Volume 30,Issue 5,2014 Table of Contents

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  • 1  Fabrication and Characterization of Water-soluble Antimicrobial Gliadin Nanoparticles
    WANG Li-juan HU Er-kun YIN Shou-wei YANG Xiao-quan
    2014, 30(5):1-5.
    [Abstract](1209) [HTML](0) [PDF 428.14 K](716)
    Abstract:
    The objective of this work is to fabricate water-soluble and antimicrobial gliadin nanoparticles stabilized by sodium caseinate (NaCas) via the synchronous-assembly process of thymol and gliadin during the anti-solvent approach. Morphological attributes, particle size, antimicrobial properties as well as release profiles of thymol-loaded nanoparticles were investigated. The gliadin/NaCas nanoparticles were spherical in shape and uniform with PDI value of 0.31, possessing the water-solubility and re-dispersibility after freeze-drying. Thymol loading resulted in a slight increase in particle size from ~ 270 nm to ~300 nm at the thymol-to-gliadin ratios of 1:10~3:4, but did not affect the re-dispersibility of the nanoparticles. Morover, these nanoparticles had strong encapsulation capacity, and the encapsulation efficiency (EE) of thymol was as high as 96%. The nanoparticles sustained the release of thymol, and the accumulative release after 7 day was about 30%. These nanoparticles were also effective in delaying the growth of Staphylococcus aureus in M-H broth at 37 ℃. This work opens a promising pathway for the manufacture of water-soluble vehicle for antimicrobials to design novel antimicrobial food formulation.
    2  Influence of Acylation on the Structures and Physico-chemical Properties of Yak Caseins
    YANG Min SHI Ying LIANG Qi WEN Peng-cheng ZHANG Wei-bing
    2014, 30(5):6-11.
    [Abstract](1037) [HTML](0) [PDF 512.20 K](912)
    Abstract:
    The influence of different acylation reagents (succinic anhydride, succinic acid and acetic anhydride) on the spatial conformation and physico-chemical properties of yak caseins were investigated. The secondary and tertiary structure, buffer capacity and calcium, magnesium, phosphorus content of original and modified yak caseins were also studied. The results showed that the acylation degree with succinic anhydride, acetic anhydride and succinic acid was 90.0%, 87.9% and 18.5%, respectively. After acylation with different reagents, the secondary structures of yak casein were mainly turn and β-sheet; a few α-helix structures formed after succinylated modification, with the content of 9.4%. Succinic anhydride had the largest influence on tertiary structure of casein, followed by acetic anhydride and succinic acid. The maximum ?uorescence intensity of intrinsic and ANS ?uorescence spectrum were reduced with modification and the maximum emission wavelength were shifted red except acetic anhydride modified casein. The modification improved the buffer capacity, reduced the content of calcium, magnesium, phosphorus. The color of modified caseins was whiter than original casein. The results could provide references for the chemical modification of yak caseins.
    3  Extraction of Anti-tumor Constituents Derived from Dendrobium officinale
    ZHENG Qiu-ping QIU Dao-shou LIU Xiao-jin CAI Shi-ke ZHANG Lei DENG Rui-yun LUO Huan-ming ZHANG Xue-wu
    2014, 30(5):12-17.
    [Abstract](1678) [HTML](0) [PDF 565.88 K](799)
    Abstract:
    To explore the anti-tumor constituents from Dendrobium officinale, the components extracted with three solvents (ethyl acetate, 95% ethanol and water) were separated and purified by silica gel column chromatography, TLC and Sephadex LH-20, and the whole process was guided by MTT method. Results showed that the strongest activity component named TD1 was achieved by the ethyl acetate extraction, the proliferation of human hapetocelluar carcinoma cell line (HepG-2), human gastric carcinoma cell line (SGC 7901) and human breast cancer cell line (MCF-7 ) were significantly inhibited by TD1 and the IC50were 0.45 μg/mL, 0.36 μg/mL and 0.34 μg/mL, respectively. TD1 was identified as denbinobin by spectroscopic data. Denbinobin was first isolated from Dendrobium nobile Lindl. and its anti-tumor effect has been certified and widely noted in recent years, the results may provide references for the development of new medicine and health food by using Dendrobium officinale as raw materials.
    4  Effects of Transglutaminase on Properties of Gelatin-CaCO3 Mineral Films
    LIU An-jun WANG Yue-meng WANG Wen-hang ZHENG Jie LI Xin ZHU Chuan-wang ZHU Hong
    2014, 30(5):18-22.
    [Abstract](1366) [HTML](0) [PDF 551.06 K](878)
    Abstract:
    Transglutaminase (TGase) was added to gelatin-CaCO3 mineral films and its effect on properties of gelatin-CaCO3 mineral films were studied. Thickness, gel strength, tensile strength (TS), elongation at break (EAB), water solubility (WS) and water vapor permeability (WVP) were characterized by scanning electric microscopy (SEM), rheological study and differential scanning calorie (DSC). The results showed that TGase treatment significantly increased (p≤0.05) the thickness, gel strength, TS and EAB of gelatin-CaCO3 mineral films by 19.69%, 17.24%, 28.05% and 21.27%, respectively; TGase treatment had no effect on the WS and WVP values of gelatin-CaCO3 mineral films. The TGase-treated films had rougher surfaces and cross-sections compared with the films without TGase. Rheological study showed that TGase significantly increased the viscosity. DSC confirmed the occurrence of cross-linking induced by TGase.
    5  Effects of Betaine on Diabetic Nephropathy in db/db Mice
    ZHANG Meng-meng HUANG Min WU Xiao-ying LIU Guang-ze ZHANG Xiao-yuan
    2014, 30(5):23-27.
    [Abstract](1226) [HTML](0) [PDF 753.76 K](725)
    Abstract:
    To evaluate the protective effects of betaine on diabetic nephropathy (DN) in db/db mice, 7 months old db/db mice were randomly divided into negative control group (physiological saline), positive control group (Zhibituo), low (200 mg/kg), middle (400 mg/kg) and high dose (800 mg/kg) betaine group. The mice were fed by high-fat diet to induce DN. After being intragastric administrated by betaines for 6 weeks, the kidney paraffin sections were prepared and the pathological changes were analyzed based on staining, the body weight and BUN, GLU, TC, TG, LDL, TNF-α, TGF-β1 level were also investigated. The results showed that the glomerular basement membrane in the betaine and Zhibituo treatment group did not thicken; extracellular matrix, the glycogen material deposition and fiber content reduced; protein casts and inflammatory cell infiltration disappeared. Furthermore, the structure of renal tubule gradually returned to normal; the body weight and BUN, GLU, TG, TC, LDL, TNF-α, TGF-β1 level were significantly decreased (P < 0.05) by 11.5 g, 3.0 mM, 5.3 mM, 3.1 mM, 0.42 mM, 0.64 mM, 21 ng/L and 30 ng/L, respectively. It can be speculated that betaine has a hypoglycemic activity, lipid-lowering effect, and protective effect on the kidney injury of db/db mice. It may delay or inhibit the inflammatory process of the capillary vessel in diabetic nephropathy.
    6  Analysis of Antioxidant Activities of Oligopeptides from Sea Cucumber Guts Based on ESR and Cell Culture System
    DUAN Xiu-hong QI Shen ZHAO Ya-pin WU Hai-tao
    2014, 30(5):28-32.
    [Abstract](1261) [HTML](0) [PDF 414.77 K](673)
    Abstract:
    In this paper, the antioxidant activities of oligopeptides (Val-Gly-Thr-Val-Glu-Met and Val-Thr-Pro-Tyr) from sea cucumber guts were studied by measuring the scavenging abilities on hydroxyl radical, superoxide radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical using an ESR spectrometer. Moreover, the influence of oligopeptides on H2O2-induced oxidative damage in Jurkat cells was also investigated. The results showed that two kinds of oligopeptides from sea cucumber guts showed scavenging abilities on ?OH, O2-? and DPPH? in a dose-dependent manner. The scavenging ability of Val-Gly-Thr-Val-Glu-Met was significantly higher than that of Val-Thr-Pro-Tyr at different concentrations (p<0.05). The oligopeptides failed to protect the DNA oxidative damage induced by H2O2 at concentrations of 5 mM in Jurkat cells, while induced cell death at concentration of 20 mM. These results suggest that the oligopeptides from sea cucumber guts (Val-Gly-Thr- Val- Glu-Met,Val-Thr-Pro-Tyr) possess free radical scavenging abilities, and have certain development value.
    7  Food-grade Expression of β-Glucosidase from Aspergillus aculeatus in Lactococcus lactis
    HUANG Jian-fei CHENG Li-li LI Na SI Li-fang LUO Li-xin
    2014, 30(5):33-37.
