Volume 30,Issue 1,2014 Table of Contents

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  • 1  In Vitro Antioxidant Activities and Hepatoprotective Effects of Polysaccharides from Allium macrostemon Bunge
    ZHANG Zhan-jun WANG Fu-hua ZENG Xiao-xiong
    2014, 30(1):1-6.
    [Abstract](1540) [HTML](0) [PDF 543.31 K](784)
    Abstract:
    The in vitro antioxidant activities of polysaccharides from Allium macrostemon Bunge were evaluated by radical scavenging activity, and three kinds of polysaccharides were extracted from fractional alcohol precipitation. The preliminary structures and compositions were analyzed by infrared spectroscopy. During in vitro antioxidant assay, AMP40 exhibited the strongest scavenging activity than the others in scavenging hydroxyl radical (?OH) and superoxide radical (O2-?). The in vivo antioxidant activities of crude AMP were investigated that against CCl4-induced acute liver damage in Kunming mice. The results showed that pretreatment with AMP40 could markedly improve the activities of those antioxidant enzymes in CCl4-treated mice. The antioxidative system tended to be normalized by the protective action of AMP40, and scavenging activity of AMP40 was in a dose-dependent manner. It also showed that antioxidant properties directly related to the molecular weight and the uronic acid content of polysaccharide.
    2  Effect of Polysaccharide From Paphia undulate on Blood Lipid of Hyperlipidemia Model Mice
    FAN Xiu-ping DONG Xiao-jing WU Hong-mian ZHONG Min HU Xue-qiong
    2014, 30(1):7-10.
    [Abstract](985) [HTML](0) [PDF 512.66 K](661)
    Abstract:
    Polysaccharides (PUG-1) were prepared from Paphia undulate by protease hydrolysis, and the effect of PUG-1 on blood lipid of hyperlipidemia model mice was investigated. PUG-1 was separated to two fractions named PUG-1a and PUG-1bby DEAE-52-cellulose exchange chromatography, with relative molecular weight of 30.0 kDa and 10.0 kDa respectively. The glycosaminoglycan contents of PUG-1a and PUG-1b were 68.3% and 62.8%, respectively. And the ratio of gucosamine, galactosamine, hexuronic acid and sulfate in PUG-1a and PUG-1b were 1.8:0.9:1.3:1.0 and 1.5:0.8:0.9:1.0, respectively. FT-IR spectrum showed the characteristic absorption of glycosaminoglycan. The hyperlipidemia model mice were established by feeding with high fat diet (basal laboratory diet with 2% cholesterol). Meanwhile, the mice were administered PUG-1 orally at dosage of 400, 200 and 100 mg/kg?d, respectively. Normal control and positive control group were treated with distilled water and Simvastatin (0.2 mg/kg?d). The contents o f total cholesterol (TC), triglyceride (TG), low density lipoprotein-cholesterol (LDL-c) and high density lipoprotein-cholesterol (HDL-c) in serum were examined after four weeks. The PUG-1 decreased the contents of TC, TG and LDL-c in serum and increased HDL-c significantly (p<0.05 or p<0.01) in the experimental hyperlipidemic mice. These results suggest that PUG-1 can modulate the level of blood lipid in hyperlipidemia mice and can be prevention of atherosclerosis.
    3  Relationship between Enzyme Activity and Biochemical Changes of Pinctada martensi Koji-making
    CUI Chun LAI Chen-rong XIA Ke-sheng ZHAO Hai-feng ZHAO Mou-ming
    2014, 30(1):11-15.
    [Abstract](1053) [HTML](0) [PDF 527.93 K](744)
    Abstract:
    The solid-state fermentation of Aspergillus oryzae cultivated with Pinctada martensi were studied. The various biochemical changes were detected and compared in different growth conditions in order to explore the relationship between metabolism and protease activity during the fermentation. Results showed that the weight of koji and water content decreased with the extension of fermentation time, and the dry matter showed the same trendency. During the fermentation, the temperature of koji increased firstly, and then decreased. The metabolic change of nutritional material consumption was divided into 4 stages with 24 h being of the key point, and after then the citric acid cycle became the main way of glucose metabolism. During the period of 24~36 h, the reducing sugar and amino acids were rapidly absorbed and reached the highest values. While the protease activity was at its highest value at 40-46 h. Therefore, the secretion of enzyme lagged than the consumption of materials in metabolism. Glycometabolism was closely correlated with neutral protease activity (Pearson=-0.943). Meanwhile, the protease activity was increased by 26.81% after adding α-amylase at the beginning of the fermentation.
    4  Effects of 1-methylcyclopropene (1-MCP) Treatment on Postharvest Physiology and Storage Quality of Carambola Fruits
    CHEN Yi-hui ZHANG Hua LIN He-tong LIN Yi-fen LIN Yuan
    2014, 30(1):16-21.
    [Abstract](1376) [HTML](0) [PDF 518.20 K](796)
    Abstract:
    Effects of 1-methylcyclopropene (1-MCP) on postharvest physiology and storage quality of ‘Xiangmi’ (Averrhoa carambola Linn. cv. Xiangmi) fruit were investigated. The harvested ‘Xiangmi’ fruits were treated with 0.6 μL/L 1-MCP for 12 hours, then the fruit were stored at (15±1) ℃ and 90% relative humidity. During storage, the changes of respiration rate, cell membrane relative permeability, contents of chlorophyll and carotenoid in pericarp, fruit firmness, total soluble solids and titratable acid content, good fruit rate, weight loss and sensory evaluation of quality of fruit were determined. The results showed that compared with the control fruit, 1-MCP treatment had obvious effects on the fruit by lowering respiration rate and respiratory peak value, inhibiting apparent color change, keeping higher firmness and titratable acid content, ande delaying the increase of cell membrane relative permeability, weight loss and fruit decay. Moreover, the good fruit rate was 78% by 1-MCP treated on the 20th day of the storage, while only 63% in control fruit. Therefore, 0.6 μL/L 1-MCP treatment could delay ripening and senescence of harvested ‘Xiangmi’ fruit and maintain fruit storage quality.
    5  Free Radicals Scavenging and Inhibition of Lipid Peroxidation Activity of the Enzymatic Acetylated EGCG
    ZHU Song MA Chao-yang AI Lian-zhong LOU Zai-xiang WANG Hong-xin
    2014, 30(1):22-27.
    [Abstract](1171) [HTML](0) [PDF 580.79 K](927)
    Abstract:
    (-)-Epigallocatechin-3-O-gallate (EGCG) acetylated derivatives were prepared by enzymatic acylation with vinyl acetate and catalyzed by Lipozyme RM IM in acetonitrile. Liquid chromatography tandem mass spectrometry (LC-MS/MS) and infrared (IR) spectrometry were used to confirm the acylated EGCG product. It indicated that the product was a mixture of different degrees of substitutions. IR spectra showed that the acetylated EGCG derivatives had two strong absorption peaks of carbonyl and methyl, and the other parts were similar to EGCG. The antioxidant activity of acetylated EGCG in vitro was investigated by measuring scavenging effects of superoixide anion (O2-?), hydroxyl radical (?OH) and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical. The acetylated EGCG was found to have good scavenging effects on O2-?, ?OH and DPPH? and the 50% inhibitory concentrations (IC50) were 0.52 mg/mL, 0.43 mg/mL and 11.5 mg/L, respectively. Anti-lipid peroxidation experiments showed that the inhibition rates of malonyldialdehyde (MDA) formation in rat liver mitochondria and hemolysis for rat red blood cells induced by H2O2 were 61.11% and 93.54% , respectively, when acetylated EGCG concentration was 320 mg/L. Therefore, acetylated EGCG had strong antioxidant activity in vitro, and their antioxidant activity is positively related to their concentration.
