Volume 28,Issue 3,2012 Table of Contents

1 The Research of Salicylic Acid Signal Transduction in Postharvest Jujube induced by Oligosaccharins

GUO Hong-lian , SUN Yuan-yuan , WANG Xiao-feng

2012, 28(3):249-251.

[Abstract](1219) [HTML](0) [PDF 363.16 K](673)

Abstract:
The salicylic acid signal transduction pathways influence on postharvest fruit under oligosaccharins was studied in this paper. The results showed that, induced by exogenous inducer-oligosaccharins, endogenous salicylic acid content increased, which may play a role as signal molecules of antagonistic reaction in postharvest jujube. The signal transduction pathway of salicylic acid may be involved with the synthesis of nitric oxide, calcium ion channel and phenylalanine metabolism pathways and the PAL enzymes activities changed too.

2 Effect of High Pressure on Aggregation Behavior of Kidney Bean (Phaseolus Vulgaris L) Protein Isolate

LI Kang-kang , MA Wen , YIN Shou-wei , TANG Chuan-he , YANG Xiao-quan , QI Jun-ru

2012, 28(3):252-255.

[Abstract](1185) [HTML](0) [PDF 418.39 K](712)

Abstract:
The influence of high pressure (HP) treatment (200-600 MPa) on molecular distribution of kidney bean (Phaseolus vulgaris L) protein isolate (KPI) was investigated by High-performance size-exclusion chromatography combined with multi-angle laser light scattering technique (HPSEC-MALLS), to explore the possible HP-induced protein association-dissociation behavior. The molecular weight (Mw) of phaseolin, the major component in KPI, calculated based on the Debye plot, was about 161 kDa. HP treatment at 200 MPa led to dissociation of soluble aggregates (at void volume), while HP treatment at 400 and 600 MPa led to dissociation of insoluble aggregates in KPI, thus improved PS.

3 Effect of Different Carbon Sources on the Fermentation of Celery Juice by Lactic Acid Bacteria Mixture

CHEN Zhong , SU Zhi-min , LIN Wei-feng

2012, 28(3):256-259.

[Abstract](1010) [HTML](0) [PDF 384.03 K](738)

Abstract:
A study on lactic acid bacteria mixture (the ratio of Lactobacillus casei and Leuconostoc mesenteroides being of 1:1) for the fermentation of celery juice was carried out. During the fermentation the changes and internal relation of viable count, pH, total acid and reducing sugar were observed. The experimental results indicate: sugar, glucose and fructose syrup were added to the celery juice respectively, and the total acid of celery juice were 8.52 mg/g, 8.18 mg/g and 8.32 mg/g. They were larger than the total acid of original celery juice (7.26 mg/g). The utilization rate of reducing sugar was also improved. After the adjunction of fructose syrup the stability period, whole viable count, amount of acid and utilization rate of reducing sugar were increased effectively. And then the delicious fermented celery juice with celery fragrance was obtained.

4 The Influence of Quercetin on the Trypsin Properties

ZHAO Hong-hui , WEI Qing-yi , CHEN Lei , YUAN Er-dong , NING Zheng-xiang

2012, 28(3):260-262.

[Abstract](1105) [HTML](0) [PDF 380.03 K](625)

Abstract:
The interaction between quercetin and trypsin was studied by measuring the catalytic activity, the enzymatic kinetic analysis and fluorescence spectra. Quercetin showed inhibition effect on catalytic activity of trypsin. When trypsin was treated by quercetin with the molar ratio of quercetin to trypsin of 44:1 for 10mins under 37 ℃, the inhibition rate reached 32.5%. Reaction time had little effect on the inhibition rate. The type of inhibition effect was reversible competitive inhibition. Quercetin can cause the quenching of intrinsic fluorescence of trypsin in physiological condition. With fluorescence quenching method，the quenching constant Kq was found to be 4.7415×1012 (mol/L)-1?S-1 and the number of binding site N was 0.9206.

5 Selection and Adsorption Behavior of Resin for the Decaffeination of Tea

WANG Jie , WU Hui

2012, 28(3):263-266.

