Volume 30,Issue 4,2014 Table of Contents

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  • 1  Effect of Cyclocarya paliurus Polysaccharide on Hyperlipidemia and Anti-lipid Peroxidation in Hyperlipidemic Rats
    YE Zhen-nan LI Nan SHENG Dan-dan WANG Wen-jun
    2014, 30(4):1-5.
    [Abstract](1380) [HTML](0) [PDF 388.48 K](637)
    Abstract:
    The hyperlipidemic rats were randomly divided into model control, simvastatin, Cyclocarya paliurus polysaccharides (CPP) low dose, middle dose, high dose groups (16 rats per group). After 8 weeks treatments, the levels of TC, TG, HDL-C, LDL-C, T-SOD, GSH-Px, CAT, T-AOC and MDA were measured. The results showed that CPP decreased serum TC, TG, LDL-C, MDA remarkably (P <0.01) with the decreasing rate of 29.17%, 50.00%, 57.25% and 25.72% respectively, while increased the levels of HDL, T-SOD , GSH-Px and T-AOC (P<0.01) with the highest growing rates of 72.22%, 16.27%, 16.38% and 59.43%. It was indicated that CPP could regulate lipid metabolism, enhance the anti-oxidation and reduce the lipid peroxidation in rats with hyperlipidemia.
    2  In Silico Cloning and Sequence Analysis of F3H Gene in Phaseolus coccineus
    MA Guang GUO Ji-ping
    2014, 30(4):6-9.
    [Abstract](1037) [HTML](0) [PDF 500.47 K](721)
    Abstract:
    Flavanone 3-hydroxylase is a key enzyme in the biosynthetic pathway of plant flavonoids. The putative cDNA sequence of Phaseolus coccineus F3H gene was in silico cloned by using Glycine max F3H gene cDNA sequence (AAU06216.1) as a probe. According to the putative cDNA, the primers were designed for RT-PCR. The coding sequence of F3H gene in Phaseolus coccineus cDNA was cloned using RT-PCR. Then the secondary structure and advanced structure of F3H in Phaseolus coccineus were analyzed by bioinformatics methods. The results showed that the cDNA contains an open reading frame of 1128 bp, which encoded the protein containing 375 amino acids. The protein coded by Phaseolus coccineus F3H gene cDNA showed 92% similarity to Glycine max. Its secondary structure contained 40.8% α-helix, 14.93% extended strand, 39.73% random coil and 4.53% β-turn. The homology analysis of three-dimensional structure showed that the three-dimensional structure of the protein was a compact globular structure.
    3  Polyketones from Aspergillus terreus Associated with Apostichopus japonicus
    XIA Xue-kui QI Jun LIU Chang-heng ZHANG Yong-gang JIA Ai-rong YUAN Wen-peng LIU Xin ZHANG Mian-song
    2014, 30(4):10-14.
    [Abstract](1430) [HTML](0) [PDF 560.54 K](757)
    Abstract:
    Sea cucumber comprised of rich bioactive components is an important marine food and also used as a traditional medicine. There are various microbes associated with sea cucumber. In order to obtain effective bioactive compounds from Aspergillus terreus associated with Apostichopus japonicus from Zhifu Island, the fungus was cultivated on solid medium to investigate its secondary metabolites. Thin liquid chromatography (TLC), column chromatography and high performance liquid chromatography (HPLC) were used to separate secondary metabolites, and NMR, MS were used to identify their structures. As a result, dihydrogeodin (1), Territrems A (2), Territrems B (3), 1-(2, 4-dihydroxyphenyl)-ethanone (4), questin (5) and emodin (6) had been obtained and identified. KB and KBv200 were used to detect the cytotoxicity of 1, 5 and 6. It was the first time to determine intact Dihydrogeodin (1) by NMR and MS and it could be metabolized by marine fungus. In addition, it was firstly found that Territrem B (3) had the strongest inhibitory effects on acetylcholinesterase activities. Aspergillus terreus might be a new candidate for the development of functional food that can be used for preventing and treating Parkinson disease.
    4  Toxicity of Organic Solvents to Microbial Cells with Catalytic Activity
    WU Hui YANG Mei-yan LAI Fu-rao LI Xiao-feng
    2014, 30(4):15-20.
    [Abstract](1368) [HTML](0) [PDF 522.80 K](676)
    Abstract:
    Using Aspergillus oryzae and Pseudomonas fluorescens as representative types of mold and bacteria microbes respectively, the toxicity of commonly-used organic solvents to the cell growth of microbial cell with catalytic activities was investigated through measurement of microbe growth, hypha ball size and microscopic observation,. It was found that the toxicity of organic solvent to fungi and bacteria has close relationship to its lgP value and also related to the type of solvent. For A. oryzae, n-propanol (lgP value 0.55), t-butanol (lgP value 0.80) and toluene (lgP value 2.5) inhibited the formation of the hypha ball. No mycelium formed when n-butanol (lgP value 0.82) and chloroform (lgP value 2.00) existed in the culture, indicating that they could complestely inhibite the growth of hypha. Though the existence of acetone, short chain alcohols and long chain alkanes hardly changed the total mycelium quality(0.81?0.07)and hypha morphology, they have significant effects on reproductive period and spore morphology. For P. fluorescens, the solvents with lgP values ranged in 0.8~4.6, including n-butanol, chloroform, toluene and octane, completely inhibited the growth of cells(OD560 < 1.17?0.05). Other solvents made no significant differences from the control(OD560=2.27?0.05)in the bacteria growth. In addition, organic solvent will affect the cell shapes and the arrangement of the cells in the process of culturing.
    5  Preventive Effect of Ilex kudingcha C.J. Tseng on Gastric Injury SD-rats
    FENG Xia ZHAO Xin
    2014, 30(4):21-25.
    [Abstract](1044) [HTML](0) [PDF 553.43 K](694)
    Abstract:
    Commercial Ilex kudingcha C.J. Tseng (KDC) was purchased from Chongqing market for the evaluation of gastric injury preventive effect in SD-rat. Two concentrations of KDC samples and omeprazole as pharmic control were tested. KDC and omeprazole reduced the levels of serum proinflammatory cytokines of IL-1β, IL-6, IL-8, and increased the IL-4 level as compared to the control in rats. SS and VIP serum levels of KDC and omeprazole groups were higher than those of the control group, while MOT and SP serum levels of KDC and omeprazole groups were lower than those of the control group. The gastric secretion volumes from high to low order were control rats, 500 mg/kg KDC-treated rats, 1000 mg/kg KDC-treated rats, omeprazole-treated rats, and normal rats, whereas pH levels of gastric juice showed the opposite trend. The gastric injury level was significantly decreased by KDC, demonstrating its anti-inflammatory properties. 1000 mg/kg of KDC showed the strongest anti-inflammatory effect that similar to the clinical drug omeprazole. For gastric tissues of KDC groups and omeprazole group rats, RT-PCR assay showed that the mRNA expression levels of inflammation-related genes of iNOS and COX-2 were significantly decreased, as compared with the control group. These results suggested that KDC had a gastric injury preventive effect as omeprazole.
    6  Impact of Crude Polysaccharides from Abalone Viscera on the Physiological Function of Diabetic Mice
    YE Dan-rong HUANG Yue-e CHEN Jin-quan FANG Ting
    2014, 30(4):26-33.
    [Abstract](1199) [HTML](0) [PDF 547.85 K](742)
    Abstract:
    In this study, effects of abalone viscera polysaccharide (AVP) on the glucose tolerance, serum glucose level, the antioxidant ability and organ protection of diabetic mice were investigated, in order to explore the AVP impact on the physiological function of diabetic rats induced by alloxan. Results showed that, the AVP model groups controlled the weight of mice significantlywhere. Especially for the high and middle dose groups (p<0.01), the weight of mice were 33.96 g and 32.95 g respectively after three weeks treatments. AVP lowered the blood glucose in diabetic mice and improved impaired glucose tolerance in a certain extent. The middle dose group (200 mg/kg) had the best effect, decreasing blood glucose to 15.45 mmol/L after three weeks. Meanwhile, the activity of SOD and GSH-Px promoted obviously, while the MDA content in blood serum reduced after three-week dosage. The activity of SOD, GSH-Px and MDA content of middle dose group were 155.25 U/mL, 529.63 μmol/L and 14.41 μmol/L, respectively, with significant difference compared to the control group (p<0.01). Moreover, AVP protected liver, kidney and spleen of sick mice, the viscera index of middle dose group were 5.23, 0.94 and 0.27, respectively, showing significant difference (p<0.05).
    7  Enhanced Yield of Biomass and Fatty Acids from Coccomyxa subellipsoidea C-169 by CO2 Supplement
    WEI Dong LI Lu
    2014, 30(4):34-39.