    6  Adsorption Equilibrium and Kinetics of Fe3+ by Sugar Beet Pulp
    ZHAO Yi YU Shu-juan ZHU Si-ming MAO Jun
    2014, 30(1):28-32.
    [Abstract](1168) [HTML](0) [PDF 515.60 K](733)
    Abstract:
    Sugar beet pulp (SBP) is rich in dietary fiber and is the major by-product in sugar industry, which is often used to treat the pollution of heavy metals and pigments in wastewater because of its strong combining capacity of cations. The effects of sorbent dosage, sorbent particle size, contact time, and initial concentration of Fe3+ on adsorption of the necessary macro element Fe in body by SBPwere studied andthe adsorption equilibrium and kinetics models were also conducted. Results showed that the uptake of Fe3+ increased with decreasing particle size and increasing initial concentration of Fe3+; the sorption process reached equilibrium after 80~100 min of contact; 65% of Fe3+ was removed by using 5g/L of SBP (particle size 75 μm~150 μm) with 93% water and 0.001 mol/L Fe3+ at 25 ℃ for contacting 100 min; the pseudo second-order kinetic model could be described by the adsorption process(R2≥0.99); and the adsorption equilibrium data fitted well with the Freundlich adsorption isotherm equation, showing the adsorption of Fe3+ by SBP was not in monomolecular layer type. SBP, which is cheap and highly selective, seems to be a promising substrate to develop organic iron agent with high bioactivity.
    7  Irreversible Sediment Formation in Green Tea Concentrate
    XU Yong-quan CHEN Gen-sheng HU Xiong-fei DU Qi-zhen HONG Zhi-yong YIN Jun-feng
    2014, 30(1):33-37.
    [Abstract](1580) [HTML](0) [PDF 486.56 K](924)
    Abstract:
    In order to study the chemical constitutes and forming process of irreversible sediment in green tea concentrate, the main chemical components and the forming of irreversible and reversible sediment at different storage periods (0~20 d, 20~180 d, 180~250 d) under low-temperature conditions were studied and compared. The results showed that irreversible sediment contained large amounts of mineral elements and oxalic ion, while reversible sediment was comprised of polyphenols, carbohydrates, caffeine, protein and flavones. Most of sediment in green tea concentrate was reversible tea sediment. During storage of green tea concentrate, sediment contents increased, and most of the reversible and irreversible tea sediment were formed during 0~20 d. Elements as Mg, Mn, Ga, Ni and Zn mainly were participated in the formation of irreversible sediment during 0~20 d, Fe and Cu were during 20~250 d, and Al and Ca were during 180~250 d. In addition, the combination of ellagic acid and protein were also confirmed to form irreversible sediment. This research revealed that irreversible sediment was mainly composed by insoluble oxalates.
    8  Effects of Legume Seed Flours on the Formation of Acrylamide and 5-Hydroxymethylfurfural (HMF) in a Model Reaction System
    CAI Yun CHANG Sam K C OU Shi-yi LIU Zhi-sheng
    2014, 30(1):38-43.
    [Abstract](1311) [HTML](0) [PDF 363.96 K](660)
    Abstract:
    Seven legumes (black soybean, chickpea, green pea, lentil, mung bean, yellow pea, and soybean) were used to test their effect on the formation of acrylamide and HMF in an asparagines/glucose model reaction system. Five varieties inhibited the formation of acrylamide (from 10.3% to 55%) but all varieties improved the formation of HMF. Defatting legumes flour showed improved inhibition capacity for acrylamide formation, and a dose-effect relationship was observed for all the tested materials when 0.2, 0.4, and 0.6 g of the defatted flours were added. When the defatted-dehulled flours were added, acrylamide production was further inhibited in some treatments along with an increase in the HMF content. However, the addition of 0.2 g of hull flour from four varieties also decreased the acrylamide content and significantly increased browning. Defatted legume flours from five legumes eliminated the formed acrylamide, ranging from 28.5% of soybean to 5.9% of mung bean. Addition of the defatted-dehulled flours from four varieties also resulted in pH decrease and glucose depletion. Most of the 39 treatments studied in this research showed a negative relationship between the contents of acrylamide and HMF.
    9  Establishment of the Cell Suspension Culture System of Cyclocarya paliurus and Matrix Consumption Laws
    CHEN Ji-guang SHANGGUAN Xin-chen YIN Zhong-ping REN Min-hong FU Xiao
    2014, 30(1):44-49.
    [Abstract](1322) [HTML](0) [PDF 630.18 K](660)
    Abstract:
    Cyclocarya paliurus is a unique plant resource in China. As one of the threatened plants, it has been received increasing attention. Cyclocarya paliurus is rich in flavonoids, polysaccharides, triterpenoids and other bioactive substances. However, the its application is restricted for the problems of its sexual and asexual reproduction. Nowadays, employing cell culture technology to get more bioactive compounds is a vital way to make full use of Cyclocarya paliurus. The suspension cell system influenced by the factors of inoculum density, the liquid medium volume per flask, pH, sucrose concentration, phytohormone combinations and the consumption rules for culture medium in the process of cells proliferation were studied. The dynamic curve of cells proliferation and total flavonoids, polysaccharides and triterpenoids synthesized in the suspension cell system were measured. The result revealed that the preferable conditions for suspension cells proliferation were as follows: MS medium supplemented with 1.0 mg/L KT, 0.1 mg/L 2,4-D, 0.5 mg/L NAA and sucrose 30 g/L. The optimum culture situations were seed volume 8%, liquid medium volume per flask 40% and initial pH 5. Moreover, the proliferation of Cyclocarya paliurus cells correlated closely with the consumption of sugar, nitrate and phosphate. After 8 days, sugar and phosphate in the medium were absorbed completely, while NH4+ was utilized faster than NO3-, and the concentration of NH4+ showed a linear decreasing trend.
    10  Effects of Three Natural Starches Excipients on Quality Characteristics of Rice Vermicelli
    WANG Yong-hui TANG Xiao-jun ZHANG Ming-wei WEI Zhen-cheng ZHANG Ye-hui
    2014, 30(1):50-54.
    [Abstract](1287) [HTML](0) [PDF 505.96 K](738)
    Abstract:
    The effects of natural starches from mung bean, corn and potato as excipients on quality characteristics of rice vermicelli in cooking and texture were investigated. The results showed that adding appropriate amount of starches from mung bean, corn and potato could significantly improve cooking characteristics and textural properties of rice vermicelli. Rice vermicelli had higher cooking quality when adding 0.5~1.5% of bean starch and the textural properties obviously promoted when t adding 1% starch. Meanwhile, adding 6% of corn starch and 2% of potato starch resulted in better cooking quality ofrice vermicelli also . When the additive amounts were 4~6% and 2~3% respectively, the rice vermicelli texture was also improved. Therefore, the cooking characteristics and textural properties of rice vermicelli could all improved significantly when the starch of bean, corn and potato adding amount up to 1%, 6% and 2%.
    11  The Correlation of Protein Structural Features and Properties of Dry Noodles Added with SPI
    FENG Lei LI Meng-qin LI Chao-ran
    2014, 30(1):55-62.
