Volume 31,Issue 8,2015 Table of Contents

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  • 1  Mechanism of Hypoglycemic Activity of Vaccinium bracteatum Thunb. Leaf Polysaccharides in Streptozotocin-induced Diabetic Mice
    WANG Li CHENG Su-jiao XU Yuan QIAN Hai-feng ZHANG Hui QI Xi-guang SHAO Jing LU Mei-juan
    2015, 31(8):1-6. DOI: 10.13982/j.mfst.1673-9078.2015.8.001
    [Abstract](992) [HTML](0) [PDF 737.84 K](1309)
    Abstract:
    The mechanism of hypoglycemic activity of Vaccinium bracteatum Thunb. leaf polysaccharide (VBTLP) was investigated using streptozotocin (STZ)-induced diabetic mice and dimethylbiguanide as the positive control. The results showed that after mice were administered VBTLP by gavage for six months, the serum insulin levels of mice in the high-dose VBTLP group was increased by 4.38%, the pancreatic β-cell function index increased by 83.40%, and the insulin secretion index increased by 63.83%, when compared with the control group. The liver antioxidant capacity of mice was significantly enhanced as well, wherein activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were increased by 2.49%, 1.74%, and 6.04%, respectively, and malondialdehyde (MDA) level was decreased by 6.12%. Based on mouse pancreatic tissue sections, VBTLP was speculated to have significant repair activity on pancreatic beta cell structure. According to the results of this study, we speculate that the hypoglycemic activity of VBTLP in STZ-induced diabetic mice results from stimulating insulin secretion, repairing the damaged pancreatic beta cells, and enhancing antioxidant capacity.
    2  Antioxidant Activity of Fermented Plant Extracts (FPE) in a Mouse Model of D-Galactose-induced Aging
    CHEN Hong-yun CUI Hong-yan WU Bin-bin LIU Chun-hua LUO Qian XU Fang-fang PAN Yong-long YANG Li-li LIANG Yan
    2015, 31(8):7-11. DOI: 10.13982/j.mfst.1673-9078.2015.8.002
    [Abstract](991) [HTML](0) [PDF 692.69 K](1330)
    Abstract:
    Mice were administered subcutaneous injection of D-galactose to produce an animal model of aging, which was used to study the in vivo effect of fermented plant extract (FPE) on antioxidant activity. Parameters including the activity of three characteristic antioxidant enzymes, namely superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) as well as the malondialdehyde (MDA) content in the serum and liver of mice of both sexes were extensively evaluated. Meanwhile, spleen index and thymus index were used as the indicators for the preliminary assessment of the impact of FPE on mice immunity in vivo. The results showed that compared with the model group, the activities of SOD, CAT, and GSH-Px in serum and liver of mice (both sexes) were significantly enhanced and corresponding MDA content was decreased in the group that received 1.5 mL/kg FPE gavage. Additionally, spleen and thymus indices of mice were increased to some extent in groups that received 0.24 and 0.6 mL/kg FPE gavage. Thus, FPE enhanced antioxidant activities in vivo, implying an anti-aging effect and may have potential to strengthen the immune system.
    3  Lead-expelling and Liver-protecting Effects of Yeast Metallothionein on Mice with Chronic Lead Poisoning
    WANG Ying XU Bing-zheng WANG Xin-hui LI Jing-jing ZHANG Dong-jie ZHANG Gui-fang
    2015, 31(8):12-17. DOI: 10.13982/j.mfst.1673-9078.2015.8.003
    [Abstract](981) [HTML](0) [PDF 879.04 K](1202)
    Abstract:
    The aim of this study was to investigate the effect of yeast metallothionein (MT) with known lead-expelling and liver-protecting properties on mice in which, chronic lead poisoning was induced by lead acetate solution gavage for 35 days. Dimercaptosuccinic acid (DMSA) and animal MT (rabbit liver Zn-MT) were used as controls and MT was administered to the mice. Subsequently, the weight, blood lead levels, and liver function indices were measured and a routine blood tests were conducted to observe the severity of pathological changes in the liver tissue. Compared with that of the control group, the weight of MT-treated groups was not significantly different. The blood lead level in high-dose MT-treated group was significantly decreased, while the levels of white blood cells (WBC), mean corpuscular volume (MCV), and hemoglobin (HGB) were significantly increased (p < 0.05). However, there were no significant differences in granulocyte (GR) counts between all groups (p > 0.05). The levels of glutamate pyruvate transaminase (GPT) in all MT-treated groups were significantly decreased (p <0.05). Meanwhile, the levels of glutamate oxaloacetate transaminase (GOT) in the high-dose MT-treated group were significantly decreased (p <0.05), pathological changes in liver tissue were ameliorated, and the degree of improvement was higher than that of DMSA group. Two types of yeast metallothionein exhibited lead-expelling and liver-protecting effects on mice with chronic lead poisoning, similar to animal metallothionein.
    4  Mechanism of Anti-diarrheal Effect of Rubus corchorifolius Leaves on Isolated Rabbit Intestine
    ZHANG Rui-lian LIU Xiao-juan ZHANG Miao XIONG Ping CHEN Xue-xiang CAO Yong
    2015, 31(8):18-24. DOI: 10.13982/j.mfst.1673-9078.2015.8.004
    [Abstract](998) [HTML](0) [PDF 1.15 M](1320)
    Abstract:
    Ethyl p-coumarate (EC), a compound with a relatively strong activity was extracted from Rubus corchorifolius leaves by bioactivity-guided isolation. Dose responses of Rubus corchorifolius leaf extract (RE) and EC for inhibition of intestinal movement were studied in terms of movement of isolated rabbit intestine model. The effects of RE and EC as well as four spasmogenic agents (acetylcholine, phentolamine, histamine, and barium chloride) that are related to four key channels in antidiarrheal effects on the movement of isolated intestine were also investigated. The results showed that the tensional variation percentage (TVP) of intestine was above 30% when RE concentration was in the range of 1 to 10 mg/mL and reached maximum (45.37%) at 4 mg/mL. When the concentration of EC was in the range of 10 to 800 μg/mL, the inhibitory effect on intestinal movement was significantly higher than that of atropine (p < 0.01) at the same concentration and TVP value reached the maximum (70.45%) when the concentration of EC was 400 μg/mL. Thus, the inhibition of intestinal movement by RE was mainly achieved through its effects on the cholinergic M receptor of acetylcholine and histamine channels, whereas that by EC was mainly achieved through its effects on the adrenergic a-receptor, histamine channel, and calcium ion channel. Therefore, RE and EC act on different targets and are effective antidiarrheal drugs, where EC in RE exerts a significantly stronger effect than atropine.
    5  Estrogen-like Effects of Oviductus Ranae
    KANG Lan LI Na JIANG Da-cheng
    2015, 31(8):25-30. DOI: 10.13982/j.mfst.1673-9078.2015.8.005
    [Abstract](948) [HTML](0) [PDF 965.86 K](1250)
    Abstract:
    The effects of long-term, high-dose oviductus ranae on growth, sexual organs, and hormones levels of mice were investigated. A total of 24, female Kunming mice were randomly assigned to the high-dose, low-dose, and control groups. Test groups received intragastric administration of oviductus ranae, and the control received intragastric administration of saline solution. After treatment, wet weight of the ovaries, uterus, and adrenal glands were measured and processed for histopathology. Hormone levels in the serum were measured by chemiluminescent immunoassay (CLIA), whereas protein expression of follicle-stimulating hormone receptor (FSHR), Type Ⅰ Transform growth factor β receptor TβRI), and TβR II in the uterus, ovary, and adrenal tissue were measured using the western blot. Oviductus ranae did not have a significant effect on the weight of female mice or wet weights of the uterus, ovary, and adrenal glands; while serum E2 and P (p < 0.05), FSH (p < 0.01), and T (p < 0.001) content increased significantly. Oviductus ranae did not have a significant effect on prolactin (PRL) and luteinizing hormone (LH) content. High doses of oviductus ranae led to an increase in the adrenal tissue protein, FSHR (p < 0.05), but did not show a significant effect in other groups. The results show that long-term, high-dose oviductus ranae alters serum E2, T, FSH, and P as well as increases FSHR protein expression. Thus, oviductus ranae exhibits estrogen-like effects, which may lead to the occurrence of reproductive tumors.
    6  Enhancing the Immunogenicity of Hapten 3-Amino-5-morpholinomethyl -2-oxazolidone (AMOZ) Using Dendrimer as a Carrier
    LIU Feng-yin SHEN Yu-dong XIAO Zhi-li YANG Jin-yi SUN Yuan-ming WANG Hong LEI Hong-tao XU Zhen-lin
    2015, 31(8):31-36. DOI: 10.13982/j.mfst.1673-9078.2015.8.006
    [Abstract](987) [HTML](0) [PDF 741.78 K](1265)
    Abstract:
    3-Amino-5-morpholinomethyl-2-oxazolidone (AMOZ), a metabolite of antibiotic furaltadone, is a potential teratogenic and carcinogenic substance. However, an immunoassay for the direct estimation of AMOZ was so far unavailable due to its low molecular weight and lack of a specific antibody. In this study, polylysine dendrimer (G5) was used for the first time instead of the traditional carrier (bovine serum albumin (BSA)), to conjugate with AMOZ glyoxylate derivative hapten (AMOZA) to generate the immunogen (AMOZA-G5) that would produce AMOZ-specific antibodies. Balb/c mice were immunized, antisera were collected, and examined by competitive indirect enzyme-linked immune sorbent assay (ciELISA). The results revealed that the antiserum from AMOZA-BSA immunization was not specific to free AMOZ, however, that from AMOZA-G5 immunization showed specificity. ciELISA experiment showed an inhibition rate of 35% for 1 μg/mL AMOZ). The results indicated that polylysine dendrimer as a carrier effectively improved the immunogenicity of small-molecule haptens. This study provides a new strategy for the production of specific antibodies against small-molecule haptens.
    7  Effects of Ovotransferrin on the Maturation of Mouse Bone Marrow-derived Dendritic Cells
    ZHAO Man-yun XU Ming-sheng RAO Hong-hua DAI Yi LIU Lin
    2015, 31(8):37-41. DOI: 10.13982/j.mfst.1673-9078.2015.8.007
    [Abstract](925) [HTML](0) [PDF 675.73 K](1199)
    Abstract:
    To explore the effect of ovotransferrin (OVT) on the maturation of mouse bone marrow-derived dendritic cells (BMDCs) in vitro, different concentrations of OVT as well as lipopolysaccharides (LPS) + different concentrations of OVT were used to stimulate a 6-day culture of BMDCs for 48 hours. Changes in DC morphology were observed using inverted phase microscopy, whereas the proportion of CD11c+ cells and expression of MHC-II, CD80, and CD40 molecules were determined by flow cytometry (FC). The results showed that different concentrations of OVT caused an increase in finer dendritic protrusions with the typical morphology of DCs compared to the negative control. The proportion of CD11c+ cells and expression of MHC-II, CD80, and CD40 molecules were all up-regulated as well. Low concentration (≤ 25 μg/mL) of OVT+LPS up-regulated the proportion of CD11c+ cells and the expression of MHC-II, CD80, and CD40, while high concentration (> 25 μg/mL) of OVT+LPS inhibited both, the proportion of CD11c+ cells and the expression of MHC-II, CD80, and CD40. In conclusion, different concentrations of OVT induced the maturation of DCs. LPS + low concentration of OVT induced a synergistic effect, while LPS + high concentration of OVT showed an antagonistic effect.