[Abstract](1196) [HTML](0) [PDF 382.75 K](691)

Abstract:
Taking the adsorption rate and adsorption capacity as indexes, the adsorption abilities of 10 kinds of resins were compared and the resin AL-1 was shown to be the best one with its caffeine-adsorption rate of 98.58%. Based on the thermodynamics and kinetics characteristics of the resin AL-1, the change of enthalpy was 21.84 kJ/mol, which indicated that the adsorption was exothermic physical absorption process. The value of free energy was positive and was reduced with the gradual increase of temperature. It indicated that the higher ambient temperature, the more easily caffeine was adsorbed. Equilibrium adsorption data was consistent with both Langmuir and Freundlich isotherms equation, which showed that it was single molecule layer adsorption. A Lagergren pseudo-first order rate equation was suitable to the adsorption process, which was mainly controlled by liquid film.

6 Antimicrobial Property of Slow-releasing and Antimicrobial Film

CAI Dan-dan , XIAO Kai-jun , WANG Zhao-mei , ZHAN Ting

2012, 28(3):267-269.

[Abstract](1048) [HTML](0) [PDF 316.46 K](662)

Abstract:
E. coli, Bacillus subtilis, Fungi were selected for the antibacterial property study. The slow-releasing film loading different antimicrobial substances were studied for their properties of slow-releasing, water vapour transmission and antimicrobial activity. Results showed that the release rates of the film loading rosemary, cinnamon oil, ginger oil and clove were 90.6%, 90.2%, 89.0% and 85.1%, respectively. The water vapor transmission rates were 0.07584, 0.2995, 0.4185 and 0.1193 g/m2.d for the obove-mentioned films. Obvious inhibition zones were observed on E. coli, Bacillus subtilis and Fungi with the selected film. The slow-releasing film loading rosemary showed best characteristics of the above three properties in comparison other films. So it shows great application potential.

7 In silico Analysis of Phytoene Synthase and its Promoter Reveals Hints for Regulation Mechanisms of Carotenogenesis in Duanliella bardawil

TANG Chun-hui , LAO Yong-min , JIANG Jian-guo

2012, 28(3):270-273.

[Abstract](1239) [HTML](0) [PDF 380.50 K](703)

Abstract:
Previous researches showed that phytoene synthase (PSY) is the first regulatory point in carotenogenesis in Dunaliella bardawil. In this study, two sets of adjacent gene specific primers (pSP1, pSP2 and pSP3; tSP1, tSP2 and tSP3) were designed and LA PCR-based genomic walking approach was performed for isolation of psy promoter and terminator in D.bardawil, respectively; and subsequent analysis of conserved regulatory sequences were conducted by online promoter analysis softwares. Finally, using bioinformatics methods, the protein structure of DbPSY was also predicted. The calculated results found two conserved regulatory sequences in PSY promoter: BOXLCOREDCPAL and GT1GMSCAM4. BOXLCOREDCPAL was induced by UV to up-regulate expression of downstream gene; and GT1GMSCAM4 up-regulates expression of downstream gene induced by NaCl. Protein structure analysis demonstrated low homology of N-terminus between D. bardawil and other algae. Therefore we speculated the regulation mechanisms may partly involve in the conserved sequences of psy promoter and the diversity of N-terminus of DbPSY compared to other species.

8 Study on Color Protective Treatment of Fresh-cut Yacon

CAI Wen-tao , XIA Yan-bin

2012, 28(3):274-277.

[Abstract](1239) [HTML](0) [PDF 393.95 K](681)

Abstract:
The effects of different inhibitors on fresh-cut yacon were studied. It was optimized comprehensively for a variety of protect color inhibitors through orthogonal experiment and using multi-index experimental design and weighted score. The results showed that the optimum combination treatment was 0.5% citric acid +0.5%ascorbic acid +0.05‰ sodium pyrosulfite, and the optimum time for the fresh-cut yacon dipping in the solution was 10 min. After the treatment, the value of fi was of 97.6414; the PPO activity was of 0.007; BD value was of 3.62; the quality of appearance was of 7; and the best color protective effect was found within 10d.