    [Abstract](1218) [HTML](0) [PDF 640.21 K](691)
    Abstract:
    The effects of 2% CO2 supplement or air (contain 0.04% CO2) on cell specific growth rate, biomass dry weight, content and yield of total fatty acids, neutral lipids content of Coccomyxa subellipsoidea C-169 grown autotrophically in Basal and BBM media were investigated in this study. Compared with the results from aeration with air, 2% CO2 supplement significantly increased the cell specific growth rate of 2.6 times in Basal medium and 2.3 times in BBM medium, respectively. After cultured for 13 days, the maximal biomass concentration was obtained at 4.67 g/L by 2% CO2 supplement in Basal medium, which was much higher than other groups (p < 0.05). The highest content of total fatty acids reached 37.53% (DW) by supplying 2% CO2 in BBM medium, which was 5 times higher than that by inletting air. And the yield of total fatty acids was up to 77.49 mg/(L?d) while neutral lipids referred as fluorescence intensity was significantly higher than other groups (p<0.05). These results indicated that 2% CO2 supplement in Basal medium could promote cells to produce more biomass. In BBM medium, it could increase the yield of fatty acids and neutral lipids in the microalga, which was excellent raw material for biodiesel production.
    8  Chemical Structures of Anthocyanins in Red Radishes
    LI Ping-fan YAO Yong-fang
    2014, 30(4):40-43.
    [Abstract](1510) [HTML](0) [PDF 462.66 K](688)
    Abstract:
    Radish anthocyanins were isolated from pigment-riched extracts of red radish by using XAD-7HP and Sephadex LH-20 for purification, and half prepared liquid chromatograph (HPLC) for preparation of anthocyanin monomer. The anthocyanin structures were analyzed using LC-MSn and NMR. Four anthocyanins in red radishes were identified as pelargonidin derivatives with one or two sugar moieties and some with acylation. By 1H NMR analysis, three anthocyanins were identified as pelargonidin-3-(6-coumaroyl)- sophoroside-5-D- pyranoglucoside, pelargonidin-3-(6-feruloyl)-sophoroside-5-D-pyranoglucoside, and pelargonidin-3-(6-coumaroyl)- sophoroside-5-(6-malonyl)- pyranoglucoside. In addition, pelargonidin-3-(6-feruloyl)-sophoroside-5-(6-malonyl) -D-pyranoglucoside as the fourth anthocyanin has been found in red radishes by mass spectrum data.
    9  Analysis of the Microbial Community Structure of Gujinggong Liquor Starter through Culture-free Approach
    ZHANG Hui-min SHU Ying ZHOU Qing-wu LI An-jun HE Hong-kui ZHANG Zhi-zhou
    2014, 30(4):44-49.
    [Abstract](1378) [HTML](0) [PDF 508.90 K](760)
    Abstract:
    Molecular analysis of microbial community structure of GujingGong liquor starter has not been reported so far. 16S rDNA clone library technique was conducted to analysis the bacterial community diversity in high-temperature Daqu and medium-temperature starter of GuJingGong liquor. All clone strains were classified to 36 OTUs, belonging to Firmicutes, Proteobacteria and uncultured bacteria, of which, Firmicutes was the majority. Overall, the bacterial diversity of medium-temperature starter was significantly more complex than that of high-temperature starter. Thermoactinomyces sanguinis accounted for the main majority of the high-temperature starter strains. Bacterial diversity of the two medium-temperature starter samples was apparently different. Dominant bacteria of the sample S1 belong to Virgibacillus sp., accounting for 85.3% in total, in addition to a small amount of uncultured bacteria (12.9%). The dominant bacteria of the sample S2 were Lactobacillus (25.2%), Staphylococcus (14.3%), Bacillus (13.4%) and some uncultured bacteria (16.8%). There are a lot of potential new species that need to be further identified.
    10  Structure and Antitumor Activity of Water-soluble Polysaccharide from Craterellus cornucopioides
    FAN Xiao-dan CHEN Yao-hua CHANG Jie CHEN Jian
    2014, 30(4):50-54.
    [Abstract](1342) [HTML](0) [PDF 552.61 K](875)
    Abstract:
    One polysaccharide, named CCPⅠ, was isolated and purified from the sporophore of Craterellus cornucopioides. The relative molecular mass and monosaccharide composition of CCPⅠ were determined by using high-performance gel permeation chromatography and gas chromatography, and its spectra of IR and NMR were also investigated. The weight-average relative molecular mass of CCPⅠ was 16270 Da. It possessed typical infrared absorptions of polysaccharides and showed α- and β-configuration pyranoside. In addition. It was determined as a kind of heteropolysaccharide containing fucose, mannose, glucose and galactose in a molar ratio of 1:2.11:3.13:6.45. Most of glycan C-6 were substituted, and part of C-2, C-3 or C-4 was replaced. Moreover, its anti-complement activity in vitro and antitumor activity by MTT were evaluated, which indicated that the anti-complement activity reached 70.44% when the concentration of CCPⅠ was 4 mg/mL and it remarkably inhibited the growth of human liver cancer cell line Hep G2 and human breast cancer cell line MCF-7 in a dose-dependent manner. When the concentration of CCPⅠ was 1000 μg/mL, the inhibition ratios of Hep G2 and MCF-7 were 60.06% and 55.80%, respectively.
    11  Texture Properties, Characteristic Smell, Microbial Isolation and Identification of Smelly Mandarin Fish
    YANG Pei-zhou QIAN Jing JIANG Shao-tong PAN Li-jun WANG Jian-qiang ZHANG Dan-feng CAO Xin-min
    2014, 30(4):55-62.
    [Abstract](1383) [HTML](0) [PDF 724.58 K](1042)
    Abstract:
    Smelly Mandarin fish is a representative flavor dish of Anhui. The traditional food possesses the representative characteristic of Anhui cuisine, such as mild rot, high concentration salt and bright color. To explore the key influence factors during fermentation for smelly Mandarin fish, the determination of texture properties and amino acids ingredients, distinction of characteristic smell components and identification of the key microorganism species during fermentation were carried out. The results showed that Mandarin fish reached optimum quality through eight days fermentation. The processed meat exhibited light smell without the fishlike smell. And the hardness of the processed meat was 3000.37 N, 1.72-fold higher than that of the fresh one. The content of crude protein and crude fat were 19.2% and 10.54%, respectively. Both histidine (3.44%) and methionine (5.01%) were 3.32-fold and 2.09-fold higher compared with those of the fresh. The volatile components of smelly Mandarin fish were mainly composed of 41.17% isopropyl amine and 20.91% propionic acid by DHS-GC-MS, and the major composition of characteristic smell was defined by propionic acid. Using the techniques of cell morphology, physiology, biochemistry, 16S rDNA molecular identification and evolutionary tree analysis, the microorganisms related to the fermentation of Mandarin fish were mainly Bacillus cereus and Bacillus thuringiensis.
    12  In vitro Evaluation of Immunomodulatory Activity for Polysaccharide LPII from Arillus longanae
    YI Yang ZHANG Ming-wei
    2014, 30(4):63-67.
    [Abstract](1314) [HTML](0) [PDF 555.27 K](677)
    Abstract:
    LPII is one of the main fractions of polysaccharides from Arillus longanae. The immunomodulatory activities of LPII, and the effect of enzymolysis on its activity were investigated in vitro. Splenic lymphocytes were injected into a nylon fiber column to separate T cells and B cells. The stimulating effects of LPII on lymphocytes in the dose range of 25~400 μg/mL indicated that LPII could stimulate the proliferations of splenic lymphocyte and B cell and promote the antibody production of B cell. However, its activation on T cells was not significant. In addition, LPII could effectively enhance the proliferation, phagocytosis and NO production of macrophage in the dose range. The fraction of LPII with higher molecule weight obviously degraded by papain, pronase or trypsin, following with the weakened effect on ConA-induced splenic lymphocyte proliferation (P < 0.05) and the strengthened effects on LPS-induced splenic lymphocyte proliferation and macrophage phagocytosis (P < 0.05). LPII has the significant immunomodulatory activity in vitro, and the activity can be enhanced with appropriate degradation, which is confirmed as the most important functional component in Arillus longanae.
    13  Effect of Sodium Nitroprusside on the Biosynthesis of Triterpenic Acids in Suspended Cultured Cyclocarya paliurus Cells
    GUO Chun-mei YIN Zhong-ping SHANGGUAN Xin-chen CHEN Ji-guang Chen FU Xiao
    2014, 30(4):68-73.
    [Abstract](1474) [HTML](0) [PDF 609.60 K](805)
    Abstract:
    Cyclocarya paliurus cell suspension culture was established in this paper, and sodium nitroprusside was added as an extraneous inducer to stimulate the biosynthesis of triterpenic acids. The effects of sodium nitroprusside in terms of concentration, adding time and inducement duration on the cells growth, total triterpenic acids accumulation, and the biosynthesis of five representative triterpenic acids were investigated. The results showed that 10~50 μmol/L sodium nitroprusside had little effect on the growth of Cyclocarya paliuru cells, and little stimulant effect on the biosynthesis of triterpenic acids. 150 μmol/L sodium nitroprusside was suitable for the accumulation of triterpenic acids, and had little effect on the cells growth. High concentrations (200~500 μmol/L) of sodium nitroprusside inhibited the growth seriously. The highest production of triterpenic acids was obtained when 150μmol/L sodium nitroprusside was added at the 8 th day after inoculation and continuous inducement for 4 days. Under this optimal conditions, the production of total triterpenic acids was as higher as 1228.74 mg/L, which was 2.14 times higher than that of the control group. And the output of ursolic acid and oleanolic acid increased more obviously among the five representative triterpenic acids of this cells, which was 2.28 and 2.48 times, respectively, higher than the control group. Our researches indicated that extraneous sodium nitroprusside effectively increased the biosynthesis of triterpenic acids in suspended cultured Cyclocarya paliuru cells.
