts using the Distillation (with a Nitrogen Flow)–Ortho-phthalaldehyde Fluorescence Method
    MA Zhan-ling ZHANG Jing LI Jian-rong WANG Ying LI Ning-ning CHEN Si
    2016, 32(7):243-248. DOI: 10.13982/j.mfst.1673-9078.2016.7.037
    [Abstract](864) [HTML](0) [PDF 765.68 K](1245)
    Abstract:
    A new method was established for the determination of sulfite (SO2) content in mung bean sprouts. Mung bean sprouts were distilled with a nitrogen flow, and the volatilized SO2 was absorbed by sodium hydroxide solution. At room temperature, the absorbed sulfite, ammonium salt and ortho-phthalaldehyde (OPA) could react to generate compounds with strong fluorescence in a medium with a pH of 6.6. The fluorescence intensity and concentration of SO2 showed good linearity in the range of 0 to 9.60 mg/L, and the regression equation was y = 403.1x – 147.41, with a correlation coefficient of 0.9996. This method for determination of SO2 content in mung bean sprouts was simple, sensitive, and selective, and the results obtained showed no significant differences from those using the national standard method (the distillation-distillation method). Furthermore, appropriate methods for removal of sulfite in mung bean sprouts were studied. Additionally, the effects of water, acetic acid solution, salt solution, sodium carbonate solution, and rice washing water on removal of SO2 from mung bean sprouts were investigated. The results showed that the sulfite in mung bean sprouts could be effectively removed with rice washing water and sodium carbonate solution. At 65°C, mung bean sprouts were soaked in 150.00 g/L rice washing water and 2.00 g/L sodium carbonate solution for 1.5 h, and the removal rates of SO2 reached 66.41–72.83% and 67.07–80.12%, respectively.
    38  Fruit Characteristics and Quality of Red Fuji Apples Grown in Xinjiang and Yellow River Basin
    JIN Xin-xin TIAN Ying-zi YING Li MA Qian-li ZHAO Cui LUO Yu-nian GAO Fang
    2016, 32(7):249-254. DOI: 10.13982/j.mfst.1673-9078.2016.7.038
    [Abstract](903) [HTML](0) [PDF 584.72 K](939)
    Abstract:
    Sixteen cultivars of Red Fuji apples grown in Xinjiang and Yellow River basin were selected as the study objects, sensory evaluation and analyses of their fruit characters and nutritional components were carried out, and optimum quality was found in the Red Fuji apples grown in Aksu, Tekesi, and Luochuan. The individual fruit weights of the samples produced from Shandong, Xinjiang, Shanxi, and Gansu were in the descending order of Gansu > Shanxi > Xinjiang > Shandong, showing a significant variation (coefficient of variation (CV) > 15%) and a significant difference (p = 0 < 0.05). Significant variations were presented in the nutritional components among 16 cultivars of Red Fuji apples, especially for vitamin C, protein, and dietary fiber (CV > 25%). The samples from different production areas showed significant differences in reducing sugar content (p = 0 < 0.05), soluble solids (P = 0.05), and dietary fiber (p = 0.023 < 0.05). There was a significant positive correlation between flavor score and solid acid ratio (p = 0 < 0.05, r = 0.886). The Red Fuji apples grown in Xinjiang had a higher solid acid ratio, and showed a pronounced difference from other apple cultivars, so that Xinjiang Red Fuji apples can better meet a high flavor taste requirement compared with other apple cultivars (p = 0.003 < 0.05). In addition, positive correlations were found between reducing sugar and soluble solid contents (p = 0.001 < 0,05, r = 0.75), as well as between total acid and soluble solids (p = 0.014 < 0.05, r = 0.602).
    39  Determination of Eight Biogenic Amines in Soy Sauce by Using QuEChERS and Ultra-high Performance Liquid Chromatography-tandem Mass Spectrometry
    ZHOU Chao-hui
    2016, 32(7):255-260. DOI: 10.13982/j.mfst.1673-9078.2016.7.039
    [Abstract](713) [HTML](0) [PDF 689.88 K](843)
    Abstract:
    An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established for the simultaneous determination of eight biogenic amines in soybean sauce. 1, 7-Heptanediamine was added to the samples and used as the internal standard. Samples were diluted in water and pH values were adjusted using ammonia water. The sample solution was then extracted by acetonitrile using liquid-liquid extraction and salting out methods. The extract was subsequently purified by using Quick Easy Cheap Effective Rugged Safe (QuEChERS). After the acidity of the extract was adjusted and the solution was concentrated and reconstituted, all samples were separated and measured by using UPLC-MS/MS and quantitatively AND analyzed using an internal standard method. Under the optimized conditions, the calibration curves of eight analytes showed a good linearity over a concentration range of 5.0~500 μg/L, with coefficients of determination (R2) greater than 0.998. The limits of detection (LODs) and the limits of quantitation (LOQs) of the method were in the range of 30~60 μg/kg and 120~250 μg/kg, respectively. The spike and recovery experiments at two levels of concentration in soybean sauce samples (n = 6) were performed. The average recoveries were found to be between 83.7% and 110%, with relative standard deviation (RSD) values of 3.8~11.5%. The detection results on the actual soybean sauce samples revealed that the content of tyramine and phenylethylamine were the highest in the samples. The developed method is accurate, sensitive, rapid, and suitable for the simultaneous determination of eight biogenic amines in soybean sauce.