    [Abstract](1341) [HTML](0) [PDF 570.29 K](778)
    Abstract:
    The food-grade secretion expression vector of β-glucosidase from Aspergillus aculeatus was constructed and expressed in Lactococcus lactis MG1363. Secretion signal peptide Usp45 from the L. lactis MG1363 genome, Nisin resistance genes NisI from plasmid pLEB590 and Abgl from plasmid pPIC9k-Abgl were amplified by PCR and ligated to construct the Usp45-Abgl-NisI fragment. The fragment was subcloned into plasmid pMD19 and then transformed into E.coli DH5α by CaCl2 method. It was identified by sequencing and inserted into the E.coli-Lactic acid bacteria shutter vector pMG36e. The recombinant strain E.coli XL1-Blue/pMG36e-Usp45-Abgl-NisI was obtained by transformation. Food-grade secretion expression vector pMG36N-Usp45-Abgl-NisI, in which erythromycin resistance gene of plasmid pMG36e-Usp45-Abgl-NisI was knocked out by PCR method, was constructed and then electrotransformed into L. lactis MG1363. β-Glucosidase produced by E.coli XL1-Blue was active on the chromogenic substrate aesculin. L.lactis MG1363/pMG36N-Usp45-Abgl-NisI could grow on the plates containing 20IU/mL Nisin. β-Glucosidase expressed in L.lactis MG1363 was verified by RT-PCR.
    8  Inhibitory Effect of Mulberry Fruit Anthocyanins on Advanced Glycation End-product Formation
    ZHANG Chao-hong BAI Guang-ling LI Ju-xiu FAN Ming-tao
    2014, 30(5):38-43.
    [Abstract](1425) [HTML](0) [PDF 564.32 K](745)
    Abstract:
    Advanced glycation end product (AGE) is a complex group of compound that formed through Maillard reaction, a nonenzymatic reaction between free amino groups of protein and the carbonyl group of reducing sugar, which is one of the important factors that induce diabetes and other chronic diseases. In this paper, Mulberry anthocyanins were extracted with 0.5% acidic ethanol and purified by AB-8 macroporous resin. To investigate inhibitory effect of Mulberry anthocyanins on the formation of AGEs, BSA/Glucose model systems were carried out. Meanwhile, the effects of protein carbonyl and thiol groups content, hydroxyl radicals (?OH) on AGEs formation were observed to study the inhibition mechanism of mulberry anthocyanins, and the molecular weight change in natvie and glycated-BSA was analyzed by SDS-PAGE gel electrophoresis. The results indicated that AGEs decreased significantly (P < 0.05) with the increase of mulberry anthocyanins concentration. Mulberry anthocyanins had a significant (P < 0.05) inhibitory effect on the formation of AGEs induced by hydroxyl radicals (?OH), and it could inhibit the generation of AGEs by protecting thiol and capturing reactive carbonyl intermediates. The SDS-PAGE electrophoretogram showed that mulberry anthocyanins could inhibit the formation of protein crosslinking caused by glycosylation reaction.
    9  Effect of Initial Central Temperature of Trachurus murphyi on the Fish Quality During Refrigerated Storage
    LV Fei HU Zhuo-jin HUANG Rui-ji DING Yu-ting
    2014, 30(5):44-48.
    [Abstract](1268) [HTML](0) [PDF 427.13 K](763)
    Abstract:
    Changes in quality of Chilean jack mackerel (Trachurusmurphyi) with different initial central temperatures stored at 4 ℃ temperature for 6 days were studied. Three different initial central temperatures including 0 ℃ (A group), 3 ℃ (B group) and 6 ℃ (C group), and pH values, total volatile basic nitrogen (TVB-N), trimethylamine (TMA-N), 2-thiobarbituric acid reactive substances (TBARS)and sensory assessment for whole jack mackerel were determined.The results indicated that pH, TVB-N, TMA-N and TBARS values increased as refrigerated storage progressed and it showed that in the 6th day, these values of fishes in C group were 6.13, 0.29 mg/g, 0.13 mg/g, 7.12 mg/kg, respectively, and they were significantly higher than those in A and B group (p<0.05). In addition, there was a negative correlation between sensory scores and storage time. The lower initial central temperature of fish resulted in the more decrease of speed of sensory scores. The lower initial central temperature may contribute to the better quality of Chilean jack mackerel during refrigerated storage.
    10  Screening and Identification of Amine Oxidase Productive Strains from Smoked Horse Intestine
    MA Yu-xia LU Shi-ling LI Kai-xiong LI Rui-ting
    2014, 30(5):49-55.
    [Abstract](1332) [HTML](0) [PDF 586.74 K](736)
    Abstract:
    In order to obtain good amine oxidase productive starters for meat product, amine oxidase productive strains were isolated from 44 samples in different areas of the smoked horse intestine. Productive amine bacteria were eliminated by double color method in monolayer culture. The oxidase test, bacteriostasis experiment and the resistance to salt and nitrite test were conducted for isolated strains. The same strains were eliminated by DGGE and the ability of oxidizing biogenic amine was verified by HPLC. Finally, the DNA was extracted from the screened strains, and V6-V8 segment of 16s rDNA were sequenced after PCR amplification. The results showed that six strains productive amine oxidase bacteria were screened out, with salt tolerance above 6%, nitrite tolerance above 0.15 g/kg, and had good inhibitory effect to Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus, and they had strong oxidizing ability of biogenic amines. The strains were Lactobacillus rhamnosus, Bacillus subtilis, Staphylococcus saprophyticus, Staphylococcus xylosus, Pediococcus pentosaceu and Lactobacillus plantarums. This research provides a good theoretical basis for the industrial production and security of fermented meat.
    11  Effect of Hot-air Drying of Litchi on Antioxidant Activity of Polysaccharides in the Pulp
    HUANG Fei ZHANG Rui-fen DONG Li-hong ZHANG Ming-wei SU Dong-xiao GUO Jin-jie
    2014, 30(5):56-61.
    [Abstract](1313) [HTML](0) [PDF 494.78 K](708)
    Abstract:
    Drying is commonly used for preservation and processing of litchi. However, its polysaccharide structure may be altered by drying, resulting in biological activity changes. In order to study the effect of hot-air drying of litchi polysaccharides in the pulp, the physicochemical properties and antioxidant activity of polysaccharides from fresh (LPF) and dried litchi pulp (LPD) were investigated, respectively. The results showed that the protein content of LPD was higher than that of LPF, contained less neutral sugar and lower intrinsic viscosity. LPD exhibited high antioxidant activity in DPPH? scavenging activity (IC50 value 0.11 mg/mL), ABTS+? scavenging activity (98.81% at 4 mg/mL) while LPF were 1.98 mg/mL and 21.87%, respectively. In addition, the FRAP and ORAC value of LPD were 8.98 and 4.35 folds of those of LPF, respectively. In summary, the drying process of litchi can effectively change the chemical structure of polysaccharides to improve their antioxidant activity.
    12  Comparison of Signal Peptides for Nattokinase Secretory Expression
    HE Xiao-tian LIU Zhong-mei CUI Wen-jing ZHOU Zhe-min
    2014, 30(5):62-68.
    [Abstract](1783) [HTML](0) [PDF 507.46 K](908)
    Abstract:
    The gene pre-pro-nk (encoding signal peptide, propeptide and mature peptide) and pro-nk (encoding propeptide and mature peptide) were amplified from Bacillus natto chromosome by PCR. Three recombinant vectors (pMA0911-wapA-pro-nk, pMA0911- yncM-pro-nk, pMA0911-pre-pro-nk (m)) with different signal peptides were constructed. Overexpression of nattokinase with those different signal peptides were achieved in B. subtilis expression system. The recombinant nattokinase with wapA signal peptide was expressed at the highest level, and exhibited the strongest fibrinolytic activity. The recombinant nattokinase was purified, and the purification factor and activity recovery of the nattokinase were 2.15 and 21.5%, respectively. The enzymatic property was analyzed. The optimal pH and temperature were 8.0 and 50 ℃, respectively. And the recombinant nattokinase was stable at pH of 5.0~11.0 and temperature of less than 60 ℃. This study could be useful for genetic reconstruction of nattokinase and improvement of expression level of nattokinase in B. subtilis.
    13  Comparative Study of the Pesticide Sensitivity of Butyrylcholinesterases from Chicken Serum and Horse Serum
    LI Wei HE Shao-Zhi ZHANG Quan YANG Xiao RAO Yu QIAN Shan CHEN Xiang-Gui
    2014, 30(5):69-74.
    [Abstract](1177) [HTML](0) [PDF 521.45 K](811)
    Abstract:
    The inhibition effect of butyrylcholinesterase (BChE) in the chicken serum to pesticide was investigated, and new sensitive enzyme source to the quick examination of pesticide were provided. Taking the horse serum BChE for comparison, enzymology properties of the chicken serum BChE and its sensitivity to pesticides were studied by the colorimetric method of Ellman’s, and then the half inhibitory concentration value (IC50) was calculated. The results showed that both BChE reached their best reactivity at 35 ℃ and pH 8.0, no substrate inhibition effect was observed, and both were sensitive to physostigmine but relatively insensitive to donepezil HCL. The IC50 value for trichlorfon, carbofuran, methomyl, metolcarb, dichlorvos to the chicken serum BChE were 0.77, 31.99, 1.14, 5.49, 0.95 μmol/L, respectively, while the IC50 value for those five pesticides to horse serum BChE were 3.88, 1.22, 22.58, 24.18, 5.46 μmol/L, respectively. Thus, the chicken serum BChE has good sensitivity to pesticides and could be used as a candidate enzyme source for rapid detection of pesticide residues.