    8  Genotoxicity Biotransformation Products of Low-Dose T-2/HT-2 Toxin
    QIU Mei CHEN Hai-yan SUN Li-jun WANG Ya-ling XU De-feng NIE Fang-hong LI Jian-rong
    2015, 31(8):42-46. DOI: 10.13982/j.mfst.1673-9078.2015.8.008
    [Abstract](1065) [HTML](0) [PDF 706.60 K](1073)
    Abstract:
    The work was to determine whether low doses of degradation products of T-2 toxin and HT-2 toxin, after Pseudomonas geniculata biotransformation, showed genetic toxicity. The rates of micronucleated, polychromatic erythrocyte formation in bone marrow and sperm deformity, characterized by a swollen head and folded tail, were measured, 7 d after continual intragastric administration of T-2 and HT-2 toxin biotransformation products, at different doses, in mice. The results showed that the micronucleus formation rate in male mice was higher than that of the females, with significant differences (p < 0.05) between each dose-level and the negative control groups. Additionally, the micronucleus formation rate in male mice from the 10/20 and 25/50 ng/mL dose-level groups showed insignificant differences than that of the positive control group (p > 0.05). Sperm deformity rates in mice from the 2.5/5 ng/mL T-2/HT-2 dose group was significantly different (p < 0.05) than that of the negative group. As the dose of T-2/HT-2 toxin increased, the sperm deformity rate in mice increased linearly. Therefore, T-2 and HT-2 toxins were confirmed to still show genetic toxicity after biotransformation by Pseudomonas geniculate, and males were more susceptible than females. The study also provide evidence that there were binding forms of T-2 toxin in the biotransformation products of T-2 and HT-2.
    9  Antibacterial and Coaggregation Activities of Pediococcus pentosaceus and Its Putificatiion Effect on Vibrio parahaemolyticus-contaminated Water
    YANG Zhen-quan GAO Lu JIN Cai-juan WANG Xiao-lin FANG Wei-ming GU Rui-xia
    2015, 31(8):47-52. DOI: 10.13982/j.mfst.1673-9078.2015.8.009
    [Abstract](878) [HTML](0) [PDF 788.24 K](1159)
    Abstract:
    Coaggregation and antibacterial activity of seven P. pentosaceus strains against Vibrio parahaemolyticus ATCC33847 were evaluated. And their cellular morphological characteristics as well as impact on o Vibrio parahaemolyticus ATCC33847 in contaminated water, were explored. The results showed that the inhibitory effect of the seven P. pentosaceus strains tested was 1.1 to 1.3 times that of lactic acid at the same pH, while the antibacterial activity was resistant to catalase, proteinase, and heat treatments. The 2-h coaggregation rate of the seven isolates against V. parahaemolyticus varied between 14.8% and 37.6%, showing a significant inter-strain difference. Among the seven isolates, the coaggregation activity of F28-8 reached 37.6%, which was significantly higher than those of other strains (p < 0.01). The results from scanning electron microscopy (SEM) showed that strain F28-8 had a unique cell surface structure and cell adhesion pattern. P. pentosaceus also played a role in promoting aggregation and reducing numbers of viable V. parahaemolyticus in water. After a suspension of V. parahaemolyticus was treated with strain F28-8 for 60 h, the concentration of culturable cells in the upper suspension layer was lowered by 3.1 Log10 CFU/mL compared to that of the untreated group, which was significantly higher than that of strain H13, which showed low coaggregation activity (2.5 log10 CFU/mL). On the other hand, the concentration of culturable cells in the coaggregates was 1.6 log10 CFU/mL, which was lower than that of the control group and showed no significant change with H13 treatment (p > 0.05).
    10  The Up-regulated Expressed Proteins of the Viable but Nonculturable State of Vibrio parahaemolyticus by iTRAQ
    TIAN Juan YE Chen LIU Yu-fei WANG Li ZHONG Qing-ping
    2015, 31(8):53-58. DOI: 10.13982/j.mfst.1673-9078.2015.8.010
    [Abstract](1063) [HTML](0) [PDF 713.74 K](1347)
    Abstract:
    Vibrio parahaemolyticus was induced into viable but nonculturable (VBNC) state by food preservative at low temperature and oligotrophic condition. The aim of this study is to screen differentially expressed proteins of VBNC state and exponential phase of V. parahaemolyticus using isobaric rags for relative and absolute quantitation (iTRAQ) combined with LC/MS. Functional annotations of unigenes were analyzed using protein sequence similarity, KEGG pathway and GO analysis. The results showed that only 40~45 days V. parahaemolyticus could induce into VBNC state at 4 ℃ in seawater containing 10 mmol/L potassium sorbate. A total of 135,880 proteins, including 1,088 unique proteins were identified. Of the quantitatively different proteins under the VBNC state, 15 were significantly up-regulated and 36 were down-regulated. The up-regulated expressed proteins were mainly focused on outer membrane protein, transporter proteins, ferritin and other key components involved in metabolism. This study provided basis for understanding the mechanism of adaptation of the VBNC state of V. parahaemolyticus.
    11  Effect of Over-expressing Farnesyl Pyrophosphate Synthase (FPS) Gene of Panax notoginseng Cell on Saponin Synthesis
    YANG Yan LIU Di-qiu GE Feng CHEN Chao-yin
    2015, 31(8):59-64. DOI: 10.13982/j.mfst.1673-9078.2015.8.011
    [Abstract](819) [HTML](0) [PDF 727.38 K](1079)
    Abstract:
    To study the effect of over-expressing farnesyl pyrophosphate synthase (FPS) in Panax notoginseng (P. notoginseng) cells on saponin synthesis, an FPS over-expression vector was constructed and integrated into the genome of P. notoginseng cells via Agrobacterium tumefaciens. Relative expression levels of FPS in the positive cell lines were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). The contents of Panax notoginseng saponins (PNSs) and monomer ginsenosides were estimated by vanillin-perchloric acid-glacial acetic acid colorimetric method and high performance liquid chromatography (HPLC), respectively. The results showed that the relative FPS expression levels and PNS content were both higher in the four transgenic FPS-positive cell lines, than those in non-transgenic control, with highest levels at 3.01-times and 2.09-times higher, respectively. Additionally, the content of important monomer ginsenosides (Rh1, Rg1, Re, and Rd) were all higher in the four transgenic FPS-positive cell lines than those in the non-transgenic control. Among these, the increase in Re content was the most significant, with highest level was up to 4.35 times as much as that of control. Moreover, the content of Rh1, Rd, and Rg1 were increased to some extent as well, with highest levels at 2.66-, 2.90-, 1.76-times that of the control, respectively. These results suggest that FPS is one of the rate-limiting enzymes in the PNS biosynthetic pathway. Thus, over-expressing FPS in P. notoginseng cells could enhance PNS content, which has potential applications in metabolic engineering to realize homologous or heterologous expression of PNS.
    12  Recombinant Peroxidase A4-Prx Purification and Zearalenone Degradation Activity
    ZHONG Feng WU Hui LIU Si-li TANG Yu-qian
    2015, 31(8):65-70. DOI: 10.13982/j.mfst.1673-9078.2015.8.012
    [Abstract](985) [HTML](0) [PDF 901.35 K](1017)
    Abstract:
    Recombinant peroxidase A4-Prx derived from Acinetobacter sp. SM04 and expressed by genetically-engineered recombinant Pichia pastoris GS115/pPIC9K-A4-Prx was purified to analyze its enzymatic characteristics and ability to degrade zearalenone (ZEA). Ammonium sulfate precipitation and dextran column elution were used to purify A4-Prx, with a final purification factor of 12. High-performance liquid chromatography (HPLC) showed that purified A4-Prx degraded ZEA at a rate of 63%. Further analysis of A4-Prx enzymatic characteristics showed that pH and temperature had significant effects on peroxidase activity; enzymatic activity peaked at pH 9.0 and 60 ℃. Lineweaver-Burk plots of A4-Prx peroxidase reaction showed that when H2O2 concentration was 9.7 mM, Km was 4.85 mM and Vmax was 204.1 U. A4-Prx also showed significant inhibitory effect on ethylenediaminetetraacetic acid (EDTA). These results provide preset conditions for subsequent research on the degradation mechanisms of A4-Prx and further research on ZEA biodegradation.
    13  Inhibitory Effect of Quercetin on Tyrosinase and Its Molecular Mechanism
    GUAN Xiao YANG Cheng LIU Jing WANG Wen-gao HAN Fei
    2015, 31(8):71-76. DOI: 10.13982/j.mfst.1673-9078.2015.8.013
    [Abstract](2895) [HTML](0) [PDF 980.15 K](3394)
    Abstract:
    The type and intensity of the inhibitory effect of quercetin on tyrosinase were studied using enzyme inhibition kinetics with L-dopa as a substrate. The type of fluorescence quenching, binding sites, and the type of interaction between quercetin and tyrosinase were analyzed using fluorescence spectroscopy. Furthermore, the molecular mechanism of the inhibitory effect was investigated using flexible molecular docking. The results showed that quercetin inhibited the activity of tyrosinase with an inhibitor constant (KI) of 36 mM. Quercetin can be regarded as a competitive and reversible inhibitor of tyrosinase. Quercetin bound to the active site of tyrosinase via hydrophobic interactions and hydrogen bonds at a ratioof 1 : 1, and quenched the fluorescence of tyrosinase by static quenching. Concomitantly, molecular docking results confirmed that quercetin occupied the active site of tyrosinase and formed strong hydrogen bonds with residues Asn260 and Gly62 located at the active site of tyrosinase. Moreover, hydrophobic interaction played a key role in stabilizing the structure of the complex formed.