    [Abstract](1371) [HTML](0) [PDF 719.10 K](846)
    Abstract:
    The properties and protein structural features of dry noodles added with soybean protein isolate (SPI) were analyzed by texture analysis,NMR and FT-IR technologies. The results showed that SPI had significant influence on texture and cooking properties of dry noodles. T21 of dry noodle added with SPI was increased while T22 was decreased. When addition level of SPI was increased, hydrosulphonyl content of dry noodle fluctuated increased (10.53~14.22 μmol/L) and disulfide bond content decreased in volatility (12.26~6.56 μmol/L). Meanwhile, the characteristic peaks in the secondary structures of protein, including anti-parallel β-sheet, aggregated strands, β-strand, α-helix, β-sheet, extension and intramolecular coupling were appeared. With SPI content increased, the percentage of protein secondary structures displayed significant difference. The bending distance to dry noodle and percentage of characteristic peak in protein secondary structures of anti-parallel β-sheet, aggregated strands, and β-strand were highly significant positive correlation. The percentage of characteristic peak in protein secondary structure including α-helix, β-sheet, reverse parallel structure was negative correlation.
    12  Effects of Paenibacillus brasilensis YS-1 Crude Extracts on Storage of Nanfeng Mandarin
    GUO Juan-hua CHEN Ming CHEN Chu-ying TU Qi-hong CHEN Jin-yin
    2014, 30(1):63-68.
    [Abstract](1389) [HTML](0) [PDF 565.81 K](852)
    Abstract:
    The fruits of Nanfeng mandarin “97-2” were treated with the crude extracts of Paenibacillus brasilensis YS-1, then stored at 5±1 ℃ for 100 days. The postharvest physiology and storability of fruits were investigated and compared with 500-fold dilution of an antistaling agent named “Kelixian” treatment and distilled water as control. The result showed that the treatment of crude extracts of YS-1 and 500-fold dilution of “Kelixian” effectively inhibited the growth of P. intalicum, and the inhibition diameters were 20.20 cm and 51.12 cm respectively. The rotting rate and weight loss rate of fruits which treated with crude extracts of YS-1 were 20.67% and 3.75%, which significantly higher than distilled water but lower than “Kelixian” treatment. And the contents of total soluble solids, total sugars and Vc were increased to 15.70%、19.57% and 24.58%, respectively. It also delayed the decline rate of total soluble solids and contents of total sugars and titratable acids, while effectively kept the storage quality of the fruit. In addition, crude extracts of YS-1 treatment decreased respiration rate and MDA content in the middle and later periods of storage, and increased the SOD, POD and PAL activities. It indicated that crude extracts of P. brasilensis YS-1 treatment can keep the quality of fruit, improve the ability of disease resistance, and delay the fruit senescence of Nanfeng mandarin during storage.
    13  Characterization of Polyphenol Oxidase Extracted from White Radish
    HUA Ying SHEN Guo-hua LIU Da-qun
    2014, 30(1):69-73.
    [Abstract](1526) [HTML](0) [PDF 478.13 K](772)
    Abstract:
    As the second major vegetables in China, the mainly browning of white radish during its storage and processing was enzymatic browning. A comprehensive and systematic understanding of polyphenol oxidase (PPO) in white radish and its suppression means is of great significance to promote quality and commercial value of white radish and its products. In this study, the fresh white radish was taken as the material, the PPO was extracted and characterized. The results showed that,with catechol as substrate, the optimum pH and reaction temperature of the enzyme were 6.0 and 40 ℃, respectively. Km and Vmax were 53.8 mmol/L and 588 U/min, respectively. The enzyme activity was completely inactivated by heating at 90 ℃ for 2.5 min or 85 ℃ for 3.5 min, and ascorbic acid, isoascorbic acid as well as L-cys had obvious inhibition effects on the PPO enzyme activity.
    14  Antioxidant Activity and Molecular Weight Distribution of Hydrolysates from Paphia Undulate Protein
    HE Xiao-qing CAO Wen-hong ZHANG Chao-hua ZHAO Zi-ke
    2014, 30(1):74-80.
    [Abstract](1195) [HTML](0) [PDF 559.52 K](738)
    Abstract:
    Three types of protein including sarcoplasmic protein, myofibrillar protein and stromal protein from Paphia undulate were isolated. The amino acid composition, antioxidant activity in vitro and molecular weight distribution of the hydrolysates prepared with trypsin were investigated. All of the three protein fractions contained higher contents of essential amino acids, alkaline, hydrophobic and branched-chain amino acid. Protein hydrolysates showed a good radical scavenging activity with dose-effect. The hydrolysates of sarcoplasmic protein with the highest contents of small molecule peptide exhibited the strongest radical scavenging activities including DPPH radical, hydroxyl radical and superoxide anion radical, with the IC50 values being 4.82, 4.70 and 3.75 mg/mL, respectively and the molecular weight less than 1500 u accounted for 42.55±0.27%. The hydrolysates of sarcoplasmic protein and myofibrillar protein showed similar reducing power and their OD700 were 0.58 and 0.57 at 10 mg/mL, respectively. While the hydrolysates of stromal protein displayed lower reducing power.
    15  Effects of Different Precursors on the Formation of β-Carboline Norharman and Harman in Braised Sauce Meat
    PAN Han WANG Zhen-yu NI Na LIU Jin-kai LIU Yue ZHANG De-quan
    2014, 30(1):81-86.
    [Abstract](1048) [HTML](0) [PDF 580.96 K](794)
    Abstract:
    Lamb was used to make braised sauce meat. The effects of possible precursors on the formation of norharman (9H-pyrido- [4,3-b] indole) and harman (1-methyl-9H-pyrido-[4,3-b] indole) in braised sauce meat were studied by adding different concentrations of tryptophan, phenylalanine, creatine and glucose. The results showed that the amounts of norharman and harman in braised sauce meat and soup were enhanced with increasing the levels of tryptophan. With addition of 2.4 mmol tryptophan, the total amounts of norharman and harman in both sauced meat and soup were 3.85 times and 2.33 times more than that in the blank control groups. Except with the concentration of 1.2 mmol, phenylalanine did not show any consistent effect of concentration on β-carboline. Creatine with low levels (eg. 0.12 mmol) had a strong influence on the formation of β-carboline in braised sauce meat and soup rather than high levels. The contents of norharman and harman increased and then decreased with the increasing of glucose. When adding1.2 mmol glucose, the total amounts of norharman and harman in sauced meat and soup increased by 54% and 66%, respectively.
    16  Biofilm Characteristics of Several Foodborne Bacteria in Spoiling Milk
    ZHOU Wen-yuan ZHANG Hong-mei JIANG yan HUANG Hui-chang CHEN Sheng-hua LIAO Ding-mei GUO Kai ZHANG Wen-yuan YANG An-lin
    2014, 30(1):87-90.
    [Abstract](1668) [HTML](0) [PDF 490.31 K](831)
    Abstract:
    Bacterial biofilm brought great threat in milk preservation. Thus it is very important to research the formation features of biofilm during milk corruption and find an effect way to eliminate the biofilm. The relationship between the biofilm formation ability, the viable count in the biofilm and the AI-2 activity of Staphylococcus aureus, Salmonella and Escherichia coli in the process of milk spoilage were investigated by the method of microtitreplate. The change of biofilm and AI-2 activity after the addition of furanone was tested. Then the gradient concentrations of furanone indicated the relevance between the furanone and the quantity of bateria in the biofilm. The results showed that the sequence of three bacteria for biofilm formation ability, the viable count in the biofilm and the AI-2 activity was Staphylococcus aureus>Escherichia coli>Salmonella. Besides, the biofilm formation ability and AI-2 activity both declined after adding furanone, and the biofilm formation ability of Staphylococcus aureus reduced to 25%. Thus the results indicated that the ability of biofilm formation might be regulated by the AI-2 activity which was secreted by the viable isolates in the biofilm.