    14  Effects of Curcumin on Proliferation and Apoptosis of Colorectal Carcinoma LoVo Cells
    WU Ya-li XIE Jun-xia LU Nan GUO Li-da LIANG Shi-zhong
    2014, 30(4):74-79.
    [Abstract](1260) [HTML](0) [PDF 500.03 K](757)
    Abstract:
    To study the biological function and regulation mechanism of curcumin on proliferation and apoptosis of colorectal carcinoma cells LoVo, the LoVo cells were cultured and treated by curcumin in different concentrations in vitro. Effect of Curcumin on cell proliferation level was examined by MTT colorimetry method. The morphological changes of curcumin-treated LoVo cells were observed under inverted microscope. The mRNA levels of Bax, Bcl-2 and Caspase-3 were tested by RT-PCR. The cell apoptosis rate was detected by Annexin V-FITC/PI double staining. Western blotting and immunofluorescence staining were used to detect the different expressions of c-myc protein of LoVo cells before and after curcumin treatment. MTT test indicated curcumin could inhibit the growth and proliferation of LoVo cells in a time- and concentration-dependent manner. The inhibitory concentration 50% (IC50) of curcumin were 26.45±0.41 μmol/L, 19.13±0.09 μmol/L and 10.12±0.04 μmol/L in LoVo cells at 24, 48 and 72 h, respectively. Flow cytometry instrument analysis showed that curcumin induced apoptosis of LoVo cells. Curcumin activated the expression of Bax and Caspase-3 genes, while inhibited the expression of Bcl-2 gene and c-myc protein. Curcumin significantly inhibited the proliferation and induced the apoptosis of human colorectal carcinoma cells LoVo. Such biological effect may be associated with activating Caspase-3 signal channel by activating Bax expression and inhibiting Bcl-2 and c-myc expression.
    15  Thermo-oxidation of Cholesterol in Glyceryl Tristearate and Glyceryl Trioleate
    XU Gui-hua LIU Dong-hong MO Hai-zhen CHEN Jian-chu WANG Jun YE Xing-qian
    2014, 30(4):80-84.
    [Abstract](1567) [HTML](0) [PDF 394.77 K](754)
    Abstract:
    In order to elucidate the effects of saturation of fatty acids in triglycerides on cholesterol oxidation, thermo-oxidation of cholesterol in glyceryl tristearate(GTS) and glyceryl trioleate (GTO) was investigated by GC-MS, and their peroxide values were also measured. The results indicated that the main cholesterol oxidation products in GTS and GTO were 7α-hydroxycholesterol, 7β-hydroxycholesterol, 5,6β-epoxycholesterol, 5,6α-epoxycholesterol, and 7-ketocholesterol. At 160 ℃, the cholesterol oxidation products increased and then decreased over heating time, while unoxidized cholesterol reduced gradually in the process. The highest peroxide value (500.46 meq/kg) in GTO was achieved after 1 h heating. The peroxide value in GTS increased to the highest value of 401.30 meq/kg after 3 h heating, but then decreased with prolonging the treatment time. At 110 ℃, no cholesterol oxidation occurred in GTS, and the peroxide value kept lower, with its peak value (278.43 meq/kg) appearing after 96 h heating. However, cholesterol was almost completely oxidized in GTO, and the peroxide value increased rapidly, reaching its highest (1486.88 meq/kg) after 12 h heating, and then gradually decreased. Generally, cholesterol was more stable in GTS than GTO at 160 ℃ and 110 ℃, and the appearance of peroxide delayed with lower amounts. It was suggested that the saturated fatty acids in triglycerides were more beneficial to stabilize cholesterol under high temperature.
    16  Inhibitory Effect of Rubus corchorifolius Leaves Extract on the Movement of Isolated Intestinal from Rabbit and Its Active Stability
    CHANG Yun-pei LIU Xiao-juan ZHOU Li-ping XIONG Ping CHEN Xue-xiang CAO Yong
    2014, 30(4):85-92.
    [Abstract](1271) [HTML](0) [PDF 726.07 K](746)
    Abstract:
    Using the movement of isolated intestinal from rabbit as the model, the extraction of anti-diarrhea active components from Rubus corchorifolius leaves and their active stability were investigated. The active components were extracted with 80% ethanol, followed by five different polar solvents. The effects of temperature, pH, light quality, illumination time, and the tannins removal treatment on the activity of the extracts were also studied. The results showed that the active components mainly existed in ethyl acetate layer, the sequence of the extract activity in different solvent layer was petroleum ether layer>water layer>n-butanol layer>chloroform layer. The ethanol extract of Rubus corchorifolius leaves were stable in the range of 30~60 ℃. But at high temperature of 90 ℃ and 120 ℃, the tensional variation percentage of isolated intestinal from rabbit decreased by 15.43% and 32.45%, respectively. pH showed significant influence on the activity, and the highest activity was found under acidic conditions, followed by neutral and alkaline conditions. The tensional variation percentage was only 11.90% at pH 12. The ethanol extract after different light qualities and different illumination time treatments still had high activity (P<0.01), while the activity was decreased by tannin removal treatment, indicating tannin might be one of the components for anti-diarrheal activity in Rubus corchorifolius leaves.
    17  Effect of Xanthan Gum on the Rheological Characteristic and Stability of Sucrose Ester-stabilized Emulsion
    ZHAO Qiang-zhong LIU Dao-lin LONG Zhao KUANG Wan-mei FANG Min ZHAO Mou-ming
    2014, 30(4):93-98.
    [Abstract](1489) [HTML](0) [PDF 686.14 K](895)
    Abstract:
    The influences of xanthan gum concentration on hydrodynamic diameter (DH), ζ-potential of sucrose ester solutions and droplet size, ζ-potential, microstructure, viscosity, modulus and creaming index of sucrose ester-stabilized emulsions were studied. The effect of xanthan gum on the rheological characteristic and stability of sucrose ester-stabilized emulsion were also investigated. The results showed that DH value of sucrose ester-xanthan gum solutions increased and ζ-potential decreased with the increase of xanthan gum concentration. ζ-potential of emulsions changed insignificantly (p > 0.05), while the droplet size increased firstly and decreased afterward, the viscosity and modulus increased with increasing xanthan gum concentration. The oil off was attributed to coalescence between fat droplets at low xanthan gum concentrations (0~0.01 wt%). The emulsion exhibited the worst stability when xanthan gum concentration was 0.05 wt% due to depletion flocculation. The stability of emulsion was improved with the increase of xanthan gum concentration due to the formation of weak gel network structure. There only existed serum phase when xanthan gum concentration was higher than 0.15 wt%.
    18  Effect of Transport Proteins SstT and RhtC Modification on L-threonine Production in Escherichia coli
    LIANG Yuan YANG Shu-yao LIU Hong-liang HAO Xiao-ming LIN Hai-long XIE Xi-xian CHEN Ning
    2014, 30(4):99-103.
    [Abstract](1465) [HTML](0) [PDF 529.73 K](823)
    Abstract:
    L-threonine is an essential amino acid and has wide application in food, pharmaceutical and feed fields. It has been reported that the reduction of the intracellular L-threonine concentration could remove the feedbacks on the enzymes in L-threonine synthetic pathway, which was benefit for L-threonine production. Hence, in this work, gene sstT was deleted in E. coli TRFC, an L-threonine producer, by Red recombination technology and gene rhtC was over expressed in TRFCΔsstT. Compared to the control strain TRFC, TRFCΔsstT was found to produce 4% more L-threonine. And compared to TRFCΔsstT+pSTV28,TRFCΔsstT+pSTV28-rhtC produced 18.16% more L-threonine in shake flask fed-batch fermentation. Besides, the intracellular L-threonine concentrations of all mutants were lower than the control strains. Finally, in the 5 L fed-batch fermentation, L-threonine production and yield on glucose of TRFCΔsstT+pSTV28-rhtC were 15.33% and 16.14% higher than those of TRFC, respectively. The results suggested that modification of transport system could effectively decrease the intracellular L-threonine concentration and enhance the excretion of internal synthesized L-threonine, and could be benefit for L-threonine production.
    19  Effect of Soy Protein Isolate on Quality of Fried Breaded Shrimp
    JI Hong-wu PAN Guang-kun LIU Shu-cheng SU Wei-ming LU Hong-yu PAN Chuang
    2014, 30(4):104-111.