    14  Separation and Antioxidant Activity Evaluation of Acaudina molpadioides Peptide
    WANG Tian-ming SU Yi-gang MA Yong-jun QIN Qian-an YE Xing-qian CHEN Shi-guo HU Ya-qin
    2014, 30(5):75-81.
    [Abstract](1402) [HTML](0) [PDF 618.71 K](700)
    Abstract:
    Amino acid composition of body wall powder and hydrolytic peptide from Acaudina molpadioides (A. molpadioides) was analyzed and in vitro antioxidant activities of peptide separated from the hydrolytic fractionations were detected. The total oxidant activity of A. molpadioides hydrolytic peptide was evaluated. Results showed the both body wall and hydrolytic peptide contained 19 kinds of amino acids, which were occupied 63.06% and 82.90% of sample dry weight, respectively. Among which, the essential amino acid content were 10.87% and 15.60%, respectively. Three compositions with different molecular weight were separated from hydrolytic peptide by ultrafiltration. The small peptides (<3 kDa) took over the highest level (43.9%) , followed by 3k-10kDa molecular weight peptides(36.8%), and the polypeptide above 10kDa was the minimum (19.3%). The ABTS and FRAP assays showed that compared to other compositions, the antioxidant activity of small peptides (<3 kDa) was the highest, the TEAC value was 0.61 ± 0.03 mmol Trolox/g and 0.32 ± 0.02 mmol Trolox/g, respectively. The result of cell culture experiments displayed that the three compositions from A. molpadioides hydrolytic peptide significantly enhanced the ability of HEK293 and HepG-2 cells against H2O2 oxidative damage. The small peptides (<3 kDa) appeared to be more active than the other components. Six major peaks in the small peptide composition were observed by glucose gel separation with G-25, and the highest antioxidant activity peptide was detected in the sample of the 5th fraction.
    15  Solubility and in vivo Bioavailability of Astilbin-β-cyclodextrin Complexes
    ZHANG Qing-feng NIE Hai-chun FU Ying-juan SHANG GUAN Xin-cheng ZHENG Guo-dong YIN Zhong-ping
    2014, 30(5):82-86.
    [Abstract](1221) [HTML](0) [PDF 503.44 K](724)
    Abstract:
    The inclusion reaction of astilbin with β-cyclodextrin (β-CD) was investigated by UV spectrometry in this study. β-CD could form complex with astilbin in ratio of 1:1 with formation constant of 1788.54±273.41 M-1, and gradually decrease the absorbance of astilbin at 291 nm. The complex was prepared by co-grinding method. The effects of water content and molar ratio on inclusion rate during grind were investigated. The results showed that properly increasing of water content and β-CD molar ratio enhanced the formation of astilbin complexes. Finally, the solubility and in vivo bioavailability of astilbin and its β-CD complexes prepared with molar ratio of 1:2 were investigated. The solubility of astilbin in β-CD complexes was increased 106.14 times and its dissolution profiles were improved. The in vivo bioavailability study showed that β-CD enhanced the absorb rate of astilbin, shortened Tmax and increased Cmax. However, the absolute bioavailability between astilbin and its β-CD complexes had no difference, and were both around 3.7%.
    16  Screening of Lactic acid bacteria for Production of Anti-listeria Bacteriocin
    ZHU Chuan-sheng GAO Yu-rong XU Guo-dong
    2014, 30(5):87-91.
    [Abstract](1234) [HTML](0) [PDF 477.89 K](646)
    Abstract:
    By double agar diffusion methods, the strain producing bacteriocin with inhibitory activity against Listeria monocytogenes was screened and identified from Chinese northeast fermented cucumber. And the bacteriocin was separated and purified and its molecular mass and stability were researched. After eliminating the effects of organic acids and hydrogen peroxide, the strain of Lactobacillus spp. ZLG85 which still had activity against Listeria monocytogenes was screened. The inhibitory activity was degraded sharply by pepsin, trypsin and neutral protease in enzymatic hydrolysis, which was confirmed that ZLG85 can produce bacteriocin. By appearance detection, physiological and biochemical characteristics analysis and 16S rDNA gene sequence homology analysis, ZLG85 was identified as Leuconstoc mesenteroides subsp.mesenteroides. Physical and chemical analysis showed that the mesentericin ZLG85 was heat-stable. Its relative inhibitory activity was 93.77% after incubation at 121 ℃ for 30 min, and above 80% after incubation 4 h within a wide pH range from 2.0 to 10.0. The molecular weight of mesentericin ZLG85 was 2.5 kDa conformed by tricine-SDS-PAGE electrophoresis. Mesentericin ZLG85 is a new kind of bacteriocin with strong stability against Listeria monocytogenes.
    17  Identification of Anthocyanins from the Peel of Purple-fleshed Potato
    FANG Fang WU Qi-hui GUO Hui JIANG Yi-hong
    2014, 30(5):92-97.
    [Abstract](1324) [HTML](0) [PDF 659.71 K](788)
    Abstract:
    This research aimed at the purification and identification of anthocyanins from the peel of purple fleshed potato (Solanum tuberosum L.). By using 2% citric acid solution and D101 macroporous resin, anthocyanins were extracted from the peel of purple fleshed potatoes. The anthocyanin content was 207.33 mg/g freeze-dried powder measured by the external standard method of HPLC. Then, the anthocyanin composition was characterized by HPLC-DAD-ESI-MS/MS. Fourteen kinds of anthocyanin were found, and 3-O-p-coumaroylrutinoside-5-O-glucoside of petunidin was the main ingredient. Four kinds of anthocyanins which existed in the form of aglycon-3-rutinoside-5-O-glucoside, and nine in the form of aglycon-3-coumaroyl (/caffeoyl/feruloyl) rutinoside-5-O-glucoside. Besides, an anthocyanin was inferred with substitutions at C3 and C7 sites. Most of the anthocyanins in the peel of purple fleshed potatoes were acylated with organic acids and substituted with disaccharide residues, which greatly increased the stability. As a byproduct in food processing, the peel of purple fleshed potatoes has good development prospects and high value in use.
    18  Thermal Properties of the Starch from Germinated Oat
    TIAN Bin-qiang DENG Qian-chun XIE Bi-jun
    2014, 30(5):98-103.
    [Abstract](1299) [HTML](0) [PDF 664.55 K](713)
    Abstract:
    Germination is an important method to enhance grain seed value. In this research, Jinyan Ⅷ oat was soaked and geminated at 16℃ in the dark, then starches were extracted from raw and germinated oat at different time. Their thermal properties of starches were characterized by differential scanning calorimetry and thermogravimetric analysis. The results showed that germination had little effect on start gelatinization temperature, the average temperature was 57.44 ℃ within 144 h germination, but the range of gelatinization temperature expanded when germinating was beyond 72 h. Moreover, all the gelatinization enthalpies before and after 72 h germination period increased with time increasing, which suggested that there was an alternating change of the starch structure from disorder to order during germination. Under nitrogen atmosphere, the decomposition temperature of starch was within 275-363℃ and mass loss of starch was 65~73% among the temperature range. Decomposition activation energy of the raw oat starch was higher than that of soaked and germinated samples. And the minimum activation energy presented in 144 h sample was 157.75 kJ/mol while the value of raw starch was 219.44 kJ/mol. In addition, reaction orders of all samples were of the first reaction level.
    19  Comparison of Physical and Chemical Characteristics of Collagen from Silver Carp Skin using Different Extraction Methods
    ZHANG Qiang WANG Qian-qian LU Jian-feng LV Shun YE Ying-wang JIANG Shao-tong LIN Lin
    2014, 30(5):104-110.
    [Abstract](1195) [HTML](0) [PDF 617.41 K](993)
    Abstract:
    Acid soluble collagen (ASC), pepsin soluble collagen (PSC) and hot water-soluble collagen (HWSC) were successfully extracted from silver carp skin, and the physical and chemical characteristics of them were investigated and compared. The results showed that UV and FT-IR measurements of ASC, PSC and HWSC were quite similar, and all of them showed maximum absorption peak at 232 nm and almost no absorption peak at 280 nm. SDS-PAGE pattern indicated that all the collagen extracted by three methods contained two different α chains -(α1) 2α2, and their amino acid composition and proportion were similar. It was conformed to the characteristics of type I collagen. The hydroxyproline (Hyp) content of HWSC was lower than those of other two extracting methods, but the gel property by this method was better. The acid extraction had minimal effect on the network structure of collagen. The thermal denaturation temperature of ASC, PSC and HWSC were 31.05±0.14 ℃, 31.45±0.01 ℃ and 43.75±1.20 ℃, respectively. The Hyp content, rheological characteristics, thermal denaturation temperature and the microstructure of collagen were affected by different extraction methods.
    20  Screening and Identification of a Lactic acid bacteria Strain With Lychee Fresh-keeping Function
    MA Ke XU Cong ZHANG Chang-yong HUANG Ying-wei LUO Hua-jian LUO Shi HU Wen-feng
    2014, 30(5):111-117.