    17  Antagonistic Activity of Debaryomyceshansenii Induced by Chitin
    YAN Yan WANG Ming-li LI Cen LU Ya-li
    2014, 30(1):91-95.
    [Abstract](1447) [HTML](0) [PDF 509.53 K](765)
    Abstract:
    To improve the biocontrol efficacy of antagonistic yeast Debaryomyceshansenii (D.hansenii), the combination of the yeast with different concentrations of chitin against postharvest diseases caused by Penicilliumdititatum(P.dititatumthan) in orange fruits were investigated in vitro and in vivo. Meanwhile, the population dynamics of D.hansenii and the activity changes of chitinas were tested. The results showed that combining D.hansenii with chitin provided more effective control on P.dititatumthan than that only using the antagonistic yeast, and D.hansenii combined with 1.2% chitin showed the best effect. The disease incidence rate and decay index were 15.51% and 14.62%, respectively after 6 days. Chitin at different concentrations had less inhibit effects on the growth and proliferation of D.hansenii in NYDB medium. The chitin (1.2%) in wounded oranges showed the strongest stimulus for the growth of D.hansenii. And D.hansenii with 1.2% or 1.4% chitin had a positive effect on inducing the increasing activity of chitinas in orange fruits. Therefore, the combination of D.hansenii with chitin may have great potential value against green mold of orange fruits.
    18  Heat Stability of Laoshan Goat Milk
    LIU Chang SHI Yong-cui XU Xiao-dan WANG Cun-fang
    2014, 30(1):96-100.
    [Abstract](1151) [HTML](0) [PDF 510.64 K](785)
    Abstract:
    The general physicochemical properties of Laoshan goat milk were analyzed and the heat stability of goat milk was discussed. The effects of lactation period, heating temperature, pH and additives on the heat stability of goat milk were studied by analyzing the heat coagulation time (HCT) of the milk. The results showed that pH of goat milk was close to neutral with titration acidity of 11~23°T, and it positively correlated with lactation period. The heat stability of goat milk enhanced along with the extension of lactation period and sharply reduced with the temperature increased. The influence of pH was enormous on heat stability, and HTC value was increased with pH increased. The solidification did not appear in the milk samples when pH>6.5. Some additives such as citrate, phosphate and EDTA (0.01~0.20 mol/L) were used to overcome destabilization and the higher concentration of additives, the greater improvement of heat stability. On the contrary, calcium content had a negative impact on heat stability of milk. In addition, the result showed a special relationship between heat stability and sucrose concentration. With the increasing of sucrose concentration, the heat stability of milk ascended first and then descended. The heat stability and HTC value exhibited the highest by addition of 35% sucrose.
    19  Effects of Storage Condition on Phenolics and Antioxidant Activity of High Hydrostatic Pressure Treated Blueberry Juice
    WANG Xing MA Yong-kun YU Li-zhi MA Hui DENG Na-na ZHANG Hai-ning
    2014, 30(1):101-107.
    [Abstract](1428) [HTML](0) [PDF 802.49 K](809)
    Abstract:
    The changes of total phenolics content, total flavonoids content, anthocyanins content, and antioxidant activity presented in blueberry juice treated with high hydrostatic pressure (HHP) (400 MPa/10 min) were investigated during storage for 5 weeks at 4 ℃, 25 ℃ and 37 ℃. The results showed that total phenolics content and antioxidant capacity were significantly decreased (p<0.05). In addition, total flavonoid content had less change, while anthocyanins content reduced obviously (p<0.05). The degradation of anthocyanins was followed pseudo-first-order reaction kinetics model with activation energy (Ea) of 55.75 kJ/mol. Total phenol content, anthocyanins content, and antioxidant capacity were highly correlated. No significant correlation existed between flavonoids and antioxidant capacity at 4 ℃, while it was negatively correlated at 25 ℃ and 37 ℃. Moreover, color analysis showed that the blueberry juice under different storage temperatures, had increasing a*, b* and C values with the extension of storage time, but L* value reduced. The chromatic aberration of blueberry juice (ΔE) was more than two after 4 weeks of storage at 37 ℃ which illustrated the quality and sensory of the juice had been influenced. The study indicated that low temperature and short storage time could help preserve phenolics content and the antioxidant activities of blueberry juice.
    20  Effect of High Oxygen Atmospheric Packaging on the Browning and Quality of Litchi Fruits with Leaves
    YU Mao-lan CHEN Yu-long XU Yu-juan WU Ji-jun WANG Sheng-you FU Man-qin
    2014, 30(1):108-114.
    [Abstract](1376) [HTML](0) [PDF 558.08 K](742)
    Abstract:
    The changes of nutritional quality and activities of browning-related enzymes were studied in the litchi fruits with leaves under high oxygen atmospheric packaging. Compared with the control (air packaging), high oxygen atmospheric packaging inhibited respiratory intensity of litchi fruit,with decreasing of formation of carbon dioxide (CO2). The treatment reduced the degree of browning after storage. Peroxidase (POD) activity in the pericarp of litchi fruit was significantly lower than control, while the maximal activity of polyphenol oxidase (PPO) was markedly delayed. It was illustrated that the browning of the litchi fruits with leaves had certain correlation with POD and PPO. The variation trends of soluble protein, anthocyanin and total polyphenol contents were similar: the contents of them were lower than control during the first 6 days of storage. But at day 9 and day 12, the contents were higher than control. Vitamin C (Vc) in litchi juice decreased significantly under high oxygen packaging, while soluble solids and titratable acid showed little changes. Therefore, high oxygen atmospheric packaging was benefit to the delay of browning, but not benefit with the maintenance of Vc.
    21  Preparation and Antioxidant Activity of Stevioside-resveratrol Complex
    YANG Xiao-quan WANG Li-ying WAN Zhi-li WANG Jin-mei YUAN Yang
    2014, 30(1):115-119.
    [Abstract](1268) [HTML](0) [PDF 613.83 K](726)
    Abstract:
    Resveratrol (RES) is an active food compound, but the insolubility in water limits its application in food industry and contributes to its low bioavailability. In this study, the solubility of RES was enhanced by utilizing the solubilizing properties of stevioside (STE). The particle size, morphology, stability, and antioxidant activities of STE-solubilized RES were evaluated. The results indicated that the solubility of RES in water increased linearly with increasing STE concentrations, which promoted to 2.55±0.06 mg/mL in the presence of 10% (m/V) STE at 60 ℃ for 30 min. Dynamic light scattering and atomic force microscope studies found that RES and STE formed STE-RES nanomicelles (4.70±0.24 nm) complex, suggesting the solubilization of hydrophobic RES in STE self-assembled micelles. After freeze-dried and reconstitution, the STE-solubilized RES was still stable under physiological conditions (water, gastric fluid, and intestinal fluid) over 12 h cultivation. Furthermore, antioxidant activity assays demonstrated that the STE-solubilized RES showed an enhanced DPPH radical scavenging ability and reducing power.