    14  Variations in the Content of Melatonin and Its Isomer During Ethanol Fermentation by Different Saccharomyces cerevisiae Strains
    WANG Cheng SHI Xue-ying XIAO Hua WANG Li-hua WEN Yun WANG Xiao-lei ZHAN Ji-cheng HUANG Wei-dong
    2015, 31(8):77-82. DOI: 10.13982/j.mfst.1673-9078.2015.8.014
    [Abstract](1056) [HTML](0) [PDF 929.17 K](1615)
    Abstract:
    The variations in melatonin and its isomer content were studied during ethanol fermentation by three different Saccharomyces cerevisiae strains, that is, A, B, and F. Additionally, the relationship between melatonin/melatonin isomer and the fermentation process was preliminarily explored and verified by wine fermentation of four types of berries (strawberry, blueberry, mulberry, and raspberry). The results showed that the melatonin content reached the maximum on day 1 and then decreased rapidly. Maximum values obtained for S. cerevisiae strains A, B, and F were 0.773, 0.647, and 0.825 ng/mL, respectively. The content of melatonin isomer reached the maximum on day 3 and then gradually decreased toward later stages. The maximum values obtained for S. cerevisiae strains A, B, and F were 34.89, 19.24, and 26.79 ng/mL, respectively. Thus, the content of the melatonin isomer was significantly higher than that of melatonin (p < 0.01). However, there were no significant differences in melatonin content before and after wine fermentation of the berries (strawberry, blueberry, mulberry, and raspberry), whereas the melatonin isomer content after fermentation was 64.4, 7.37, 81.9, and 55.5 ng/mL, respectively, which was significantly higher than the melatonin content. In summary, melatonin and its isomer were produced in the early fermentation stage and their individual content gradually decreased during the mid-to-late stage, which was speculated to be closely related to the stress response by S. cerevisiae during early stages of fermentation.
    15  Dynamic Changes in Bacterial Community Structure During Soy Sauce Fermentation
    GENG Yu-huan XIE Xian-hua LI Guo-ji
    2015, 31(8):83-87. DOI: 10.13982/j.mfst.1673-9078.2015.8.015
    [Abstract](1033) [HTML](0) [PDF 583.76 K](1380)
    Abstract:
    Techniques such as 16S rDNA polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprinting and phylogenetic analysis were used to reveal the dynamic changes in bacterial community structure during a high-salt-diluted fermentation of guangdong soy sauce. Total bacterial DNA was extracted from the samples and touchdown PCR was performed to amplify the V3 region of 16S rDNA. Subsequently, based on DGGE fingerprints, the specific gel bands were excised, sequenced, and analyzed using Basic Local Alignment Search Tool (BLAST). The DGGE fingerprints showed that various types of bacterial communities existed in the initial fermentation period, but only few survived in the later stages. The evolutionary pattern of the microbial community structure during soy sauce fermentation progressed from complex to simple, which demonstrated that the growth of microorganisms was inhibited by the conditions of fermentation. The sequencing identified the bacterial strains as Weissella cibaria and uncultured Enterobacter sp. with highest similarity, followed by Tetragenococcus halophilus, Weissella paramesenteroides, Citrobacter freundii, Enterobacter aerogenes, and Enterobacter sp. BF1-8.
    16  Phosphorylation of Zein and Its Structure
    LUO Jing TU Jin HUANG Ting-yu WU Lei-yan YANG Wu-ying
    2015, 31(8):88-94. DOI: 10.13982/j.mfst.1673-9078.2015.8.016
    [Abstract](2525) [HTML](0) [PDF 982.21 K](2307)
    Abstract:
    Zein has widespread applications in food, medicine, biological materials, and the textile industry, but its use is limited to some degree due to the insolubility in water. To overcome this drawback, zein was phosphorylated by POCl3 and its physical properties of modified zein, such as viscosity, isoelectric point, as well as stability in acid and alkali were determined. Secondary and tertiary structures of zein before and after phosphorylation were measured by circular dichroism (CD), while thermal stability was determined using differential scanning calorimetry (DSC). The results showed that in 80% ethanol solution, the isoelectric point (PdI) of zein was at pH 5.97 and particle size was 1436 nm. Post modification, phosphate was combined with zein by O- and N- phosphate bonds, which mainly formed O-phosphate bonds under acidic conditions (pH 5.0) and N-phosphate bonds under neutral and alkaline conditions (pH 7.0 and 9.0). In addition, the viscosity of modified zein increased, the isoelectric point showed acidic shift, α-helix structure content reduced, and glass transition temperature increased.
    17  Preliminary Identification of Microorganisms from Jiuqu Used for Guangdong Hakka Rice Wine and Their γ-aminobutyric Acid-producing Capacity
    HUANG Min-xin ZHAO Wen-hong ZHU Hao BAI Wei-dong YAN Dong-mei LI Bin
    2015, 31(8):95-102. DOI: 10.13982/j.mfst.1673-9078.2015.8.017
    [Abstract](1281) [HTML](0) [PDF 1.05 M](1152)
    Abstract:
    Microorganisms present in red jiuqu, wheat jiuqu, and rice jiuqu used for Guangdong Hakka rice wine fermentation were isolated and identified and γ-aminobutyric acid (GABA) production by these microorganisms was studied. The results showed that red jiuqu contained two fungal isolates, a Monascus strain and a yeast strain; wheat jiuqu contained seven fungal isolates, a Mucor strain, four Aspergillus strains, one Rhizopus strain, and one yeast strain; while rice jiuqu contained six fungal isolates, one Rhizopus strain, four Aspergillus strains, and one yeast strain. Analysis of biochemical characteristics and sequence analysis identified one of the Aspergillus strains and the yeast strain isolated from wheat jiuqu as Aspergillus oryzae and Saccharomyces cerevisiae, respectively. The isolates were cultured separately by submerged fermentation and the amount of GABA in the fermentation broth was estimated by high-performance liquid chromatography (HPLC). The results showed that all fungal isolates from red jiuqu, wheat jiuqu, and rice jiuqu could produce GABA, but they had varyed GABA production capacities. Rhizopus and several Aspergillus strains produced relatively high amount of GABA, especially Aspergillus oryzae (more than 40 mg/L), followed by a Mucor strain (34.22 mg/L). Yeast strains produced the least amount of GABA, at approximate 10 mg/L.
    18  Effect of Different Ripening Stages on Antibacterial and Antioxidant Activity of Water-soluble Extracts from Mozzarella Cheese with Various Strains
    MA Ling PENG Deng-feng LI Hui WANG Xiao-wen LIU Hui-ping
    2015, 31(8):103-109. DOI: 10.13982/j.mfst.1673-9078.2015.8.018
    [Abstract](842) [HTML](0) [PDF 752.95 K](1103)
    Abstract:
    In order to determine the influence of various starter strains and ripening periods on the formation of antibacterial and antioxidant materials in water soluble extracts for Mozzarella cheese, activities of antibacterial for E.coli, Bacillus subtilis, Staphylococcus aureus, yeast and mould were detected by filter paper dispersion method. DPPH scavenging rate, reducing power in vitro and the antioxidant in vivo were also investigated. The results indicated: the antibacterial and antioxidant property of extracts changes with strains and ripening stages exhibited stronger inhibition against bacteria than fungi, extracts of cheese with AB+LH ripening 60 days showed higher bacterial inhibition than the other cheeses, cheese with AB+LA ripening 40 days demonstrated highest scavenging rate of DPPH and the inhibition value was 67.76%, cheese with AB ripening 50 days displayed greatest reducing power of 1.23, the extracts also have antioxidant in vivo.
    19  Relationship between Protein Hydrolysate and the Formation of Melanin during Pure-breed Fermentation of Douchi
    WANG Xue-meng MA Liang YU Wei GUO Xue-xia ZHANG Yu-hao ZHANG Yu-hao
    2015, 31(8):110-116. DOI: 10.13982/j.mfst.1673-9078.2015.8.019
    [Abstract](995) [HTML](0) [PDF 1002.56 K](1072)
    Abstract:
    The complex microbial flora during traditional fermentation of douchi makes it a challenge to conduct in-depth analysis of the correlation between douchi protein hydrolysate and the formation of melanin. In this study, four main Mucor species from naturally Mucor-fermented douchi, namely Mucor racemosa PR9.00140, Actinomucor elegans PR9.00018, Mocor sufu PR9.00148, and Mucor wutongqiao PR9.00151, were used and the correlation between changes in the content of protein hydrolysates and color of douchi during pure-breed fermentation was studied. The results showed that the degree of correlation between three protein hydrolysates and color was in the following order: polypeptides > free amino acids > macromolecular soluble proteins, while the changes in the content of polypeptides and free amino acids significantly correlated with changes in the douchi color. The correlation evulation between polypeptides in different relative molecular mass ranges and color change of douchi during pure-breed fermentation of douchi indicated that polypeptides with a relative mass of 500 to 200 were more involved in the formation of melanin. Therefore, these results provide data for the development of improved quality control and evaluation system as well as rapid production of douchi.
    20  Effect of Glycosylation on the Antigenicity and Structural Properties of Soybean Protein Isolate-lactose Conjugate
    ZHANG Nan BU Guan-hao ZHU Ting-wei CHEN Fu-sheng
    2015, 31(8):117-121. DOI: 10.13982/j.mfst.1673-9078.2015.8.020
    [Abstract](1180) [HTML](0) [PDF 769.04 K](1208)
    Abstract:
    Lactose was introduced into soybean protein isolate (SPI) via glycosylation to produce an SPI-lactose conjugates, under different temperatures, protein and sugar mass ratios, as well as reaction durations. Subsequent changes in the antigenicity of β-conglycinin in the SPI-lactose conjugates was estimated by indirect-competition enzyme-linked immunosorbent assay (ic-ELISA). The structural properties of the SPI-lactose conjugates were also studied. The results indicated that glycosylation reduced the antigenicity of β-conglycinin from 93.79% (control) to 37.75% (conjugates). Compared to SPI, the content of free amino groups in the complex also decreased after glycosylation. The reduction was highest at 60 hours after the of the reaction. Fourier transformed infrared spectroscopy (FT-IR) showed that the quantity of α-helices, β-turns, and random coil structures were lower in the SPI-lactose glycosylation product than that in the SPI, while that of β-sheet increased. Results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and periodic acid-Schiff (PAS) staining showed that the SPI band gradually became weaker with the progress in glycosylation reaction, indicating that the glycosylation reaction occurred between SPI and lactose molecules.
    21  Effect of Dose Rate on Lipid and Protein Oxidation and the Properties of Beef Proteins
    WANG Ning WANG Xiao-tuo DING Wu WANG Zhi-dong
    2015, 31(8):122-128. DOI: 10.13982/j.mfst.1673-9078.2015.8.021
    [Abstract](934) [HTML](0) [PDF 1.06 M](1363)
    Abstract:
    The Chilled beef meat was irradiated with electron beams and the effect of irradiation dose rate on the degree of lipid and protein oxidation was examined. Additionally, physicochemical properties of beef proteins such as the solubility, surface hydrophobicity, and water-holding capacity (WHC) were evaluated. The results demonstrated that after irradiation with 2 kGy electron beam, the degree of lipid and protein oxidation increased, and the surface hydrophobicity of beef proteins increased significantly (p < 0.05). In contrast, the solubility and water-holding capacity of the proteins decreased. On increasing the irradiation dose rate from 0 to 2500 Gy/s, the thiobarbituric acid reactive substances (TBARS), acid value, peroxide value (POV), and carbonyl and disulfide (SS) content decreased; thiol group (SH) content of beet meat increased; and the degree of beef protein oxidation decreased. The dose rate, showed significant positive correlation with protein solubility and water-holding capacity (WHC), whereas a significant negative correlation with surface hydrophobicity of beef proteins (p < 0.05). The results revealed that the dose rate of electron beam irradiation could significantly affect the oxidation of lipid and protein. Radiation oxidation could result in damage to the protein structure and significant changes in the physicochemical properties of proteins. These results provide a theoretical reference to control chilled beef oxidation during electron beam irradiation.