    [Abstract](1182) [HTML](0) [PDF 647.20 K](765)
    Abstract:
    An antagonistic bacteria from litchi fermentation medium, and the inhibitory effects of antagonism on Peronophythora litchii, Colletotrichum gloeosporioides, polyphenol oxidase (PPO) and peroxidase (POD) were studied. A strain was isolated by plating method, and the improved agar diffusion method and plate confrontation method were used to detect the effect of this strain on Colletotrichum gloeosporioidesand Peronophythora litchi, respectively. The activity of PPO and POD were determined by oxophenic acid and guaiacol as substrate. Results showed that the inhibition zone radius of fermentation broth antagonize Penorophythora litchi was 1.5 cm and Colletotrichum gloeosporioides was 0.75 cm, and the inhibition rate of crude metabolites on litchi peel PPO was close to 60%. Crude metabolites and cell homogenates on POD was 58.8% and 51.4%, respectively. This isolation was identified as a strain of lactobacillus plantarum according to the results of morphological characteristics, physiological and biochemical characteristic, the 16s rDNA analysis and phylogenetic tree construction, which had a good application prospect in litchi bio preservation.
    21  Analysis of Intracellular Proteins of E. coli Inactivated by High Pressure Carbon Dioxide
    YANG Yang LI Xin RAO Wei-li CHEN Li ZHANG De-quan
    2014, 30(5):118-124.
    [Abstract](974) [HTML](0) [PDF 538.73 K](719)
    Abstract:
    The variation of proteins in E. coli after 10~50 MPa HPCD treatment at 37 ℃ for 30 min was investigated in this study. The total bacterial counts, cell structure, protein solubility, proteome and secondary structure of protein were analyzed. The results showed that the logarithm of the total bacterial counts of E. coli after HPCD treatment was significantly decreased when the pressure increased to 30 MPa. The cell structure did not change with different HPCD treatments (10~50 MPa). The soluble protein content significantly decreased from 1.77 mg/mL to 0.57 mg/mL when the extraction of E. coli proteins was treated by 20 MPa HPCD in comparison with control (0.1 MPa treatment). The content of proteins decreased as the pressure of HPCD increased. Forty-six protein spots with the greatest expression difference were isolated from the control group and 30 MPa HPCD treatment group using two-dimensional gel electrophoresis. There were 16 representative protein spots were identified by MALDI TOF/TOF mass spectrometry, which were involved in cytoskeleton structure, cell metabolism, transmission of signal and transcription. The circular dichroism results of protein solutions showed that the α-helix accounted for 68.04% and the β-sheet accounted for 0.33% in the control group. The α-helix content significantly decreased (P<0.05) as the pressure of HPCD increased, while theβ-sheet content significantly increased (P<0.05) when treated by 20 MPa HPCD, but no further change occurred when the pressure continued to increase.
    22  The Quality of Zhedong Goose Meat during Postmortem Aging
    LIU Tao PAN Dao-dong ZHANG Xiao-tao SUN Yang-ying CAO Jin-xuan
    2014, 30(5):125-130.
    [Abstract](1202) [HTML](0) [PDF 525.74 K](745)
    Abstract:
    The physicochemical index of postmortem aging of Zhedong Goose was investigated, which was established the foundation for improving the goose meat quality. 90 days geese were involved in the research. Meat samples were taken after 0 h, 4 h, 12 h, 1 d, 4 d and 7 d at 4 ℃, then frozen immediately. Soaking the samples for 1 d, 4 d and 7 d by using H2O2 and N-acetylcysteine (NAC), respectively. Then the change of myofibrillar fragmentation index (MFI) and the degradation of desmin were analyzed. The results showed that the MFI of breast meat increased 80.70 from 12 h to 1 d (P<0.01) and decreased 83.63 from 1 d to 7 d (P<0.01) under H2O2 treatment. However, under NAC treatment, the MFI value decreased 27.76 from 4 h to 12 h (P<0.01), increased 98.00 from 12 h to 1 d (P<0.01), decreased 87.60 at 1~4 d (P<0.01), and increased 33.36 at 4~7 d (P<0.01). During 0~4 d, 50 kD degradation fragments was observed in desmin (55 kD), which were degraded to more smaller segments at 7 d. The best quality of goose meat could be got within 12~96 h during the maturing process.
    23  The Relationship between Fermentation Activity of Saccharomyces cerevisiae in High-sugar Dough and Sucrase Activity
    FENG Bing ZHANG Cui-ying LIN Xue XIAO Dong-guang
    2014, 30(5):131-135.
    [Abstract](1639) [HTML](0) [PDF 457.24 K](907)
    Abstract:
    Six active dry yeasts with two strains BY-6 and BY-14 were used as the tested strains. The sucrase activities, specific growth rates in different types of culture medium and fermentation activities in high and low sugar dough were detected. The yeast ADY2 and BY-6 showed the highest and lowest sucrase activities, respectively, being of 128.70 U/g dry yeast and 30.55 U/g dry yeast, respectively. For the fermentation activity in high-sugar dough, the outputs of CO2 were 850 ccm and 225 ccm, respectively. It was proved that the strain with lower sucrase activity had better fermentation activity in high-sugar dough. By measuring the consumption of sucrose and accumulation of glucose in the simulation of high-sugar dough, the results showed that ADY2 with higher sucrase activity consumed more sucrose and accumulated glucose faster than BY-6 with lower sucrase activity; meanwhile, it accumulated more glucose than BY-6. For BY-6 with lower sucrase activity and strong fermentation activity, there was still a large number of glucose accumulations in the simulation of high-sugar dough. Therefore it was a control target spot to breed the strains whose sucrase activity was consistent with the speed of glucose consumption.
    24  Effects of Three Ethylene-action Inhibitors on Storage Quality of Actinidia arguta
    WANG Yue-hua DAI Hui-yuan FENG Xu-qiao XU Fang-xu LI Ke-qing WANG Shi-qi
    2014, 30(5):136-144.
    [Abstract](998) [HTML](0) [PDF 1023.49 K](759)
    Abstract:
    Effect of treatment with 1-pentylcyclopropene (1-PentCP) and 1-octylcyclopropene (1-OCP), as ethylene action inhibitors, on post-harvest physiology and storage quality of Actinidia arguta was investigated, and the same concentrations of 1-methylecyclopropene (1-MCP) was as control. Fruits were respectively fumigated with 0.4, 0.8 or 1.2 μL/L 1-PentCP and 1-OCP at room temperature for 20 h. After fumigation, the treated fruits were packed with 0.02 mm thickness PE fruit bags, and stored at room temperature [(20±1) ℃, RH 85~90%] for ripening evaluation. Respiration intensity, firmness, Vc content, titratable acid content, soluble solids, MDA content, activity of SOD and POD were determined every five days during fruit storage. The results showed that all treatments significantly delayed the appearance of respiratory rate and SOD, POD activity peaks, suppressed fruit softening, decreased titratable acid content and good fruit rate, increased soluble solids content, and inhibited MDA accumulation during storage. Moreover, 1.2 μL/L 1-MCP showed the best effect, followed by 0.8 μL/L 1-OCP and 1.2 μL/L 1-PentCP.
    25  Degradation of Imidacloprid and Acetamiprid in Aqueous Solution by Ultraviolet Irradiation
    LI Bin YIN Tao ZHANG Yuan-yan WANG Bing LU Hai-yan LI Di CHEN Zhong-zheng
    2014, 30(5):145-149.
    [Abstract](1067) [HTML](0) [PDF 558.16 K](889)
    Abstract:
    The effects of irradiation time, UV light intensity, pH of aqueous solution and initial concentration of imidacloprid and acetamiprid on both pesticides were studied. Results indicated that UV irradiation was effective in the degradation of imidacloprid and acetamiprid, while acetamiprid was more resistant to UV irradiation than imidacloprid. Furthermore, the degradation rate of both pesticides increased obviously with the increase of UV light intensity and irradiation time. The pH of the aqueous solution also showed significant influence on the degradation of acetamiprid, especially at alkaline and basic conditions. The maximum degradation rate of imidacloprid and acetamiprid were 100% and 46.30%, respectively, under 650 μW/cm2 UV light intensity for 30 min treatment with the initial concentration of 0.2 μg/mL (pH=6). Moreover, the degradation of imidacloprid and acetamiprid in aqueous solution followed the first-order kinetics well (R2≥0.95).
    26  Numerical Simulation of Hydrodynamic Cavitation Bubble Dynamics in Chitosan Solution
    HUANG Yong-chun YUAN Yuan WU Yu REN Xian-e GAO Hai-fang
    2014, 30(5):150-155.
    [Abstract](1070) [HTML](0) [PDF 634.67 K](716)
    Abstract:
    Based on equation of Gilmore, the dynamics of cavitation bubble in chitosan solution was investigated with the cavitation reactor of orifice. By numerical simulation the effect of solution concentration, solution temperature, pipeline diameter of downstream, gular diameter, inlet pressure, outlet pressure and initial bubble radius on the motion of cavitation bubble were discussed. The results showed that with the increase of concentration, the amplitude of cavitation bubble decreased, and Rmax/R0 was only 8 when the concentration was 1%. The amplitude of cavitation bubble increased when increasing of temperature and pipeline diameter of downstream, Rmax/R0 reached 215 at 60 ℃ and 335 with 100 mm pipeline diameter, respectively. Moreover, with the decreasing of gular diameter, the amplitude of cavitation bubble increased,while the gular diameter was 2 mm, and Rmax/R0 was 290. It was found that with higher inlet pressure and lower outlet pressure the amplitude of cavitation bubble increased. The investigation also indicated that smaller initial bubble radius improved the effect of cavitation in chitosan solution, and Rmax/R0 was 275 with radius of 5 μm.