    40  Comparison of the Flavor Components of Chinese Mitten Crab at Different Growth Stages
    ZHAO Liang WU Na WANG Xi-chang WU Xu-gan WANG Ya-hui
    2016, 32(7):261-269. DOI: 10.13982/j.mfst.1673-9078.2016.7.040
    [Abstract](840) [HTML](0) [PDF 901.97 K](1009)
    Abstract:
    The differences in the flavor components of Chinese mitten crab between August and December were studied. The taste profiles of three edible parts (meats, gonads, and hepatopancreas) of Chinese mitten crab, in different months, were distinguished by an electronic tongue. The contents of free amino acids and flavor nucleotides were measured, and the taste activity value (TAV) and equivalent umami concentration (EUC) were calculated. The results showed that differences in the taste profile of each edible part in different months could be effectively distinguished. The taste profiles in November and December were significantly different from those in August and September. The content of sweet tasting amino acids in the three edible parts and the content of umami amino acids in hepatopancreas reached their peak values in November. The total content of flavor nucleotides in meat was the highest and showed a large fluctuation. After November, the contents of sweet tasting nucleotides and umami nucleotides in meat were increased significantly, but the change in the flavor content nucleotides in gonads and hepatopancreas was less significant. The TAV values of glutamate (Glu), alanine (Ala), arginine (Arg), and lysine (Lys) in all edible parts of Chinese mitten crab at different growth stages were higher than 1, and these amino acids contributed the most to the overall taste of the crab. In gonads, the EUC value was significantly higher than that in other parts and reached the peak value in September and December. Therefore, it was confirmed that the male crab has best taste in November.
    41  Identification of Flavonoids in the Leaves of Laurus nobilis
    YANG Yun-shu LI Rong JIANG Zi-tao LIU Tao
    2016, 32(7):270-275. DOI: 10.13982/j.mfst.1673-9078.2016.7.041
    [Abstract](933) [HTML](0) [PDF 714.49 K](996)
    Abstract:
    Flavonoids in the leaves of Laurus nobilis were identified using liquid chromatography-quadrupole-time of flight mass spectrometry combined with comparison of the retention times and tandem mass spectrometric fragment patterns of standards or from related literature. Flavonoid contents were measured by liquid chromatography-triple quadrupole tandem mass spectrometry in multiple reaction monitoring mode. Sixteen flavonoids were detected in L. nobilis leaves, including vitexin-2-O-rhamnoside (1658.53 ± 56.9 μg/g), rutin (19,883.54 ± 494.33 μg/g), vitexin (4430.87 ± 89.72 μg/g), type-A procyanidin trimer (2281.88 ± 78.90 μg/g), epicatechin (148.10 ± 2.32 μg/g), kaempferol-3-O-rutinoside (3491.02 ± 47.98 μg/g), isorhamnetin-3-O-rutinoside (6643.78 ± 99.04 μg/g), hyperoside (11,979.66 ± 317.79 μg/g), kaempferol-7-glucoside (738.55 ± 10.86 μg/g), astragalin (508.60 ± 6.96 μg/g), quercetin-3-O-xylopyranoside (2044.22 ± 57.65 μg/g), isorhamnetin-3-O-glycosidase (2079.94 ± 76.38 μg/g), quercitrin (2079.94 ± 61.84 μg/g), kaempferol-3-O-rhamnoside (6412.37 ± 78.65 μg/g), quercetin (1629.45 ± 47.65 μg/g), and kaempferol (364.29 ± 2.84 μg/g). The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activities of the extract were determined, and the results clearly demonstrated that flavonoids from L. nobilis possessed significant radical scavenging activities.