    22  Antibacterial Activity and Stability of Antimicrobial Peptides in Chinese Prickly Ash Seed Proteins
    JIANG Tai-ling WU Hong-yang SHEN Guang-hui DONG Xiao-hua ZHANG Zhi-qing
    2015, 31(8):129-135. DOI: 10.13982/j.mfst.1673-9078.2015.8.022
    [Abstract](1215) [HTML](0) [PDF 794.93 K](1628)
    Abstract:
    Colony count method was used to evaluate the stability of antimicrobial peptides from prickly ash seed proteins and their antimicrobial activity. The results revealed that the peptides showed inhibitory effects on Escherichia coli, Salmonella, Bacillus subtilis, and Staphylococcus aureus. The antimicrobial activity of these peptides increased in a dose-dependent manner. After treating at different temperatures and heating time, the antibacterial activity of the peptides showed no significant differences when compared with that of the control (p > 0.05). The peptides retained excellent antibacterial activity even after the treatment at pH values between 2.0 and 12.0, with lowest activity at pH 2.0 (58.13%) and the highest activity at pH 12.0 (79.17%). With increasing concentration of metal ions, the antibacterial activity decreased, increased, and changed slightly after treatment with K+, Ca2+, and Fe3+, respectively. However, the antibacterial activity increased significantly after treatment with 0.1 mol/L K+. The antibacterial activity decreased slightly after treatment with organic solvents, whereas it increased significantly (p < 0.01) when treated separately with Tween 20 and Tween 80, while the increase was not significant after treatment with SDS. Therefore, the antimicrobial peptides had excellent stability against changes in temperature, pH, metal ion content, and organic solvent concentration, while surfactants (Tween 20 and Tween 80) could significantly improve the antibacterial activity.
    23  Prediction of Miscibility in Chitosan/Amylose Blends by Molecular Dynamics Simulation
    LIU Hua ZHONG Ye-jun LI Shi-xiang LI Ji-hua LI Zi-ling LIN Li-jing ZHOU Wei
    2015, 31(8):136-142. DOI: 10.13982/j.mfst.1673-9078.2015.8.023
    [Abstract](950) [HTML](0) [PDF 1.20 M](1480)
    Abstract:
    Miscibility in chitosan/amylose blends is of great significance in research, as chitosan and starch show good complementary effects in terms of mechanical and thermal properties. In order to predict the miscibility of chitosan with starch, the Flory-Huggins parameter χ, radial distribution function of atom pair, and diffusion coefficient of the polymer chain were simulated by molecular dynamics simulation, and under the condensed-phase optimized molecular potential for atomistic simulation studies (COMPASS) force field and NPT ensemble. Results indicated that the value of parameter χ was the smallest, the bonding force of molecular chains and diffusion coefficient between amylose and chitosan chain segment were the largest when the mass ratio of amylose/chitosan was 30/70 at the same temperature when compared to the mass ratios of 70/30 and 50/50. This showed that the miscibility of the binary system (mass ratio of 30/70) was better than that of the other two systems. The addition of amylose into chitosan suppressed the mobility of chitosan chains due to a decrease in crystallization and relaxation rate of chitosan caused by amylose chain segments.
    24  Genomic Study of Foodborne Bacillus cereus using Solexa Genome Sequencing Technology
    LI Lin JI Li-li DUAN Jing-jing JIN He-po LI Bing XU Zhen-bo
    2015, 31(8):143-152. DOI: 10.13982/j.mfst.1673-9078.2015.8.024
    [Abstract](854) [HTML](0) [PDF 1.36 M](1506)
    Abstract:
    The DNA of two Bacillus cereus strains, isolated from soy sauce residue, was extracted using a DNA extraction kit and purified using a gel recovery kit. A high-quality sequencing library was constructed, followed by whole-genome resequencing using Solexa sequencing technology. The quality of genome sequencing was assessed and the genomic information was analyzed. Mapping analysis was used to compare the mutant genes of two strains using the reference genome, the common mutant genes were singled out, and Clusters of Orthologous Groups (COG) annotation, Gene Ontology (GO) functional annotation, and Kyoto Encyclopedia of Genes and Genomes (KEGG) biological pathway analysis were conducted on the common mutant genes. Using the results of these analyses of common mutant genes combined with previous literature related to salt tolerance of Bacillus cereus, the key genes that determine salt tolerance were singled out based on the analysis of gene function. In this study, 49 genes were found to be associated with salt tolerance that may play an important part in the process. The mechanism of salt tolerance was explored in this study, creating conditions for comprehensive utilization of soy sauce residue and providing an important basis for further research on the mechanism of salt tolerance in microorganisms during the fermentation of food.
    25  Factors Affecting Furan Formation in Lactose-amino Acid Models during Sterilization
    LV Xiao-ling LIANG Yu-hang ZHU Jie-mei ZHANG Jian ZHANG Ying
    2015, 31(8):153-158. DOI: 10.13982/j.mfst.1673-9078.2015.8.025
    [Abstract](868) [HTML](0) [PDF 881.26 K](1200)
    Abstract:
    Furan, a Group 2B carcinogen, is often found in heat-processed foods and has several precursors including ascorbic acid, carbohydrates, amino acids, polyunsaturated fatty acids, and carotenoids. It is particularly harmful when present in baby food. To determine the factors contributing to formation of furan in food, four types of lactose-amino acid models were constructed based on the composition and content of free carbohydrates and amino acids in mashed tuna. A two-level, fractional factorial experiment was designed to systemically investigate the effects of sterilization time, sterilization temperature, pH, phase state, and buffer system on the furan formation. The results showed that the effects of these factors were similar in all four lactose-amino acid models, wherein, high temperature, long durations of sterilization, neutral pH, liquid state, and the presence of phosphates all promoted the furan formation. Additionally, phase state had a relatively lesser impact as compared to the other factors tested. This work provide data for the prevention and control of furan formation in food as well as a reference for the study of other hazards in food.
    26  Monitoring Alanine Concentration During the Temperature Triggered Glutamate Fermentation by Near-infrared Spectroscopy
    GUI Yong-li LIANG Jing-bo ZHANG Cheng-lin MA Lei XIE Xi-xian XU Qing-yang CHEN Ning
    2015, 31(8):159-164. DOI: 10.13982/j.mfst.1673-9078.2015.8.026
    [Abstract](1064) [HTML](0) [PDF 773.31 K](1315)
    Abstract:
    Alanine is one of main by-products produced during process of glutamate fermentation. High concentration of alanine significantly affects glutamate production and yield, so accurately and rapidly monitoring alanine concentration is rather important for controlling fermentation process. In this study, to realize the rapid detection of alanine during glutamate fermentation, the calibration models for monitoring concentrations of alanine in the temperature-triggered glutamate fermentation process were developed by the near infrared (NIR). The NIR measurements of samples were analyzed by partial least-squares (PLS) regression with selecting spectral pre-processing methods and different wavelength. The root-mean square error of cross-validation (RMSECV), determination coefficient (R2) and residual predictive deviation (RPD) of the model was 0.21 g/L, 0.97 and 5.55, respectively, indicating that the model had good predictive ability. New batch fermentations as external validation were used to check the model. Compared with concentrations of predict value and measured value, the determination coefficient and average relative error of the model was 0.97 and 5.83%, respectively. These results showed that prediction model could accurately and quickly predict and monitor alanine concentration during the temperature-triggered glutamate fermentation process, and the study could provide theoretical basis for the real-time control and optimization of the temperature-triggered glutamate fermentation.
    27  Purification and Characterization of Protease from Marine B. thuringiensis SWJS07
    ZHAO Mou-ming HUAN Hui-jie LEI Fen-fen CUI Chun
    2015, 31(8):165-170. DOI: 10.13982/j.mfst.1673-9078.2015.8.027
    [Abstract](814) [HTML](0) [PDF 819.98 K](1207)
    Abstract:
    The protease produced by the marine strain B. thuringiensis SWJS07 was purified to homogeneity by ultrafiltration, ammonium sulfate precipitation, anion-exchange chromatography (DEAE-Sepharose Fast Flow) and gel filtration chromatography (Sephadex G-75), with a 6.39-fold increase in specific activity and 37.14% recovery and the molecular weight was estimated to be 37.0 kDa on SDS-PAGE. The optimal temperature and pH for the purified protease were determined to be 55 ℃ and pH 6.5. The protease was highly stable from 30 ℃ to 45 ℃ and between pH 6.0 and 9.0 and it was activated by Ca2+and Mn2+, while Hg2+, Cd2+, Al3+ had a strong inhibitory effect. The optimal temperature were 60 ℃ and 55 ℃ in the presence of 2 mM Ca2+and Mn2+, and the activity were increase by 32.86%, 28.35%, respectively. Meanwhile, thermostability of the protease was enhanced by Ca2+ and Mn2+. In the presence of 2 mM Ca2+and Mn2+, the activity of the protease were retained unchanged after heating for 30 min at 60 ℃, however, it retained 21.02% of its initial activity in the absence of them. It was strongly inhibited by EDTA-Na2, indicating that the protease may be metalloprotease.
    28  Studies on the Critical Control Points of Lead in Solid-state Fermentation Vinegar Production
    XU Qing-ping YAO Jun-ying ZONG Wei
    2015, 31(8):171-176. DOI: 10.13982/j.mfst.1673-9078.2015.8.028
    [Abstract](912) [HTML](0) [PDF 722.01 K](1036)
    Abstract:
    This study aims to explore the key points of lead control in solid-state fermentation vinegar production during the study of migration rules of lead. The Tessier sequential extraction method and organic membrane filtration methods were employed to investigate the changes in lead speciation in solid or liquid phase, respectively. Atomic absorption spectrometry method was adopted to determine the lead content. The increasing of lead content in solid phase during acetic acid fermentation was caused by the migration and transformation of lead-protein complexes and lead oxalate in vinegar Pei. Equipment material used during processing or storage was the major influencing factor of lead content in vinegar. Lead in vinegar was regulated by vinegar Pei due to the strong adsorption of lead ion by vinegar Pei. The content of precipitable material in liquid phase was influenced by vinegar production process, including mixing with bran and rice husk, fermentation, boiling sterilization, and storage. And lead can be enriched in precipitable material. Lead content in vinegar may be reduced by improving production equipment materials, using lead ion adsorbents and removing the vinegar precipitation.
