Table of Content

01 April 2010, Volume 31 Issue 7
Analysis on Technological Status and Trend of Chicken Processing Industry in China
XU Xing-lian,WANG Hu-hu
2010, 31(7 ):  1-5.  doi:10.7506/spkx1002-6300-201007001
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There has recently been a prompt increase of chicken production in China and chicken processing industry is exhibiting good potential in China. Compared with developed countries, China still lags behind in research of basic theory, equipment innovation and application of new technology. In this paper, current status related to chicken slaughter, deep processing, quality and safety control of chicken as well as the utilization of chicken by-product is reviewed and a comparison between China and the developed countries is conducted. Based on these analyses, the future development trend in chicken processing industry is also proposed.

Electrochemical Study on Structure-activity Relationship of Flavonol Antioxidants
XU Xin-rong,HE Jian-bo*,CHENG Ping
2010, 31(7):  6-9.  doi:10.7506/spkx1002-6300-201007002
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To understand the relationship between structure and antioxidant activity of flavonols, cyclic voltammetry and UVvisible spectroelectrochemical method in situ were used to investigate electro-oxidation mechanisms of myricetin and dihydroquercetin through the comparison with electrochemical-chemical mechanism of quercetin. Results indicated that 5'-OH at the B-ring of myricetin hindered the subsequent chemical transformation to a certain extent, while C-C saturated bond at 2,3 positions in dihydroquercetin completely stopped the subsequent transformation step, thus leading to the decrease in antioxidant activity. These findings suggest that the subsequent chemical transformation provide very important contribution to antioxidant activity of flavonols.

Effect of Compression Ratio on Textural Characteristics of Ham Sausage
HAO Hong-tao,LIU Yan-xia,LI Miao-yun,ZHAO Guang-hui,ZHAO Gai-ming*
2010, 31(7):  10-13.  doi:10.7506/spkx1002-6300-201007003
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To explore textural characteristics of ham sausage, the effect of compression ratio within the range of 30% to 80% on textural characteristics of ham sausage was investigated. Results indicated that fracturability property provided an important reference to compression ratio. Compression ratios tended to be consistent when an appropriate strength of gelatin system for ham sausage preparation was reached.

Antioxidant Activity of Whey Protein Hydrolysates on Raw Pork Patties
PENG Xin-yan1,2,KONG Bao-hua2,*
2010, 31(7):  14-18.  doi:10.7506/spkx1002-6300-201007004
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Whey protein isolate (WPI) was hydrolyzed with alcalase and its hydrolysates were added to raw pork patties for evaluating their antioxidant activity. WPI hydrolysates at the concentration levels of 1.0%, 1.5% and 2.0% were added to pork patties. During the storage period, a* value, thiobarbituric acid-reactive substances (TBARS), pH, Metmyoglobin (MetMb) were measured and sensory evaluation was conducted. The pork patties without the addition of WPI hydrolysates and with the addition of nonhydrolyzed whey at the concentration of 2.0% or BHA at the concentration of 0.02% were used as controls. Results showed that WPI hydrolysates had a significant inhibitory effect on lipid oxidation of pork patties during 7-day storage period when compared with the controls. The most obvious effect was observed in pork patties with the addition of 2.0% WPI hydrolysates. Compared to the control without the addition of hydrolysates, 2% WPI hydrolysates resulted in the decrease of TBARS and the increase of a* value (P < 0.05). The MetMb level in pork patties with the addition of 2.0% WPI hydrolysates was only 79% level of the control group without the addition of hydrolysates. The similar results were observed in BHA group. Therefore, WPI hydrolysates have a higher inhibitory effect on lipid oxidation than nonhydrolyzed whey protein. These investigations demonstrate that enzymatically hydrolyzed whey protein can retard the peroxidation of lipids.

Structural Identification and in vitro Digestion Characteristics of Casein Hydrolysate-Zinc Complex
WANG Xu,WANG Lei,WANG Qiang,ZHAO Yang,MAO Xue-ying*
2010, 31(7):  19-21.  doi:10.7506/spkx1002-6300-201007005
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Characteristics of casein hydrolysate and casein hydrolysate-zinc complex were analyzed by Fourier transform infrared (FTIR) spectroscopy and UV-visible absorption spectrum. Results showed that casein hydrolysate chelated with zinc ion to form complex. Comparative study on zinc-releasing amount in casein hydrolysate-zinc complex and ZnSO4·7H2O digestion in vitro exhibited that zinc digestibility of the complex was significantly better than that of ZnSO4·7H2O.

Effect of Thermal Treatment on Quality of Litchi Juice
WAN Peng1,2, LIU Liang2,PAN Si-yi1, XU Yu-juan2,*
2010, 31(7):  22-27.  doi:10.7506/spkx1002-6300-201007006
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To explore the effect of thermal treatment on quality of litchi juice, the changes in browning index (A420, absorbance at 420 nm), pH and the contents of soluble solid (SS), ascorbic acid, 5-hydroxy-ethylfurfural (5-HMF), sugar, total phenols and volatile aromatic compounds of litchi juice during thermal treatment at 60-100 ℃ were measured. Results showed that the A420 of litchi juice was followed by zero order reaction kinetics within 0-60 minutes of thermal treatment. During the thermal treatment, the contents of ascorbic acid and total phenols were sharply declined, while the change of sugar content was not obvious. These results suggest that degradation of ascorbic acid and condensation of phenols are the major factors affecting non-enzymatic browning of litchi juice. Meanwhile, thermal treatment exhibited a negative effect on flavor components of litchi juice. Detected by headspace solid phase micro extraction combined with gas chromatography-mass (HS-SPME-GC/MS), the contents of lower alcohols and esters exhibited a significant decrease, whereas some sulfur containing compounds and fatty alcohols were generated.

Effect of Temperature and Relative Humidity on Rice Hygroscopicity
YANG Guo-feng,CHEN Jiang,WANG Zheng
2010, 31(7):  28-32.  doi:10.7506/spkx1002-6300-201007007
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In this study, multiple molecular absorption theory, heat and mass transfer theory through porous media and stress theory were used to analyze the effect of temperature and humidity on rice hygroscopicity process and explain the reason for fissure formation. Results showed that air relative humidity affected the whole hygroscopicity progress; however, air temperature only exhibited an obvious effect on hygroscopicity on the surface of rice. Meanwhile, both temperature and relative humidity were positively correlated to the cracking rate of rice. Temperature alone was negatively related to hygroscopicity rate, whereas relative humidity was positively related to hygroscopicity.

Change in Lipid Oxidation, Physio-chemical Index and Sensory Quality of Traditional Chinese Bacon during Low-temperature Smoking
SHANG Yong-biao1,2,XIA Yang-yi1,2,WU Jin-feng1
2010, 31(7):  33-36.  doi:10.7506/spkx1002-6300-201007008
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Chongqing traditional bacon was used as experimental material to analyze the change in water, benzo (α) pyrene and nitrate contents, acid value (AV), peroxide value (POV), textural and sensory properties during low-temperature smoking. Results indicated that the water content in Chongqing traditional bacon was lower and the hardness of Chongqing traditional bacon was higher when compared with normal bacon. Low-temperature smoked bacon had excellent color and flavor. AV and POV of Chongqing traditional bacon were 3.02 mg/g fat and 0.0273 g/100 g fat, respectively. The contents of benzo (α) pyrene and nitrate in this bacon were 7.23 mg/kg and 4.6 μg/kg, respectively. All of these indices met the requirements of the relavent national standards. These investigations suggest that long-time, low-temperature smoked Chongqing traditional bacon is good edible safety and the optimal smoking time is 20 d.

Effect of Water Immersion Conditions on Textural Properties and Microstructure of Dried Sea Cucumber
XU Zhi-bin,CHEN Qing,LI Jian-rong*
2010, 31(7):  37-41.  doi:10.7506/spkx1002-6300-201007009
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Dried sea cucumber (Acaudina molpadioidea) must be soaked as the pretreatment for cooking. Its textural properties depend on water immersion conditions. In this study, the effect of immersion conditions on textural properties and microstructure of sea cucumber were investigated. The textural properties of water-immersed sea cucumber were determined by instrumental texture profile analysis (TPA) and Masson staining method. Textural parameters including hardness, elasticity, adhesiveness, resilience, cohesiveness and chewiness were measured. Results indicated that hardness, adhesiveness, elasticity, cohesiveness and resilience were significantly affected by heating temperature. Holding temperature had a pronounced effect on hardness, adhesiveness, chewiness, cohesiveness and resilience. Hardness and adhesiveness were affected by interaction between heating temperature and holding temperature. Moreover, structural changes were also observed under a light microscope due to different immersion conditions. Furthermore, adhesiveness had a negative correlation with hardness, chewiness, elasicity and cohesiveness. However, hardness was positively correlated well with chewiness, cohesiveness and resilience.

Application of Recombinant Elastase in Pork Tenderization
CHEN Zhuo-jun1,WANG Lei2,XU Wen-tao1,2,*,GU Xin-xi2,LI Xiao-ting1,MEI Xiao-hong2,HUANG Kun-lun1,2
2010, 31(7):  42-45.  doi:10.7506/spkx1002-6300-201007010
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The application of recombinant elastase from Pseudomonas aeruginosa in pork tenderization was investigated using papain as control. The enzymological properties of the enzyme were measured. Meanwhile, the optimal conditions affecting pork tenderization including elastase concentration, addition style, and pre-treatment temperature and time for pork were explored. The shear force change was determined to evaluate the degree of tenderness. Results indicated that the optimal pork tenderization was achieved by injecting the elastase at the concentration of 20-37 mg/mL into pork with pre-treatment at 75 - 80 ℃ water bath for 20 - 30 min for 2.5 - 6 h tenderization treatment.

Effect of Dynamic High-pressure Microfluidization Treatment on Properties and Conformation of Stem Bromelain
ZHANG Zhao-qin,LIU Wei,LIANG Rui-hong*,LIU Cheng-mei,WU Wei
2010, 31(7 ):  46-50.  doi:10.7506/spkx1002-6300-201007011
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The effect of dynamic high-pressure microfluidization (DHPM) treatment on activity, stability, and conformation of stem bromelain was studied. Results indicated that bromelain activity was inhibited by DHPM treatment although the residual activity did not decrease with increasing pressure. Under the pressures of 60, 80, 100 MPa and 120 MPa, 94%, 93%, 98% and 92% of bromelain activity were remained, respectively. The optimal temperature of bromelain treated under different pressures exhibited a significant difference, whereas, the optimal pH was not affected. However, DHPM treatments under 60 MPa and 120 MPa resulted in an obvious increase of pH stability. After incubation at pH 8.0 for 40 min, the residual rates of bromelain activity treated under 60 MPa and 120 MPa were 85% and 82%, respectively, which exhibited increases of 14% and 11% compared with untreated bromelain. In addition, conformational change of bromelain induced by DHPM treatment was observed in the change of spectra. Ultraviolet and fluorescence spectra indicated that DHPM treatment induced the unfolding of bromelain and microenvironment changes of tryptophan and tyrosine residues. FTIR spectral analysis indicated that the secondary or tertiary structure of bromelain also disturbed by DHPM.