    [Abstract](1438) [HTML](0) [PDF 415.01 K](681)
    Abstract:
    Higher oil content in fried food shortens the shelf life of the product and causes a decrease of product acceptability to consumers. The fat content absorbed by fried food can be reduced by using appropriate coatings such as flour or batter. In this paper, the effects of soy protein isolate (SPI) addition to the wheat flour-based batter on the quality of fried breaded shrimp were evaluated. The coating powder rate, moisture loss, oil absorption, color, texture and sensory attributes of the samples were determined. Breaded shrimps were fried at 175 ℃ for 3 min. The results showed that SPI significantly increased the coating rate of the fried breaded shrimps (p<0.05), meanwhile decreased moisture loss and oil content. When the content of SPI increased from 2 g to 10 g, the amount of moisture loss and oil absorption in the fried breaded shrimps decreased from 15.12% to 11.64%, and 25.07% to 19.82%, respectively. In addition, adding 8 g SPI to the batter provided the best texture property and the highest sensory score. However, there was no significant difference for the variation of L*, a * and b* value with respect to different concentrations of SPI added to the batter formulation.
    20  Effect of Slightly Acidic Electrolyzed Water on the Phytohormones Content and Nutrients of Mungbean Sprouts
    LIU Rui ZHANG Dong-chen NIRASAWA Satoru TATSUMI Eizo LIU Hai-jie
    2014, 30(4):112-117.
    [Abstract](1898) [HTML](0) [PDF 432.22 K](807)
    Abstract:
    Slightly acidic electrolyzed water (SAEW) was used to produce mungbean sprouts in the research. In order to observe promoted effect of SAEW in mungbean sprouts growth, phytohormones content of mungbean sprouts during germination was investigated by using ELISA, and the nutrients contents were also evaluated. The results showed that the contents of abscisic acid and jasmonic acid methyl ester of mungbean sprouts treated by SAEW maintained at lower level than tap water control group, while the ratio of indole acetic acid to abscisic acid kept higher level mostly. On the 3rd germination day, the ratio of 10 mg/L SAEW treatment group was 54.37% higher than control. On the 4th germination day, the Vc contents of samples treated by 20 and 30 mg/L SAEW were 57.45% and 28.72%, respectively, higher than the control. All of those contributed to the growth of sprouts. SAEW with higher available chlorine concentration contributed to the increase of total ascorbic acid content. When sprouts treated by 20 and 30 mg/L SAEW, total ascorbic acid content was increased by 5.30% and 9.33% respectively. The reducing sugar content of mungbean sprouts treated by SAEW was lower than control, while total sugar and crude protein contents showed no significant difference.
    21  Properties of Corn Starch Modified by Cross-linked Hydroxypropyl Carboxymethyl Compound
    ZHANG Ben-shan DENG Dan-dan LU Hai-feng
    2014, 30(4):118-123.
    [Abstract](1374) [HTML](0) [PDF 619.92 K](776)
    Abstract:
    Corn starch was used to prepare hydroxypropyl starch by ethanol solvent, and then hydroxypropyl starch was modified using epichlorohydrin as cross-linked agent and chloroacetic acid as etherification agent. The microstructures of corn starch, hydroxypropyl starch, cross-linked hydroxypropyl starch, hydroxypropyl carboxymethyl starch, cross-linked hydroxypropyl carboxymethyl starch were analyzed by Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Modified corn starch showed new absorption peaks at 1287 cm-1 and 1328~1603 cm-1, which indicated that carboxymethyl and hydroxypropyl groups were attached to the native starch. A type X-ray spectra was assigned to modified starch, which confirmed the reaction mainly occurred in the amorphous region. The surface transformation change of starch granules before and after modification was observed, showing that the reaction occurred both inside and outside starch granules. Physical and chemical characteristics of modified corn starch showed that cross-linked hydroxypropyl carboxymethyl starch had good properties of transparency, freeze-thaw stability and rheology.
    22  The Reaction Kinetics of the Change of Nutrition Ingredients in Crab Flavor Mushroom during Ice-temperature Storage
    ZHANG Hui QIAO Yong-jin ZHANG Na-na TANG Jian MA Li QI Wen-yuan
    2014, 30(4):124-129.
    [Abstract](1404) [HTML](0) [PDF 539.10 K](848)
    Abstract:
    Crab flavor mushroom (Hypsizygus mammoreus Bigelow L.) was used as test materials, and stored at 25 ℃, 15 ℃, 4 ℃ and -0.5 ℃. Nutrition ingredients (ascorbic acid, soluble sugar and soluble protein) were measured throughout the storage periods. The kinetic and thermodynamic characteristics of nutrition ingredients degradation were analyzed based on the reaction kinetics theory. The results showed that ascorbic acid, soluble sugar and soluble protein degradation ofcrab flavor mushroom followed first-order kinetic reaction model, with degradation activation energies of 81.51 kJ/mol, 83.88 kJ/mol, 100.52 kJ/mol, respectively. The degradation half-life, the molecular effective collision percentages, the degradation activation enthalpy and the degradation activation Gibbs free energy of ascorbic acid, soluble sugar and soluble protein were the highest in the ice temperature storage group. However, the degrade transition state equilibrium constant K≠ was less than other temperature treatment groups. In addition, the degradation activation entropy and steric factors of ascorbic acid and soluble sugar were the largest in the ice temperature storage group, while soluble protein had the maximum values in 4 ℃ storage group. From above all, ice-temperature storage changed kinetics and thermodynamic parameters, thus slowing down the degradation of nutrition ingredients in crab flavor mushroom.
    23  Effect of 1-MCP on Quality of Different Harvested ‘Wujiuxiang’ Pears during Cold Storage
    GUAN Jun-feng GAO Man-man ZHAO Qian
    2014, 30(4):130-135.
    [Abstract](1352) [HTML](0) [PDF 497.08 K](729)
    Abstract:
    ‘Wujiuxiang’ pear showed a rapid softening and presented superficial scald on peel during a long term cold storage and at shelf life. In this study, the ‘Wujiuxiang’ pear harvested at three different dates were applied and treated with 1.0 μL/L 1-methylcyclopropene (1-MCP), then placed at 0 ℃ for cold storage and after forward for shelf storage at 20 ℃. The results indicated that the firmness of the pear decreased and soluble solid content (SSC) increased. Superficial scald of peel and core browning were enhanced during cold storage, and theses changes were more significant during shelf storage. 1-MCP had less influence on firmness and SSC during cold storage, but significantly delayed the softening and increased SSC at shelf life after cold storage, and this effect was more obvious in later harvested fruits. 1-MCP also decreased the indexes of superficial scald and core browning, which was more visible at shelf life. It also markedly inhibited the biosynthesis of α-farnesene and conjugated trienol of peel. The comprehensive analysis suggested the 1-MCP significantly reduced softening and superficial scald at shelf life, and maintained higher quality of earlier harvested fruits. The reduction of superficial scald by 1-MCP was closely correlated with the inhibition on production of the conjugated trienol of peel in ‘Wujiuxiang’ pear.
    24  Prediction of Textural Properties of Grass Carp (Ctenopharyngodon idellus) by Near Infrared Spectroscopy
    XU Wen-jie HONG Xiang-sheng XIONG Shan-bai
    2014, 30(4):136-141.
    [Abstract](1239) [HTML](0) [PDF 451.34 K](732)
    Abstract:
    Texture and water-holding capacity of 211 grass carp samples were analyzed by near infrared spectrum and chemometric method. The diffuse reflectance spectra of samples were performed with different spectral pretreatments, such as multiplicative scatter correction (MSC), orthogonal signal correction (OSC), and standardization (S). The near-infrared quantitative analysis models were obtained for texture and water-holding capacity by partial least square regression. The results showed that the measured values met the modeling requirements. The optimized spectral pretreatments was orthogonal signal correction (OSC) which was suitable for analysis of water-holding capacity, hardness, resilience, springiness and shear force models of grass carp, while standardization was used for chewiness model. Partial least square method was applied to build near infrared spectrum models of grass carp texture indexes, and the correlation coefficients of the models were 0.9194, 0.9812, 0.9830, 0.9871, 0.7860 and 0.9896 for water-holding capacity, hardness, resilience, springiness, chewiness and shear force, respectively. The results indicated that the models have the potential to predict texture and water-holding capacity of grass carp expect chewiness. The NIR spectroscopy offers great advantages for the rapid and on-line application.
    25  Analysis of Triglycerides Composition Structure and Physicochemical Properties of Peony Seed Oil
    MAO Cheng-xin LI Gui-hua LI Pu-xuan ZHU Pin KANG Xue-mei
    2014, 30(4):142-146.
    [Abstract](1764) [HTML](0) [PDF 422.47 K](908)
    Abstract:
    The physical and chemical properties of the peony seed oil, the fatty acid compositions were analyzed by using gas chromatography. The relative content of unsaturated fatty acids was more than 92.00%, mainly consisted of oleic acid (23.92%), linoleic acid (27.58%) and linolenic acid (40.50%). Except free fatty acids, the content of the triglycerides were about 95.89% and the diacylglycerols were about 4.11% in the peony seed oil. By the method of pancreas lipase hydrolysis, the Sn-2 position fatty acids were analyzed and the triglycerides composition of peony seed oil were calculated according to 1,3-random-2-random distribution doctrine. The majority compound in peony seed oil was triacylglycerol which was made up of oleic acid, linoleic acid and linolenic acid. Among them, the content of three unsaturated fatty acid esters was 71.00%, and a saturated and two unsaturated fatty acid ester contents were more than 15.00%. HPLC analysis showed that vitamin E content of the peony oil was 0.56 mg/g). Rancimat determination showed that oxidation stability of the oil was somewhat low (2.85 h at 110 ℃).