    29  Mesoscopic Simulation of Tween80/n-Alkanol Microemulsion System
    WAN Zi-yuan WU Fang LI Yan XIE Xin-an LI Lu
    2015, 31(8):177-183. DOI: 10.13982/j.mfst.1673-9078.2015.8.029
    [Abstract](826) [HTML](0) [PDF 1.40 M](1157)
    Abstract:
    The Tween80/n-alkanol (C2~C8)/ethyl butyrate/water four-component microemulsion system was simulated using the dissipative particle dynamics (DPD) method. Effect of n-alkanol concentration and n-alkanol alkyl chain length on the phase behavior and microstructure during the formation of microemulsion was also studied. The simulation results indicated that the concentration and alkyl chain length of n-alkanol greatly affected morphological changes in the self-assembly of the system. When the n-alkanol concentration was low, particle size of the microemulsion increased with an increase in alcohol concentration. After the n-alkanol concentration was increased to a certain extent, a further increase in concentration led to a change in the structure of microemulsion from spherical shape to pipe-like and net-like shapes. A comparison of the n-alkanol concentrations when morphological changes occurred in microemulsion systems with different alkyl chain lengths revealed that an increase in alkyl chain length of n-alkanol promoted morphological changes in the microemulsion system at low n-alkanol concentrations and the interfacial tension of the system stabilized rapidly. In addition, the results showed that increasing chain length of alcohol increased the water/oil (W/O) and bicontinuous microemulsion region of Tween80/n-alkanol (C2~C8)/ethyl butyrate/water system. This result provides guidance for the control of type, morphology, and size of the microemulsion system, to thus achieve selective extraction of proteins.
    30  Kinetic Analysis of the Acid-catalyzed 5-Hydroxymenthylfurfual Formation from Sugar
    LIU Shu-lan YU Xiao-jie ZHAO Jing ZOU Bin YE Xiao-fei ZHOU Cun-shan
    2015, 31(8):184-191. DOI: 10.13982/j.mfst.1673-9078.2015.8.030
    [Abstract](968) [HTML](0) [PDF 871.58 K](1166)
    Abstract:
    Acids such as phosphoric acid and citric acid in food can catalyze the transformation of sweet substances including glucose and fructose, into 5-hydroxymenthylfurfual (5-HMF). In this study, different sugar-acid solutions, namely, glucose-phosphate acid (GP), glucose-citric acid (GL), fructose-phosphate acid (FP), and fructose-citric acid (FL) systems were placed in ampoules and heated using an oil bath at three reaction temperatures: 373 K, 393 K and 413 K. 5-HMF concentration in the sugar-acid systems over time were monitored using high-pressure liquid chromatography (HPLC) during the eight-hour heating period. The formation kinetics model was estabishedby Origin 8.0 software. The catalytic efficiency of inorganic ternary phosphate acid was found to be higher than that of organic ternary citric acid. The conversion rate of fructose was higher than that of glucose. The concentrations of 5-HMF increased linearly with reaction time for all four sugar-acid systems tested, in accordance with the zero-order kinetics model, the reaction activation energy values were 109.16, 121.09, 102.89, and 112.36 kJ/mol, respectively, with highest values in GP and lowest values in FL system. Thus, phosphoric acid and fructose content had a major impact on 5-HMF concentration of sugar-acid food during thermal processing.
    31  Preparation of nPAM-papain-cellulose Nanocrystal (CNC) Biocatalyst by Double-layer Electrostatic Self-assembly Technique
    LOU Wen-yong YUE Dong-mei CAO Shi-lin FAN Xiao-dan
    2015, 31(8):192-198. DOI: 10.13982/j.mfst.1673-9078.2015.8.031
    [Abstract](1109) [HTML](0) [PDF 987.26 K](1202)
    Abstract:
    A novel, immobilized papain (PA) was prepared by double layers electrostatic self-assembly using the surface charge characteristics of support material cellulose nanocrystal (CNC), papain (PA), and non-ionic polyacrylamide (nPAM). The electrostatic interaction mechanism of the immobilization process was explored via zeta potential (ZP) analysis and Fourier transform infrared spectroscopy (FTIR) was used to analyze the composition of immobilized PA and the interactions between each substance. The optimal immobilization conditions were obtained through a study of each factor in the immobilization process, as follows: pH: 5.0; CNC/PA mass ratio: 36:1; dosage of 5% (by mass) nPAM: 0.3 mL; the enzyme layer assembly time: 30 min. Under these conditions, the enzyme activity recovery was as high as 85.8%. Subsequently, the kinetic parameters of the free and immobilized enzymes were studied, and the results showed that the Vmax/Km of immobilized enzyme (1.40 min-1) was significantly higher than that of free enzyme (0.80 min-1), indicating that the prepared immobilized enzyme had higher catalytic efficiency as well as wider optimal pH and temperature range. Moreover, the immobilized PA still remained > 96.5% of its initial enzyme activity after the repeated use for five cycles. Therefore, double-layer electrostatic self-assembly technique is a novel and convenient method for enzyme immobilization.
    32  Effects of Temperature, Salinity, and Alkalinity in Liquid Culture on Growth and Physiological Characteristics of Nostoc flagelliforme
    GUO Jin-ying LI Tong-hui SHI Ming-ke REN Guo-yan WANG Ping ZHANG Yu-xian LUO Deng-lin FENG Hui-min
    2015, 31(8):199-204. DOI: 10.13982/j.mfst.1673-9078.2015.8.032
    [Abstract](776) [HTML](0) [PDF 1.05 M](1402)
    Abstract:
    The temperature, salinity, and alkalinity of Nostoc flagelliforme liquid culture were varied and the effects on the growth and physiological characteristics of the cells were studied. Modified BG-11 culture medium containing different concentrations of NaCl and Na2CO3 was used to culture N. flagelliforme cells at 25 ℃, 35 ℃, and 45 ℃, under light intensity of 80 μmol/(m2?s). Cell biomass of N. flagelliforme, plasmalemma permeability, and superoxide dismutase (SOD) activity, as well as the content of malondialdehyde (MDA), proline, soluble proteins, and soluble polysaccharides were determined at 8, 12, 16, and 24 h of incubation. The results indicated that, under high temperature and saline-alkali stress, the relative plasmalemma permeability of N. flagelliforme cells was increased by 193.2% and MDA content declined after an initial increase. With increase in the duration of treatment, SOD activity and proline content increased at first and then decreased. Soluble protein showed an upward trend, which was positively correlated with the duration of treatment. The soluble polysaccharide content declined after an initial increase. Compared with the growth rate of the control group, that of N. flagelliforme cells decreased significantly with theincrease in temperature and salinity-alkalinity. The results indicate that, during the process of artificial culture of N. flagelliforme in liquid medium with different levels of salinity and alkalinity at different incubation temperatures, soluble proteins and polysaccharides exert an important physiological effect. Thus, different temperatures and salinity-alkalinity can induce physiological response of N. flagelliforme.
    33  High-throughput Sequencing of the Archaeal Community in Cellar Pit Mud used in Luzhou Flavor Liquor Production
    DENG Jie WEI Chun-hui LUO Hui-bo HUANG Zhi-guo ZHU Yun-fei WANG Yan-li LI Mi WAN Shi-lv
    2015, 31(8):205-210. DOI: 10.13982/j.mfst.1673-9078.2015.8.033
    [Abstract](1391) [HTML](0) [PDF 717.66 K](1436)
    Abstract:
    The structure of the archaeal community in pit mud from 30-year-old cellars that is used for the production of Luzhou flavor liquor was analyzed by a Roche GS junior high-throughput sequencing platform. A total of 8,706 valid sequences and 282 operational taxonomic units (OTUs) were obtained from samples inthree cellars. The Shannon curves of archaea were stable in the range from 4 to 5 and the value of Chao curves increased with increasing sequence number. The predominant archaeal groups were of the phylum Euryarchaeota: Thermoplasmataceae of class Thermoplasmata, Methanobacteriaceae of class Methanobacteria, as well as Methanomicrobiaceae, Methanocorpusculaceae, and Methanosarcinaceae of class Methanococci. Saccharococcus sp. and WCHD3-02 were also detected. Among these, the dominant archaea groups were Thermoplasmataceae and Methanobacteriaceae, accounting for 39% and 27%, respectively; Methanomicrobiaceae, Methanosarcinaceae, Methanocorpusculaceae, Saccharococcus sp., WCHD3-02, and unclassified sequences accounted for 9%, 7%, 4%, 1%, 1%, and 12%, respectively. Further study on methanogens showed the presence of Methanoculleus marisnigri, Methanoculleus bourgensis, Methanosarcina siciliae, Methanobacterium, Methanocorpusculum and Methanomicrobia.
    34  Effect of Microwave Roasting on the Quality and Volatile Compounds of Sunflower Oil
    CHEN Jie HONG Zhen-tong LIU Guo-qin WANG Yuan-hui
    2015, 31(8):211-218. DOI: 10.13982/j.mfst.1673-9078.2015.8.034
    [Abstract](893) [HTML](0) [PDF 860.47 K](1489)
    Abstract:
    How microwave roasting affects the quality and volatile compounds of pressed sunflower oil was investigated here. The results showed that with an increase in microwave power and duration of treatment, the color of pressed sunflower oil gradually became deeper, while acid value did not change significantly. Peroxide value increased initially and then decreased under moderate and low microwave power, showing a decreasing trend under high microwave power. The induction time did not have a significant effect at middle and low microwave power, but showed an increasing trend at high power. Finally, vitamin E content decreased gradually. By referring to various indexes, seven sunflower oil samples (700 W 5 min, 700 W 4 min, 700 W 3 min, 560 W 4 min, 560 W 5 min, 420 W 5 min, and 420 W 6 min) with high total sensory scores were selected and their volatile compounds were analyzed using headspace solid-phase microextraction-gas chromatography- mass spectrometry (HS-SPME-GC-MS). A total of 65 kinds of volatile compounds were detected, including 16 aldehyde compounds, 6 ketone compounds, 15 heterocyclic compounds, 12 terpenes, 4 alcohols, 9 alkanes, 2 esters, and 1 acid. Additionally, the oil samples shared 14 volatile compounds in common. It can be seen from the results above that microwave roasting has a significant effect on the quality of sunflower oil. The characteristic flavor of sunflower oil is produced by the combination of the inherent natural fragrance of the sunflower seeds, lipid oxidation products, and Maillard reaction products during the roasting process.