Distribution of Patulin in Rotten Apples
LIU Hua-feng,HAN Shun-yu*,SHENG Wen-jun,ZHU Xia,JIANG Yu-mei
2010, 31(7):  51-53.  doi:10.7506/spkx1002-6300-201007012
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To explore the distribution of patulin in rotten apples, Fuji apples were used as experimental materials to analyze patulin by HPLC. Results indicated that higher patulin levels were concentrated in apples with higher decay degree. A declined patulin content was determined in apples from locations far way from decayed locations. Therefore, serious rotten apples should be removed.

Development of Efficient Preparation and Identification Methods for Bovine Collagen
TANG Jun1,WEI Dong-zhi1,ZHANG Guo-jun2,SHEN Ju-quan3,DONG Ying1Z,HOU Wen-yu1,MA Zhi-ying3,SHEN Ya-ling1,*
2010, 31(7):  54-60.  doi:10.7506/spkx1002-6300-201007013
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Generally, collagen is extracted mainly from animal skin under the aid of acids or enzymes. However, these methods usually have disadvantages of lower yield, time-consuming extraction, rigorous experimental requirements, and broken triplehelix structure. Based on the consideration of advantages and disadvantages of acid and enzymatic extraction methods, a novel approach, acid-enzyme combined method, for separating type I collagen from bovine skin was developed. This method provided a convenient process and a high yield of 54.5% within short time. In addition, products obtained could remain the natural triple helix structure. Meanwhile, a new method for identification and quality evaluation of collagen and gelatin designated as speedy identification and evaluation method was established based on qualitative and structural analysis of collagen. Therefore, the acidenzyme combined method and the speedy identification and evaluation method can offer promising practical applications in industrial production of collagen, and identification and evaluation of various commercial collagen products.

Digestibility of Mechanical Activated Cassava Starch and Acetylated Starch
CHEN Yuan1,LI Jia-gui1,HUANG Zu-qiang2,*,HE Shao-fan1,WEI Hui-fang1
2010, 31(7):  61-66.  doi:10.7506/spkx1002-6300-201007014
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In-Vitro model and 76-13 standard method of the American Association of Cereal Chemistry (AACC) were used to evaluate the digestibility and enzymatic resistance of mechanical activated cassava starch and its acetylated starch. Results indicated that mechanical activation significantly improved the digestibility of cassava starch granules. Meanwhile, longer activation time could result in enhanced digestion rate and less enzymatic resistance starch. The major reason was due to the damage of crystal structure and compact granule surface of cassava starch, which improved the sensitivity of starch granule digestibility and reactivity. Acetylation also resulted in an increase in digestibility of activated starch granules, a reduction of digestibility of starch pastes, and destroyed and inhibited the formation of enzymatic resistance starch. However, decreases in digestion rate of starch granules and pastes and enzymatic resistance starch content were also observed due to increasing degree of substitution (DS).

Recovery and Regeneration of Weak Cation Exchange Agent Based on Silica with Different Ligands
WANG Yan,ZHANG Fan,LI Rong*,CHEN Guo-liang,WANG Xiao-gang
2010, 31(7):  67-70.  doi:10.7506/spkx1002-6300-201007015
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Used silica with different ligands was recovered and regenerated by means of acid treatment. Iminodiacetic acid (IDA)- recycled silica column was synthesized using IDA as new ligand and pickled silica with different ligands as matrix by direct or indirect methods. The chromatographic performance of synthesized packing materials was investigated. Results indicated that IDA-recycled silica column exhibited an excellent separation efficiency to proteins although its chromatographic performance was lower. IDA-recycled silica column synthesized by direct method revealed much better chromatographic performance than indirect synthesis method. The IDA-recycled silica column was successfully used to extract and purify lysozyme and cytochrome C from egg and pig heart, respectively. These investigations demonstrate the feasibility for recovery and regeneration of silica.

Effect of Physical Force on Emulsion Activity Index and Stability of Soybean Protein Isolate
ZHOU Ying,HUANG Xing-jian,LU Si-yi,LU Qi,PAN Si-yi*
2010, 31(7):  71-74.  doi:10.7506/spkx1002-6300-201007016
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To under the effect of physical force on emulsion activity index (EAI) and emulsifying stability (ES) of soybean protein isolates (SPIs) obtained from different varieties of soybeans, various concentrations of NaCl, NaSCN, urea and 1,2-propylene were respetively used to treat SPI for changing its physical force. Results indicated that the increasing concentration of NaCl and NaSCN resulted in an initial increase and a following reduction of EAI of SPI. This suggests that electrostatic interaction was a dominant force and hydrophobic interaction is unfavorable to EAI of SPI. The fact that emulsifying stability was decreased with increasing concentrations of NaCl and NaSCN demonstrates that electrostatic interaction is stronger than hydrophobic interaction. The addition of urea improved the exposure of hydrophobic groups in protein and promoted the increase of EAI of SPI. However, no obvious effect of added urea at different levels on EAI was observed. Furthermore, as 1,2-propylene concentration increased, there was an increase of EAI. Therefore, hydrogen bonding interactions are beneficial to EAI and ES of SPI.

Factors Affecting Textural Properties and Water-holding Capacity of Heat-induced Gels of Porcine Blood Plasma Protein
KONG Bao-hua1,ZHANG Li-juan1,DIAO Xin-ping2
2010, 31(7):  75-80.  doi:10.7506/spkx1002-6300-201007017
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Effects of protein concentration, heating temperature, heating time, ionic species, ionic strength and pH on textural property and water-holding capacity of heat-induced gels of porcine blood plasma protein were investigated in this study. Gel hardness and adhesiveness were studied using TA-XT analyzer and water-holding capacity (WHC) was measured by centrifugation. Results showed that porcine blood plasma protein was easy to form protein gels under the condition of over 6g/100mL protein concentration via heating for 45 min at 80 ℃. Increasing concentration of porcine blood plasma protein resulted in a significant increase of gel strength and WHC (P < 0.05). Meanwhile, gel strength exhibited a significant improvement with increasing pH within the range of 3 to 9 (P < 0.05). The lowest and the highest WHC of heat-induced gels of porcine blood plasma protein were observed at pH 5.0 and 3.0, respectively. In addition, the highest hardness of porcine blood plasma protein gel was observed in the presence of 0.2 mol/L NaCl and 0.6 mol/L CaCl2, respectively. These findings suggest that many factors affect the textural properties and WHC of heat-induced gels of porcine blood plasma protein. Therefore, heating conditions should be controlled to improve gel quality during practical processing.

Chitooligosaccharide: Free Radicals Scavenging Activity and Protective Effect against Lipopolysaccharide-induced Oxidative Injury in Microglial Cell Line N9
ZHANG Ji1,LIU Hong-tao2,LI Xiu-ying1,XIE Xiao-yan1,LI Wen-ming1,YU Chao1,*
2010, 31(7):  81-85.  doi:10.7506/spkx1002-6300-201007018
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Objective: To study anti-oxidant activity of chitooligosaccharide (COS) and its protective effect against lipopolysaccharide (LPS)-induced oxidative injury in microglial cell line N9. Methods: The antioxidant activity of COS in vitro was evaluated by DPPH and hydroxyl free radical and hydrogen peroxide scavenging assays. Microglial cell line N9 was treated with LPS alone at the dose of 1 μg/mL or co-treated with LPS at the dose of 1 μg/mL and COS at doses of 50, 100, 200, 300 μg/mL and 400 μg/mL, respectively. Cell morphology was examined under microscope with HE staining and NO level in cell culture supernatant was determined. Intracellular generation of reactive oxygen species (ROS) was detected using 2',5' dichlorofluorescin diacetate (DCFH-DA) and flow cytometry combined with fluorescence microscope. Cell apoptosis was detected by DNA ladder assay. Results: COS exhibited an effective scavenging activity against DPPH and hydroxyl free radicals but no scavenging activity against H2O2. Meanwhile, COS attenuated the activation of microglial cell line N9 induced by LPS. The level of NO in cell culture supernatant was significantly decreased due to the presence of COS, and ROS generation induced by LPS was inhibited by COS in a dose-dependent manner. COS also inhibited the apoptosis of microglial cell line N9 induced by LPS. Conclusion: The antioxidant activity of COS is beneficial for protecting microglial cell line N9 from oxidative injury induced by LPS.

Effect of Respective Additions of Selenium and Cerium on Contents of Polysaccharide and Triterpene in Fermentation Supernatant and Mycelia of Ganoderma lucidum
SUN Juan,WEN Lu*,CHEN Ju-ping,WENG Liang,WANG Jing-jian,FENG Han
2010, 31(7):  86-89.  doi:10.7506/spkx1002-6300-201007019
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Objective: To investigate the effect of respective additions of selenium and cerium at various concentration levels on contents of polysaccharides and triterpene in fermentation supernatant and mycelia of Ganoderma lucidum. Methods: Ganoderma lucidum was statically grown for 30 d in shallow liquid medium containing various concentrations of sodium selenite or ammonium ceric nitrate. At the end of fermentation, the fermentation broth was harvested and separated into supernatant and mycelia to measure polysaccharide content in both of them by phenol-sulfuric acid method and ganoderic acid content in the mycelia by glacial acetic acid-vanillina method. Results: Added sodium selenite at the level of 40 mg/L to culture medium resulted in 42.3% and 10.6% increases of polysaccharides and ganoderic acid contents in the mycelia, respectively. An increase of 51.1% in polysaccharide content in the mycelia resulting from the addition of 15 mg/L ammonium ceric nitrate was observed, whereas ganoderic acid content exhibited a decrease. Respective additions of selenium and cerium resulted in an obvious increase of polysaccharide content in the supernatant. Conclusion: Respective additions of selenium and cerium to culture medium at an appropriate level significantly enhance polysaccharide contents in m fermentation supernatant and mycelia of Ganoderma lucidum, although added selenium increases ganoderic acid content, while added cerium decreases ganoderic acid content. To obtain high-quality fermentation supernatant and mycelia of Ganoderma lucidum, selenium and cerium should be added appropriately according to actual production requirements.