    27  Preparation of Chitosan Gallic Acid Derivatives and Its Effect on Preservation of Fresh-cut Apple 2 (1.) (2.) Abstract: Key words:
    WU Hao ZHU Jun-xiang WANG Cheng-rong WANG Dong-feng
    2014, 30(5):151-257.
    [Abstract](1311) [HTML](0) [PDF 594.69 K](829)
    Abstract:
    According to the spoilage characteristics of the fresh-cut fruits and vegetables as well as structural features of chitosan (CTS) and gallic acid (GA), a kind of water-soluble CTS-GA was prepared by conjugating GA onto CTS and the effect of CTS-GA on preservation quality of fresh-cut apples was studied. The preliminary characterization of derivatives was studied through a series of testing methods, such as UV spectrum, FTIR spectrum, X-ray diffraction and HPLC, which shown that CTS-GA was formed by connecting amine groups from GA and hydroxyl groups from CTS. Some biochemical changes of fresh-cut apples coated with CTS, GA and CTS-GA were investigated. The results showed that after 4 d storage, polyphenols content of CTS-GA group was 1.29 ± 0.067 mg/g, which was significant higher than that of the blank group. Vc content of CTS-GA group was (1.36±0.03)?10-2 mg/g, higher than those of blank, CTS group and GA group, while PPO activity by CTS-GA treatment was 141.78 ± 4.31 U/g md, lower than the blank and CTS treatments. And the amount of microorganism in CTS-GA group was 5.406 ± 0.012 (lg CFU/g), obviously lower than the blank, CTS group and GA group.
    28  Effects of Aspergillus oryzae and Lactic acid bacteria Mixture on Wheat Koji-making
    CUI Chun PENG Huan-huan REN Jiao-yan ZHAO Hai-feng SU Guo-wan ZHAO Mou-ming
    2014, 30(5):156-160.
    [Abstract](1173) [HTML](0) [PDF 478.69 K](766)
    Abstract:
    The total bacterial count ,neutral protease activity, acid protease activity, total acid and the quality of fermented liquid in separated koji-making by Aspergillus oryzae (KP) and mixed koji-making by Aspergillus oryzae and Lactic acid bacteria (KR) were measured in this paper. The feasibility of multi-strains for koji-making was discussed to provide theoretical guidance for high quality of wheat tasty substance. The results showed that lactic acid bacteria and fungi grew well in KR system, and the count of lactic acid bacteria was reached 4.15×108 cfu/g after 12 h, while the growth of lactic acid bacteria had inhibitory action on fungi growth; the effect of mixed koji-making was better than separated koji-making in all respects. The neutral protease activity and acid protease activity of KR after 48 h fermentation were increased by 22.79% and 22.26% compared to KP, respectively. The total nitrogen content and amino acid nitrogen content in KR fermentation liquor were more than those in KP. However, the free amino acid content in KR system was more than that in KP after 60 days fermentation. Especially, glutamic acid was improved by 24.21%, making the fermentation liquid more obvious umami taste.
    29  Design of an Ohmic Heating Rate Control System for Food Processing
    XIE Zi-ming YANG Peng ZHANG Bo LI Xing-shu
    2014, 30(5):161-166.
    [Abstract](1200) [HTML](0) [PDF 573.52 K](741)
    Abstract:
    Heating rate has a great influence on food quality, ohmic heating provides a new heating method for food processing. However, the control of the heating rate has been considered as the difficulty in food industry for the constant voltage control applied in current ohmic heating systems. In this study, an ohmic heating rate control system was designed based on single chip microcomputer (SCM), including a single chip microcomputer, a voltage regulator circuit, a data acquisition circuit, function keys, a LCD screen and a heating cell. The system could not only set the heating rate, but also give a real-time monitoring to the temperature change during the heating process. Compound control method was adopted to maintain the heating rate at the setting value during heating. Afterwards, the system was tested by heating milk. The result showed a good linear relationship between the temperature of milk and time when setting the heating rate of 6 ℃/min, 8 ℃/min, 10 ℃/min and 12 ℃/min respectively, and the relative error between actual heating rate and setting value was 0.50~3.83%. The study can provide a reference for the control of heating rate in the ohmic heating process.
    30  Effect of Vacuum Cooling Treatment on Cold-chain Cooking Lettuce
    LI Bian-sheng ZHANG Xiao-yin RUAN Zheng HUANG Zhi-jun
    2014, 30(5):167-171.
    [Abstract](918) [HTML](0) [PDF 463.02 K](780)
    Abstract:
    Effect of vacuum cooling treatment on blanched cooking lettuce in tray was researched in this paper. Results showed that during the vacuum cooling process, the temperature difference between the center and the surface of cooked lettuce in tray was very small, not more than 1.73 ℃, and the temperature difference was only 0.23 ℃ when cooked lettuce temperature reached 10 ℃. In addition, the cooling rate of cooked lettuce per 1 kg increased with the increase of condensation temperature and cooling capacity. When cooling capacity increased from 37.5 kg to 150 kg, the cooling time was effectively shortened by 46.34%. Vacuum cooling also caused weight loss of cooked lettuce, and 1% of weight loss bring about 7 ℃ temperature decline. This research proposed a two-step vacuum cooling mode to effectively reduce energy consumption, which was only 47.29% of energy consumption of traditional vacuum cooling, and also lower condensate system equipment requirements by reducing the maximum condensate load.
    31  Quantitative Evaluation of Orange Juice Sensory Quality using Electronic Tongue
    HUANG Xing-yi DAI Huang XU Fu-bin YAO Li-ya HAN Fang-kai
    2014, 30(5):172-177.
    [Abstract](1312) [HTML](0) [PDF 474.78 K](978)
    Abstract:
    The sensory quality of three kinds of commercial available juice samples (20 brands) was evaluated by sensory evaluation combined with fuzzy mathematics. The samples were also analyzed by using the electronic tongue to obtain the corresponding electronic tongue data. The weight of each sensory indicator of the orange juice was determined using factor analysis method. The total score of the sensory quality was derived based on the weight of each sensory indicator. Subsequently, partial least squares (PLS) and back propagation neural network(BPNN) methods were contradistinctively used to establish the quantitative prediction model between sensor signals and the total score of sensory quality. The results showed that, sensory indicators of different types of orange juice could be effectively analyzed through factor analysis which accurately reflected the quality of the orange juice by the sensory evaluation results. The weights of color, aroma, acidity, sweetness, bitterness, body were 0.15, 0.06, 0.20, 0.24, 0.15 and 0.20, respectively. When the number of principal component was 3, the performance of BPNN model was better than PLS. The correlation coefficient (Rp) between the value predicted by the BPNN model and the reference value in the prediction set was 0.93 and the root mean square error of prediction (RMSEP) was 0.20. The results could provide a reference for intelligently evaluation of the sensory quality of orange juice.
    32  Reducing the Endogenous Protein Background of Aspergillus niger Cell Factory by RNA Interference Technology
    YIN Chao WANG Yun-yan HE Pan CHEN Jing WANG Bin PAN Li
    2014, 30(5):178-184.
    [Abstract](1218) [HTML](0) [PDF 589.47 K](760)
    Abstract:
    RNA interference (RNAi) technology was used to modify Aspergillus niger cell factory by reducing the expression level of its endogenous proteins. The effect of the specificity of reverse complementary sequence on RNA interference was investigated. Simultaneous interference of glucoamylase gene glaA, amylase gene amyA and protease regulator gene prtT was conducted in A. niger SH-2, and heterologous lipase tll was expressed in the RNAi-modified A. niger SH-2 host. Results illustrated that the reverse complementary sequence of different lengths exhibited RNA interference effect in different extent. RNAi vector pAMDS-RNAi-glaA388 with short reverse complementary sequence owned better interference effect (94.40%) than RNAi vector pAMDS-RNAi-glaA784 with long reverse complementary sequence (70.60%). Simultaneous interference of the three genes by pAMDS-multi-RNAi resulted in reduced expression of glaA (5.30%), amyA (17.10%) and prtT (34.60%) in A. niger SH-2. The expression of lipase tll in such RNAi-modified A. niger SH-2 reached the highest lipase activity of 97.27 U/ml, which was improved by 33.16% compared to tll expression in wild A. niger SH-2 (73.05 U/mL). Thus, RNAi technology could effectively reduce the expression background of endogenous proteins in A. niger SH-2, and could improve the expression level and stability of heterologous genes in A. niger cell factory.
    33  Preparation and Characterization of Soy Sauce Residue Dietary Fiber using Low Temperature Continuous Phase Transition Extraction
    ZHANG Yong ZHAO Li-chao HE Li-ping LAI Ying-yi YAO Xue-yi CAO Yong
    2014, 30(5):185-190.