    22  Effects of Different Deacidification Methods on the Trans Fatty Acids in the Grape Oil
    LI Gui-hua WANG Xiang-yun ZHAO Fang YANG Ying REN Guo-wei
    2014, 30(1):120-125.
    [Abstract](1364) [HTML](0) [PDF 501.83 K](736)
    Abstract:
    Grape seed oil with acid value of 15.12±0.016 mg KOH/g, was used as raw material, and the effects of chemical, physical and enzymatic deacidification on the content and kind of trans fatty acids in the grape seed oil were investigated. The changes of trans fatty acids content and acid value in different refined technologies were discussed. The acid values were reduced to 0.10±0.022 mg KOH/g, while the content of trans fatty acids increased by 0.31±0.0011% when chemical refined was employed. The optimal conditions of physical deacidification of the grape seed oil were deacidification temperature 240 ℃and time 8 h, under which the acid value of 0.13±0.018 mg KOH/g, and trans fatty acids content of 1.86% were obtained. The conditions of enzymatic esterification to deacidificate the grape seed oil were as follows: temperature 80 ℃, addition of glycerol 300% and enzyme 3% for 8 h. Under these conditions, the acid value declined to 2.36±0.026 mg KOH/g, while the content of trans fatty acids increased from 0.034±0.001% to 0.035±0.001%~0.041±0.0016%. Among the methods tested, the enzymatic esterification deacidification has the least influence on trans fatty acids content and followed by chemical refining.
    23  Effects of Different Drying Methods on Flavonoids Content and Bioaccessibility of Saussurea involucrate Tissue Culture
    XU Chun-ming LI Ting WANG Ying-ying WANG Cheng-tao SUN Bao-guo
    2014, 30(1):126-130.
    [Abstract](1426) [HTML](0) [PDF 674.99 K](828)
    Abstract:
    Flavonoid is one of the main active ingredients in Saussurea involucrate. The influences of five drying methods including natural air drying, freeze drying, 40 ℃ drying, 60 ℃ drying and vacuum drying on the flavonoids content of Saussurea involucrate’s tissue culture were discussed in this paper. Freeze drying had the least effect on flavonoids content, t followed by natural air drying, while 60 ℃ drying resulted in the loss of the most flavonoids. Then samples obtained from natural air drying, freeze drying and 40 ℃ drying were used to conduct in vitro simulated digestion experiments. The results showed that the biological acceptable rate of flavonoid was 30% to 45%. Flavonoids bioaccessibility was influenced by the culture condition and digestive environment of Saussurea involucrate.
    24  Empirical Model for Predicting Contents of Monoglyceride and Diglyceride during the Synthesis of Acyglycerols by T1 Lipase-Catalyzed Esterification
    QIN Xiao-li ZHONG Jin-Feng WANG Yong-hua
    2014, 30(1):131-136.
    [Abstract](1652) [HTML](0) [PDF 533.74 K](764)
    Abstract:
    Monoglyceride (MAG) and diglyceride (DAG) are a kind of multifunctional additives. They are widely used in food and cosmetic industries. Acylglycerols are synthesized by esterification of glycerol with oleic acid in the presence of T1 lipase. The effects of substrate molar ratio (glycerol: oleic acid), water content, time and temperature on esterification progress were studied. An empirical model for predicting MAG and DAG contents during the synthesis of acylglycerols was proposed. The results showed that MAG content increased first and then slowly decreased with an increase of reaction time, DAG content increased rapidly first and tended to stable during the time increased, while triglyceride (TAG) content exhibited a keep increasing pattern. MAG and DAG contents were hardly influenced by reaction temperature ranging from 40–60 oC. Based on the effects of substrate molar ratio and water content, two empirical models [ErDAG% = 0.5967 × r0.271 × (–1.01Dw + 40.2) and ErMAG% = 0.7422 × r0.366 × (–0.745Dw + 23.7)] were established for predicting MAG and DAG contents, respectively. The results showed that the present models had a good correlation (R2 = 0.99) with the experimental data for predicting MAG and DAG contents. Such data would be valuable for the process control and optimization of the synthesis of acylglycerols.
    25  Purification and Catalyst Kinetics of α-galactosidase Derived from Lactobacillus salivarius XH4B
    DU Xin-yong LIU Tong-jie GAO Shi-yang HE Guo-qing
    2014, 30(1):137-142.
    [Abstract](1261) [HTML](0) [PDF 676.34 K](830)
    Abstract:
    In this study, α-galactosidase was derived from Lactobacillus salivarius XH4B (GeneBank accession number: JX1125456), and purified by super filtration and size exclusive chromatography of Sephedax G200. The results showed that the compounds with molecular weight (MW) more than 100 kDa had enzymatic activity and those washing constituents of 370~400 min showed significant activity. The SDS-PAGE appeared that the MW of the monomer of the enzyme was 70~80 kDa, while the native enzyme was a polymer with a MW exceeded 100 kDa. Compared with the crude enzyme, the purification efficiencies of super filtration and column chromatography were 149.80% and 391.91%, respectively. The optimal catalyst conditions determined by responding surface method were citric buffer pH 5.5, ion strength 0.15 mol/L and reaction temperature 52 ℃. The Km value of the enzyme to pNPG was 0.817. Compared to pure water system, only K+ and Na+ could improve the catalyst activity to 102.50% and 104.18% respectively. EDTA (96.54%), Mg2+ (91.53%), Ca2+ (82.51%), and DTT (79.38%) could reserve most of the activity, while Zn2+, Cu2+, Pb2+, Fe3+ and Vc could only remain 5~7% activity.
    26  Numerical Analysis of Water Jet Processing Nozzles’ Internal Flow Field
    WANG Jia-zhong LI Qiu-shi YI Jing-gang JIANG Hai-yong LIU Jiang-tao
    2014, 30(1):143-146.
    [Abstract](992) [HTML](0) [PDF 612.74 K](700)
    Abstract:
    The subject relies on “The National Marine Public Industry Science And Technology Project”. Water jet technology for scallops shelling processing has many advantages: high processing quality; sanitary and safety; material is easy to obtain. Research on the bay scallop in adductor muscle processing was to obtain a new type of scallop in shell adductor muscle processing mode, and water jet on scallop processing was discussed. The nozzle is critical component in shelling equipment, and nozzle parameters would affect the flow velocity distribution. Based on 2-D flow mathematical model, quad-dominated grid was divided. The narrow-angle fan nozzle’s internal flow field was simulated by standard turbulence model. The influence on nozzle velocity distribution such as cone angle, outlet diameter, outlet length were analyzed. After comprehensive analysis, the optimal parameter combination of the nozzle for water jet processing were obtained.
    27  Simulation Analysis of Food Materials Damage Effect Based on Chewing Movement
    CHEN Li SUN Yong-hai LIU Jing-jing XIE Gao-peng
    2014, 30(1):147-152.
    [Abstract](1423) [HTML](0) [PDF 716.04 K](776)
    Abstract:
    Reverse engineering technology was used to reconstruct three-dimensional models of the incisors as well as top and bottom first molars which played a major role in the chewing movement. The simplified chewing movement models were constructed by modern occlusion theory and temporomandibular articulation movement theory, and it was divided into three modes: cutting mode, compressing mode and grinding mode, which simulated the whole process of chewing and crushing food. Based on the elastic-plastic constitutive model of food materials, the joint strength theory was introduced to analyze the effect of chewing movement rule on the degree of material damage. Five different rates were taken by uniform motion mode, and the results showed that under the grinding mode, the higher rate of chewing had good effect on the destruction of the food. And the greatest shear stress and mises stress were achieved after chewing for 0.3 s, being of 16.07 MPa and 14.20 MPa respectively. When the simulation time of variable motion model was 0.2 s, the effect of chewing acceleration was relatively weak. Therefore, the larger shear stress and mises stress were produced by uniform variable motion, which were 15.64 MPa and 13.86 MPa, respetively. So it was more suitable for grinding flexible and durable food.