Chemical Composition and Antibacterial Activity of Volatile Oil from Fructus liquidambaris
LIU Yu-min1,LIU Ya-min1,LI Chang-xiao2,LI Peng-xia3
2010, 31(7):  90-93.  doi:10.7506/spkx1002-6300-201007020
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GC-MS based on steam distillation extraction was used to analyze chemical composition of volatile oil from Fructus liquidambaris. Quantitative determination was conducted using area normalization method. GC-MS results exhibited that 43 peaks were separated and 38 components were identified with 97.28% total detection rate. Twenty-eight of these compounds belonged to the family of terpenes accounting for 83.21% of total volatile oil; 6 were aliphatic compounds and 4 were aromatic compounds, accounting for 12.02% and 2.05% total volatile oil, respectively. Major compounds in Fructus liquidambaris volatile oil were β-pinene (21.96%), α-pinene (21.32%), limonene (8.43%), (E)-2-hexenal (8.04%), and β-caryophyllene (5.67%). Antimicrobial activity of Fructus liquidambaris volatile oil was evaluated by paper disc method. Results indicated that Fructus liquidambaris volatile oil had an obvious antimicrobial activity against Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Aspergillus flavus, and Penicillium oxalicum. The volatile oil exhibited the strongest and weakest antimicrobial activities against Bacillus subtilis and Escherichia coli, respectively. However, the control group had no antimicrobial effect. Variance analysis suggested that there was a significant difference in antimicrobial activity of the same concentrations of Fructus liquidambaris volatile oil against various microorganisms and various concentrations of Fructus liquidambaris volatile oil also had a significant difference in antimicrobial activity against the same microorganisms.

Antioxidant Activity of Sour Meat Peptide
YE Chun1,MA Shun-qiang1,ZHANG Qian2,*,LIU Shi-hui1
2010, 31(7):  94-97.  doi:10.7506/spkx1002-6300-201007021
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Antioxidant activity of sour meat peptide was studied by measuring its scavenging capacity against 2,2-Diphenyl- 1-picrylhydrazyl (DPPH) free radicals, hydroxyl free radicals and nitrite, and its reducing power. Results indicated that sour meat peptide had better scavenging capacity against DPPH free radicals with the IC50 value of 247.96μg/mL, which was 4.97 times higher than that of BHT. In addition, it possessed remarkable scavenging capacity against hydroxyl free radicals with the IC50 value of 33.60μg/mL, which was 1.52 times higher than that of BHT. Moreover, it possessed strong reducing power, which was approximately one quarter of that of BHT. Furthermore, it also exhibited strong scavenging capacity against nitrite. Therefore, sour meat peptide has an obvious antioxidant activity.

Formation of Volatile Flavor Components during Sour Meat Processing
ZHOU Cai-qiong,DAI Xiao-rong,DU Mu-ying
2010, 31(7):  98-104.  doi:10.7506/spkx1002-6300-201007022
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The change of volatile flavor components during sour meat processing was analyzed by SDE-GC-MS to investigate the relationship between degradation of lipid and protein and flavor formation. Results showed that flavor compounds rose from 31 kinds in raw materials to 85 kinds in final products, and esters, aldehydes and hydrocarbons rose from 7, 8 and 10 at the beginning of fermentation to 23, 23 and 27 at the end of fermentation, respectively. In addition, relative content of esters, aldehydes and hydrocarbons rose from 24.34%, 23.71% and 31.63% at the beginning of fermentation to 33.86%, 38.40% and 20.87% at the end of fermentation. Linear correlation analysis revealed that POV exhibited a significantly negative correlation with relative content change of aromatic esters (P<0.05). The characteristic volatile flavor components such as eucalyptol, [(2-ethoxyethyl) sulfanyl]-acetic acid, and 2-methoxy-phenol were generated during fermentation processing. Moreover, the major flavor components were 2,4-decadienal and ethyl decanoate, which formed special ester aroma, acidic taste and delicate fragrance of fermented sour meat. Flavor formation was possibly due to the growth and reproduction of microorganism and secretion of extra-cellular enzymes, which led to the degradation of lipid and protein to generate volatile flavor components including aldehydes, ketones, alcohols and acids and other substances, and result in esterification reaction for forming a unique acidic meat flavor.

Nutritional Evaluation of Protein in Tartary Buckwheat Grain and Its Response to Selenium
TIAN Xiu-ying,LI Hui-he
2010, 31(7):  105-108.  doi:10.7506/spkx1002-6300-201007023
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Pot-culture experiment was conducted to nutritional evaluation of protein in tartary buckwheat grain and its response to selenium. Results indicated that the ratios of E/T (essential amino acid/total amino acid) and E/N (essential amino acid/nonessential amino acid) in buckwheat grain cultured in soil without selenite were 34.4% and 52.2%, respectively, which was similar with WHO/FAO standard (40% for E/T and 60% for E/N). Meanwhile, proteins in buckwheat grain exhibited excellent quality. The content, amino acid score (AAS) and chemical score (CS) of sulfur amino acids (methionine + cystine) exhibited the lowest level in all determined essential amino acids. This demonstrates that they were the first limited amino acid. However, an increase of threonine and lysine contents and a reduction of sulfur amino acids (Met + Cys) were observed in tartary buckwheat cultured in soil containing 0.5 mg/kg selenite. In addition, when soil supplemented with selenite larger than 1.0 mg/kg, crude protein, essential amino acids, non-essential amino acids and total amino acids in tartary buckwheat grain exhibited an increase. Compared to the control without selenite treatment, the soil supplemented with selenite in the range of 1.5-2.0 mg/kg could result in an obvious enhancement in ASS and CS of all other essential amino acids except methionine and cystine in tartary buckwheat grain.

Effects of Postmortem Chilling Time and Following Freezing of Fresh Pork on Quality of Chinese Sausage
YU Xiao-ling1,LI Xue-bin2,ZHAO Hui1,MA Han-jun1
2010, 31(7 ):  109-113.  doi:10.7506/spkx1002-6300-201007024
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Uniform design was applied to examine the effects of postmortem chilling time and following freezing of fresh pork on quality change of Chinese sausage. Thiobarbituric acid reactive substance (TBARS), pH, water holding capacity (WHC) under pressure, yield and sensory quality were measured. Results exhibited that both factors had significant effects on pH, WHC, TBARS and yield in a nonlinear manner. However, no obvious effect on sensory quality was observed. The optimization calculation indicated that there was no optimal solution when materials were frozen pork. On the other hand, the earlier freezing can result in higher yield and smaller TBARS value of raw Chinese sausage when materials were fresh pork. Therefore, better quality of Chinese sausage can come from fresh pork materials and earlier freezing during manufacturing.

Analysis of Saponins from Carica papaya Pulp
HU Chang-ying,PAN Hui-fang
2010, 31(7):  114-116.  doi:10.7506/spkx1002-6300-201007025
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Objectives: To investigate bioactive compounds from Carica papaya pulp. Methods: Chemical components in Carica papaya pulp was extracted using 85% ethanol and purified by marcoporous resin adsorption followed by ODS and MCI column chromatography. The structures of these compounds were elucidated through NMR spectroscopic analysis. Results: Three compounds were isolated from Carica papaya pulp and their chemical structures were identified as 2β, 3β-dihydroxy-ursolic acid (Ⅰ); 3-O-glycoside-sterol (II); diosgenin-3-O- β-D-glucopyranosyl(1 → 3)- β-D-glucopyranosyl(1 → 4)-[α-Lrhamnopyranosyl(1 → 2)]- β -D-glucopyranoside (III), respectively. Conclusion: To the best of our knowledge, this paper is the first one that reports compounds I - III obtained from Carica papaya pulp.

Preservation of Free-living Conchocelis of Porphyra yezoensis
GUO Jin-yao, YANG Xiao-ling
2010, 31(7 ):  117-122.  doi:10.7506/spkx1002-6300-201007026
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To achieve an optimal preservation and protection of free-living conchocelis of Porphyra yezoensis with excellent characters, the preserving conditions including temperature, light intensity and nutrition were studied. Results showed that temperature, light intensity and nutrition were all important factors affecting preservation of free-living conchocelis of Porphyra yezoensis and the safe preservation period in liquid medium supplemented with enriched seawater supplement (ESS) nutrients was over 40 days under the illumination level of 300 lx at 5 ℃ or10 ℃, with a survival rate of 90%, which was higher than that under the illumination level of 1000lx or 1500 lx at 20 ℃. Frequent alternation of the supplemented liquid medium was required for higher survival rate of the conchocelis preserved at higher temperature. In the preservation of the conchocelis encapsulated into beads made from 20% sodium alginate in its suspension at - 20 ℃, a close relationship between survival rate and water content in the beads was observed and longer dehydration time corresponding to lower water content in sodium alginate beads resulted in higher survival rate of the conchocelis.

Stability of Pigment from Black Sticky Rice
LIU Jing-jing,DUAN Ling-ling,WANG Xue-feng,HAN Yao-ping
2010, 31(7):  123-126.  doi:10.7506/spkx1002-6300-201007027
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Stability of pigment from black sticky rice was studied. Results indicated that the pigment exhibited a good stability in acidic media, while its stability was weak in alkaline media. The pigment exhibited excellent thermal and light stability. Little effect of sugars, salts, citric acid, starch, potassium sorbate, sodium benzoate and metal ions including Mn2+, Na+, K+, Zn2+, Cu2+, Ca2+ and Mg2+ on pigment stability was observed. However, Fe3+ had an obvious adverse effect on the stability of black sticky rice pigment.

Antibacterial Activity and Stability of Extracts from Potentilla ansterina L.
YANG Dong-mei1,ZHU Xing-yi2,WANG Qiu-shuang3,BI Yang1,QIU Zhao-zheng1
2010, 31(7):  127-130.  doi:10.7506/spkx1002-6300-201007028
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Inhibitory effects of water extract, 60% ethanol extract and ethyl acetate extract from Potentilla ansterina L. against 6 common foodborne pathogenic bacteria were tested using agar diffusion method. Meanwhile, pH and thermal treatment affecting the antibacterial activity of the 60% ethanol extract were also investigated. Results indicated that all the 3 extracts from Potentilla ansterina L., especially the 60% ethanol extract exhibited an obvious inhibitory effect against 6 pathogenic bacteria tested. The inhibitory effects of the 60% ethanol extract against 6 pathogenic bacteria tested all reached the highest levels at pH 7. The antibacterial activity of the 60% ethanol extract exhibited good thermal stability, although the heating treatment at 121 ℃ for 30 min resulted in an obvious decrease in the antibacterial activity.