    42  Non-destructive Measurement of the Active Acidity of Pitaya by Near-infrared Spectroscopy
    LUO Xia HONG Tian-sheng LUO Kuo LIN Lin LIANG Xiong-jian DAI Fen WU Wei-bin
    2016, 32(7):276-282. DOI: 10.13982/j.mfst.1673-9078.2016.7.042
    [Abstract](790) [HTML](0) [PDF 797.67 K](969)
    Abstract:
    Pitaya is a fruit that exhibits health benefits. The FieldSpec 3 spectroradiometer was used to collect spectral data of pitaya in the wavelength range of 350–2500 nm. Multiple pretreatments, successive projections algorithm (SPA), and partial least squares regression (PLSR) were adopted to establish the active acidity prediction model for pitaya. The experimental results showed that the optimal partial least squares (PLS) model was established after the original spectrum was processed by using the Savitzky-Golay convolution smoothing method (SGS). The correlation coefficients of cross-validation (RCV) and root mean square error of cross-validation (RMSECV) were found to be 0.8862 and 0.1535, respectively. In combination with SPA algorithm, the preferentially selected 25 variables were used to establish the PLS model with a correlation coefficient of prediction (RP) of 0.8702 and a root mean square error of prediction (RMSEP) of 0.1682. The predictive accuracy of the model was higher than that of the model constructed by using 2151 variables from the original spectrum. The effect of the fruit peel on the model accuracy was analyzed. After the optimal normalization pretreatment of spectral data, the RP of the whole fruit PLS model was 0.8151 and that of the RP of the fruit flesh PLS model was 0.8583, which showed that the fruit peel affected the model, but the effect could be reduced by spectral optimization. The results obtained indicate that it is feasible to use diffuse reflectance based on near infrared spectroscopy combined with SPA for the non-destructive measurement of the active acidity of pitaya.
    43  Research Progress in the Structure and Physiological Activity of Soluble (1→3)(1→4)-β-D-glucan from Cereal
    WU Hui HE Ping-wei LAI Fu-rao MIN Tian ZHANG Ting HE Jia-min
    2016, 32(7):283-294. DOI: 10.13982/j.mfst.1673-9078.2016.7.043
    [Abstract](879) [HTML](0) [PDF 911.87 K](1537)
    Abstract:
    Cereal β-glucans are a type of linear homopolysaccharides formed by the linkage of β-D- glucopyranosyl units via (1→4)-β-linkage and separated by single (1→3)-β-linkages. They are the main component of water-soluble dietary fibers from cereals and are mainly found in barley, oat, hull-less barley, wheat, and rye. The physiological activity of soluble β-glucan from cereal is closely related to its unique structure of (1→3)(1→4)-β-D-glucan. This paper focused on the relationship between the characteristics of the molecular structure of cereal β-glucans and their physiological activity in the gastrointestinal tract. The physiological activities of cereal soluble β-glucans in reducing cholesterol, postprandial glycemic index, and insulin levels are summarized and new mechanisms underlying the effect of β-glucans on the intestinal flora and immune function are discussed. Studies on several mechanisms underlying the physiological activities of β-glucan are described. The viscosity level in the small intestine was increased, delaying the gastric emptying, digestion, and absorption of molecules, including glucose, dietary cholesterol, and bile acids. β-glucans bound with bile acid in the intestine to decrease the bile acid reabsorption, thus promoting the synthesis of bile acids from cholesterol. β-glucans improved insulin sensitivity by reducing postprandial glycemic index and insulin level and underwent colonic fermentation to improve intestinal health.
    44  Progress of Electrospun Protein and Polysaccharide Nanofiber Application in Food Industry
    WU Hong FENG Kun ZHU Ding-he YANG Huan WEN Peng ZONG Min-hua
    2016, 32(7):295-303. DOI: 10.13982/j.mfst.1673-9078.2016.7.044
    [Abstract](979) [HTML](0) [PDF 629.99 K](1187)
    Abstract:
    Electrospinning is an easy and effective method for preparing polymer nanofibers. Electrospun nanofibers possess excellent properties such as adjustable diameter, high porosity, and large specific surface area, and have shown promise in the fields of biomedicine, filtration materials, sensors, enzyme fixation, and food packaging, among others. The electrospun nanofibers used in food industry should have good biocompatibility, low toxicity, and controllable biodegradability; thus, proteins, polysaccharides, and other natural polymers are commonly used natural polymers for electrospinning. The development of methods to prepare electrospun protein (soy protein isolate, zein, whey protein, etc.) or polysaccharide (chitosan, hylauronic acid, starch, pullulan, etc.) nanofibers; effect of major factors on the electrospinning process, such as the morphology of nanofibers; and properties of nanofibers and their potential applications in the food industry, including antibacterial, antioxidant, controlled release applications, are summarized in this paper. Additionally, future research directions for electrospun polysaccharide and protein nanofibers are discussed.

    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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