    [Abstract](1487) [HTML](0) [PDF 664.22 K](847)
    Abstract:
    Soy sauce residues (SSR) were the main by-products of soy sauce fermentation, which contained a large amount of valuable components but failed to be reused reasonablely. Recycling the dietary fiber (DF) from SSR could make good use of the waste and remedy the issue of environmental hazards. The SSR insoluble dietary fiber (IDF) was prepared by a novel method of low temperature continuous phase transition extraction. Based on previous single factor experiments, the process parameters were optimized through the response surface methodology (RSM) for maximum IDF yield. Washing and enzymolysis were accompanied for purification. The functional characteristics of SSR IDF were investigated. In combination with the scanning electron microscopy (SEM), mechanism of the relationship between its microstructure and functional characteristics was explained preliminarily. Results showed that the best extraction conditions were 50 mesh raw material ,extraction regent n-butane solvent, extraction pressure 0.5 MPa, extraction temperature, 45 ℃ and extraction time 67 min, under which the oil content of obtained IDF was less than 1%. After purification, the purity could reach as high as 70.9±0.28%. Functional tests showed that SSR IDF had good features, and water holding capacity, expansibility and oil binging ability were 6.65±0.07 g/g, 5.83±0.11 mL/g and 2.23±0.03 g/g, respectively. Compared with commercially available soybean IDF products, the oil binging ability of SSR IDF was paticulary significant. From the SEM figures, the good functional characteristics of SSR IDF were related to its loose structure formed by the cellulose.
    34  Purification of Acidic Pectinases Produced by Aspergillus niger YY-22
    KANG Jing LIU Xiao-lan ZHENG Xi-qun TIAN Ying-hua DENG Yong-ping
    2014, 30(5):191-195.
    [Abstract](1130) [HTML](0) [PDF 511.26 K](793)
    Abstract:
    Purification of pectin lyase (PL), polygalacturonase (PG), and pectin esterase (PE) from the fermentation culture supernatant of Aspergillus niger YY-22 was investigated. All the three enzymes PL, PG and PE were precipitated by ammonium sulfate precipitation (0~65%). PE was further purified by hydrophobic interaction chromatography using Phenyl-Sepharose FF, while PG and PL were purified by Q-Sepharose HP ion exchange chromatography. The highest recovery of PL was obtained with 65% ammonium sulfate saturation precipitation. After three steps of separation, PL was purified 13.30 folds with a recovery of 33.05% and a specific activity of 79.37 U/mg.
    35  High Cell Density Fermentation of Lactobacillus salivarius XH4B Via pH Adjustment
    DU Xin-yong GAO Shi-yang LIU Tong-jie LIN Yong-hua HE Guo-qing
    2014, 30(5):196-201.
    [Abstract](1471) [HTML](0) [PDF 532.73 K](911)
    Abstract:
    Culture medium ingredients of nitrogen, carbohydrate and inorganic salts were optimized based on MRS for high cell density fermentation of Lactobacillus salivarius XH4B, including the adjustment of pH value as well as culture medium fed-batch. According to the biomass of L. salivarius XH4B, the best nitrogen and carbon sources were yeast extract and sucrose, respectively. Addition of sodium acetate (2%) and monosodium orthophosphate (0.6%) provided buffer effect for the pH value during incubation, these salts also contributed to LAB growth. By using the optimized PY-Suc culture medium, the biomass of L. salivarius XH4B reached 6.36~6.91 g/L, higher than that in MRS culture medium which was 5.01~6.30 g/L (P < 0.05). When lactic acid concentration exceeded 10 g/L, the accumulation of biomass ceased which meant the acid inhibited L. salivarius XH4B growth. Therefore, the optimization of MRS culture medium with sodium acetate and monosodium orthophosphate could buffer the pH value of culture medium, and new culture medium combined with fed-batch fermentation resulted in high cell density of L. salivarius XH4B.
    36  Effect of Thermal and High Pressure Treatment on Quality Characteristics of Dried Longan
    BU Zhi-bin TANG Dao-bang XIAO Geng-sheng XU Yu-juan YU Yuan-shan WEN Jing
    2014, 30(5):202-208.
    [Abstract](987) [HTML](0) [PDF 531.02 K](731)
    Abstract:
    The effects of different thermal and high pressure treatments on the color, texture, microstructure, total phenolic content (TPC) and antioxidant capacity of dried longan were investigated. The results showed that the physical parameters of the pulp of high pressure-treated longan only slightly changed compared with those of the unprocessed. High pressure treatment had no effect on yellowness/blueness (b*) and only slight effect on lightness/darkness (L*) and redness/greenness (a*). However, thermal treatment significantly influenced L*, a*, and b*, and caused higher degradation of hardness than that of high pressure treatment. The hardness of the longan pulp treated at 400 MPa for 10 min (232.86) was similar to that of the unprocessed (246.90) and was approximately two-fold higher than that of which treated at 80 ℃ for 60 min (118.87). The TPC of the thermal treated longan was significantly higher than those of the high pressure-treated and unprocessed, and the longan treated at 85°C for 60min had the highest TPC (535.53±14.40 mg GAE/100g DW). However, the 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals scavenging activity of the high pressure treated longan was significantly higher than that by thermal treatment (P<0.05). These results suggested that high pressure treatment effectively retained the color, texture, and antioxidant capacity of dried longan. High pressure treatment can be an efficient method to preserve dried longan quality.
    37  Fermentation Optimization of a Novel Recombinant Peroxiredoxin in Pichia pastoris for Zearalenone Detoxification
    CHEN Yi ZHU Zhen WU Hui ZHONG Feng TANG Yu-qian LAI Fu-rao
    2014, 30(5):209-217.
    [Abstract](1280) [HTML](0) [PDF 763.12 K](728)
    Abstract:
    In order to maximize the expression of a novel peroxiredoxin purified from Acinetobacter sp. SM04 in recombinant Pichia pastoris GS115/pPIC9K-A4-Prx, a single-factor test coupled with response surface methodology (RSM) was used to adjust the induction condition. The results showed that pH value, temperature and glycine concentration were significant influencing factors for A4-Prx expression, and the optimized induction conditions were as follows: pH 7, 0.11% glycine at 30 ℃, and the theoretic yield of A4-Prx could reach to 129.873 mg/L. Then further experiments under the optimized induction conditions illustrated that the concentration of the novel peroxiredoxin synthesized by Pichia pastoris GS115/pPIC9K-A4-Prx was 128.941 mg/L and had a significantly ZEA-degrading effect on DDGS and some food materials. This study laid the foundation for the high-density industrial fermentation of peroxiredoxin as well as the development of ZEA degradation.
    38  Effect of Heat Treatment on Browning Delaying and Phenolics Metabolism in Pericarp of Harvested Longan Fruit
    ZHAO Yun-feng LIN He-tong LIN Yi-fen CHEN Yi-hui MING Yan-lin
    2014, 30(5):218-224.
    [Abstract](1220) [HTML](0) [PDF 498.95 K](735)
    Abstract:
    Harvested longan is susceptible to pericarp browning, which is the most important factor affecting the quality and shelf-life of harvested longan. Heat treatment is an environment-friendly postharvest physical treatment, which can delay senescence and maintain quality of harvested fruits and vegetables. Effects of heat treatment on browning and phenolics metabolism in pericarp of harvested longan (Dimocarpus longan Lour.) were investigated in this paper. The harvested ‘Fuyan’ longans were treated with hot water at 50 ℃ for 10 minutes. Then they were dried, packaged and stored at (15?1) ℃. During storage, browning index, total phenolics content, activities of phenylalanine ammonialyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) in pericarp of harvested longan were determined. The results showed that as compared to the control fruits, the treatment with hot-water effectively reduced browning index, decreased PPO and POD activity, increased PAL activity, and remained higher total phenolics content in pericarp of harvested longan. Therefore, hot water treatment at 50 ℃ for 10 minutes can effectively reduce phenolics metabolism, thereby delaying the occurrence of browning in pericarp of harvested longan.
    39  Effects of Osmo-dehydration on Quality Attributes of Mangoes during Frozen Storage
    ZHAO Jin-hong WEN Xin PENG Yu MENG Xin-xin KANG Jia-qi NI Yuan-ying
    2014, 30(5):225-231.
    [Abstract](1274) [HTML](0) [PDF 542.15 K](732)
    Abstract:
    The effects of osmotic dehydration pretreatment on the freezing time and the quality attributes of frozen mangoes were investigated. Mangoes were dehydrated in mixed osmotic solutions (sucrose: glucose: fructose, 3.6:1:3) at three concentrations (30%, 40%, and 50%, m/m) for 2 h at 30 ℃, and then stored at -18 ℃for six months. The results revealed that the freezing time of the osmo-dehydrofrozen samples was 6.3~13.8% lower than that of the conventional frozen samples. Moreover, osmotic dehydration pretreatment improved the quality attributes of frozen mango in terms of color (total color difference reducing by 12.5~36.8%), hardness (increasing by 35.8~65.5%), drip loss (reducing by 11.3~44.5%) and vitamin C content (increasing by 21.2~134.8%) compared to the untreated ones after six months of frozen storage. Pretreatment with higher solution concentration showed smaller alterations in the quality attributes of samples. Through comprehensive analysis, dehydration in osmotic solution of 40% concentration was considered as the optimum pretreatment condition for frozen storage. In addition, the quality was better maintained in shaded side (firmer) of mangoes than the sun-exposed side (softer). With progression of storage time, mangoes pretreated by osmotic dehydration showed less reduction than the untreated ones. The current study indicates osmotic dehydration enhances both freezing rate and quality attributes of frozen mango.