Ethanol Extract of Syringa reticulate: Evaluation of Antibacterial Activity and Antioxidant Activity and Analysis of Trace Elements
ZHANG Chong-xi1,CAI En-bo2,CHEN Yan2,LI Jin-ping2,HUANG Kun2,GUAN Jian2,XUE Chang-chun2,ZHENG You-lan2,*
2010, 31(7):  131-134.  doi:10.7506/spkx1002-6300-201007029
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Objectives: To evaluate the antibacterial activities of 80% ethanol extract of Syringa reticulate stem bark against 5 common bacteria and its antioxidant activity and analyze trace elements. Methods: The minimal inhibitory concentrations (MICs) of Syringa reticulata extract against bacteria tested were determined by filter paper method. The effects of temperature, pressure, pH and ultraviolet irradiation on antibacterial activity of the extract were also investigated. DPPH free radical scavenging assay was used for antioxidant activity evaluation. The contents of trace elements such as iron, manganese, zinc and copper were determined using atomic absorption spectrophotometry. Results: The MICs of the extract was 1.563 mg/mL against Staphylococcus aureus, and 6.25 mg/mL against both Pasteurella and Salmonella enterica. The extract exhibited stable antibacterial activity when exposed to high temperature, ultraviolet light and acidic environment. The EC50 (median effective concentration) of the extract for scavenging DPPH free radicals was 0.042 mg/mL. The contents of trace elements such as Fe, Mn, Zn and Cu were 880.5, 26.03, 60.9μg/g and 10.13 μg/g, respectively. Conclusion: Syringa reticulata stem bark has an excellent antibacterial activity and antioxidant activity and exhibits high levels of trace elements. This demonstrates its promising development potential.

Antibacterial Activity and Chemical Composition of Volatile Oils from Herba Agastaches Rugosae and Herba Artemisiae Annuae and Their Half-and-half Mixture
XIONG Yun-hai1,2,RAN Lie1,WANG Mei2
2010, 31(7):  135-139.  doi:10.7506/spkx1002-6300-201007030
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The chemical composition of volatile oils from Herba Agastaches Rugosae and Herba Artemisiae Annuae and their half-and-half mixture were determined by gas chromatography-mass spectrometry (GC-MS). The qualitative and quantitative analyses were conducted by chemometric resolution method and overall volume integration method, respectively. Meanwhile, both volatile oils and their half-and-half mixture were tested for antibacterial activity. Results indicated that half-and-half mixture of the above oils exhibited enhanced inhibitory effects against microorganisms tested when compared with each of them. Totally 48, 69 and 73 components were identified in volatile oils from Herba Agastaches Rugosae and Herba Artemisiae Annuae and their half-and-half mixture, which accounted for 93.23%, 88.85%, and 89.25% of total volatile oil, respectively. Two new components in the mixed oil were detected to be 1, 1-dimethyl-1, 2, 3, 4-tetrahydroisoquinoline and epiglobulol. Although the volatile active components of the mixture of both oils were almost the sum of components from two single herbs, the relative content of each component was changed. The active components with higher relative contents were mainly from Herba Agastaches Rugosae. Therefore, the half-and-half mixture of volatile oils from Herba Agastaches Rugosae and Herba Artemisiae Annuae has promising development value as an effective antibacterial agent.

Identification of Kokumi Taste Peptides in Hydrolyzed Milk Protein
WANG Bei,XU Shi-ying*
2010, 31(7):  140-145.  doi:10.7506/spkx1002-6300-201007031
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The molecules responsible for food taste perception are defined as kokumi flavor compounds. Sensory evaluation revealed 6 Sephadex G-15 column chromatographic (GPC) fractions (P1, P2, P3, P4, P5 and P6) from hydrolyzed milk protein contained some kokumi flavor compounds, compared to skimmed fresh milk. P4 fraction separated by reversed-phase high performance liquid chromatography (RP-HPLC) exhibited the strongest kokumi sensation. Totally 11 peptides in P4 fraction were identified by matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry (MALDI-TOF-MS). Most peptides were originated from β -casein. MALDI-TOF-MS also exhibited that Glu and Cys in these peptides were the most important composition related to the kokumi flavor as previously reported.

Comparative Study on Fatty Acid Composition and DPPH Free Radical Scavenging Activity of Oat Oils Extracted by Different Methods
LI Lin,ZHANG Da-shun *
2010, 31(7):  146-149.  doi:10.7506/spkx1002-6300-201007032
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Oat oils extracted by supercritical carbon dioxide fluid (SCF-CO2) with and without ethanol added as entrainer and those extracted with n-hexane or methanol were compared for differences in fatty acid composition and DPPH free radical scavenging activity. GC analysis showed that the fatty acid composition of 4 oat oils mainly consisted of palmitc acid, elaidic acid and linoleic acid and they together accounted for 93% of total fatty acid in each oat oil. Oat oils extracted by SCF-CO2 with and without ethanol added as entrainer and those extracted with n-hexane or methanol exhibited relative contents of unsaturated fatty acids of 79.41%, 77.86%, 77.56% and 76.51% and ratios of saturated fatty acids to monounsaturated fatty acids to polyunsaturated fatty acids of 1:2.74:1.85, 1:2.08:1.71, 1:2.21:1.60 and 1:1.74:1.73, respectively. The DPPH free radical scavenging activity of the oat oils and vitamins C and E decreased in the following order: vitamin C>oat oil extracted with methanol >oat oil extracted by SCF-CO2 with ethanol added as entrainer>vitamin E >oat oil extracted with n-hexane>oat oil extracted by SCF-CO2 without ethanol added as entrainer.

Effect of High Voltage Electrostatic Field on Sporulation and Germination of Penicillium Spores
LI Xin-jian
2010, 31(7):  150-153.  doi:10.7506/spkx1002-6300-201007033
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Penicillium as one of the microorganisms causing apple mouldy core and core rot was subjected to high voltage electrostatic field (HVEF) treatment for different time to compare sporulation and germination of treated Penicillium spores during suspension culture at different temperatures. Meanwhile, the treated Penicillium spore suspension was inoculated into wounds in apples and infection rate and lesion diameter were measure every day during storage at 25 ℃. Results showed that no obvious difference in germination rate was observed between Penicillium spores with and without HVEF treatment during suspension culture at the same temperatures. However, the germination time of Penicillium spores was delayed due to HVEF treatment. In addition, sporulation had an obvious relationship with the treatment time of HVEF. Compared with Penicillium spore suspension treated with HVEF for 15 min or without FVEF treatment, Penicillium spore suspension with 30 min of HVEF treatment exhibited a lower sporulation after 7 days of culture at 20 ℃. Therefore, lower infection rate and smaller lesion diameter in apple inoculated with Penicillium spore suspension treated with HVEF were observed.

Essential Oil Compositions and Antioxidant Activities of Two Ziziphora Species in Xinjiang
XING Si-lei,ZHANG Pi-hong,JI Qiao-ling*,JIA Hong-li,WANG Xue-hua
2010, 31(7 ):  154-159.  doi:10.7506/spkx1002-6300-201007034
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The chemical composition of essential oils isolated by hydrodistillation from the aerial parts of Ziziphora clinopodioides Lam. and Ziziphora pamiroalaica Juz. were analyzed by gas chromatography/mass spectrometry (GC-MS). Ten constituents representing 99.7% of the Z. clinopodioides oils were identified, which contained (+)-(R)-Pulegone (80.7%), Menthone (8.3%), Piperitenone (4.9%) and (+)-Isomenthone (2.6%) as the major components; On the other hand, twenty-nine constituents representing 99.8% of the oils from Z. pamiroalaica. were identified, the major compounds consisted of (+)-(R)- Pulegone (45.9%), (+)-Isomenthone (24.1%), (+)-Neomenthol(10.1%), Thymol (9.4%). The antioxidant activity of the oils was assessed by measurement of the free radical scavenging (DPPH) activity, the reductive potential, Superoxide anion scavenging activity, NaNO2 scavenging ability and by the TBARS assay, compared with that of synthetic antioxidants: Thymol, Vitamin C (VC) and butylated hydroxytoluene (BHT). Results showed that the oil from Z. pamiroalaica. was better than that from Z. clinopodioides in antioxidant abilities.

Non-isothermal Crystallization Kinetics of Cocoa Butter
SHI Su-jia1,XIE Shi-chao2,CAO Dong2,LIU Li-na2,JING Hong-bing3
2010, 31(7):  160-163.  doi:10.7506/spkx1002-6300-201007035
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The crystallization behavior of cocoa butter was investigated using DSC under non-isothermal environment. Results indicated that crystallization peaks exhibited a shift to lower temperature direction and increasing intensity. Moreover, double peaks were combined into a single peak. Several models including Ozawa, Jeziorny and Mo s method were used to analyze and compare crystallization behavior. Results indicated that Mo s method was more suitable to demonstrate the crystallization behavior of coca butter in non-isothermal environment.

Effects of Organic Acids on Thermal Stability of Anthocyanins from Purple Corn
WANG Yu-bin1,2,ZHANG Chao2,MA Yue2,YUE Xi-qing1,ZHAO Xiao-yan2,*
2010, 31(7):  164-167.  doi:10.7506/spkx1002-6300-201007036
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Effects of organic acids on thermal stability of purple corn anthocyanins (PCA) was evaluated by copigmentation with tannic acid, succinic acid, oxalic acid, malic acid, citric acid, and ascorbic acid. The degradation of PCA and copigmented PCA exhibited a first-order kinetic model. The copigmentation of tannic acid, oxalic acid and citric acid improved the thermal stability of PCA. This is due to the fact that copigmentation of tannic acid, oxalic acid and malic acid enhances the ratio of acylated anthocyanins of PCA and activation energy of copigmented PCA.