9 The Calclum Holding Capacity of Casein Phosphopeptide

XU Man , HE Dong-ping , WEI Na , TONG Yu-yuan

2012, 28(3):278-281.

[Abstract](1336) [HTML](0) [PDF 435.06 K](913)

Abstract:
The blocking calcium phosphate precipitation ability of casein phosphopeptide (CPP) was studied by in vitro simulation. The degree of hydrolysis, adding volume of CPP, the different levels of CPP and other factors of food processing influence to the calcium holding capacity of CPP were analyzed. The research results provided references for evaluation and food application of CPP.

10 Extraction of the Dietary Fiber from Jack Fruit

YE Sheng-quan , YE Chun-hai , GUO Si-yuan , LV Qing-fang , MAO Qi , YANG Si-ming

2012, 28(3):282-284.

[Abstract](1285) [HTML](0) [PDF 370.63 K](725)

Abstract:
The dietary fiber was extracted from the skin of jack fruit, and the extractive process was optimized. The dietary fiber was extracted from the skin by zymochemistry method using α-amylase concentration, enzymatic hydrolyzing temperature, NaOH concentration, NaOH hydrolyzing temperature as the main factors of the single factor test. The optimal conditions were follows: α-amylase concentration 0.3%, enzymatic hydrolyzing temperature 65 ℃, NaOH concentration 0.5% and NaOH hydrolyzing temperature 60 ℃. Under these conditions, the extracting rate of insoluble the dietary fiber was up to 37.8%. Retention rates of starch and the protein were 6.34% and 7.88%, respectively. By extracting the dietary fiber and increasing its comprehensive utilization way, the economic and ecological benefits of planting and processing jackfruit can be enhanced, thereby promoting local agriculture and rural economic development.

11 Macroporous Resin for Decolorization of Korla Pear Juice

FAN Ai-jun , CUI Zheng-tao , XIE Xiao-xia , WANG Chen-qiang , ZHAO Chang-lan , LI Ying-biao

2012, 28(3):285-288.

[Abstract](2421) [HTML](0) [PDF 397.19 K](890)

Abstract:
Seven kinds of macroporous resin were selected by studying the soluble solids and the decolorization rate. Through the static and dynamic separateness factor experiments，the optimum conditions of decoloration of stevioside and resin regeneration were obtained. The results showed that LSA-900C macroporous resin was the best resin with decolorization rate being of 80.37% and transmission rate being of 95.3%. The best decoloration technology conditions were: the flow rate 3.8 mL/min, the temperature 40 ℃, and soluble solids 12.5 Brix. The best regeneration technology conditions were: 4.0% NaOH eluent as the regenerates and flow rate of 3.3 mL/min.

12 Fermentation of CHU-R for Astaxanthin Production

TAN Ying-chang , LIAO Mei-de , QIN Peng , XIA Feng-geng

2012, 28(3):289-291.

[Abstract](1338) [HTML](0) [PDF 402.19 K](812)

Abstract:
The fermentation process parameters of CHU-R, such as medium, incubation temperature, inoculation, etc. were discussed in this paper. It was found that the best medium formulas was: 6% sucrose, 1% molasses, 0.5% ammonium sulfate, 0.3% Na2HPO4，0.05% KI，and 0.05% MgSO4?7H2O. The optimum fermentation conditions in 50 L fermenter were: temperature 28℃, venti1ation 0.1~0.15 (V/V/min), the initial speed of 120rpm, tank pressure 0.05~0.08 MPa, liquid volume 30 L, the initial pH 6.8~7.0 and inoculum size 6%, the fermentation process to maintain dissolved oxygen at 40-60%. The results showed that the CHU-R yield pigment nearly reached 23 mg/g of its dry weigh fermented in 50 L fermenter.

13 Separation and Purification of Total Flavones from Lycium barbarum Leaves by Macroreticular Resin

LIU An-jun , LIU Hui- hui , GUO Dan- xiao , TENG An-guo , ZHOU Shao-qian

2012, 28(3):292-296.