    28  Drying Characteristics and Kinetics of Kiwifruit Slice under Mediumand Shortwave Infrared Radiation
    ZENG Mu-cheng BI jin-feng CHEN Qin-qin LIU Xuan WU Xin-ye JIAO Yi
    2014, 30(1):153-159.
    [Abstract](1552) [HTML](0) [PDF 738.99 K](768)
    Abstract:
    The experiment was carried out at different drying temperatures (50, 60, 70, 80 ℃) and infrared powers (675, 1350, 2025 W). The results showed that drying temperature had a significant influence on the drying rate of kiwifruit. The drying time decreased with the increase of the drying temperature and infrared power. The processing time of kiwifruit was less affected by the power. According to statistical parameters. The Page model was found to be the best to simulate medium and shortwave infrared radiation drying of kiwifruit slices among the six mathematical models. There was a good agreement between the experimental and predicted values. Since the medium and shortwave infrared radiation drying of kiwifruit slices was mainly dominated by falling period, the Fick’s second law of diffusion was employed to calculate the value of moisture effective diffusivity (Deff), which ranged from 3.3970×10-9 to 1.2960×10-8 m2/s, and increased with increasing the drying temperature and infrared power. The activation energy determined from Arrhenius equation was varied from 30.237 to 41.551 kJ/mol. This research provided the technique basis for the application of medium and shortwave infrared radiation drying technology in drying kiwifruit.
    29  Analysis of Nutrition Compositions of Cantonese Sausage
    ZHU Ding-he ZHU Lin XIAO Zi-jun GUO Hong-hui LUO Xiu-qi XIA Min
    2014, 30(1):160-164.
    [Abstract](1495) [HTML](0) [PDF 490.64 K](1199)
    Abstract:
    Cantonese sausage is a kind of the traditional preserved food in Guangdong province, and its unique taste and aroma attracted numerous consumers. To investigate the nutrition compositions of Cantonese sausage, the national standard methods, HPLC and GC methods were used to determine the contents of basic nutrition compositions, fatty acids and amino acids of five representative Cantonese sausages named as Jin qi lin,Jin ao, Jin rong, Huang shang huang, Cang zhou. The major components of the Cantonese sausage were as follows: protein (19.30~27.30%), lipids (13.53~21.54%), moisture (5.40~9.87%), carbohydrate (13.66~17.87%), sodium chloride (4.20~7.01%). Furthermore HPLC and GC analysis revealed that the proportion of polyunsaturated fatty acids was 54.32~57.88%; all five kinds of sausage contained 17 kinds of amino acids, and the contents of essential amino acids from them were similar, which accounted for 33.82~33.82% of total amino acid. Therefore, Cantonese sausage was a high quality protein source. The result could provide scientific basis of Cantonese sausage nutritional values for people.
    30  Determination of Paraffin in Food by Oxidation Purification and GC-MS
    WU Yu-luan CHEN Yi-guang LUO Dong-hui LUO Hai-ying ZHU Li-ping XIAN Yan-ping CHEN Li-wei DONG Hao
    2014, 30(1):165-169.
    [Abstract](1170) [HTML](0) [PDF 509.92 K](945)
    Abstract:
    In this paper, an oxidation purification and GC-MS method was established for the determination of paraffin in food. Samples were extracted twice with cyclohexane and the supernatant was collected by centrifugation, then the extraction was purified by mixed oxidation reagents (chromium trioxide: concentrated sulfuric acid: water = 1: 1: 2, V/V) and silica gel column. After that, the purified extraction was detected by GC-MS. The results indicated that the linearity range, the correlation coefficient (r) and the detection limit of greasy hotpot condiment were 40~800 mg/kg, 0.9991 and 8 mg/kg, respectively; while those of the low-fat dry shiitake mushroom and vermicelli were 10~400 mg/kg, 0.9995 and 3.5 mg/kg, respectively. The recoveries ranged from 90% to 117% and the relative standard deviations were between 2.9% and 6.6%. This method is simple, sensitive and accurate, which might be used for the detection of paraffin in greasy hotpot condiment and low-fat food such as dry shiitake mushroom, vermicelli, rice and sunflower seeds.
    31  Qualitative and Quantitative Detection of Benzoyl Peroxide in Wheat Flour
    ZHANG Yu-rong ZHANG De-wei ZHOU Xian-qing LIU Yue-ting
    2014, 30(1):170-174.
    [Abstract](1258) [HTML](0) [PDF 591.98 K](751)
    Abstract:
    Based on the principle that Fe2 + is oxidized to Fe3+ by benzoyl peroxide (BPO) under acidic and heating conditions, and orange complex was generated by Fe3+ and diantipyryl methane (DAPM), visual colorimetry for fast qualitative analysis and spectrophotometric for quantitative analysis of BPO in wheat flour were built. In this paper, the experimental conditions of BPO detection method were optimized, and the experimental influencing factors including buffer solution content, ammonium ferrous sulfate content, DAPM content, reaction temperature and reaction time were studied. The results showed that under the optimum conditions,the color of the complex gradually deepened with the increase of BPO content, and chromatic values changed regularly. It was obeyed Beer’s law when the concentration range of BPO was within 0~12 mg/L. The linear regression equation was ΔA = 0.036 + 0.110 C (mg/L) with correlation coefficient of 0.9996, and the apparent molar absorption coefficient was 2.765×104 L/(mol?cm) at 420 nm. The recovery rate for spiked standards was 97.0~101.8%, with the relative standard deviation (RSD) less than 5%. The BPO content range was rapidly determined by visual colorimetry, and its detection limit was 0.016 mg/L.
    32  Effect of Resin Debittering on the Monoterpene Hydrocarbons Content in the Headspace of Xiangyuan Juice
    NIU Li-ying YU Meng LI Da-jing LIU Chun-quan
    2014, 30(1):175-179.
    [Abstract](1108) [HTML](0) [PDF 605.82 K](690)
    Abstract:
    The monoterpene hydrocarbons in the headspace of Xiangyuan (Citrus wilsonii Tanaka) juice after debittering treatment by macroporous resin were identified and qualified. Eleven monoterpene hydrocarbons were identified by solid phase micro extraction gas chromatography-mass spectrometry (SPME-GC-MS) and rentation index (RI) which was calculated from n-alkane. Then, eight terpenes (α-Pinene, β-Pinene, β-Myrcene, β-Phellandrene, α-Terpinene, Limonene, γ-Terpinene, α-Terpinolene) were quantified by headspace-gas chromatography-flame ionization detector (HS-GC-FID) using partial external standards method. Results showed that the contents of the eight terpenes after debittering were 90.95, 27.5, 26.22, 8.37, 4.17, 843.46, 107.66 and 4.24 ng/L, respectively, and all values were about one tenth of the control. Moreover, the proportions of the substances were not changed by debittering. the limonene had the highest content, followed by γ-Terpinene.