    35  Migration Behavior of Epoxidized Soybean Oil from Polyvinyl Chloride Gaskets into Food Simulants
    CHEN Yan-fen ZHONG Huai-ning YI Rong WANG Zhi-yuan HU Chang-ying WANG Zhi-wei
    2015, 31(8):219-225. DOI: 10.13982/j.mfst.1673-9078.2015.8.035
    [Abstract](1028) [HTML](0) [PDF 588.72 K](1290)
    Abstract:
    The migration behavior of epoxidized soybean oil (ESBO) from polyvinyl chloride (PVC) gaskets in the lids of glass jars into food simulants such as 3% acetic acid, 50% ethanol, or olive oil was studied at 25 ℃, 40 ℃, and commercial sterilization conditions (121 ℃ and 0.1 MPa). The results showed that the migration level of ESBO increased with increasing temperature and time of contact. At migration equilibrium, ESBO migration rates in 3% acetic acid, 50% ethanol, olive oil, and olive oil after sterilization observed were 0.06%, 0.46%, 30.36%, and 31.35% at 25 ℃, respectively. In contrast, they were 0.14%, 1.40%, 31.57%, and 33.87% at 40 ℃, respectively. The maximum migration rate of ESBO was found in olive oil, followed by 50% ethanol. Since the dissolution rate of ESBO in 3% acetic acid was the lowest, almost no migration occurred. The amount of ESBO in olive oil at migration equilibrium exceeded the overall migration limit in Regulation (EU) No 10/2011. Thus, high-pressure high-temperature sterilization played a certain promoting effect on the migration of ESBO in oil.
    36  Effect of Microwave Drying on Quality and Volatile Substances of Wild Capsella bursa-pastoris (L.)
    ZHANG Li XUE Yan-jun DENG Jin-hua LIU Chen YU Li RU Hua DONG Ming-hui YU Zhi-fang
    2015, 31(8):226-236. DOI: 10.13982/j.mfst.1673-9078.2015.8.036
    [Abstract](902) [HTML](0) [PDF 1.21 M](1135)
    Abstract:
    The effect of different microwave-drying methods on the quality and volatile substances of wild Capsella bursa-pastoris (L.). Different microwave powers (120, 240, 360, 480, 600, and 700 W) were applied to dry the samples of wild Capsella bursa-pastoris (L.) and a combination of head space-solid phase micro-extraction and gas chromatography (HS-SPME-GC-MS) was used to analyze the volatile substances in the dried samples. The results showed that microwave drying extensively decreased the content of characteristic alcohols such as cis-3-hexen-1-ol, trans-2-hexene-1-alcohol, and 2,6-dimethyl cyclohexanol. The types and content of aldehydes slightly decreased, whereas the content of isovaleraldehyde, (E)-2-pentenal, n-octylaldehyde, and phenylacetaldehyde increased. The content of isoamyl nitrite and 2-methyl-ethylvalerate also increased. Acids such as 3-methylbutanoic acid, 2-methylbutanoic acid, and caproic acid were generated, whereas styrene, cyclotetradecane, and other hydrocarbons disappeared during the microwave-drying process. The results showed that good sensory quality of dried Capsella bursa-pastoris (L.) can be obtained with microwave-drying at 480 W, wherein retention rates of chlorophyll and Vc reached 67.14% and 71.20%, respectively. Volatile components comprised a majority of aromatic compounds. Retention rate of volatile substances was 93.68%, where those of alcohols and aldehydes were relatively high, with β-ionone retention rate reaching as high as 84.21%.
    37  Preparation and Physicochemical Properties of the Naringin and Lecithin Complex
    XU Lu LAN Mu-xiang YANG Ji-guo YUAN Er-dong NING Zheng-xiang
    2015, 31(8):237-241. DOI: 10.13982/j.mfst.1673-9078.2015.8.037
    [Abstract](896) [HTML](0) [PDF 989.65 K](1397)
    Abstract:
    Naringin exhibits several bioactivities such as antioxidant activity, but it is poorly lipophilic and has low oral bioavailability, which limits its application. In order to improve solubility in lipidand itsbioavailability. Naringin was combined with lecithin to obtain a naringin-lecithin complex. The physicochemical properties of the complex were analyzed by ultraviolet-visible (UV) spectrometry, infrared (IR) spectrometry, differential scanning calorimetry (DSC), and X-ray diffractometry (XRD). It was found that the combination of naringin and lecithin did not form a new compound; rather they combine via non-covalent bond such as hydrogen bonds and Van der Waals force, where naringin is scattered in an amorphous state within lecithin. Meanwhile comparing the naringin solubility ofnative and naringin forms in n-octanol were compared, indicating that the solubility of naringin was significantly improved from 3.29 (native)to 755.50 μg/mL (complex). The result of antioxidant activity tests of samples in a linoleic acid system showed that the antioxidant activity of naringin in oil could be significantly improved by complexing with lecithin.
    38  Detecting Phenobarbital Residue in Pork via the Combination of Gas Chromatography-Mass Spectrometry (GC-MS) with Quick-Easy-Cheap-Effective-Rugged-and-Safe (QuEChERS)
    ZHAO Ying-bo GUAN Li ZHOU Yan-ming
    2015, 31(8):239-333. DOI: 10.13982/j.mfst.1673-9078.2015.8.051
    [Abstract](936) [HTML](0) [PDF 717.79 K](1090)
    Abstract:
    A novel method for the detection of phenobarbital residue in pork using gas chromatography–mass spectrometry (GC-MS) combined with the “Quick, Easy, Cheap, Effective, Rugged and Safe” (QuEChERS) was established here. The analytes were extracted using acetonitrile, MgSO4, and NaAc solutions and purified with MgSO4+PSA+GCB+C18 adsorbents. The samples were then separated on a DB-17 capillary column (30 m × 0.25 mm × 0.25 μm) and the ion source was electron ionization (EI). The target compound was detected in the selected ion monitoring (SIM) mode; the quantitative ion was 204 m/z, the reference ion was 232 m/z, and external standard calibration was used for the quantitative analysis of phenobarbital. To optimize the pretreatment for QuEChERS, conditions such as acidification of the extraction solution, choices of extraction salts, and adsorbent type were discussed using the spike-recovery rate as the evaluation index. The derivative conditions and matrix effects were discussed as well. The results indicated that phenobarbital had satisfactory linearity from 0.05 to 0.5 μg/mL. The limit of detection (LOD) was 0.003 μg/mL and the limit of quantitation (LOQ) was 0.01 μg/mL. The recovery rates at three spiking levels (0.01, 0.05, and 0.1 μg/g) were 75.4% to 88.3%, and the relative standard deviations were 4.66% to 5.77%. The QuEChERS method combined with GC-MS was simple and convenient, which may provide a reference method for detecting hypnotic residues in meat matrix.
    39  Effect of Static Ice Slurry on the Preservation of Squid
    YUAN Peng-xiang DENG Shang-gui ZHANG Bin LI Yue-qin SANTIAGO Aubourg
    2015, 31(8):242-247. DOI: 10.13982/j.mfst.1673-9078.2015.8.038
    [Abstract](1016) [HTML](0) [PDF 801.71 K](1224)
    Abstract:
    The effect of using static ice slurry, freshwater crushed ice, or refrigeration for preservation of fresh squid from the East China Sea was studied, in terms of sensory score, physicochemical properties, and microbial counts. After a 15-day preservation period the values of sensory scores, moisture content, pH, total volatile base nitrogen (TVB-N), total viable counts, elasticity, and chewiness of samples were as follows: 3.36, 77.42%, 7.65, >30 mg/100 g, 7.04 log CFU/g, 0.05 mm, and 0.06 MJ for refrigerated samples; 3.95, 78.33%, 7.23, >30 mg/100 g, 6.61 log CFU/g, 0.06 mm, and 0.10 MJ for samples stored in freshwater crushed ice; and 6.57, 84.78%, 6.64, 13.26 mg/100 g, 4.73 log CFU/g, 0.16 mm, and 0.16 MJ for samples stored in static ice slurry, respectively. The results show that (1) ice slurry conditions maintained the freshness and physicochemical properties of squid, which met food safety standards; (2) the preservation effect of ice slurry was significantly better than that of refrigeration and freshwater crushed ice. The results also showed that as compared to freshwater ice and refrigeration, ice slurry preservation significantly retards the spoilage rate and extends the shelf life of squid, thus helping to improve the quality of aquatic products during transportation and storage.
    40  Effect of Pulsed Electric Field Treatment on Glucoamylase Activation
    TIAN Mei-ling FANG Ting DU Mu-ying ZHANG Fu-sheng
    2015, 31(8):248-253. DOI: 10.13982/j.mfst.1673-9078.2015.8.039
    [Abstract](883) [HTML](0) [PDF 887.56 K](1293)
    Abstract:
    The efficient, safe, and rapid application of pulsed electric field (PEF) technology to enzymatic modification was studied. The effect of PEF treatment on the enzymatic activity, properties, and kinetic parameters of glucoamylase were investigated, while conformational transitions were studied using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), circular dichroism (CD) and fluorescence spectroscopy. The results showed that the maximum increase in activity obtained was 20.74 ± 0.71% as compared to control, observed when 15 kV/cm electric field intensity and 80 mL/min flow rate were applied and this activation effect lasted for up to 17 h at 4 ℃. Moreover, PEF treatment widened the range of optimum temperature for glucoamylase activity, increased the Vmax and decreased the Km, but had a negligible effect on the optimum pH of glucoamylase. Results of SDS-PAGE indicated that the primary structure of glucoamylase did not change after PEF treatment. However, according to CD and ?uorescence spectra, PEF treatment enhanced the α-helix and β-sheet content in glucoamylase by 3.00% and 2.80%, respectively, leading to more ordered conformation. Additionally, intrinsic fluorescence spectra analysis showed that PEF treatment resulted in a red shift of the emission maximum of glucoamylase due to the exposed microenvironment of Trp residue. Therefore, based on these results, both, secondary and tertiary structures of glucoamylase were modified.
    41  Effect of Different Drying Methods on Several Endogenous Enzyme Activities of Muraenesox cinereus Fillets
    LI Jia WAN Jin-qing ZOU Lei ZHONG Yao-guang
    2015, 31(8):254-260. DOI: 10.13982/j.mfst.1673-9078.2015.8.040
    [Abstract](943) [HTML](0) [PDF 891.61 K](1125)
    Abstract:
    Drying can endow aquatic products with unique flavor, whose formation is related to endogenous enzymes. In this study, the effects of different drying methods on enzyme activities and their metabolites inosinemonpho sphate (IMP) and free amino acid contents of Muraenesox cinereus fillets were investigated. Several enzymes playing the leading role in taste substances (such as AMP deaminase, acid phosphatase, cathepsin B and leucyl aminopeptidase) were selected. The drying methods included controlled freezing-point vacuum (CFVD), vacuum freeze drying (VFD) and hot air drying (HAD). Results showed that potential activities of the four enzymes mentioned above were decreased after drying. The highest retention of enzyme activities of fillets was observed in VFD, representing 92.99%, 85.58%, 65.53% and 54.26%, respectively, followed by CFVD. While HAD fillets had the lowest enzyme activities. The IMP and free amino acid contents in CFVD fillets were significantly higher than those in other treatments. IMP content increased from 174.37 mg / 100 g (dry basis) to 625.08 mg/100 g and free amino acid content increased by 33.07%. Therefore, four kinds of enzyme in CFVD fillets reach better retention in activities and the highest conversion rate.