[Abstract](1224) [HTML](0) [PDF 412.47 K](645)

Abstract:
Purification of total flavones of Lycium Chinese leaves using macroreticular resins was investigated. Dynamic elution ratio of AB-8, ADS-5, ADS-7, ADS-17, ADS-21, and HP-20 were studied respectively and compared in order to find the optimum macroreticular resin. Results indicated that the HP-20 resin was the best due to its highest adsorption and desorption properties. The optimum conditions were: ratio of flavonoid volume to the bed volume of 13 BV, the pH value of sample 6, concentration of sample 2.336 mg/mL, current velocity 2 BV/h, 70% alcoholas eluant for desorption, current velocity 2B V/h and eluant volume 3.5 BV. Under those conditions, and the content of Lycium Chinese leaves flavonoids increased from 29.02% to 83.75%. The technique condition is scientific and reasonable. It can be used to separate and purificate total flavonoids from Lycium Chinese leaves. Flavonoid compounds in leaves of Lycium bararum were analyzed by using HPLC. Lutein content greatly increased from 9.88%to 23.79% after the column purification.

14 Optimization of Saccharification Conditions of Syrup for Brewing Produced by Wheat β-Amylase

ZHOU Chun-hai

2012, 28(3):297-299.

[Abstract](1430) [HTML](0) [PDF 385.32 K](711)

Abstract:
This paper studied the use of a starch enzyme (wheat β-starch enzyme) instead of the traditional technology using of barley β-starch enzyme in saccharification of starch liquefaction liquid to produce syrup for brewing. Meanwhile, effects of some factors on maltose content, such as added amount of wheat β-starch enzyme, saccharification temperature, pH value, and saccharification hours, were discussed. These studies concluded the optimum conditions combined with economic benefit which wheat β-starch enzyme added 0.010% (m/m), saccharification temperature at 60 ℃, pH value 5.5, and saccharificate for 24 hours.

15 Optimization of Protein Extraction from Chlorella using Response Surface Methodology

WANG xiao-qin , ZHANG xue-wu

2012, 28(3):300-303.

[Abstract](1236) [HTML](0) [PDF 454.44 K](763)

Abstract:
The optimization of the extraction process of protein from Chlorella was achieved by response surface methodology. The optimization strategy used was a series of one-factor-at-a-time investigations and subsequent response surface analysis based on a quadratic regression rotary combination design. Results showed that Liquid-to-solid ratio of 21:1, pressure of 170 MPa and cycling times of 4 were found optimum for protein extraction from Chlorella. Under these optimum conditions, the yield of protein was 45.78%.

16 Extraction of Protease from Squid Viscera

YIN Qing-chun , CEN Yan-zhao , XU Chun-xuan , Duan SHAN , YAO Wei-xin , JI Yu-ming

2012, 28(3):304-308.

[Abstract](1226) [HTML](0) [PDF 453.33 K](728)

Abstract:
In this paper, extraction of protease from squid viscera was studied. Factors such as the concentration of NaCl solution used in protease extraction, the ratio of squid viscera solid to NaCl solution, extracting temperature, extracting time and so on, which influenced the extraction effect, were investigated. The pH of the crude protease extraction solution was adjusted to remove impurity based upon the isoelectric precipitation principle. Various flocculants were compared in terms of their removing effect of impurity from crude protease extraction solution. Results showed that the optimal extracting conditions were as follows: the concentration of NaCl solution 0.5%, the ratio of solid to solution 1.0:1.5, ambient temperature and extraction time 60 min. Under the above-mentioned conditions, 96.06 % of total protease activity was recovered; the specific protease activity reached 1.33 U/mg. by Adjusting the pH of crude protease extraction solution to 4.5, the impurities was removed. Among various flocculants, Fe2(SO4)3 was found to be the best. By adding 1% Fe2(SO4)3 solution to crude protease extraction solution, the impurities can be removed when the ratio of crude protease extraction solution to Fe2(SO4)3 solution reaching 4:1 (V/V). Under such conditions, 80.33 % of total protease activity was recovered; the specific protease activity reached 9.37 U/mg.