Enzymatic Preparation and Hydroxyl Free Radical Scavenging Activity of Polypeptides from Grass Carp Scales
DU Yun-jian,ZHAO Yu-qiao,LI Nian-nian
2010, 31(7):  168-172.  doi:10.7506/spkx1002-6300-201007037
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Complex proteases were used to hydrolyze grass carp scales for preparing polypeptides with high hydroxyl free radical scavenging activity in the present study. To maximize hydroxyl free radical scavenging activity of polypeptides prepared from grass carp scales, three crucial hydrolysis parameters were investigated by response surface analysis based on central composite design. Besides, hydrolysis products of grass carp scales obtained were purified/fractionated by Sephadex G-15 column chromatography and the resulting fractions were evaluated for hydroxyl free radical activity. The optimal values of the above parameters for improved hydrolysis of grass carp scales were determined as follows: substrate concentration 6 g/100 mL, enzyme dose 5.22 g/ 100 mL and reaction temperature 49.33 ℃ for a hydrolysis duration of 2.11 h. Under the optimized parameters, a maximum hydroxyl free radical scavenging activity of hydrolyzed grass carp scales of 99.24% was obtained. Sephadex G-15 column chromatographic separation resulted in 5 fractions and the highest scavenging rate (98.34%) against hydroxyl free radicals was observed in the fourth fraction.

Effect of Metal Ions on Gel-forming Characteristics of Peanut Protein Isolate
ZHONG Shi-rong,FENG Zhi-ping,WU Shi-ye
2010, 31(7 ):  173-176.  doi:10.7506/spkx1002-6300-201007038
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Peanut protein isolate was prepared by the method of alkaline extraction followed by acid precipitation. Effects of metal ions such as NaCl, MgCl2, CaCl2 and CuSO4 at various concentrations on gel-forming characteristics of peanut protein isolate were explored under the conditions of 90 ℃, pH 9 and 14 g/100mL peanut protein solution. Results indicated that CaCl2 at the concentration of 0.06 mol/L was a good coagulatant for peanut protein isolate. Higher hardness, shorter gelatin time and thicker colloidal particles of peanut protein isolate were observed under this condition.

Isolation, Identification and RAPD Analysis of Lactobacillus delbrueckii from Different Commercial Brands of Yogurts
MA Cheng-jie1,WU Zheng-jun1,DU Zhao-ping2,LIU Xin2,MA Ai-min2,*
2010, 31(7):  177-181.  doi:10.7506/spkx1002-6300-201007039
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Ten strains of Lactobacillus delbrueckii were isolated from ten commercial brands of yogurts. L.d 3, L.d 4, L.d 5, L.d 6, L.d 8 and L.d 10 were identified as Lactobacillus delbrueckii subsp. bulgaricus, and L.d 1, L.d 2, L.d 7 and L.d 9 were identified as Lactobacillus delbrueckii subsp. lactis according to physiological and biochemical tests and specific PCR identification. The genetic diversity of ten strains was evaluated through random amplified polymorphic DNA (RAPD) analysis using 24 random primers, and the similarity coefficient matrix and clustering analysis were achieved according to statistical analysis of fingerprinting data using NTSYSpc-2.10e software. Results indicated that genetic similarity coefficients of ten strains were ranged in 0.4167 and 0.8833. The genetic relationship and heterogeneity existed among different strains to a certain extent.

Identification of Extracellular Protein Profile of Aspergillus oryzae AS 3.951 Grown on Wheat Bran Koji
PAN Li,MIAO Xiao-kang,LIANG Yan-chang
2010, 31(7):  182-185.  doi:10.7506/spkx1002-6300-201007040
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Aspergillus oryzae AS 3.951 is the most widely used strain in soy sauce manufacture in China, but the extracellular protein profile during the culture of wheat bran koji have not been identified. Totally 11 protein bands in SDS-PAGE were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) and searching in Swissport protein database and Dogan genome database. According to the comparison with databases, 8 proteins including amylase, glucoamylase and proteases were identified. The extracellular protein profile of Aspergillus oryzae AS 3.951 during soy sauce manufacture were completed through the combination of our data and previous reports.

CFD Simulation of A Mechanically Stirred Bioreactor and Its Application in Lactic Acid Production
WU Xue-feng,JIANG Shao-tong*,ZHANG Min,LIU Mo,PANG Rui
2010, 31(7):  186-189.  doi:10.7506/spkx1002-6300-201007041
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Mixsim, one of computational fluid dynamics (CFD) methods, was used to simulate a 3 L mechanically stirred bioreactor to study the effect of agitation speed on agitation current field. Along with this, effect of agitation speed on formation of mycelial pellets of Rhizopus oryzae and lactic acid production in the real bioreactor. Results showed that higher agitation speeds corresponding to higher shear stress rates resulted in the formation of more than 98% of mycelial pellets of 0.1 – 0.3 mm in diameter, with lower lactic acid production and biomass. In contrast, when agitation speed was controlled at lower levels and shear stress rate was also lower, the formation of mycelial pellets was inhibited and higher lactic acid production was achieved. However, the large amount of dispersed mycelia exhibited a negative impact on latter fermentation. A maximum lactic acid production of 106.7 g/L fermentation broth was achieved at the agitation of 400 r/min. Meanwhile, more than 80% of Rhizopus oryzae mycelia were formed into pellets of 1.0-1.5 mm in diameter. The biggest shear stress rate simulated by CFD was 1.58 m/s.

Screening of RAPD Markers Linked to Acid Resistance-related Gene in Oenococcus oeni
LIU Shu-wen1,2,LI Xi-zhu2,WANG Zuo-jing2,ZHOU Li-guo2
2010, 31(7):  190-195.  doi:10.7506/spkx1002-6300-201007042
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Major factors affecting RAPD reaction system were optimized and an optimal RAPD reaction system was established for laboratory investigations. Subsequently, 33 acid-resistant Oenococcus oeni strains and 9 acid-sensitive Oenococcus oeni strains were used as experimental materials for screening RAPD markers linked to acid resistance-related genes. Random amplified polymorphic DNA (RAPD) and bulked segregate analysis (BSA) techniques were employed in this study. Three RAPD markers S40-1400, S333-2500 and S333-650 linked to acid resistance in Oenococcus oeni were obtained through a selection from 45 random primers and confirmation in a single Oenococcus oeni strain.

Effect of Sodium Selenite on Microorganism Growth in the Presence of Chitooligosaccharide
WANG Lian-sheng,PENG Hui-e,LI Wei,QIN Cai-qin*
2010, 31(7):  196-198.  doi:10.7506/spkx1002-6300-201007043
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Chitooligosaccharides were prepared through the hydrolysis of chitosan with α -amylase. Escherichia coli, Staphylococcus aureus and Lactobacillus acidophilus were used as experimental microorganisms. The effect of sodium selenite on microorganism growth in the presence of various concentrations of chitooligosaccharides was investigated by microcalorimetric and turbidity methods. Results indicated that the inhibitory effect of sodium selenite on microorganism growth exhibited an obvious decrease with increasing chitooligosaccharides concentration.

Immobilization of Amylase on Rare Earth Coordinated Rosin Based Functional Polymers
LEI Fu-hou,LU Jian-fang,ZHAO Kang,QIN Dong-mei,YAO Xing-dong
2010, 31(7):  199-204.  doi:10.7506/spkx1002-6300-201007044
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With polyhexmethylene maleic rosinate, polyethylene maleic rosinate polymer or its copolymer with acrylic acid as matrix, amylase was immobilized on La(III), Eu(III), Tb(III), Y(III) or Dy(III) coordinates of the matrix. The performance of the immobilized enzyme and the mechanism of immobilization were investigated. High activities were observed for the Y(III) and Dy(III) coordinates of the functional polymers. The optimal temperature and pH were both 60 ℃ and 6.03, respectively. The residual activities after used for 4 cycles were 31.49 and 29.76 mg/g·5 min. In addition, the correlation between the activities of the immobilized enzymes and surface area of the matrix as well as pH was established.

Pulsed-field Gel Electrophoresis Types and Drug Resistance of Enterobacter sakazakii
XU Long-yan1,YUAN Mu-yun1,LIU Jing-yu1,ZHAO Gui-ming2,ZOU Zhi-fei1,YANG Jing1,JIAO Hong1,*
2010, 31(7):  205-209.  doi:10.7506/spkx1002-6300-201007045
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Objectives: To investigate molecular types and drug resistance patterns of Enterobacter sakazakii isolated from foods from Beijing, Xinjiang, Guangdong, and Liaoning or imported foods from New Zealand, USA, and India. Methods: E. sakazakii chromosomal DNA was digested by restriction endonuclease Xba I and analyzed by pulsed-field gel electrophoresis (PFGE). PFGE patterns of E. sakazakii strains from different areas were compared using BioNumberics software to analyze the similarity among strains. Antibiotic susceptibility test was carried out using VITEK2 to analyze drug resistance patterns. Results: Totally 38 E. sakazakii strains revealed 37 PFGE patterns with similarity ranged from 25% to 100%. Neither significantly predominant PFGE patterns nor area specificity were observed. Moreover, some food samples were contaminated by genetically related E. sakazakii clonal strains. Furthermore, the antibiotic susceptibility test also exhibited 9 drug resistance patterns including resistance to furans, cephalosporins, and β-lactam antibiotics. Conclusion: The PFGE method described above may be used for molecular typing and source tracing of E. sakazakii.

Optimization of Fermentation of Porcine Bone Powder by Lactic Acid Bacteria for Enhanced Free Calcium Content
HU Lin-lin,ZHAO Yan-yan*,QIN Xiu-qing,JIANG Shao-tong
2010, 31(7):  210-213.  doi:10.7506/spkx1002-6300-201007046
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In this experiment, Lactobacillus bulgaricus and Streptococcus thermophilus were used to co-ferment porcine bone powder for enhancing free calcium level in fermentation broth. The optimal fermentation process of porcine bone powder was investigated by single-factor and orthogonal array design methods. Results indicated that the optimal values of fermentation conditions including ratio of Lactobacillus bulgaricus to Streptococcus thermophilus, sucrose amount, inoculum amount and porcine bone powder amount were 2:1, 6%, 7%, and 6%, respectively. The fermentation broth obtained under the optimized conditions exhibited a free calcium content of 0.9942% and a ratio of calcium to phosphorus of 2.3:1.

Molecular Biological Identification and Application of Yeast Strain for Fermentation of Sea-buckthorn Wine
NIU Guang-cai1,ZHU Dan2,WANG Xian-qing1,WEI Wen-yi1,LI Zhi-jiang1
2010, 31(7):  214-218.  doi:10.7506/spkx1002-6300-201007047
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Currently, a special yeast strain for industrial fermentation of sea-buckthorn wine has highly required and it is necessary to screen a fine yeast strain suitable for the fermentation of sea-buckthorn wine. A yeast Y23 was identified by ITS1- 5.8S-ITS2 rDNA sequence analysis and phylogenetic dendrogram construction. Results showed that the complete sequence of 5.8S-ITS rDNA (GenBank Accession: FJ793809) was 874 bp. The yeast Y23 had the nearest heredity with Saccharomyces cerevisiae CBS423T (AM262829), and the homology of their gene sequences were up to 100% so that the selected yeast Y23 was identified as Saccharomyces cerevisiae belonging to the family of Saccharomyces. The yeast Y23 was used as experimental strain to evaluate the effects of initial sugar degree, fermentation temperature and inoculum amount on the quality of sea-buckthorn wine by response surface methodology (RSM). A regression equation with high reliability was obtained and the above technological parameters were optimized using this equation model. Inoculum amount revealed a significant effect on the quality of seabuckthorn wine (P<0.01). The optimal values of technological parameters for improved quality of sea-buckthorn wine were as follows: original sugar degree 19.9%, fermentation temperature 25.4 ℃ and inoculum amount 10.3%.