    40  Production of Cookies with low N-(carboxyethyl) lysine Concentration by Addition of Antioxidant of Bamboo Leaves and Tea Polyphenols
    CHENG Lu OUYANG Li-qun ZHANG Ying
    2014, 30(5):232-238.
    [Abstract](1002) [HTML](0) [PDF 567.40 K](629)
    Abstract:
    N-(carboxyethyl) lysine (CEL) is a kind of advanced glycation end-products (AGEs) derived from Maillard Reaction. The effect of four natural sources of antioxidants, including water-soluble antioxidant of bamboo leaves (AOB-w), water-soluble tea polyphenols (TP-w), oil-soluble antioxidant of bamboo leaves (AOB-o) and oil-soluble tea polyphenols (TP-o) on CEL formation in cookies were investigated and the optimal mitigation strategy was summarized. The cookie dough with or without addition of the selected antioxidants was all baked at 205 ℃ for 11 min and the CEL contents in the final products were quantified by UPLC-MS/MS. The antioxidant activity, sensory evaluation and evaluation of other cookie quality attributes, including diameter, thickness, spread ratio, color, moisture content and texture were also performed. The results showed that the CEL content in control cookies was 11.97 ± 0.26 mg/kg. Four antioxidants at the addition level of 0.01~0.05% (m/m) effectively inhibited CEL formation with 7.29~67.25 % inhibitory rates. And the ddition of 0.03% (m/m) AOB-o induced the lowest CEL content (3.71 ± 0.01 mg/kg) in cookie. Further experiments confirmed that 0.03% AOB-o addition treatment significantly increased the antioxidant activity of cookies by DPPH and ABTS assays and kept the original quality attributes and sensory properties of cookies.
    41  Effect of Super Chilling Combined with Modified Atmosphere Package on Beef Quality
    SUN Tian-li YUE Xi-qing ZHANG Ping LI Jiang-kuo ZHANG Peng
    2014, 30(5):239-244.
    [Abstract](1211) [HTML](0) [PDF 401.85 K](737)
    Abstract:
    Beef was stored in freezing point temperature combining with modified atmosphere package. The characters including total counts, total volatile basic nitrogen (TVB-N), color difference (L* value and a* value), drip loss and sensory evaluation (red color and off-odor) were analyzed regularly during storage. The results indicated that shelf life of the 50% O2+50% CO2 group and the 30% O2+70% CO2 group were at least 4 days longer than the control group and 80% O2+20% CO2 group. There was no difference between TVB-N values in different groups. High concentration oxygen increased drip loss during storage; it kept good color in the initial period, but became worse in later period; meanwhile, it accelerated the spoilage of beef and the appearance of off-odor. High concentration carbon dioxide deteriorated color but delayed beef spoilage. In summary, the combination of super chilling technique and 50% O2+50% CO2 package was useful for beef storage.
    42  Enzymatic Hydrolysis Coupled with Autoclaving-cooling Cycles for the Preparation of Resistant Starch
    WU Heng YIN Xiu-hua XIE Li-yan XIAO Man-feng LIN Ying
    2014, 30(5):245-250.
    [Abstract](1100) [HTML](0) [PDF 618.35 K](751)
    Abstract:
    Maize starch was used as raw material to prepare resistant starch by enzyme method coupled with autoclaving–cooling cycles. Hydrolysis and debranching degree of starch, amylose content, resistant starch content and thermodynamic stability were detected in the experiment. The thermodynamic characteristics, particle morphology of resistant starch were analyzed by differential scanning calorimeter (DSC) and scanning electron microscope (SEM), respectively. The results showed that the hydrolysis degree of starch was increased significantly after enzymolysis of thermostable α-amylase. Resistant starch content of coupled thermostable α-amylase with autoclaving-cooling cycles was 10.51% to 12.16%. Debranching degrees, resistant starch and amylose content were declined significantly with autoclaving-cooling cycles increasing before digestion of pullulanase, but thermal stability of the resistant starch was increased. The resistant starch content reached the highest value (17.94%) after digestion of pullulanase before three times processing of autoclaving-cooling cycles. Gelatinization peak temperature of resistant starch was from 119.5 ℃ to 121.1 ℃. The gelatinization enthalpy was increased with resistant starch content increasing, and the granule shape of resistant starch was of irregular gravel type.
    43  Nutrition Quality Evaluation of Main Walnut Cultivars in Xinjiang
    LUO Yu-nian TIAN Ying-zi YING Li MA Qian-li WANG Qing-qing ZHAO Cui
    2014, 30(5):258-261.
    [Abstract](1463) [HTML](0) [PDF 383.50 K](688)
    Abstract:
    For the development of rich walnut resources in Xinjiang, the content of protein and fat, the composition and content of fatty acids and amino acids of seven main walnut cultivars from two walnut main producing areas (Wensu, Yechen) in Xinjiang were studied, and the protein nutrition quality was evaluated by SRCAA. The result showed that the average content of protein and fat was 19.35% and 60.91%, respectively. Compared to other areas in China, walnut from Xinjiang had a feature of high protein and low fat. The composition of fatty acids was palmitic acid, oleic acid, stearic acid, linoleic acid, α-linolenic acid. The average content of unsaturated fatty acids was 90.45%, and polyunsaturated fatty acid was 66.19%. The ratio of stearic acid (ω-6) - linoleic acid (ω-3) was in line with WHO recommendations which indicated good oil quality. The total content of amino acid was high with all amino range. Essential amino acid content was 27~30% of the total amino acid content, and the value of SRC ranged from 68.85% to 78.40%. The first limiting amino acid was Lys. The main walnut cultivars in Xinjiang were superior varieties that with a good quality of oil and protein.
    44  Screening Detection of Bt Genes in Genetically Modified Crops Using a Multiplex PCR Assay
    LI Fei-wu YAN Wei LONG Li-kun LI Cong-cong ZHANG Shi-hong ZHANG Ming
    2014, 30(5):262-266.
    [Abstract](1311) [HTML](0) [PDF 549.27 K](708)
    Abstract:
    Since Bt genes were widely used in insect-resistant transgenic crops, they became the most important target genes in screening genetically modified food. Based on nucleotide sequences analysis, eight common Bt genes (cry1Ab, cry1Ac, cry1Ab/Ac, cry1A.105, cry1Ac-M, cry2Ab, cry3A and cry3Bb) in transgenic crops were divided into cry1A, cry2A and cry3A groups. To detect three groups of Bt genes, degenerate primers for cry1A group and specific primers for cry2A and cry3A groups were designed according to the consensus sequences of each group, and three singlet PCR methods for each group respectively were established after testing specificity and sensitivity in this study. In addition, using the three pairs of PCR primers, a triplex PCR method also established to screen the three groups of Bt genes simultaneously. The results revealed that these methods could accurately detect the targeted Bt genes from the various transgenic samples, and the detection sensitivity was up to 0.1%. As the method established in this study showed highly specific and sensitive, it would be a good prospect in the screening of genetically modified organism.
    45  Development of a Colorimetric Sensor Array for Rapid Discrimination of Chinese Liquors
    HUO Dan-qun SONG Chun-xia LI Jun-jien WANG Zhi-hong LI Yong-jiao ZHOU Jun LIU Shi-long HOU Chang-jun
    2014, 30(5):267-272.
    [Abstract](1156) [HTML](0) [PDF 686.80 K](732)
    Abstract:
    The constitution of main flavor components resulted in different types of Chinese liquors. Focused on the main flavor components, a new 5×4 colorimetric sensor array was constructed to differentiate 15 different liquor samples after selective screening of 20 specific sensitive materials. The new sensor showed good accuracy to discriminate all liquor samples which was closely related to the main flavor components in the liquors. Data analysis was performed by principal component analysis (PCA), which suggested that the contribution rate of the main flavor components followed a descending order of esters and aldehydes (34.5%), acids (19.2%) and alcohols (11.9%). Further Hierarchical cluster analysis (HCA) elucidated that analogous liquors sample were correctly classified into one group, and those of the same type from different brands lay closer and were more easier to be clustered. Besides, the clusters indicated good accordance to the similarity of the main flavor components in the liquor, and the distance of different clusters indicated a close relationship between the liquors and raw materials, diastatic fermented agent and brewing process.
    46  Determination of Monascus Pigments in Red Yeast Rice Using Near Infrared Spectroscopy
    ZHANG Xiao-wei WANG Jia-hua WANG Chang-lu LI Zhen-jing CHEN Mian-hua
    2014, 30(5):273-279.