    42  Screening for Quality Strains of Yeast from Yellow Rice Wine and Stress Resistance Analysis
    YANG Yi-jin YU Jian-shen XIA Yong-jun FANG Yi-qun Ni Bin WANG Guang-qiang AI Lian-zhong
    2015, 31(8):261-267. DOI: 10.13982/j.mfst.1673-9078.2015.8.041
    [Abstract](929) [HTML](0) [PDF 636.02 K](1223)
    Abstract:
    Four strains of yeast, namely BR 20, BR 25, BR 26 and BR 30, with preferable values for initial fermentation capacity, alcohol-producing ability, and fermentation performance were isolated from the main fermentation broth, yeast starter culture as well as from industrial units in the Shanghai area producing yellow rice wine. These four strains were identified as Saccharomyces cerevisiae by 5.8S rDNA-ITS sequence analysis. These four strains were analyzed in terms of tolerance to high concentrations of ethanol, sugar, and lactic acid as well as high osmotic pressure. The results showed that not only could the BR 20 and BR 30 strains withstand 18% alcohol concentration, but they could also adapt to high osmotic pressures of up to 1.6 mol/L. On the other hand, BR 20 and BR 26 stains had preferable growth capacity in the presence of high content of lactic acid, up to 54 g/L, while BR 30 strain showed highest tolerance to sugar, at 40% concentration. Thus, BR 20 and BR 30 strains showed highest resistance to stress and were chosen for further experiments. Comparison of the fermentation efficiency of BR 20 and BR 30 strains showed that the average substrate utilization rate of BR 20 strain was 1.67% higher than that of the BR 30 strain, and the average ethanol yield of BR 20 strain was 6.76% higher than that of the BR 30 strain. Thus, the use of the BR 20 and BR 30 strains as hybrid strains for wine fermentation from yellow rice will reduce fermentation time, improve the utilization of raw materials, and increase alcohol yield.
    43  Optimized Enzymatic Hydrolysis for Flavor Peptide Preparation from Cultured Obscure Pufferfish (Takifugu obscurus) using Sensory Evaluation and Electronic Tongue
    MIAO Xiao-dan LIU Yuan MA Lei LI Lin WANG Zheng-quan DANG Ya-li WANG Xi-chang
    2015, 31(8):268-272. DOI: 10.13982/j.mfst.1673-9078.2015.8.042
    [Abstract](1123) [HTML](0) [PDF 621.79 K](1365)
    Abstract:
    Previous studies conducted on the taste of obscure pufferfish have mainly focused on content of free amino acids, inorganic ions, nucleotides and other related compounds, but the peptides contributing to the flavor as well as the sensation of mellow, creamy taste has rarely been studied. Therefore, the enzymatic extraction of flavor peptides responsible for prominent taste characteristics of obscure pufferfish has significant research and economic value for the food industry. Cultured obscure pufferfish muscle was used as to extract flavor peptides using neutral protease, flavorzyme, proteolytic enzyme, and protamex. A method combining the degree of hydrolysis (DH), oligopeptide content, taste sensor outputs from an electronic tongue, and sensory evaluation was used to identify the optimal enzyme and hydrolysis conditions. The results indicated that the DH of hydrolysates from flavorzyme and oligopeptide content of the hydrolysates from proteolytic enzyme showed the highest values. Electronic tongue could clearly differentiate different hydrolysates and correlated with the results from sensory evaluation to some extent. However, there were some differences between the relative intensities of umami, saltiness, and sourness between theresults from electronic tongue and sensory evaluation. Finally, neutral protease was identified as the optimum protease for the enzymatic hydrolysis to produce flavor peptides from cultured obscure pufferfish muscle.
    44  Preservation of the Commercial Quality of Takoyaki by Antimicrobial Zein Coating
    LI Miao-miao ZHANG Hou-cheng ZHANG Meng XU Da-lun WANG Jiang-feng YANG Wen-ge ZHANG Jin-jie
    2015, 31(8):273-279. DOI: 10.13982/j.mfst.1673-9078.2015.8.043
    [Abstract](1138) [HTML](0) [PDF 768.95 K](1123)
    Abstract:
    To enhance the practical application of active edible coatings in the food industry, edible zein coatings incorporated with nisin or nisin/ethylenediaminetetraacetic acid (EDTA) were used to preserve the quality of commercially manufactured Takoyaki. The microbial load, total basic volatile nitrogen (TVB-N) content, weight loss and sensory quality were served as quality indicators. The increase of microbial load of Takoyaki coated with antimicrobial zein during a 18-day refrigeration storage period was less than 1 log cfu/g, while the microbial load increased about 3 log cfu/g for the control group without the coating treatment. The formation of TVB-N was significantly (P<0.05) reduced when Takoyaki were coated with antimicrobial zein. With or without antimicrobial agent, coated Takoyaki exerted significantly (P<0.05) less weight loss and better sensory quality than uncoated Takoyaki. The zein coating can extend the high quality Takoyaki shelf life to 12 days, and the zein coatings incorporated with nisin or nision-EDTA can prolong the high quality Takoyaki shelf life to 18 days. The result of this study can be a technical reference to improve the process technology of Takoyaki.
    45  Optimization of Kelp Fermentation Conditions using Probiotics and the Analysis of Nutrient Composition
    GUO Li-qiong GUO Xin-yue CHU Xuan LIN Jun-fang LIU Ying-li YE Zhi-wei LI Hong-lue LIAO Xue-yi
    2015, 31(8):280-285. DOI: 10.13982/j.mfst.1673-9078.2015.8.044
    [Abstract](1847) [HTML](0) [PDF 744.82 K](2979)
    Abstract:
    Lactobacillus plantarum strain La10 was isolated and screened from kelp (Laminaria japonica) and used for the fermentation of fresh kelp. During the fermentation process, nutritional content of the fermentation products and changes in nitrite content were determined. The results showed that the optimal conditions were as follows: (1) The OC1 fermentation conditions for sensory evaluation as the ultimate target were: temperature 20 ℃, amount of inoculum 5%, sugar concentration 9%, salt concentration 4%, and duration of fermentation 10 d. (2) The OC2 fermentation conditions for total acid in the fermentation liquid as the ultimate target were: temperature 30 ℃, amount of inoculum 10%, sugar concentration 9%, salt concentration 2%, and duration of fermentation 7 d. (3) The fishy smell in the kelp fermentation products was eliminated. Using OC1 and OC2, algin content decreased significantly from 32.07% to 19.60% and 14.01%, respectively. In contrast, reducing sugar and total sugar content increased significantly from 2.19% to 9.15% and 11.01%, respectively. The taste of the kelp fermentation products was better than that of non-fermented products. During the fermentation, nitrite content remained at a low level and the final values, using the two kinds of fermentation conditions were 93.99 and 71.43 μg/kg, respectively, which were far lower than that of the national standards used (20 mg/kg in pickles).
    46  Parameter Optimization of Rapeseed Oil Content Model Using a Miniature Near-infrared Spectrometer
    CHEN Bin LU Bing LU Dao-li
    2015, 31(8):286-292. DOI: 10.13982/j.mfst.1673-9078.2015.8.045
    [Abstract](967) [HTML](0) [PDF 1.08 M](1106)
    Abstract:
    To select characteristic NIR wavelengths for rapid and nondestructive detection of rapeseed oil content, a miniature near-infrared (NIR) spectrometer was used in combination with methods including competitive adaptive reweighted sampling (CARS), genetic algorithm (GA), successive projections algorithm (SPA), uninformative variable elimination (UVE), backward interval partial least squares (BIPLS), and synergy interval partial least squares (SIPLS). Subsequently, partial least squares regression (PLSR) and least squares-supported vector machine (LS-SVM) regression model were established and the parameters of LS-SVM model were optimized. The results showed that for PLSR model, 26 characteristic wavelengths selected by BIPLS + GA produced the optimum model, where the correlation coefficient (Rp) and root mean square error of prediction (RMSEP) for prediction sets were 0.9330 and 0.0075, respectively. For LSS-VM model, 13 characteristic wavelengths selected by SIPLS+GA produced the optimum model and the correlation coefficient (Rp) and root mean square error of prediction (RMSEP) for prediction sets were 0.9192 and 0.0055, respectively. The above results demonstrate that parameter optimization and wavelength selection can not only effectively simplify the quantitative analysis model for rapeseed oil content based on miniature NIR spectrometry, but also enhance prediction accuracy and prediction stability. These data provide useful technical references for further applications of miniature NIR spectrometry.
    47  Analysis of Egg Flavor Change during Storage Period by Electronic Sensory Methods
    MA Mei-hu BI Yu-fang ZHANG Mao-jie HE Ying
    2015, 31(8):293-300. DOI: 10.13982/j.mfst.1673-9078.2015.8.046
    [Abstract](967) [HTML](0) [PDF 860.84 K](1154)
    Abstract:
    There are few reports about using electronic sensory to analysis the egg flavor characteristics during the period of storage domestic and abroad. To quickly investigate the change of egg flavor during storage period, electronic tongue and electronic nose were used to determine the taste and odor traits of eggs with different storage times. The output values of electronic tongue were analyzed with variance analysis, and the electronic nose with principal component analysis (PCA). The electronic tongue results showed that during storage period, the bitterness, umami, and sourness output values of egg whites changed significantly. Bitterness output values, umami output values of egg whites stored at 4±1 ℃ and 23±1 ℃ changed mostly at 20th day and 10th day, respectively. The sourness output values of two groups had a biggest change at the 30th day. The bitterness, bitterness after taste, umami and sourness output values of egg yolk changed significantly during storage. Bitterness output values of yolks stored at 4±1 ℃ and 23±1 ℃ changed mostly at the 10th day. The biggest change of umami appeared at the 20th day. Sourness output values of two groups changed mostly at the 30th day. The results of the electronic nose showed that both egg whites and egg yolks at different storage times have different odor characteristics at 4±1 ℃, and presented a certain rule of changing along with the storage time at 23±1 ℃.