    26  Improvement of Nutritional Qualities and Storage Characteristics of Wheat Germ by Lactic acid bacteria Fermentation
    WEI Yi-xing DONG Ying ZHOU Xing-hua CHANG Xian-hui CHEN Guo-ping
    2014, 30(4):147-153.
    [Abstract](1255) [HTML](0) [PDF 569.57 K](908)
    Abstract:
    Lactobacillus plantarum dy-1 was used as starters for the wheat germ fermentation, and the nutritional qualities and storage characteristics were analyzed. The results show that, Lactobacillus plantarum dy-1 had glutamate decarboxylase (GAD) activity, which was enabled to catalyze the irreversible decarboxylation of glutamate to γ-amino butyric acid. The concentration of free amino acids in Lactic acid bacteria fermented wheat germ increased by 13.64 times, especially aspartic acid, leucine, γ-amino butyric acid, methionine and lysine increased significantly; during the fermentation process, phytase activity increased, while phytic acid content decreased. Lipase activity after fermentation was 55.31% lower than that found in wheat germ, and lipoxygenase activity decreased by 76.32%. The SPME-GC-MS analysis indicated that, the storage characteristics of fermented wheat germ were significantly changed. After 60 days, the oxidative rancidity of fermented wheat germ was significantly lower than the unfermented. Therefore, Lactic acid bacteria could improve the nutritional qualities and storage characteristics of wheat germ, making the fermented wheat germ suitable to be food nutritional supplements or ingredients.
    27  Induction and Resuscitation of VBNC State Beer-spoilage Lactobacilli
    DENG Yang LIU Jun-yan FANG Hui-jing CHEN Jiang LI Hui-ping LI Lin TU Jing-xia LIU Jing FENG Zhi-jian
    2014, 30(4):154-159.
    [Abstract](1386) [HTML](0) [PDF 518.50 K](790)
    Abstract:
    In this study, the induction and resuscitation of viable but non-culturable state (VBNC) of a typical hard-to-culture beer-spoilage Lactobacillus acetotolerans were investigated. Lb. acetotolerans strain 2011-11 in the exponential growth phase was repeatedly subcultured in degassed beer to reappear the survival situation in the actual beer brewing process, and the culturability on MRS agar media was examined. The viable cells were monitored based on the DNA-binding fluorescent dye (SYTO-9 and PI) plus the fluorescent microscopy assay and flow cytometry technology. Moreover, the beer-spoilage ability of VBNC cells was determined. Secondly, the effects of up shifting the temperature and adding the cytokine on resuscitation of VBNC state Lb. acetotolerans were observed. After 19 generations of culture in degassed beer, Lb. acetotolerans strain was found to be no longer detected on MRS agar despite the presence of major viable cells appearing green fluorescence, indicating that a large population of Lb. acetotolerans 2011-11 cells had entered into the VBNC state. Meanwhile, VBNC cells still exhibited the beer-spoilage ability. In addition, addition of catalase enabled cells to become culturable again before plating the MRS agar under anaerobic incubation at 26 ℃. Taken together, VBNC strain was successfully obtained from beer-spoilage Lb. acetotolerans by the prolonged adaptation to beer. It was also shown that addition of catalase in the culture media was an effective resuscitation method for the VBNC cells of Lb. acetotolerans strain.
    28  Establishment of Growth Model of Staphylococcus aureus Based on OD-TTD
    WANG Ling-ling ZHONG Wu-jie HUANG Shao-peng HAO Shu-xian
    2014, 30(4):160-164.
    [Abstract](1152) [HTML](0) [PDF 510.81 K](980)
    Abstract:
    The growth model of Staphylococcus aureus CMCC (B) 26003 based on growth rates and lag time calculated by OD-TTD data was studied in this paper. The culture was serial diluted and static cultivated in 96 pores micro-array plate at 37 ℃. When the linear relationship between the initial inoculums (N0) and the time to detection criterion of OD at specific value (TTD) was available, the growth rate could be calculated. If the viable count from well with OD at detection value (Nd) was known, the lag time could also be obtained. Then a suitable model was selected to fit the growth data. The linear relationship between TTD and N0 as follows: TTD=-154.86 N0+1202.3, R2 = 0.9997 (OD = 0.1). The growth rate of 0.0064 log [cfu/(mL?min)] (μ) and lag time of 7.8 min (λ) were obtained by the formula. If the information of μ,λ,N0, Nmax and Nd were available, and TTD could be calculated by Gompertz, Baranyi, Logistic and 3-phase linear (3PLM) model. In addition, the calculated value by 3PLM was congruent with the observed value. The growth rate from OD-TTD was almost equal with that from viable plate count, and the lag time from viable plate count was bigger than that from OD-TTD. Therefore, 3PLM based on OD-TTD was suitable to construct the growth model of Staphylococcus aureus, but the lag time from OD-TTD was uncertain yet.
    29  Construction of Recombinant Corynebacterium glutamicum for L-tryptophan Production
    CAI Xia ZHENG Sui-ping
    2014, 30(4):165-170.
    [Abstract](1360) [HTML](0) [PDF 590.19 K](690)
    Abstract:
    In the aromatic amino acid synthesis pathway, chorismic acid produces two branches. One is to synthetize tryptophan under the catalyze of anthranilate isomerase (ANS), anthranilate phosphoribosyl transferase (PRT) and tryptophan synthase (TS). And the other is to generate prephenic acid (PPA) under the catalyze of chorismic acid mutase (CM), which further produces tyrosine and phenylalanine. Meanwhile, 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase (DS) is the key enzyme in this pathway. We recently engineered Corynebacterium glutamicum SPT9 (Phe-, Tyr-, 4-FPr and 6-FTr) for improved production of L-tryptophan. Inactivation of gene csm encoding chorismate mutase was firstly conducted by homologous recombination to get auxotrophic tyrosine and phenylalanine, which was different from the classical mutagenesis method. Then aroⅡ, trpEGD and ts genes encoding DS, ANS and PRT, TS were over-expressed alone or together to obtain series of recombinant strains SPT9?csm-XK99E-aroⅡ-trpEGD, SPT9?csm-XK99E-ts, SPT9?csm-XK99E-cspB-ts, SPT9?csm-mob2 -ts and SPT9?csm-mob2-ts-aroⅡ-trpEGD. After 72 hr fermentation, the tryptophan yield in these five strains increased by 21.4%, 57.1%, 100%, 121.4% and 178.6%, respectively compared with SPT9. qPCR was employed to evaluate the transcript quantification of the target genes. The expressions of ts, aroⅡ and trpEGD genes in SPT9?csm-mob2-ts-aroⅡ-trpEGD were 9.2, 13.0 and 10.6 times, respectively of that in strain SPT9.
    30  Effects of Mechanical Stemming on Litchi Damage and Preservation Performance
    WANG Wei-zu LU Hua-zhong YANG Zhou LV En-li FAN Hao-jie YAO You-ping
    2014, 30(4):171-175.
    [Abstract](1352) [HTML](0) [PDF 489.30 K](950)
    Abstract:
    Litchis are harvested by hands in bunches during harvesting seasons. However, litchis for exportation are required to be separated. In order to realize the separation of litchi bunches, a mechanical litchi stemming machine was designed, in which a combing vibration method was used. Fresh litchi bunches were purchased and on the same day, separation efficiency tests were carried out respectively by hand stemming and machine stemming under four vibration frequencies. The results showed that 20 Hz was the best vibration frequency for mechanical stemming, and the separation efficiency was about 3 times more than that of hand stemming. The damage rate of the fruits was less than 6%. The mechanical damage tests and the storage tests were conducted with the litchis separated by hands and machine. The modulus of elasticity was measured and showed no change after the fruits were separated by the machine, which indicated that no serious mechanical damage was caused by the machine during the separation process. During the preservation process, the browning index, weight loss rate and soluble solid content of litchis separated by hands and machine under the frequency of 20 Hz showed no significant difference, indicating mechanical stemming had no significant influence on the preservation of the litchis.
    31  Water Retention of Non-water-soluble Gracilaria lemaneiformis Polysaccharides in Pork Sausage
    DU Jia-jia LIU An-jun ZHENG Jie SONG Xiao-di WANG Zi-jian HU Ying-na
    2014, 30(4):176-180.