17 Optimization of Water Extraction Process of Total Alkaloid from Aconite by Response Surface Methodology

WEI Hai-liu , LI Lin , MA Ming-song , YU Ke-yue , HU Song-qing

2012, 28(3):309-312.

[Abstract](1104) [HTML](0) [PDF 335.03 K](675)

Abstract:
Total alkaloid was extracted from white prepared lateral root of Aconite by acidic water method, which was optimized by response surface designs. Based on the results of one-factor test, response surface methodology with 4 factors and 3 levels was adopted according to box-behnken experimental design principle. Two regression equations for the influence relationships of the extraction rate and four varietals factors were established by response surface experiments. On the basis of regression models, the results with surface were simulated to give optimized result and influencing trends of the main factors on the extraction rate. The optimum extracting conditions are as follows: pH 3.4, liquid-to-solid ratio 11 mg/g, extraction time 4.6 h and temperature 30 ℃. Under these conditions, the extraction rate was 48.5%±1.7%.

18 Study on the Extraction Technology of Salt-soluble Protein in Penaeus Vannamei Muscle

LAN Wei-bing , MAO Wei-jie , CHI An-ying , JI Hong-wu

2012, 28(3):313-315.

[Abstract](908) [HTML](0) [PDF 304.08 K](690)

Abstract:
The extraction process parameters of salt-soluble protein were studied with the muscle of Penaeus Vannamei as raw materials and the salt- soluble protein yield as an indicator in this experiment. The optimized extraction conditions were determined as follows:NaCl 0.6 mol/L, extraction time 25 h, solid-liquid ratio 1:4, and pH 7. Under these conditions, the salt-soluble protein content was 105.73 mg/g and yield was 83.34%.

19 Optimization of the Formula of Healthy Sugar Substitute using Mixture Design

LUO Hai-ping , WU Sheng-xu , XU Yong , KOU Xiu-ying

2012, 28(3):316-318.

[Abstract](1223) [HTML](0) [PDF 292.55 K](716)

Abstract:
In this paper, sensory evaluation was used for optimiazation of formula of a healthy sugar substitute by mixture design model. The best formula was determined as: glucose (21.3%), xylitol (23.3%), maltodextrin (55.4%). The sensory sore was 4.66.

20 Optimizing Technology of Stirred Buffalo Milk Yogurt with Mango

SU Si-ting , LI Quan-yang , XIONG Jian

2012, 28(3):319-322.

[Abstract](969) [HTML](0) [PDF 371.75 K](726)

Abstract:
Guangxi buffalo milk and mango were used as materials to investigate the optimal processing technic of stirred buffalo yoghurt with mango. Basing on the results of the quantities and ratio of stabilizer, sugar content and fermentation time, three factors and three level of responses surface methodology (RSM) were involved to study the effects of these factors on the Susceptibility to syneresis (STS), Water holding capacity (WHC) and flavor. The result showed that the product had minimum STS and maximum WHC and best sensory evaluation at optimal conditions which were as follow: 7.66% (w:w) of sugar content; 0.13% of blending of pectin and Propylene glycol alginate (w:w=1:1) and 5.17 h fermentation time, when 8.0% of mango-granule content in 250.0 mL Guangxi buffalo milk. The adequacy of this model is confirmed, according to additional experiments.

21 Optimization of Enzymatic Hydrolysis Conditions for Preparation of Functional Oligopeptide from Silkworm Pupa Protein

FANG Jia-mao , LIU Si-qi , ZHUANG Chu-zhou , SUN Zhong-tao

2012, 28(3):323-328.