    33  Rapid Test of Alcoholicity in Alcoholic Beverages by Near Infrared Spectroscopy
    OU Chang-rong TANG Hai-qing YIN Ju-yi CAO Jin-xuan WU Wei-er CHEN Mei-zhen HE Wei-min
    2014, 30(1):180-184.
    [Abstract](1451) [HTML](0) [PDF 474.61 K](747)
    Abstract:
    The rapid determination of alcoholicity content in alcoholic beverages by near infrared spectroscopy (NIR) method was studied. The alcoholicity of 100 wine samples was detected by NIR and digital density meter method and the linear measuring range of NIR method was determined. Furthermore, the accuracy of the alcoholicity in other types of alcoholic beverages, such as fermented alcoholic beverages (fruit wine, sake and Chinese rice wine) and distilled spirits (vodka, whisky, brandy, rum and Chinese spirits ) were also investigated by using NIR . The results showed that the actual digital display measuring range was 0~28%vol,and the linear range was 0~20% vol. The alcoholicity in wine samples measured by two different methods showed a good correlation and there was no significant difference through t test (t0.05,4=2.78) and F test (F0.05(2,2)=19.0) at the level of α = 0.05. The alcoholicity in other types of alcoholic beverages determined by the two methods was consistent in evaluation of conformity. NIR method verified in this study is easy and fast to operate and has good repeatability. It is appropriate for determining alcoholicity in wine samples, and other kinds of alcoholic beverages.
    34  Detection of Staphyloccocus aureus in Meat by Helicase-dependent Isothermal DNA Amplification Assay
    ZHOU Wei ZHANG Wei WU Tao LI Yong-bo TIAN Hao ZHAO Yong ZHANG Yan ZHANG Zhi-sheng
    2014, 30(1):185-189.
    [Abstract](1277) [HTML](0) [PDF 484.66 K](749)
    Abstract:
    A helicase-dependent isothermal DNA amplification (HAD) method is used for rapid and accurate detection Staphyloccocus aureus in pork, beef, mutton and chicken. A pair of oligonucleotide primers exclusively amplified the nuc gene of Staphyloccocus aureus, thus, Staphyloccocus aureus could be directly detected in pork, beef, mutton and chicken. The final concentrations of UvrD helicase and T4 gp32 were optimized. The amplification product was detected by electrophoresis. The results showed that HAD method had high specificity in detection of Staphyloccocus aureus in meat, but the other bacteria could not been amplificated. The amplification product had the same 216 bp length as the designed gene fragment, and the detection limit was 101 CFU/g. The optimized concentrations of UvrD helicase and T4 gp32 were 0.1 μg and 5.0 μg, respectively. HDA method was faster and more sensitive for detection of Staphyloccocus aureus in pork, beef, mutton and chicken, and established the foundation for the rapid detection of Staphylococcus aureus in other foods.
    35  Isolation of Anthocyanin from Hibiscus sabdariffa by High Speed Counter-current Chromatography
    LIU Xue-hui WANG Zhen WU Qi LIU Lin-feng LI Jia-yin LU Ying
    2014, 30(1):190-194.
    [Abstract](1493) [HTML](0) [PDF 538.53 K](741)
    Abstract:
    The calyx of Hibiscus sabdariffa was extracted with 40% ethanol at room temperature, and poured through D101 resin. A solvent system of water-n-butanol-methyl tert- acetonitrile-trifluoroacetic acid (6:3:1:1:0.001, V/V) was used for isolation and purification by high speed counter-current chromatography (HSCCC) using upper phase as stationary phase and lower phase as mobile phase ,with the flow rate of 2 mL/min and injection volume of 120 mg. 21.8 mg anthocyanin 1 power was obtained with the purity and the recovery rate being of 97.8% and 95.3%, respectively. Anthocyanin 2 was isolated twice with purity of 96.2% (5.3 mg) and recovery rate of 92.3%. The chemical structures of the two anthocyanins were identified as delphindin-3-O-sambubioside for anthocyanin 1 and cyanidin-3-O-sambubioside for anthocyanin 2 by ESI-MS and NMR. The method is simple, reproducible, which is suitable for preparation of anthocyanins from Hibiscus sabdariffa, and also provides basis for further pharmacological studies and quality control of anthocyanins
    36  Determination of Tobacco-Specific Nitrosamlnes (TSNAs) in Tobacco Essence and Flavor Using Liquid Chromatography Tandem Mass Spectrometry
    DENG Qi-xin HUANG Chao-zhang ZHANG Jian-ping CAI Guo-hua WU Qing-hui HUANG Hua-fa XU Han-chun LIU Ze-chun XIE Wei
    2014, 30(1):195-199.
    [Abstract](1615) [HTML](0) [PDF 640.05 K](910)
    Abstract:
    Four tobacco-specific nitrosamlnes (TSNAs), including (R,S)-N-Nitrosoanabasine (NAB), (R,S)-N-Nitrosoanatabine (NAT), 4-(Methylnitrosoamino)-1-(3-pyridinyl)-1-butanone (NNK), and rac N’-Nitrosonornicotine (NNN) in tobacco essence and flavor were determined by liquid chromatography tandem mass spectrometry (LC-MS/MS). Sample were dissolved and extracted with 0.1 mol/L ammonium acetate methanol-water solution. The compounds were separated by gradient elution on C18 column and detected in positive ion mode using multiple reactions monitoring with a triple-quadruple MS of electrospray ionization. The results showed that the limits of detection (S/N= 3) and limits of quantity (S/N= 10) of four TSNAs were in the range of 0.4~1.6 ng/g and 1.4~4.8 ng/g, respectively. The linear correlation coefficients were above 0.9995 within 1~50 ng/L, and the recovery rates were between 93.5% to 105.9% in high, medium and low spiked levels. The relative standard deviation (RSD) of six repeat tests was below 5% (1.8~4.7%). Eight tobacco essence and flavor samples were evaluated by the method, and three samples were detected TSNAs. The method is of good efficiency, sensitivity and selectivity, and can be successfully applied to determine the TSNAs in varieties of tobacco essence and flavor.
    37  Analysis of Volatile Components in Kedong Fermented Bean Curd during the Fermentation
    SUN Jing-he SUN Bing-yu LIU Lin-lin LIU Ying YANG Yue-feng LIU Ying-ying SHI Yan-guo
    2014, 30(1):200-205.
    [Abstract](1677) [HTML](0) [PDF 546.22 K](767)
    Abstract:
    KeDong curd is mainly fermented by Micrococcus strains, with unique texture and flavor. Volatile flavor compounds were extracted from samples including tofu, broth, fermented bean curd and the soup, by simultaneous steam distillation and extraction (SDE) apparatus and then analyzed by gas chromatograph-mass spectrometer-computer (GC-MS). Compared to the volatile flavor compounds with the traditional Mucor fermented bean curd, the species of volatile flavor compounds of Kedong fermented tofu kept to increase with extending the fermentation time. ,The compounds of acid, aldehyde, ketone, and alcohol generated and the percentage compositions of them were increasing constantly. Generally ester was the main flavor substance but ester content was declined during the fermentation process. This research revealed the the change law of bacterial-type bean curd volatile flavor compounds in KeDong fermented soybean curds and provided certain theoretical guidance for Chinese traditional fermented food.
    38  Determination of Volatile Aroma Compounds of P. vannamei by SDE/GC-MS
    MAI Ya-yan YANG Xi-hong LIAN Xin JI Hong-wu LIU Shu-cheng MAO Wei-jie XIE Wan-cui
    2014, 30(1):206-210.