    [Abstract](1053) [HTML](0) [PDF 460.18 K](793)
    Abstract:
    The study is mainly to investigate the effect of water holding capacity on Gracilaria Lemaneiformis powder which had been removed acidic polysaccharides in pork sausages. The influences of G. Lemaneiformis powder and phosphate on water holding capacity, texture characteristics and microscopic structure of pork sausages were compared. The results showed that water holding capacity of composite phosphate (CPP) was the best in all kinds of phosphate with addition amount of 0.5%. .Cooking loss rate and centrifugal dehydration rate of G. Lemaneiformis powder group decreased by 95.27%,71.62%, 37.20% and 32.50%, respectively lower than those of CPP group (p<0.05). With the increase of G. Lemaneiformis powder, water holding capacity was enhanced, and elasticity, hardness, cohesiveness, chewiness and recoverability of pork sausages were also improved. Texture characteristics of G. Lemaneiformis group were better than CPP group when additive amount was 3.5~4%. SEM (200 times) showed the structure of G. Lemaneiformis powder group was denser and more homogeneous than other groups. Therefore, with adding 3.5~4% of G. Lemaneiformis powder, the quality characteristics of sausages could be improved.
    32  Effect of an Active Film from Chitosan and Pomegranate Rind Powder Extract on Shelf-life Extension of Pork Meat Patties
    QIN Yu-yue WU Yan ZHANG Zhi-hong LI Bing LIANG Xiao-bo CAO Jian-xin
    2014, 30(4):181-188.
    [Abstract](1840) [HTML](0) [PDF 423.14 K](706)
    Abstract:
    Chitosan (CH) film is widely used for the shelf life extension of food stuff. In order to improve its antioxidant activity, chitosan film containing pomegranate rind powder extract (PRP) was used as an active packaging material for pork meat patties stored at 4±1 ℃ for 20 days. The physical, chemical, microbiological, and sensory qualities of pork meat patties wrapped with CH-PRP film were compared with those wrapped with pure chitosan film and control group without chitosan film wrapping. A microbiological shelf-life extension of 8 days was achieved for CH and CH-PRP treatment groups when compared to the control group. Wrapping with CH-PRP film retarded the increases in thiobarbituric acid-reactive substances values and metmyoglobin content. The samples wrapped with CH-PRP film could maintain acceptable sensory quality throughout the storage. A gradual release of phenolic compound was observed from CH-PRP film during storage. The results indicated that pomegranate rind powder extract incorporated into chitosan film enhanced the antioxidative and antimicrobial activities of the film and thus maintained quality and shelf life of pork meat patties.
    33  Effects of High Pressure Treatment on the Restructured Properties of Minced Beef
    MA Han-jun DONG Jian-guo MA Rui-fen ZHAO Yong-hong BAI Teng-hui HAN Yan-an
    2014, 30(4):189-195.
    [Abstract](1055) [HTML](0) [PDF 703.24 K](749)
    Abstract:
    In order to improve the restructured properties and make full use of low-value minced beef, the effects of high pressure treatment on cooking loss, non-expressible water, water-holding capacity, cohesiveness and microstructure beef sausage made of minced beef were investigated. The single factor test showed that: with the pressure, temperature and time increasing, cooking loss first decreased and then increased, while non-expressible water, water-holding capacity and cohesiveness first increased and then decreased. The optimum properties were achieved under treatment conditions of about 400 MPa, 20 ℃ and 15min. Based on the response surface analysis, the optimum conditions for cooking loss and water-holding capacity of minced beef were determined as 500 MPa, 25 min, and 35 ℃. The optimum conditions for non-expressible water and cohesiveness were determined as 431 MPa, 15 ℃, 18.6 min and 383 MPa, 35 ℃, 25 min, respectively. Based on the above analysis, the optimum conditions for improving the restructured properties of minced beef were set at 469 MPa, 35 ℃, 25 min. Under these conditions, the major indexes of the obtained product could be significantly improved, and the microstructure was more regular. In brief, high pressure treatment was a promising technology since it could improve the restructured properties of minced beef.
    34  Effects of Two Microwave Heating Methods on Gelling Properties of Silver Carp Surimi
    YAN Hong LIN Lin YE Ying-wang DENG Wei JIANG Shao-tong LU Jian-feng
    2014, 30(4):196-204.
    [Abstract](1538) [HTML](0) [PDF 599.27 K](786)
    Abstract:
    To improve the quality of surimi, the effects of two microwave heating methods (microwave and water bath-microwave combined heating) on gel properties of silver carp surimi were investigated. Single-factor experiments and orthogonal array design were adopted to obtain the optimum technical conditions by using gel strength, water-holding capacity (WHC) and whiteness as the indexes of surimi quality assessment. The changes of different heating methods on the protein molecular structure of surimi were further studied through protein solubility, chemical forces, SDS-PAGE and scanning electron micrographs. The optimum power and time of microwave heating treatment were 600 W and 60 s, respectively, under which the gel strength, WHC and whiteness of silver carp surimi were 608.64 g?cm, 83.64% and 75.79, respectively. The best conditions for water bath-microwave combined heating treatment were water-bath heating at 40 ℃ for 1 h and microwave treatment at 600 W for 60 s, under which the gel strength, WHC and whiteness of silver carp surimi were 627.47 g?cm, 85.37% and 74.37, respectively. The results of verifying test showed that the two microwave heating methods aforementioned were better than the conventional heating method (two-stage water bath heating), while the water bath-microwave combined heating was also better than only microwave heating treatment.
    35  Comparative Analysis of the Membrane Concentrate and Evaporation Concentrate of Anchovy Cooking Liquid
    ZHANG Jian-you LIU Min LIN Long DING Yu-ting
    2014, 30(4):205-210.
    [Abstract](976) [HTML](0) [PDF 591.06 K](925)
    Abstract:
    The conditions of nanofiltration, and the main nutritional components and flavor substances of initial cooking soup, concentrated soup by membrane and evaporation were studied. The optimal condition of nanofiltration was 20 bar at 45 ℃ with solution containing NaOH and 0.1% (m/m) SDS. The soluble protein and the amino nitrogen of membrane concentrated soup were concentrated by 4.05 and 2.21 times respectively. However, the concentrated soup by evaporation was higher than those by membrane, being of 6.20 and 5.91 times, respectively. The energy consumption of evaporation was higher than membrane concentration. The b* value (an indicator of yellowness- blueness) of membrane concentrated soup increased by 3.96, while L* value (an indicator of light and dark) and a*value (an indicator of redness-greenness) had changed relatively little. Meanwhile, the b* value and a* value of evaporation concentrated soup increased 1.99 and 2.42, respectively. Therefore the color system of concentrated soup by evaporation had larger change. 45, 42 and 33 volatile flavor compounds were detected in the initial cooking soup, concentrated soup of membrane and evaporation analyzed by HS-SPME- Gas chromatography - mass spectrometry. Compared with evaporation, membrane concentration combined microfiltration and nanofiltration was a better way to persist the color and flavor of anchovy cooking liquid.
    36  Effect of Temperature on Antioxidation of Casein-Xylose Maillard Reaction Products
    ZHANG Yin-liang ZHANG Lu-yan ZHOU Wen-quan SHI Guo-qing
    2014, 30(4):211-219.
    [Abstract](1403) [HTML](0) [PDF 612.52 K](753)
    Abstract:
    The antioxidation determination of Maillard reaction products (MRPs) were carried out under different temperatures on the casein-xylose model system. The results showed that the browning degree of Maillard reaction increased with a rise of temperature and had significant difference (p?0.05) within 100~160 ℃. MRPs of iron chelating ability first increased and then gradually declined with increasing reaction temperature, and maximum value (53.26%) was obtained at 100 ℃. Copper chelating ability gradually decreased with temperature increasing. Free radical scavenging ability of MRPs increased with a rise of temperature and had significant difference, and DPPH free radical scavenging ability was better than hydroxyl free radical scavenging ability. Reducing power of MRPs increased with the increase of reaction temperature and had significant difference (p?0.05). GC- MS analysis combining with the determination of the antioxidation indicated that the antioxidant compounds of casein-xylose MRPs mainly were aldehydes, ketones, phenols, alkene and heterocyclic substances. There was significant correlation between the variation of free radicals clearance and change of reduction force in MRPs overall antioxidant capacity with the maillard reaction temperature. The preliminary judgment of MRPs antioxidant compounds from the mechanism was carried out with radical scavenging method instead of chelating metal ions.
    37  Vacuum Freeze-drying Characteristics of Common Berries
    ZHAO Feng-min LI Shu-jun ZHANG Xiao-yan CAO You-fu YANG Yan-chen LIU Wei YANG Bing-nan
    2014, 30(4):220-225.
    [Abstract](1453) [HTML](0) [PDF 689.73 K](959)
    Abstract:
    Berries are difficult to store and easy to rot. Therefore timely post-processing is required. Vacuum freeze drying technology can effectively maintain nutrition and sensory characteristics of fresh materials, especially for dehydration of high value-added fruits. Four common berries including banana, grape, kiwi fruit and blueberry were used as raw materials, and dehydrated by vacuum freeze drying. Results showed that banana, kiwi fruit and blueberry maintained the original status of fresh materials and the products were porous and crispy. However, shrinkage and distortion were occurred in freeze-dried grapes. Constant speed drying stages were appeared during vacuum freeze drying of berries except grape. Rehydration rates of banana, grape, kiwi fruit and blueberry were 72.34%, 76.23% and 55.88% respectively, and their preserving rates of vitamin C were 88.47%, 96.67%, and 78.11%, respectively. The rehydration rate and the preservation rate of grape were only 33.53% and 22.67%, respectively. Suitability evaluation of vacuum freeze drying for common berries is provided in the experiment, and it has a certain reference value in helf life extension and convenient transportation of berries.