Separation of Salt-tolerant and Acid-producing Yeasts from Soy Sauce Mash
YANG Qiu-ming,GUO Cai-hua,CAI Hui-nong
2010, 31(7):  219-222.  doi:10.7506/spkx1002-6300-201007048
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A strain with acid-producing ability identified based on calcium-dissolving ring, micro-morphology and colony characteristics, physiological and biochemical properties was isolated from late fermentation of soy sauce mash. Glucose consumption and growth of this strain were determined under various salt concentrations. This acid-producing yeast still grew well under the condition of 22 g/100 mL NaCl and produced acidic materials. Moreover, this strain was confirmed to be lactic acid type yeast by paper chromatography and gas chromatography. The increasing concentration of NaCl could result in the decrease of lactic acid content in fermentation broth. The lactic acid content was 1.94% (V/V) after 8 days of fermentation in the medium with 16 g/100 mL NaCl.

Isolation, Purification and Enzymological Properties of Peroxidase from Sweet Potato (Ipomoea batatas Lam.) Leaves
FU Wei-li,TANG Liang-ting,WANG Song,ZHU Hong,GAO Zhao-wei,TANG Yun-ming *
2010, 31(7):  223-227.  doi:10.7506/spkx1002-6300-201007049
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In order to obtain purified peroxidase from sweet potato (Ipomoea batatas Lam.) leaves for the study of its enzymatic properties, ammonium sulfate precipitation, ion exchange chromatography on DEAE-Sepharose column and Sephacryl S-200 gel filtration were used to purify peroxidase (POD) from sweet potato leaves. The specific activity of purified POD was 91923.14 U/mg, which exhibited a purification fold of 255.69 and a recovery rate of 1.59%. The molecular weight of this enzyme was 35 kD, and the optimal pH and temperature were 5.6 and 60 ℃, respectively. The peroxidase was stable at 20-50 ℃ and pH 4 - 8. The apparent Km of this enzyme using H2O2 as substrate at different conditions was 0.291 mol/L at 25 ℃ and pH 7.2. Its activity was enhanced by urea, Li+, Na+, K+, Mg2+ and oxalic acid, yet inhibited by SDS, KSCN, AsA (ascorbic acid) and Mn2+. Organic solvents such as methanol, ethanol, glycol and isopropanol could inhibit the activity of this enzyme and the order according to the inhibitory effect from strong to weak was isopropanol, ethanol, methanol and glycol. These results reveal that POD is very stable and therefore has promising application value.

Isolation, Identification and Characterization of Lactic Acid Bacteria with Activity to Flocculate Sweet Potato Starch
ZHANG Li-li1,2,XU Yun-he1,2,LI Xin-hua1,*
2010, 31(7):  228-231.  doi:10.7506/spkx1002-6300-201007050
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A lactic acid bacterial strain L1 was isolated from spontaneously fermented sweet potato slurry and identified as Lactobacillus paracasei subsp. paracasei. Its optimal conditions for flocculating activity were 6.5-8.5 for pH and 25-35 ℃ for temperature. Glucose, sucrose, maltose and lactose were excellent carbon sources and the optimal nitrogen source was yeast extract or beef extract. The bioflocculant produced by strain L1 was mainly adhered to the interface of cells.

Screening and Identification of Strains of Yeast and Lactobacillus with High Fermentation Performance from Fermented Rice Slurry
LIU Zhen,LIU Xiao-cui,ZHAO Si-ming*,XIONG Shan-bai
2010, 31(7):  232-235.  doi:10.7506/spkx1002-6300-201007051
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In order to realize the standardization of industrial production of traditional fermented rice cake, the strains with high fermentation performance were screened and identified from fermented rice slurry for traditional rice cake production. Totally 40 yeast-like strains and 30 lactobacillus-like strains were isolated from fermented rice slurry. One yeast strain with high fermentation performance was finally obtained through 3-step screening process including measurement of gas production in Durham tubes, characteristic analysis of fermentation broth and illustration of growth curve. One Lactobacillus strain with high fermentation performance was also obtained through initial screening of Gram staining, pH measurement and growth curve analysis. Both strains were identified as Brettanomyces custersii and Lactobacillus plantarum based on their colonial morphology and physiological and biochemical experiments.

Protective Mechanisms of Trehalose and Hyaluronic Acid on Lyophilized Bifidobacterium longum
ZHANG Yu-hua1,2,MENG Yi2, LING Pei-xue3,JI Bao-ping4
2010, 31(7):  236-241.  doi:10.7506/spkx1002-6300-201007052
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In order to explore the cellular damage caused by lyophilization and protective mechanisms of trehalose and hyaluronica acid (HA) to cellular damage, leakage of proteins and nucleic acids, change of ATPase activity, cell morphology, structural change of membrane lipids and proteins in lyophilized Bifitdobacterium longum were investigated after rehydration. Lyophilization resulted in the damage of membrane and sensitive proteins in cells. The formation of hydrogen bond between trehalose and polar groups in membrane lipids and proteins replaced water loss around polar groups and maintained the hydration status of membrane lipids and the stability of secondary structure of proteins. In addition, due to higher glass temperature (Tg) resulting from the combination of trehalose and HA, combined use of trehalose and HA provided a complementary property. Therefore, the combination of water replacement from trehalose and glassy state from HA resulted in an optimal protective effect.

Isolation, Screening and Identification of Predominant Lactic Acid Bacteria in Salted Duck
YANG Shi-zhang,ZHANG Huan-xin,SHI Shuai,CHEN Yu-yong
2010, 31(7):  242-246.  doi:10.7506/spkx1002-6300-201007053
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In order to screen lactic acid bacterial strains (LAB) with good performance for the fermentation of salted duck, six strains of LAB were isolated and purified from Yangzhou salted duck with excellent flavor. Their important fermentation characteristics were identified by salt-tolerating, nitrite-tolerating and acid-producing experiments, respectively. Results indicated that R2 and R6 strains exhibited excellent tolerance to salt and nitrite, no degradation ability to protein and fat, and excellent inhibitory effect against Escherichia coli, Staphylococcus aureus and Salmonellum. According to morphological and physiologicalbiochemical characteristics, R2 and R6 were identified to be Lactobacillus pentosus and Lactobacillus plantarum, respectively. In conclusion, both strains have excellent growth and fermentation characteristics, thereby providing excellent fermentors for salted duck production.

Hypolipidemic and Antioxidant Effects of Tartary Buckwheat Proteins in Hyperlipidemic Mice
ZUO Guang-ming1,TAN Bin2,WANG Jin-hua3,QIN Li-kang1,*
2010, 31(7):  247-250.  doi:10.7506/spkx1002-6300-201007054
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To investigate hypolipidemic and antioxidant effects of tartary buckwheat proteins (albumin, globulin, glutelin and their mixture) in vivo, healthy Kunming male mice were fed high-fat diet to create a hyperlipidemic animal model. Results showed that all the various tartary buckwheat proteins had hypolipidemic and antioxidant effects in mice and both effects were decreased in the following order: albumin >globulin > glutelin. Either high- or low-dose albumin administration, or high-dose globulin administration resulted in a significant reduction of serum total cholesterol (TC), triglyceride (TG) and low density lipoprotein (LDL-C) contents (P<0.05) and a significant increase of high-density lipoprotein (HDL-C) content in hyperlipidemic mice (P<0.05). This means a remarkable hyperlipidemic effect. Meanwhile, hyperlipidemic mice administered albumin at the low-dose level exhibited a significantly reduced content of molondialdehyde (MDA), a peroxidation product and significantly enhanced activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in both serum and liver (P < 0.05) when compared with hyperlipidemic mice without any administration.

Effect of Dietary Aetobatus flagelum on Lipid Metabolism in Rats
WANG Yu-ming,HU Xiao-qian,REN Bing-xing,WANG Jing-feng,XUE Chang-hu*
2010, 31(7):  251-255.  doi:10.7506/spkx1002-6300-201007055
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Objective: To investigate the effect of dietary Aetobatus flagelum on lipid metabolism in rats for improving the utilization value of low-value aquatic products. Methods: Twenty-one male SD rats were randomly divided into 3 groups, including normal control group (fed normal diet containing casein), low-dose treatment group (fed normal diet containing 10% of Aetobatus flagelum meat powder and 10% of casein) and high-dose treatment group (fed normal diet containing 20% of Aetobatus flagelum). After 28 days of consecutive administration, all mice were sacrificed to measure triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), free fatty acid (FFA) contents in serum and TG, TC and phospholipids contents in liver and the activities of enzymes related to lipids metabolism, such as malic enzyme (ME), glucose-6-phosphate dehydrogenase (G6PDH), fatty acid synthase (FAS), phosphatidic acid phosphophydrolase (PAP) and carnitin palmitoyl transferase (CPT). Results: Compared with the control group, serum TG, TC and FFA levels exhibited a significant decrease in both the treatment groups (P < 0.05). Both low- and high-dose treatments had no obvious effect on serum HDL-C level but resulted in an obvious reduction of arteriosclerosis index in rats. Moreover, a significant decrease in TG and TC contents in liver was observed in both the treatment groups when compared with the control group (P < 0.05). The activities of G6PDH, ME, FAS and PAP in liver were all inhibited by dietary Aetobatus flagelum, whereas no obvious effects on the activity of hepatic CPT and mRNA expression of FAS, CPT-1, CPT-2 genes were observed. Conclusion: The above results indicate that the reduction of serum lipids by dietary Aetobatus flagelum is related to the down-regulation of hepatic lipids synthesis. Dietary Aetobatus flagelum can attenuate the accumulation of serum and hepatic lipids through reducing the synthesis of hepatic fatty acid and TG.