    48  Changes in C6 Volatile Aldehyde and Alcohol Components of Nectarine Fruits Analyzed by Headspace Solid-Phase Microextraction-gas Chromatography/Mass Spectrometry
    QIN Ling KANG Wen-huai ZHANG Zhi-wen GUO Ai-ying
    2015, 31(8):301-307. DOI: 10.13982/j.mfst.1673-9078.2015.8.047
    [Abstract](1027) [HTML](0) [PDF 842.74 K](1263)
    Abstract:
    The fruits of three precocious peach cultivars, ‘Chunguang’, ‘Yanguang’, and ‘Qiannianhong’ were used to study changes in the content of C6 alcohols and aldehydes during coloring and maturity periods. Headspace solid-phase microextraction (HS-SPME) and gas chromatography/mass spectrometry (GC/MS) were used to determine the content of C6 alcohols and aldehydes in the nectarine fruits. The results showed that the main C6 volatile compounds included hexanal, trans-2-hexenal, hexanol, trans-2-hexen-1-ol, and cis-3-hexen-1-ol. Additionally, the content of C6 volatile compounds in nectarine fruits were significantly different during different stages of maturity. The content of trans-2-hexenal was the highest, averaging 331.0 and 231.6 μg/L during the coloring and maturity periods, respectively. On the other hand, the content of cis-3-hexen-1-ol was the lowest, averaging 11.1 and 5.5 μg/L during the coloring and maturity periods, respectively. ‘Qiannianhong’ contained relatively high levels of hexanal, trans-2-hexenal, and hexanol, which were significantly higher than those in ‘Chunguang’ and ‘Yanguang’. The C6 aldehydes showed relatively high odor activity values (OVAs) during the two periods, contributing greatly to the aroma of nectarine fruits. On the other hand, the OAVs of C6 alcohols were relatively low, showing less contribution to the aroma. Thus, the content of C6 volatile compounds in nectarine fruits significantly decreased during the maturity period and also differed between different cultivars and different stages of development.
    49  Geographical Origin Discrimination of Zanthoxylum bungeanum from Southwest China Using HPLC and PCA: Identification and Determination of Marker Compounds
    CHEN Huai-xuan BAI Jin-rong QIU Chen ZHONG Kai ZHAO Zhi-feng GAO Hong HUANG Yi-na
    2015, 31(8):308-315. DOI: 10.13982/j.mfst.1673-9078.2015.8.048
    [Abstract](1441) [HTML](0) [PDF 820.62 K](1585)
    Abstract:
    The geographical origin of 15 samples of Zanthoxylum bungeanum fruits obtained from five different regions in Southwest China was differentiated. The pericarps of Z. bungeanum were extracted using methanol. Fractions were obtained by column chromatography and analyzed by high-performance liquid chromatography (HPLC) analysis. Principal component analysis (PCA) and partial least-square discriminant analysis (PLS-DA) were performed to develop classification models to differentiate between samples from Hanyuan and those from other regions of Southwest China. The results showed that samples from the Hanyuan region were significantly different from those obtained from the other regions; PLS-DA analysis showed a greater discriminatory effect than did PCA approach. In addition, the chemical compounds with variable influence on the projection (VIP) > 1 from PLS-DA models and p < 0.05 for unpaired Student’s t-test were considered relevant for group discrimination. These included neochlorogenic acid, chlorogenic acid, quercitrin, hydroxy-β-sanshool, and hydroxy-γ-sanshool, which could be potential markers to distinguish Hanyuan Z. bungeanum fruits from those obtained from other regions of Southwest China. Hydroxy-γ-sanshool content alone in Z. bungeanum fruits from Hanyuan region was higher than that in Z. bungeanum fruits from other regions, while contents of other compounds were lower; the differences were significant (p < 0.05). The results of this study provide theoretical and experimental basis to some degree for screening and quality evaluation of Z. bungeanum fruits from different geographical origins.
    50  Extraction of Bound Aroma Compounds in Raspberry Juice and Analysis of the Sugar Moieties
    REN Jing-nan DONG Man YANG Zi-yu TAI Ya-nan SHAO Jin-hui PAN Si-yi FAN Gang
    2015, 31(8):316-322. DOI: 10.13982/j.mfst.1673-9078.2015.8.049
    [Abstract](854) [HTML](0) [PDF 843.01 K](1136)
    Abstract:
    Bound aroma compounds from raspberry juice were obtained by column chromatography approach via an Amberlite XAD-2 column as well as methanol direct extraction. The extracted bound aroma compounds were analyzed by gas chromatography-mass spectrometry (GC-MS) after enzymatic hydrolysis. The main aim was to compare the extraction efficiency of both methods, and to analyze the sugar moieties of the glycosides. The results showed that only 4 bound aromas were detected in the extracts by methanol direct extraction approach with a total concentration of 77.1 μg/kg including 2 benzenic compounds and 2 fatty alcohols. In contrast, a total of 20 bound aroma compounds were found in the extracts via the Amberlite XAD-2 column chromatography approach, giving a total concentration of 3 042 μg/L, including 11 benzenic compounds, 6 alcohols and 3 terpenes. Large differences were observed in terms of the types and contents of the bound aroma compounds extracted by these two methods. The bound aroma compounds extracted by Amberlite XAD-2 column were more varied than those obtained by methanol direct extraction. Mannose and glucose were determined to be the sugar moieties of the glycosides in raspberry juice.
    51  Dynamic Discrimination of SubtlyBruised Lang Jujubes Based on Different Visible/Near-infrared Spectral Ranges
    YANG Yi ZHANG Shu-juan XUE Jian-xin WANG Bin MAN Zun ZHANG Xue-hao
    2015, 31(8):323-328. DOI: 10.13982/j.mfst.1673-9078.2015.8.050
    [Abstract](941) [HTML](0) [PDF 594.79 K](1121)
    Abstract:
    For rapid and non-destructive detection of Lang jujubes with subtle bruises, dynamic visible/near-infrared (NIR) spectral data was collected to study intact and subtly bruised Lang jujubes. Based on the definition of different spectral ranges, the spectral data obtained were divided into six spectral ranges, namely, visible (Vis), short-wave NIR (SW-NIR), long-wave NIR (LW-NIR), Vis/SW-NIR, NIR, and Vis/NIR. The optimal pretreatment method for each range was selected. Successive projections algorithm (SPA) and principal component analysis (PCA) were used to reduce the dimensions of the full spectrum (FS). Using the characteristic wavelengths extracted by SPA, the principal component extracted by PCA and FS of the 6 spectral ranges as input variables, a partial least squares regression (PLSR) model and a least-squares support vector machines (LS-SVM) model were established. The optimal model was identified by comparing the discrimination accuracy of the prediction set. The results indicated that PLSR was more preferable than LS-SVM and the SW-NIR spectral range was optimal in comparison to the other five spectral ranges in terms of discriminatory power. The optimal model was identified as SW-NIR-SNV-SPA-PLSR and the discrimination accuracy of the prediction set was 93.3%. This study provide a reasonable theoretical basis for the discrimination of subtly bruised Lang jujubes and development of relevant instruments.
    52  Rapid Detection of Triazophos Residues in Navel Orange Peel based on Surface-enhanced Raman Spectroscopy
    LI Jun-jie ZENG Hai-long LIU Mu-hua WU Rui-mei WU Yan-hong WANG Xiao-bin CHEN Jin-yin
    2015, 31(8):334-339. DOI: 10.13982/j.mfst.1673-9078.2015.8.052
    [Abstract](1031) [HTML](0) [PDF 784.82 K](1355)
    Abstract:
    Surface-enhanced Raman spectroscopy (SERS) combined with chemometrics method was used to rapidly detect triazophos residues in navel orange peel. Acetonitrile was used to rapidly produce navel orange peel extract. Graphite carbon, C18 and Periodic acid-Schiff (PSA) were used to remove interferences, e.g., pigments from the navel orange peel extracts. The obtained extracts were used as the base to prepare triazophos solutions of different concentrations and their signals were collected by laser Raman spectrometer. The resultant Raman characteristic peaks were largely consistent with those of triazophos standard solution. A partial least-squares regression model was developed to predict residual triazophos content in navel orange peel. The results showed that the minimum detection concentration for triazophos in solutions of navel orange peel extract was 0.8 mg/L, the root mean square error of the model’s prediction was 1.60 mg/L, and the correlation coefficient was 0.9669. When this method was used to detect the actual triazophos residue in navel orange peel, the absolute values of the relative error were between 0.08% and 5.98%, while the prediction recoveries were 94.36% to 104.36%. The results of this study demonstrated good predicting ability and reproducibility of the model.
    53  Comparative Analysis of Volatile Aroma Components of Xiangzaolu via the Combination of Three Extraction Methods and Gas Chromatography-Olfactometry-Mass Spectrometry (GC-O-MS)
    SU Ke-ran LIU Ye HE Cong-cong SU Hang SONG Huan-lu
    2015, 31(8):340-347. DOI: 10.13982/j.mfst.1673-9078.2015.8.053
    [Abstract](1244) [HTML](0) [PDF 833.37 K](1593)
    Abstract:
    The volatile components of xiangzaolu were analyzed using three different extraction methods, i.e., solid phase micro extraction (SPME), simultaneous distillation extraction (SDE) and solvent assisted flavor evaporation (SAFE), in combination with gas chromatography-olfactometry-mass spectrometry (GC-O-MS) . The extracts were separated by two types of chromatographic columns, DB-WAX and DB-5. A total of 38 volatile aroma compounds were identified in the extracts by SPME, 32 by SDE, and only 18 by SAFE. The 9 key aroma compounds with FD≥3 from SDE were identified by aroma extract dilution analysis (AEDA), as ethyl acetate, ethanol, 2-methyl-1-propanol, ethyl lactate, acetic acid, furfural, 2-hydroxy-4-methyl valerate, diethyl succinate, and phenylethyl alcohol. These 9 key aroma compounds were further characterized and quantified using standard compounds, whose molecular ion peak positions were the same as those of the 9 aroma compounds. Then, odor activity values (OAV) were calculated and combined with AEDA for the analysis of key volatile aroma components in xiangzaolu.
    54  Advances of Research on the Lipids from Antarctic krill (Euphausia superba)
    LIU Zhi-dong CHEN Xue-zhong CHEN Yong QU Ying-hong SHI Wen-zheng FENG Chun-lei LIU Qin LIU Jian HUANG YAN-qing QU Tai-chun GAO Fei FENG Shi MA Qing-bao HUANG Hong-liang
    2015, 31(8):348-355. DOI: 10.13982/j.mfst.1673-9078.2015.8.054
    [Abstract](1007) [HTML](0) [PDF 611.38 K](1505)
    Abstract:
    Antarctic krill (Euphausia superb) plays a central role in the Antarctic waters Ecosystem. Antarctic krill likely has the largest biomass in multi-cellular animal species on the earth. It has been paid more attention on large biomass and potential value of Antarctic krill in recent years. Lipids derived from Antarctic krill have good nutritional properties, functional properties and applicable values. This paper reviews the distribution, content, composition, nutritional and functional properties of lipids derived from Antarctic krill, analyzes the captured time, captured location, age, growth stage and environment effect on the content, composition of lipids derived from Antarctic krill. This paper compares the advantages and disadvantages on the methods of lipid extraction, including physical, chemical and biological processes, introduces the processing and utilization technology on lipid derived from Antarctic krill in domestic and abroad. This paper also introduces that the stability of lipid and its products derived from Antarctic krill. In conclusion, this paper summarizes, analyzes and evaluates that the advance of research and utilization on lipids derived from Antarctic krill in domestic and abroad. It points out the direction of processing and utilization of Antarctic krill lipid and puts forward its prospect.

    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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