    38  Effect of Pre-slaughter Carbon Dioxide Anesthesia on Flesh Quality of Tilapia
    CHEN Ming-shuai FAN Xing LU Yu-qin YAN Ming-yue CHEN De-wei
    2014, 30(4):226-232.
    [Abstract](1444) [HTML](0) [PDF 490.09 K](763)
    Abstract:
    The aim of this study was to evaluate the effects of pre-slaughter carbon dioxide (CO2) anesthesia (directly percussive blow to the head as control group) on the flesh quality of Tilapia. Then the processed Tilapia were vacuum-packed in low-density polyethylene (LDPE) bags and stored at 1±1 ℃. Rigor mortis, muscle pH, weight loss, total volatile base nitrogen (TVB-N), sensory evaluation, texture hardness and shear force were measured over a 7 d time span. Results showed that carbon dioxide narcosis prolonged the pre-rigor period of the fillet; pH of muscle was higher initially while decreased in the end. Weight loss of both methods had no significant difference after 3 d post-mortem.But from 4th day to 7th day, weight loss of CO2 anesthesia group was significantly lower than the control group. Except for post-mortem of the 0 d, 4th day and 5th day, TVB-N value of CO2 anesthesia group was obviously lower than the control group. No evident difference in the texture deterioration and sensory qualities were found between the two group, but hardness, shear force and sensory quality of the sample at 7th day were dramatically lower than that at 0 day. The pre-slaughter method of CO2 anesthesia, combined with all quality indicators, was more suitable to process tilapia flesh than percussive stunning.
    39  Response Surface Methodology for Optimization of Extracting Total Flavonoids from Maca Leaves and Antioxidant Evaluation
    ZHANG Li-ming LI Rui-chao HAO Li-min TIAN Ai-ying LU Ji-ke ZHANG Jian-chun
    2014, 30(4):233-239.
    [Abstract](1634) [HTML](0) [PDF 583.32 K](815)
    Abstract:
    Response surface methodology (RSM) was employed to optimize the extraction conditions of total flavonoids from Maca leaves collected from Lijiang (Yunnan province). Based on single-factor tests, Box-Benhnken center composite experiment was carried out with three factors, including alcohol concentration, extraction temperature, solid-to-solvent ratio. RSM was used to determine the effect of prime factors on the yield of flavonoids. Besides, the antioxidant activity in vitro of flavonoids from maca leaves was evaluated. Results showed that the optimum extraction conditions by RSM were ethanol concentration 65%, extraction temperature 64 ℃, and solid-to-liquid ratio 29:1 (mL/g). Under these conditions, the extraction yield of total flavonoids was (2.49±0.02) %, which was close to the measured value. Thus, the fitted quadratic regression model was valid. The IC50 of the obtained total flavonoids against hydroxyl, superoxide anion and DPPH radicals were 0.605, 0.425 mg/mL and 0.165 mg/mL, respectively. The scavenging impact of the three radicals was more effective than that of 2,6-di-tert-butyl-4-methyl phenol (BHT) at the same concentration, but lower than vitamin C.
    40  Effects of Segmentation and Cooking on the Quality of Leafy Vegetables
    ZUO Min-er
    2014, 30(4):240-244.
    [Abstract](1126) [HTML](0) [PDF 431.65 K](873)
    Abstract:
    The effects of segmentation and cooking on the contents of Vc, chlorophyll and nitrite in brassica juncea, choy sumand lettuce were studied. The results showed that after segmented and blanched, the contents of Vc and nitrite dropped more than 40% and 45%, respectively, while chlorophyll content increased obviously with increasing the loss of cellular fluid. Steaming process could keep Vc content for about 60~67% , reduce the nitrite content about 40~70%, and had little effect on hlorophyll content. Thus it was considered as an ideal cooking method for protecting nutrients in vegetables. This research has good theoretical and practical significance, providing a good reference in reducing nutrients loss, reducing the production of harmful substances, and improving the quality of leafy vegetables during cooking process.
    41  Identification of Odor-active Compounds in Chinese Mitten Crab from Yangcheng Lake by MMSE-GC-MS/GC-O () Abstract: Key words:
    WANG Xi-chang WU Na GU Sai-qi TAO Ning-ping
    2014, 30(4):245-254.
    [Abstract](1343) [HTML](0) [PDF 677.50 K](771)
    Abstract:
    To research characteristics of odor-active compounds in different genders (male and female) and edible parts (abdomen, claw, leg and gonad) of Chinese mitten crab (Eriocheir sinensis) cultured in Yangcheng Lake, the volatile compounds were extracted by a new-type material MonoTrap and analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). Total 76 volatile compounds were identified by GC-MS and 17 kinds of characteristic odor were detected by GC-O. Grassy was the most characteristic odor in the four parts of Chinese mitten crab. In addition, the total odor intensity of abdomen meat was the weakest while gonad was the strongest with fatty and roasted meat odor. Among all 56 odor compounds (screened from 76 volatile compounds), trimethylamine, (Z)-4-heptenal, 2,5-dimethylpyrazine, (E,E)-3,5-octadien-2-ketone and (Z)-4-decenal made greater contributions to the overall flavor of Chinese mitten crab.
    42  Isolation and Antimicrobial Susceptibilities of Staphylococcus aureus in Commercially Available Raw Pork in Guangzhou
    SHI Lei ZHOU Chen-qing YAN He
    2014, 30(4):255-259.
    [Abstract](1409) [HTML](0) [PDF 410.01 K](717)
    Abstract:
    The contamination situation, molecular typing and resistance characteristics of Staphylococcus aureus from pork were investigated. S. aureus were separated and identified according to GB 4789.10-2010, MLST method was used for molecular classification, drug susceptibility was tested by disc diffusion assay, and the class one integron, integrated gene cassettes and MRSA were examined by PCR. A total of 110 samples were examined and 34 of which (30.9%) were positive for S. aureus. All strains were divided into seven kinds of STs type, namely ST6( 1/34 ), ST7( 16/34), ST9( 9/34 ), ST59( 1/34 ), ST239( 4/34 ), ST2259( 2/34 ), and one new ST typing. All 34 S. aureus isolates were resistant to penicillin, and the drug resistant rate of tetracycline, trimethoprim, erythrocin, clindamycin, were 88.2%, 76.5%, 64.7%, 61.8%, respectively. 38.3% (13/34) of S. aureus were MRSA, 5 S. aureus isolates were observed as class one integron, and 2 isolates carried integrated gene cassettes. The results showed that raw pork were severely contaminated with S.aureus, and the isolates had serious antimicrobial resistance phenomenon, ST7 was the main sequence typing, the class one integron were existed in foodborne S. aureus, and the integrated gene cassettes played a role in resistant mechanism of isolates.
    43  Determination of Aminoglycosides Residues in Milk by Microwave-assisted Derivatization and Ionic Liquid-based Dispersive Liquid-liquid Microextraction Coupled with HPLC
    WANG Zhi-bing GAO Yang LIU Yang XIE Song-lin ZHANG Feng-qing
    2014, 30(4):260-267.
    [Abstract](1428) [HTML](0) [PDF 700.48 K](727)
    Abstract:
    A new method based on simultaneous microwave-assisted derivatization and ionic liquid-based dispersive liquid-liquid microextraction was developed for the derivatization and extraction of aminoglycosides (AGs) including streptomycin (STR), gentamicin (GEN), kanamycin (KAN), tobramycin (TOB), micronomicin (MIC), amikacin (AMI) and neomycin (NEO) in milk samples. In the experiment, 9-fluorenylmethyl chloroformate (FMOC-Cl), 1-octyl-3- methylimidazolium hexafluorophosphate ([Omim]PF6) and methanol were used as derivatization reagent, extraction solvent and disperser, respectively. Aminoglycosides were simultaneously derivatized and extracted into ionic liquid phase by this method in a single step. Derivatives of the aminoglycosides were then determined by high-performance liquid chromatography coupled with fluorescence detection. The calibration curve had good linear relationship (r>0.9989). The limits of detection (LODs) of analytes were in range of 0.11~0.57 μg/L. The recoveries were between 91.95% and 106.33% with the relative standard deviations of 1.39~5.92%. The proposed method has the advantages of simple operation, high sensitivity and reliable results and should be extensively applied for determination of aminoglycosides in milk samples.
    44  Comparison of Volatile Compounds in Traditional and Commercial Pixian Broad-bean Sauce by HS-SPME-GC-MS and Electronic Nose
    LI Zhi-hua WANG Zi-peng HU Jing DONG Lin LI Feng-yuan HUANG Chi YAO Ying-zheng XIE Jiang LI Pu CHEN Fu-sheng
    2014, 30(4):268-273.