Effects of Coenzyme-Q10, Daidzein and Lecithin on Antioxidation System in Mice
BU Wen-lei1,ZHAO Xian-feng2,YIN Shi-an2,WANG Yin1,*
2010, 31(7):  256-259.  doi:10.7506/spkx1002-6300-201007056
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Objectives: To evaluate the effects of coenzyme-Q10, daidzein and lecithin alone or their combination on antioxidation system in mice. Methods: After 6 weeks of consecutive administration with the materials tested by gastric perfusion method, mice were sacrificed and their blood serum, liver and brain tissues were harvested to conduct biochemical tests related to antioxidation system. Besides, membrane lipid fluidity of brain neuron in hippocampus region was measured. Results: Individual administration of coenzyme-Q10 and lecithin resulted in a significant decrease of serum MDA content in mice. Compared with control mice, a significant decrease of MDA content in liver tissue was observed in mice administered daidzein alone (P<0.05); in addition, GSH-Px activity in liver tissue, T-SOD activity in brain and liver tissues and MDA content in blood serum and brain and liver tissues revealed an obvious increase in mice with combined administration (P<0.05); membrane fluidity of brain neuron in hippocampus region exhibited a significant amelioration in mice with individual administration of daidzein and lecithin or combined administration (P < 0.05). Conclusion: Individual administration of coenzyme-Q10, daidzein and lecithin can improve antioxidation system, lipid metabolism and membrane fluidity of brain neuron in mice. A synergistic effect among them is also achieved.

Blood Lipid Regulating Function of Propolis Soft Capsules
YU Jian-hui1,2,GAO Yin-yu1,*
2010, 31(7):  260-262.  doi:10.7506/spkx1002-6300-201007057
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To evaluate the effect of propolis soft capsules on blood lipid metabolism in rats with high fat diet-induced hyperlipidemia, 60 SD male rats were used as experimental animals and randomly divided into 6 groups designated as propolis groups fed high fat diet and orally administered low, middle and high doses (83.3, 250 mg/(kg bw·d)) and 500 mg/(kg bw·d)) of propolis, negative control group fed normal diet group and orally administered distilled water, positive control group fed high fat diet and orally administered distilled water, and solvent control group fed high fat diet and orally administered vegetable oil. All the animals were conducted corresponding administrations for 30 consecutive days. Tail vein blood was harvested for blood lipid analysis. Results indicated that TC and TG levels in the low- and high-dose propolis groups were significantly lower than those in the solvent control group. The 6 groups did not significantly differ in serum HDL-C level. Therefore, propolis soft capsules have excellent function in regulating blood lipid level in rats with hyperlipidemia.

Effect of Stropharia rugoso-annulata Extract (SRE) on Activities and Isozyme Profiles of Antioxidant Enzymes in Mice with Carbon Tetrachloride -induced Acute Liver Injury
WANG Feng1,WANG Xiao-wei1,TAO Ming-xuan1,ZHANG Chao-ying2,CHENG Guang-yu2,*
2010, 31(7):  263-268.  doi:10.7506/spkx1002-6300-201007058
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Objective: To evaluate the effect of Stropharia rugoso-annulata extract (SRE) on antioxidative enzyme activity and isozyme profile in liver and other major visceral organs of mice with CCl4-induced acute liver injury. Methods: After 4 days of normal feeding, CIR female mice (25 ± 2) g were used as experimental animals. Ten CIR mice orally administered distilled water were served as control group. Fifty-six more CIR mice were randomly divided into 4 groups of 14 mice each: SRE groups orally administered SRE solution in distilled water at low (100 mg/(kg bw·d)), medium (200 mg/(kg bw·d)) and high (400 mg/(kg bw·d)) doses and model group orally administered distilled water. All mice were administered for 30 consecutive days and low-, medium- and high-dose SRE groups and model group were fed water fasting diet for 16 h on the 30th day before oral administration of CCl4 dispersed in salad oil for creating CCl4-induced acute liver injury model. At 24 h postadministration, all mice were sacrificed to assay activities of antioxidant enzymes in liver, heart, kidney and spleen and analyze isozyme profile of CAT and SOD by gradient polyacrylamide gel electrophoresis. Results: Compared with the model group, high-dose SRE group exhibited significantly increased activities of total SOD, Mn-SOD, CuZn-SOD, GPx and CAT in liver; In addition, there was a significant increase of activities of SOD, CAT and GPx in heart and kidney in three SRE groups. Compared with the normal group, the model group exhibited a compensatory increase of Mn-SOD in kidney; however, Mn-SOD activity was decreased to the normal group level after SRE administration. One CAT band was detected in liver, kidney and heart and CCl4-induced acute liver injury resulted in a significant decrease of staining intensity of the brand. In contrast, the staining intensity of the band was increased to the normal group level after SRE administration. Similarly, one Mn-SOD and three CuZn-SOD bands were detected in liver and the staining intensity of the isozymes was also increased to the normal group level after SRE administration. One Mn-SOD and four CuZn-SOD bands were detected in heart and kidney and SRE administration resulted in the increase of staining intensity of CuZn-SOD bands. Conclusion: SRE can protect liver and other major visceral organs of mice with CCl4-induced acute oxidative injury by enhancing the activities of antioxidant enzymes and the contents of isozymes.

Anti-fatigue Effect of Polysaccharides from Pleurotus eryngii in Aged Mice
ZHENG Su-ling1,GUO Li-ying1,2,FAN Yong-shan1
2010, 31(7):  269-271.  doi:10.7506/spkx1002-6300-201007059
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Objective: To study the anti-fatigue effect of Pleurotus eryngii polysaccharides in aged mice. Methods: Healthy male Kunming mice were randomly divided into control group (A), aging model group (B) and Pleurotus eryngii polysaccharide treated aging group (C). The mice in Group B and C were intraperitoneally injected D-galactose at the dose of 100 mg/(kg bw·d) and those in Group A were intraperitoneally injected at the same volume of saline for 60 consecutive days. The mice in Group C were administered Pleurotus eryngii polysaccharides at the dose of 100 mg/(kg bw·d) and the mice in Group A and B were given distilled water from day 41. After the administration for 20 consecutive days, all mice were subjected to exhaustive swimming and exhaustive swimming time was recorded. Meanwhile, blood was harvested for determining the contents of blood urea nitrogen, lactate and hemoglobin and organ indexes were also measured. Results: The fungal polysaccharides prolonged exhaustive swimming time of aged mice, decreased blood urea nitrogen and lactate levels, and significantly increased hemoglobin content, red blood cell number, and thymus and spleen indexes. Conclusion: Pleurotus eryngii polysaccharides have an obvious anti-fatigue effect and improve exercise capacity of mice.

Preventive Effect of Momordica charantia L. Saponins on Osteoporosis in Ovariectomized Rats
YANG Zhi-gang,SHI Wan-zhen,SHEN Zong-gen,ZHANG Yan-ping,YANG Jie
2010, 31(7 ):  272-275.  doi:10.7506/spkx1002-6300-201007060
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To consider the potential of Momordica charantia L. saponins in preventing osteoporosis, female SD ovariectomized rats with osteoporosis were used as experimental animals. The rats were divided into 4 groups designated as one model and 3 experimental groups administered Momordica charantia L. saponins at the doses of 65, 130 mg/(kg bw·d) and 260 mg/(kg bw·d) for 12 consecutive weeks. After the administration, blood parameters and bone mineral density (BMD) of rats were measured and pathomorphism of femur and uterus were observed as well. Compared with the osteoporosis model group, serum E2 and Ca2+ levels and bone mineral density (BMD) of the experimental groups exhibited an obvious increase. Wider trabecular bone and smaller medullary cavity were also observed in the experimental groups. However, no difference in body weight, uterus weight and uterus pathomorphism was observed between rats with and without Momordica charantia L. saponins treatments. The above findings demonstrate a preventive effect of Momordica charantia L. saponins on osteoporosis in ovariectomized rats.

Inhibitory Effect of Ethanol Extract of Buckwheat Chaff on Renal Injury of Diabetic Rats
BAI Jing,LU Hua,HAN Shu-ying*,CHU Jin-xiu
2010, 31(7):  276-279.  doi:10.7506/spkx1002-6300-201007061
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Objective: To explore inhibitory effect and its mechanism of ethanol extract from buckwheat chaff (EBC) on renal injury of diabetic rats. Methods: The diabetic rat model was induced by intraperitoneal injection with alloxan. The level of fasting blood glucose (FBG), 24-hour urine protein, creatinine clearance rate (Ccr), renal index and fructosamine and AGEs of kidney were observed in the normal control group, model group, positive control group (administered benazepril BNPL) and low- and high-dose EBC groups. The morphological changes of kidney were observed through HE and Masson staining. Results: Compared with the normal control group, the levels of FBG, 24-hour urine protein, renal index, fructosamine and AGEs of kidney in the model group exhibited a significant increase, but the level of Ccr exhibited a significant decrease (P< 0.01). Meanwhile, obvious renal damages in the model group were observed. However, compared with the model group, the levels of FBG, 24-hour urine protein, renal index and fructosamine and AGEs of kidney in BNPL treatment group and EBC treatment groups exhibited a reduction but the level of Ccr revealed an enhancement (P<0.05, P< 0.01), and a slight renal damage was observed in all these treatment groups. Conclusion: EBC significantly inhibits renal injury of diabetic rats induced by alloxan, and the mechanism may be related to inhibition of the formation of AGEs resulting from lowered blood glucose level.

Anti-coagulation and Anti-thrombosis Effects of n-Butanol Extract from Oenanthe aquatic
PIAO Ri-long,ZHANG Hong-ying*
2010, 31(7):  280-283.  doi:10.7506/spkx1002-6300-201007062
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Objectives: To investigate anti-coagulation and anti-thrombosis effects of n-butanol extract from Oenanthe aquatic. Methods: The effect of n-butanol extract from Oenanthe aquatic on coagulation time and bleeding time of mouse tails was investigated using glass coverslip, capillary and cutting tail methods. Meanwhile, the effect of n-butanol extract from Oenanthe aquatic on thrombosis and thrombosis of arterio-venous bypass in rabbits was studied using Chandle and arterio-venous bypass methods. In addition, the effect of n-butanol extract from Oenanthe aquatic on platelet adhesion function in rabbits was also studied using Wright method. Results: n-butanol extract from Oenanthe aquatic at the doses of 500 mg/(kg bw·d)and 250 mg/(kg bw·d) significantly prolonged coagulation time and bleeding time in mice. When the dose was 280 or 140 mg/(kg bw·d), thrombosis and thrombosis of arterio-venous bypass in rabbits were significantly inhibited and a significant inhibitory effect on platelet adhesion function in rabbits was observed. Conclusion: n-butanol extract from Oenanthe aquatic has anti-coagulation and antithrombosis effects.

in vitro and in vivo Inhibitory Effect of Methanol Extract from Terminalia chebula Retz Fruits on α -Glucosidase
JING Zan1,ZENG Wei-cai1,LUO Jing-wen2,YE Hua-xia1,HUANG Yi-na2,GAO Hong1,*
2010, 31(7):  284-287.  doi:10.7506/spkx1002-6300-201007063
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In order to evaluate the inhibitory effect of Terminalia chebula Retz fruit extract (TCFE) on α-glucosidase, Caco- 2 cells were used to assay the inhibitory activity of TCFE in vitro and in small intestinal model. Results indicated that TCFE exhibited a strong inhibitory effect on maltase, while no obvious inhibitory activity on sucrase in vitro was observed. In addition, TCFE also obviously reduced 30 min postadministration blood glucose level of SD maltose-loaded male rats. On the other hand, this extract had no effect on the postprandial blood glucose level in normal SD rats administrated sucrose. These results suggest that TCFE has a preventive effect against Type II diabetes.