    [Abstract](1373) [HTML](0) [PDF 656.67 K](911)
    Abstract:
    NIR combined with chemometrics was proposed to predict orange, red and yellow pigments content in red yeast rice. Stepwise multiple linear regression (SMLR), partial least squares (PLS) and principal component regression (PCR) were used to built prediction models. Correlation coefficient of calibration (R), root mean square error of calibration (RMSEC), root mean square error of predication (RMSEP) and ratio of prediction to deviation (RPD) were suggested to evaluate the performance of models. The results showed that MSC and SNV could eliminate spectral scattering causing by uneven red yeast rice particles. Derivative treatment could eliminate the baseline drift. Three models for orange, red and yellow pigments all had good robustness. The three models were used to predict unknown monascus pigments, which all had better performance of prediction (RPD, 2.86~5.39). Therefore, the models could be used to accurately predict monascus pigments. The study shows that near-infrared spectroscopy technology has the potential beneficial for measuring the pigments content in red yeast rice online and conducive to intelligent quality control.
    47  Comparative Study of Extraction Conditions and GC-MS Analysis of Hydrocarbons from Botryococcus sudeticus
    WEI Dong XIONG Shuang
    2014, 30(5):280-286.
    [Abstract](905) [HTML](0) [PDF 472.98 K](671)
    Abstract:
    Based on ANOVA analysis of the solvents, temperatures and time, the optimal conditions for hydrocarbons extraction from small amount of algal powder of Botryococcus sudeticus were obtained as follows: 40 mg algal powder suspended in n-hexane was ultrasonicated at 35 ℃ and 70 Hz for 30 min, then extracted at 35 ℃ for 10 hours. The highest yield of hydrocarbons accounted for 2.95 ‰ of dry weight was obtained under above conditions. The programmed procedure for GC-MS analysis was compared and optimized, and long-chain alkanes from C22 to C31 were found as the dominant hydrocarbons in the lyophilized powder of Botryococcus sudeticus from the cells in exponential phase. They were consisted of docosane, tetracosane, pentacosane, 9-octylheptadecane, heptacosane, octacosane, squalene and hentriacontane, with contents of 50.40, 209.17, 351.45, 472.38, 540.48, 542.24, 473.60 and 306.86 μg/g of dry weight, respectively. This extraction and analysis process have advantages of fewer amounts of sample required, time-saving, high yield and simple operation, which is a rapid and high efficient method for the analysis and detection of hydrocarbons from Botryococcus sudeticus.
    48  Changes of the Active Ingredients of Mangostana Wine during Fermentation and Aroma Components of Finished Wine
    YU Li-mei LIU Jun-mei FENG Wei-hua BAI Wei-dong
    2014, 30(5):287-291.
    [Abstract](1453) [HTML](0) [PDF 533.91 K](770)
    Abstract:
    In order to discuss the active ingredients of mangosteen wine during fermentation process and aroma contribution in the final product, Garcinia Mangostana was used as raw material to produce fruit wine. The changes of active ingredients such as flavonoids, polyphenols and polysaccharides were studied during the fermentation process, and aroma volatile components of two kinds of finished wine (fruit wine with shell and flesh only) were also analyzed. The results showed that the content of flavonoid and polyphenol increased in the main fermentation stage and then slowed down and remained steady in later fermentation, while the total sugar content decreased during the whole fermentation process. The flavonoid content of the flesh wine was attained stable between 3.6 and 4.0 μg/mL, and polyphenol content was about 30.03μg/mL in the end fermentation. Liquid chromatography showed that polyphenols of two kinds of wine had significant difference in the fermentation stage. The aroma composition analysis showed the relative content of esters, alcohols and carboxylic acids were 42.32%, 57.32% and 0.37%, respectively, in fruit wine with shell, and 30.13%, 69.63% and 0.17% in flesh wine, respectively. Different aroma substances contributed to the aroma of the two kinds of fruit wine.
    49  Discrimination of the Adulteration of Commercial Vegetable Oils by Stable Carbon Isotope Analysis
    GUO Lian-xian LIANG Fu-rui LIANG Yi WANG Jiang-hai
    2014, 30(5):292-296.
    [Abstract](1339) [HTML](0) [PDF 325.21 K](786)
    Abstract:
    This paper aims to develop a new discrimination method for the adulteration of commercial edible vegetable oils from Guangzhou market by previously-established markers of fatty acid composition and stable carbon isotope ratios. 18 vegetable oils, including camellia oil, peanut oil, sunflower oil, maize oil and olive oil were purchased from the supermarket in Guangzhou. Then, their fatty acid compositions were determined by chromatography mass spectrometry (GC-MS); the stable carbon isotope ratios (?13C) of bulk oil samples and their individual major fatty acids were determined by elemental analysis-isotope ratio mass spectrometry (EA-IRMS) and gas chromatography-isotope ratio mass spectrometry (GC-IRMS). The measured data were compared with previously-reported discrimination markers. The results indicated that the quality of the commercial vegetable oils from market was overall high, but the adulteration still occurred in 50% of the samples. Obviously, the adulteration of vegetable oils may be sensitively discriminated by the markers of stable carbon isotope ratios and fatty acid composition.
    50  Rapid Determination of Benzo(a)pyrene in Seafood by Second-derivative Constant-energy Synchronous Fluorescence Spectrometry
    WU Ping-ping LI Xiu-ying LI Xiu-ying LUO He-dong LIU Qian LI Na LI Yao-qun
    2014, 30(5):297-300.
    [Abstract](1027) [HTML](0) [PDF 506.58 K](689)
    Abstract:
    Polycyclic aromatic hydrocarbons (PAHs) in seafood samples were ascribed to water pollution, while benzo(a)pyrene was recognized as an indicator of PAHs. A simple and rapid analytical method was developed by combining microwave-assisted pretreatment with second-derivative constant-energy synchronous fluorescence scanning technique for the determination of the benzo(a)pyrene content in seafood samples. The samples were firstly processed with microwave pretreatment, and the extractions were vaporized and redissolved into dichloromethane for further detection. According to the specific spectral properties of seafood samples, peak-to-derivative baseline measurement was used to read the fluorescence data, and standard addition method was applied to the quantitative analysis of seafood samples. The whole spectroscopic scan cost only 1 min. The recoveries ranged from 80.5% to 118.2% for seafood samples and the detection limit was 0.10 μg/kg with linear range from 0.34 to 250 μg/kg. The results obtained with this method were in consistence with those of HPLC-FL method. The satisfactory results acquired by using this method to analyze a certified reference material with a relative error of 7.1% from the certified benzo(a)pyrene concentration.
    51  Mixed Culture Fermentation of Pumpkin Juice and Its Aroma Analysis
    ZHOU Chun-li LIU Wei LI Hui ZHAO Jing YUAN Chi LI Quan-hong
    2014, 30(5):301-310.
    [Abstract](1359) [HTML](0) [PDF 581.93 K](1019)
    Abstract:
    The aromatic compounds in the mixed strains fermentation pumpkin juice were discussed in this paper. They were evaluated by solid phase micro-extraction (SPME) combined with gas chromatography mass spectrometry (GC-MS) and gas chromatography olfactometry (GC-O) methods, and the relative contents were determined by area normalization. 58 and 41 compounds were seperated from fresh pumpkin and pumpkin juice, respectively, and 19 common volatile components were detected. The aromatic compounds with higher contents included hexanal, 3-methyl-butanal, nonanal, pentanal, heptanal and cyclobutanol in fresh pumpkin. 51, 36 and 45 aromatic compounds were identified from Lactic acid fermentation, yeast fermentation and mixed fermentation pumpkin juice, respectively. The main aromatic compounds by mixed fermentation pumpkin juice were ethanol, 3-methyl-1-butanol, ethyl caprylate, 1-heptanol, 2,3-butanedione and 2-methyl-1-propanol. Compared with the pumpkin juice fermented by only lactic acid bacteria or yeast, the majority of aromatic compound was ethanol in mixed fermentation pumpkin juice.The three fermentation pumpkin juices had similar major aromatic compounds, but showed significant difference in trace amounts . Therefore, mixed fermentation pumpkin juice was not only similar to those single strain fermentation, also formed unique aroma.
    52  Advanced Research on Antifungal Lactic acid bacteria of Food Bio-protective Agent
    BAI Feng-ling LI Jian-rong
    2014, 30(5):311-319.
    [Abstract](1902) [HTML](0) [PDF 409.25 K](949)
    Abstract:
    Yeasts and moulds can cause serious spoilage of all kinds of foods and agricultural products, including fruits, vegetables, cereal, dairy products and meat and lead to sizable economic losses. Moulds also produce health-damaging mycotoxins such as aflatoxins, trichothecenes, fumonisins, ochratoxin A and patulins, and possibly bring great hidden danger to food security. Consumer demands for minimally processed foods and reduced use of chemical preservatives have stimulated to research on antifungal bio-protective agents. Lactic acid bacteria (LAB) has been widely applied as bio-protective agents in all kinds of foods, because of their effective antagonistic activity against pathogenic bacteria and spoilage microorganisms in food by ecological niche competition in which forms an acidic environment and produces various antimicrobial end-products. This review summarized the screenings and potential applications of antifungal Lactic acid bacteria in the preservation of food, and antifungal metabolites from lactic acid bacteria and their inhibitory mechanisms. Some tendencies were presented and discussed, aiming to supply reference to the further research in this paper.

    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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