    [Abstract](1409) [HTML](0) [PDF 547.30 K](777)
    Abstract:
    Combined with sensory evaluation and instrumental analysis, the volatile compounds of P. vannamei were determined by SDE/GC-MS. The characteristic aromas were identified and the fingerprint of volatile compounds was investigated. GC-MS results showed that the SDE could effectively extract the volatile aroma components of P. vannamei, and the extract condition was optimized: P. vannamei weight 100 g, solid-liquid ratio 1/3, mixture of ether 30 mL and dichloromethane 30 mL, and distillation time 3h. The volatile components determined by GC-MS indicated that hydrocarbons accounted for more than 65%, of which eicosane was over 15%, hydrocarbon compounds endowed P. vannamei with sweet smell, but their threshold value was higher. While 3-methyl-1-penten-3-ol, (E,Z)3,5-octadien-2-one, (E,E)3,5-octadien-2-one and some ester compounds had lower thresholds, which were important and specific flavor of P. vannamei.
    39  Evaluation of the Quality of Xinjiang Dry Red Date with Membership Functional Model
    MA Qian-li TIAN Ying-zi YING Li LUO Yu-nian WANG Qing-qing XU Man ZHAO Si-lang LIN Hua-guan
    2014, 30(1):211-216.
    [Abstract](1085) [HTML](0) [PDF 545.55 K](702)
    Abstract:
    Thirty-two kinds of different dry or fresh red dates were used to detect the physical indices and nutritional composition, then the key indices were selected to establish Xinjiang dry red dates membership functional model, in order to evaluate and analyze the quality comprehensively. The results showed as follows: the protein content of Xinjiang dry red dates were similar with dates from other areas such as Shandong,Shanxi,Henan and Hebei while Xinjiang,especially Hami red dates had obvious advantages in sugar-acid ratio. The Xinjiang dry red dates membership functional model was established by using fruit weight, protein, fiber and sugar-acid ratio and so on as evaluation factors. Common red dates could also be evaluated by this model. Calculation of the evaluation factors for all kinds of the dry dates showed that Hami dry red dates had better quality than the other samples. The membership functional model is not suitable for fresh dates.
    40  Determination of Five Mycotoxins in Peanuts and Products by HPLC-MS/MS
    ZENG Xian-yuan NING Huan-yan YIN yan TANG Li-na HUANG Fei LIU Sheng-guo FENG Xia-ping
    2014, 30(1):217-221.
    [Abstract](1234) [HTML](0) [PDF 520.91 K](771)
    Abstract:
    A method based on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for simultaneous determination of five mycotoxins, namely aflatoxin B1 (AFB1) , aflatoxin M1 (AFM1), Deoxynivalenol (DON), Zearalenone (ZEA) and OchratoxinA (OTA), in peanut and its products. The samples were extracted with methanol-aqueous solution (55:45, V/V), cleaned up and enriched by mycotoxin affinity column, and then analyzed by HPLC-MS/MS under the multiple reaction monitoring (MRM) mode. All the analytes were successfully detected in positive ion mode within 6 min, and the correlation coefficients (r2, n=6) were more than 0.999. The linear ranges for AFB1, AFM1, and DON were between 0.5 μg/L to 50.0 μg/L, with detection limit of (LOD, S/N=3) 0.05 μg/kg. While ZEA and OTA were ranging from 5.0 μg/L to 100.0 μg/L, and the detection limit (LOD, S/N=3) was 0.5 μg/kg. The spiked recoveries were in the range of 86.8~102.7%, and relative standard deviations (RSD, n=3) were 0.36~4.79%. The method was simple, effective and sensitive, and was suitable for the determination and confirmation of five mycotoxins in peanuts and products samples.
    41  Optimization of γ-Aminobutyric Acid Analysis in Fermented Milk by HPLC
    GUO Chao WANG Chang-lu CHEN Mian-hua LI Zhen-jing WANG Yu-rong LI Feng-juan
    2014, 30(1):222-226.
    [Abstract](1328) [HTML](0) [PDF 712.10 K](832)
    Abstract:
    Analysis of γ-aminobutyric acid (GABA) in fermented milk by HPLC was optimized. GABA was extracted from fermented milk with trichloroacetic acid - water solution. Sample solution was heated at 60 ℃ for 2 h, and centrifugated at 10000 r/min for 10 min. The most efficient and rapid detection method of GABA in fermented milk was established by adjusting the elution mode of mobile phase, mobile phase ratio, pH, and column temperature, as well as using amino acid column, automatic injector and instrument automatically derived procedures. The limit of detection (LOD) (S/N=3) and limit of quantification (LOQ) (S/N=10) for GABA were 0.005 μg/mL and 0.02 μg/mL, respectively. The linear range was 0.0025~500 μg/mL with correlation coefficient (R2) of 1. This method could provide shorter detection time, more accurate results, less reagent waste and wider applicability. Meanwhile the results are satisfying for analysis of GABA in functional food samples, red yeast rice samples, and lactic acid fermentation broth samples.
    42  Effectiveness Evaluation of Illegal Cooking Oil Identification Based on Fourier Transform Infrared Spectroscopy
    YANG Yong-cun LI Hao YANG Dong-yan DENG Xiang-xiang WU Shuang DENG Ping-jian
    2014, 30(1):227-232.
    [Abstract](1495) [HTML](0) [PDF 626.01 K](802)
    Abstract:
    One hundred-thirty seven oil samples including edible vegetable oil, raw vegetable oil, kitchen-waste oil and fried waste oil were collected. And 17 refined illegal cooking oil samples were prepared. Fourier transform infrared spectroscopy (FITR) was used to discriminate the difference in the oil samples. The shape of spectra in 1711 cm-1 and peak height ratios in 1711 cm-1 and 1745 cm-1 were analyzed and evaluated the effectiveness to separate illegal cooking oil from edible vegetable oil. The results showed that the infrared absorption peak in 1711 cm-1 or the double peaks in 1711 cm-1 and 1745 cm-1 were not specific for illegal cooking oil, but highly related to the oil acid value with positive correlation, which decreased when the acid value of illegal cooking oil decreased by refining or blending. Therefore, the FI-TR absorption peaks could not discriminate illegal cooking oil from edible vegetable oils.
    43  Extraction, Isolation and Antibacterial Mechanism of Antibacterial Peptides
    MIAO Jian-yin KE Chang GUO Hao-xian LIU Guo GAO Xiang-yang CAO Yong
    2014, 30(1):233-240.
    [Abstract](1623) [HTML](0) [PDF 589.07 K](1086)
    Abstract:
    Long-term use of antiseptic and antibiotics has led to the development of resistance among pathogens and other pests as well as the increase of environmental and health risks. Thus, there is a significant and urgent need to find new antibiotics which hardly to induce resistance. Natural antimicrobial peptides, which are the critical component of the natural defense system, are kinds of small cationic peptides with broad antimicrobial activity, and possess a different mode of action compared to traditional antibiotics. Several antimicrobial peptides can inhibit and kill Gram-positive and Gram-negative bacteria, fungi, parasite, enveloped virus and cancer cells. Antimicrobial peptides are considered as new substitutes for conventional antimicrobials and antibiotics because of their efficiency in fighting against pathogens, and have a very good application prospect in pharmaceuticals and food additive industries. In this paper, we reviewed the research progress of antimicrobial peptides,and emphatically analyzed the extraction, isolation of the peptides and their antibacterial mechanism.

    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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