Effect of Pregnant Cow s Milk on Growth and Development and Blood Lipid of Juvenile Female SD Rats
XU Zhuang-jian1,PANG Xing-fu1,ZHANG Wen-jie1,MA Ya-ping1,XU Guo-xin2,ZHOU Yuan2
2010, 31(7):  288-292.  doi:10.7506/spkx1002-6300-201007064
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Objective: To investigate the effect of pregnant cow s milk on growth and development and blood lipid of juvenile female SD (Sprague-Dawley) rats. Methods: Sixty-four female SD rats aged 21 days old were randomly divided into 4 groups, which were fed pregnant cow s milk, postpartum cow s milk, commercial whole milk (mainly from pregnant cows) and artificial milk. The growth and development index of rats were observed and their blood lipid level was determined at 29 and 54 days old. Results: There was no statistically significant difference in serum high-density lipoprotein cholesterol (HDL-C) among 4 groups at 29 days old. Serum HDL-C levels in rats fed pregnant cow s milk, postpartum cow s milk, commercial whole milk and artificial milk were (0.66 ± 0.07), (0.60 ± 0.04), (0.69 ± 0.07) mmol/L and (0.56 ± 0.12) mmol/L at 54 days old, respectively. In addition, serum HDL-C level in rats fed pregnant cow s milk was higher than that in rats fed artificial milk (P < 0.05), and serum HDL-C level in rats fed commercial whole milk was higher than that in rats fed postpartum cow s milk or artificial milk (P < 0.05). No statistically significant difference in serum total cholesterol, triglyeride and low-density lipoprotein cholesterol among 4 groups at 29 or 54 days old was observed. Conclusion: The use of pregnant cow s milk or commercial whole milk can increase serum HDL-C in juvenile female SD rats.

Effect of Laminaria japonica Polysaccharides on Reproductive Function of Male Rats with Chronic Ionizing Radiation Damage
LIU Jun1,2,LUO Qiong1,*,YANG Ming-liang1,CUI Xiao-yan1,YAN Jun1
2010, 31(7):  293-296.  doi:10.7506/spkx1002-6300-201007065
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Objective: To investigate the effect of Laminaria japonica polysaccharide (LJP) intervention on reproductive function in male rats with local chronic ionizing radiation damage. Methods: Male Wistar rats were randomly divided into control group, model group and LJP intervention group. LJP intervention group was administered LJP and the rest groups were administered saline at same volume. Except the control group, all the other groups were subjected to adaptive feeding for 7 d before the local irradiation of 60Co γ-ray at the total dose of 2.3 Gy once per day for 4 consecutive weeks. On the 1st, 7th and 14th days post-60Co γ-ray irradiation, the mating ability was observed. Body weight and testis organ coefficient, serum sex hormone (LH, FSH, T, E2) levels, sperm count and sperm viability were measured. Results: Compared with the model group, the testis organ coefficient of LJP intervention group was increased. An improved level of sex hormone secretion of rats observed in LJP intervention group. Sperm count and viability and mating ability of rats from LJP intervention group were also increased. Conclusion: LJP has an obvious protective effect on reproductive function in male rats with local chronic ionizing radiation damage and plays a vital role in promoting spontaneous recovery of reproductive function in male rats.

Hypolipidemic and Antioxidant Effects of Flavonoids from Hippophae rhamnoides L. Pomace in ICR Mice with Alloxan Induced Diabetes
WANG Zhen-yu1,2,LIU Yu1,ZHOU Li-ping1
2010, 31(7):  297-301.  doi:10.7506/spkx1002-6300-201007066
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To examine the potential hypolipidemic and antioxidant effects of flavonoids from sea buckthorn (Hippophae rhamnoides L.) pomace (SBPF) in ICR mice with diabetes, healthy IR mice were used as experimental animals to create an alloxan (ALX) induced diabetic model. Mice with ALX induced diabetes were randomly divided into 4 groups including model control group administered normal saline by gavage and SBPF groups administered low, medium and high doses of SBPF aqueous solution at the same volume as normal saline by gavage. Additional healthy IR mice were served as normal control group and also administered normal saline by gavage like the model control group. All the groups were administered once a day for 4 consecutive weeks. Results showed that compared with the model control group, the three SBPF groups exhibited significantly lowered serum glucose, blood liquid, MDA and BUN levels, elevated insulin and glycogen levels and SOD, GSH-PX and CAT activities, and enhanced antioxidant function and diet level. In conclusion, SBPF administration not only effectively regulates the levels of serum glucose and blood lipid, but also enhances antioxidant function in diabetic mice.

Research Progress in Antioxidant Mechanisms of Curcumin and Development of Antioxidant Curcuminoids
XUE Hai-peng,LI Xiang-zhou*,KUANG Chun-tao,MENG Wei,GUO Yuan-liang
2010, 31(7):  302-307.  doi:10.7506/spkx1002-6300-201007067
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Curcumin has been reported to have many pharmacological activities, such as antioxidant, antitumor, and antibacterial activities. In recent years, a number of curcuminoids have been designed and synthesized to obtain more effective antioxidants. The antioxidant mechanisms of curcumin and its derivatives are discussed, and the research progresses in the synthesis of antioxidant curcuminoids are reviewed in this paper.

Research Progress on Molecular Markers for Meat Products Traceability
WU Xiao,ZHANG Xiao-bo,ZHU Lian-long,TAN Yong-song,TANG Xue-ming*
2010, 31(7):  308-311.  doi:10.7506/spkx1002-6300-201007068
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Food traceability plays an important role in the management of food manufacturing, processing and consumption. As the major dietary protein source, the safety problem of meat products has acquired considerable importance. This article reviews the research progress of molecular markers, which are used in DNA trace technology among numerous technical methods for traceability. Three kinds of molecular markers such as AFLP, SSR and SNP markers are compared and SNP marker is considered the preferred molecular marker for animal identification.

Research Progress in Effect of Extrusion Cooking on Food Nutrition
YANG Tao,XIN Jian-mei,XU Qing,LUO Hong-yu*
2010, 31(7):  312-316.  doi:10.7506/spkx1002-6300-201007069
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Extrusion cooking has been widely used in the field of food due to its high efficiency, multi-functions, low cost and low energy consumption. However, effects of extrusion cooking on nutritional quality are still ambiguous. The beneficial effects include destruction of anti-nutritional factors, improvement of protein digestibility, enhancement of starch gelatination, increase of soluble dietary fiber and reduction of lipid oxidation. On the other hand, adverse effects include acceleration of the Maillard reaction between protein and sugar, and loss of heat-liable vitamins depending on raw material types, their composition and processing conditions. In this paper, the effects of extrusion cooking on nutritional components are reviewed, which will provide references for food extrusion industry.

A Review of PCR-DGGE Detection of Fungal Community in Fermented Food and Feedstuff
XU Ai-qing1,2,LI Zong-jun1,*,WANG Yuan-liang1,WEN Jie-yu1
2010, 31(7):  317-322.  doi:10.7506/spkx1002-6300-201007070
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PCR-DGGE technique is a recently emerging tool in microbial ecology. In this paper, the principle and background of PCR-DGGE are introduced. Meanwhile, the design and choice of PCR primers are summarized in investigation of fungal community in fermented food and feedstuff. Moreover, the experimental procedure to obtain DNA sequence information from DGGE profiles is demonstrated. Furthermore, limitations and optimization strategies of DGGE are also listed. This paper will be helpful for establishing a feasible PCR-DGGE protocol to detect fungal community structure and deduce succession pattern during fermentation process or in fermented products.

Surface Protein of Lactobacilli Interacting with Its Host: A Review
DU Li-hui1,LIU Fang2,JU Xing-rong1,HUO Gui-cheng3
2010, 31(7):  323-328.  doi:10.7506/spkx1002-6300-201007071
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It is well known that lactic acid bacteria are probiotics. To exert probiotic function, lactic acid bacteria must colonize in gastrointestinal tract first. However, during the colonization process, adhesion is thought to be the first step. Therefore, the surface protein of lactic acid bacteria must involve in the adhesion step. In this article, surface protein of lactic acid bacteria and its anchoring mechanisms to cell membrane are reviewed.

Research Progress on Bioavailibility of Lycopene
PENG Shan-li,HUANG Wei-ning,ZHANG Gen-yi*
2010, 31(7):  329-332.  doi:10.7506/spkx1002-6300-201007072
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Lycopene, a strong antioxidant, has the ability to reduce the risk of cancers and cardiovascular diseases and has been widely used in foods, drugs and cosmetics as a functional pigment, which has stronger antioxidant activity and lower bioavailability compared with other carotenoids. In this paper, the absorption and bioavailability of lycopene is reviewed.

Research Progress in Physiological Function of Calcium Citrate Malate
WU Jun-lin1,2,WU Qing-ping1,*,ZHANG Ju-mei1
2010, 31(7):  333-337.  doi:10.7506/spkx1002-6300-201007073
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Calcium citrate malate (CCM) is a new calcium nutrition additive, which is a kind of compound salt resulting from the reaction among calcium, citrate and malate. Unlike other calcium sources, CCM is characteristic of high solubility and bioavailability, which provides many physiological functions of promoting oral health, reducing risk of kidney stone and having no adverse influence on the absorption of other minerals. In addition, CCM also exhibits anti-fatigue and heart-protective functions due to its L-malate. Moreover, CCM has extensive exploitation and application prospect as a calcium health care product or a food additive. This article reviews physiological functions of CCM to provide new ideas and directions for the application of CCM.