    [Abstract](1551) [HTML](0) [PDF 584.31 K](867)
    Abstract:
    The different volatile components of three traditional naturally fermented and one known commercial Pixian Broad-bean sauces were evaluated and compared using HS-SPME-GC-MS and electronic nose. The results showed that e-nose could distinguish traditional and commercial Pixian broad-bean sauce. A total of 53 volatile components were identified by HS-SPME-GC-MS in four kinds of Broad-bean sauce, 18 of which mainly consised of 4-ethyl-2-methoxy-Phenol, phenylethyl alcohol, benzaldehyde, benzeneacetaldehyde, 2-hydroxy-methyl benzoic acid ester. The unique commercial broad-bean sauce volatile components were chiefly from the added spices. 24 volatile components were incompletely shared in three kinds of traditional broad-bean sauce, including alcohols, esters and alkanes, which might be little useful for Pixian Broad-bean sauce flavor. Sensory analysis also indicated that there were little difference except for color in traditional and commercial Pixian Broad-bean sauce, due to different fermentation time.
    45  Identification of Shark Fins in Food with PCR Method
    QIN Fang-fang WANG De-lian XIAN Yan-ping LUO Hai-ying WU Yu-luan LUO Dong-hui WANG Li WANG Bin
    2014, 30(4):274-278.
    [Abstract](1797) [HTML](0) [PDF 534.62 K](734)
    Abstract:
    In order to detect the shark ingredients in food, a rapid and sensitive polymerase chain reaction (PCR) method was developed. In this method, a pair of primers was designed based on cytochrome oxidase subunit I (COI) gene, which could produce 228bp band via PCR. To evaluate the specificity of this method, 22 shark fin samples DNA and 37 other species DNA were analyzed by PCR using the new specific primers. The results showed that the specific 228 bp band only be observed in 22 shark fin samples. The sensitivity of the PCR method was tested by mixing shark fin DNA and DNA extracted from potato in different proportions, and it was indicated that the lowest detection limit by this method was 0.1% (m/m). Forty-three samples were randomly tested, 22 of them containing shark fins, while 21 imitation samples were detected to contain plant ingredients. This method can be widely used in identification of shark ingredients in food.
    46  Application of Electronic Nose and Neural Network in Beef Freshness Detection
    HONG Xue-zhen WEI Zhen-bo HAI Zheng WANG Jun
    2014, 30(4):279-285.
    [Abstract](1425) [HTML](0) [PDF 618.76 K](785)
    Abstract:
    Fresh beef under 0~12 day cold storage were detected by sensory evaluation, semi-micro determination of nitrogen detection, microbiological testing and electronic nose (e-nose) detection. For the e-nose detection, the 50th s sensor signals were extracted for analysis. Mahalanobis Distance (MD) between fresh and stored samples enlarged with the increase of storage time, and the quality of beef significantly changed after stored for 5 days. Principle component analysis (PCA) and Linear Discriminant Analysis (LDA) results indicated that all the beef samples could be well distinguished except a little overlap between the samples stored for 0~5 days. Stepwise Linear Discriminant Analysis (Step-LDA) was applied to predict the storage time and got an accuracy of 96.19%. Back Propagation Neural Network (BPNN)and Generalized Regression Neural Network (GRNN) were also used to build a correlation model between the storage time and the physicochemical indicators, which showed that GRNN was better than BPNN. The prediction error based on the GRNN model for the storage time, total volatile basic nitrogen, microbial population and sensory scores were 1.36 days, 4.64?10-2 mg/g, 1.61×106 cfu/g and 1.31, respectively.
    47  Analysis of Flavor Components in the Coconut Juice and Beverage Based on GC-MS Method
    YANG Hui-min ZHOU Wen-hua ZHANG Qun LI Wei-min
    2014, 30(4):286-290.
    [Abstract](1340) [HTML](0) [PDF 469.51 K](903)
    Abstract:
    In order to analyze the flavor composition and content of different maturity coconut Juice in young coconut, tender coconut, mature coconut, as well as the coconut water beverage, volatile components were prepared with distillation and extraction equipment (SDE), then isolated and identified by gas chromatography-mass spectrometry (GC-MS). 67 flavor compounds were identified and classified into 7 groups, including 32 esters, 11 acids, 7 alcohols, 3 aldehydes, 3 ketones, 4 phenols and 7 others compounds. Through the analysis of flavor compounds, esters, alcohols and acids were found to be the main flavor substances. The same volatile substance was 2, 3-Butanediol. Those samples showed significantly difference in varieties and contents of aroma trace components, and aroma components in mature coconut juice were higher than those of other samples. Therefore, the sensory quality of coconut beverage was directly influenced by the aroma components in coconut water. This would provide a more theoretical basis for developing the research of sensory quality in coconut water beverage.
    48  Spectrophotometric Determination of Taurine in Shellfish by Inhibiting Methyl Orange Oxidation
    LI Yong-mei ZHU Long-sheng LI Ren-yu
    2014, 30(4):291-295.
    [Abstract](849) [HTML](0) [PDF 525.54 K](791)
    Abstract:
    Trace taurine has obvious inhibitory effect on the reaction of potassium hypermanganate oxidizing methyl orange in ammonium chloride-ammonia buffer solution at pH 11.0, resulting in fading of the system and great decrease of absorbance. The acidity, potassium hypermanganate and methyl orange dosage, temperature and time were optimized. Under the optimum reaction conditions, good linear relationship was obtained between the decreased value of absorbance and taurine concentration in the range of 0~75 μg/L with the maximum fading wavelength of 690 nm. The apparent molar absorption coefficient was 2.22×106 L/(mol?cm), with detection limit of 1.19 μg/L. Samples were pretreated using hot water extraction and ion exchange , the proposed method was applied to the determination of taurine in Meretrix meretrix, Sinonovacula constricta, Chlamys farreri and Mactra veneriformis. The results agreed well with those obtained by high performance liquid chromatography. The relative standard deviation was 0.82~1.24% (n = 6), and recovery was 98.31~101.76%. This method was sensitive, accurate, simple, rapid and environmentally friendly under, which was suitable for determination of taurine in shellfish.
    49  Establishment of a Liquidchip Method for Listeria Monocytogenes Detection
    ZHAO Li CAI Yang HUANG Wei QIU Yang
    2014, 30(4):296-300.
    [Abstract](1027) [HTML](0) [PDF 462.59 K](697)
    Abstract:
    Listeria monocytogenes liquidchip detection method was established by coupling Listeria monocytogenes monoclonal antibody (mAb930) and polystyrene microspheres, and combining with double antibody sandwich technique. The ratios of different concentration of antibody to the microsphere coupling were detected. L25(56) orthogonal test was used to optimize the reaction conditions, and verification of the sensitivity and specificity were detected by the developed method. 200 food samples were tested by the method, with comparison of the national standard method. The optimal concentrations of polyclonal antibody, , the antibody biotin labeled Goat anti rabbit IgG and SA-PE antibody were 1:100, 1:500 and 10 μg/mL, respectively. And the best reaction time of biotin labeled and SA-PE was, 30 min. The sensitivity of this method reached 103 CFU/mL. No cross reaction with other common food borne pathogenic bacteria occurred. In addition, the results were consistent with the national standard method. The false positive rate of liquid chip assay for the detection of various samples was less than 0.77%. The method has high sensitivity, strong specificity, good reproducibility, and can be used for rapid detection of Listeria monocytogenes in food.
    50  Determination of Chromium (Ⅲ) and Chromium (Ⅵ) in Dairy Products by HPLC-ICP-MS
    HU Yu-jun QIN Yi-lei LAI Yi-dong
    2014, 30(4):301-305.
    [Abstract](1375) [HTML](0) [PDF 445.83 K](818)
    Abstract:
    A method was developed for the simultaneous determination of chromium(Ⅲ) and chromium(Ⅵ) in dairy products by high performance liquid chromatography(HPLC) coupled with inductively coupled plasma-mass spectrometry(ICP-MS). The sample was boiled in EDTA buffer solution, cooled down and centrifuged at 8000 r/min for 10 min to separate the protein. Then the supernatant was filtrated through 0.45 μm filter membrane, and chromium(Ⅲ) and chromium(Ⅵ) were simultaneously extracted. Using NH4NO3 as mobile phase (pH=7.0~7.2), Chromium(Ⅲ) and chromium(Ⅵ) were separated and detected in 4 min by HPLC-ICP-MS at a flow rate of 0.6 mL/min. The effects of various pretreatment conditions on test results were researched. The amount of EDTA should be excessive to eliminate the influence of calcium, magnesium and other elements. The complexation rate of EDTA with Chromium(Ⅲ) was significantly increased by boiling, but the time should not be too long, and 2~3 min was appropriate. The two chromium species had good recoveries and separation effect under pH 7.0~7.2. The results showed that the linear ranges for Chromium(Ⅲ) and chromium(Ⅵ) were between 0.2 and 20 μg/L with linear coefficients more than 0.9995, and the detection limits were 0.034 and 0.066 μg/L. The method had a simple pretreatment procedure, high sensitivity and good accuracy and precision.

    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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