[Abstract](1308) [HTML](0) [PDF 490.29 K](967)

Abstract:
In order to optimize the production process of functional polypeptides from silkworm pupa protein by enzymatic hydrolysis, the effects of different proteases, temperature, pH, substrate concentration and enzyme amount on the degree of hydrolysis (DH) and the trichloroacetic acid nitrogen solubility index (TCA-NSI) were explored using response surface methodology. It was proved that trypsinase, flavourzyme and neutral protease were the most effective enzymes for the hydrolysis of silkworm pupa protein. The optimal conditions were found to be hydrolysis temperature of 54.6℃, pH 7.38, substrate concentration of 7.33%, protease dosage of 3.62% and hydrolysis time of 6 h. Under these optimized conditions, DH of 29.2 and TCA-NSI of 81.14% were obtained. In the obtained functional polypeptides, the content of peptide reached 74.6%, with a number average molecular weight of 665.5 Da and a weight average molecular weight of 726.9 Da, while the content of free amino acid was only 7.33%, which indicated that the low molecular peptide instead of free amino acids was the main ingredient, although the silkworm pupa protein was enzymatic hydrolysis by depth.

22 Study on Sterilization Conditions of Castanea henryi by Microwave

ZHOU Xian-gen , XIE Zheng-cheng , ZHOU Cheng-min , HU Qing-su , LAI Jun-sheng , LI Fang-fang , YE Sheng-wu

2012, 28(3):329-331.

[Abstract](1261) [HTML](0) [PDF 275.21 K](628)

Abstract:
Microwave sterilization of Castanea henryi was studied using the disinfection effects and the degree of browning as indicators. Results showed that the optimal sterilization conditions were microwave power 330W, sterilization time 60s and temperature 80℃.

23 Production for Low-sugar Mango Jam

MIAO Yan , DONG Xiao-jing

2012, 28(3):332-334.

[Abstract](1418) [HTML](0) [PDF 296.39 K](649)

Abstract:
Processing technology of a low -sugar mango jam with nutritional and healthy functions was investigated. Three levels of the factors including thickening agents concention, the ratio of jam to sugar and citric acid concention. The results showed that the jam with high quality could be obtained under the following conditions: thickening agents0.2%, the ratio of jam to sugar 5:2, and citric acid 0.15%. In this condition, the product had delicate texture, golden yellow color, dense mango fragrance, delicious taste and rich nutrition.

24 Preparation of a Beverage containing Jujube and Soybean

ZHENG Hai-ping , ZHU Xiao-peng , SHEN Li-juan

2012, 28(3):335-338.

[Abstract](1276) [HTML](0) [PDF 356.52 K](871)

Abstract:
This paper discussed the effects of the enzymatic treatment of soybean, complex emulsifiers-thickeners and sterilization on the stability of compound beverage with jujube and soybean. The best proportion of raw materials was made by sensory evaluation, calculation of stability coefficient and orthogonal experiment. The results showed that the best enzymatic conditions were soaking temperature 100 ℃ and soaking time 5min. The best stabilizer complex contained 0.10% sucrose fatty acid ester, 0.05% glycerol monostearate,0.03% xanthan gum, 0.015% guar gum and 0.015% carrageenan. For the compound beverage preparation, the best sterilization temperature and time were 122 ℃ and 22min, respectively.

25 The Contamination Situation and Exposure Assessment of Phthalate Esters

LIU Chun-hong , SUN Yuan-ming , YANG Yi-chao , LIANG Tian

2012, 28(3):339-341.

[Abstract](1604) [HTML](0) [PDF 253.11 K](729)

Abstract:
Phthalate esters are a class of manufactured chemicals widely used as plasticizers in plastic materials. Recently hhuman exposure to phthalates and its possible health effects have been an increased concern due to plasticizer event in Taiwan. The paper described the toxicity, food and environment contamination and exposure assessment of phthalates, including biomarker research and human exposure level.

26 Analysis on Heavy Metal Contaminates of Pork and Pork Liver Sampled in Huizhou District

ZHOU Xiao-li , YU Yu-juan , YU You-jun , CHEN Chang-zhou

2012, 28(3):342-344.

[Abstract](1310) [HTML](0) [PDF 310.48 K](699)

Abstract:
Cadmium and Chromium in pork and pork liver was determined by graphite furnace atomic absorption spectrometry. Copper in pork, pork liver and feed was determined by flame atomic absorption spectrometry. The qualified rate of cadmium in pork and pork liver was 100%, the detection range was 0.01~0.16 mg/kg. The qualified rate of chromium in pork and pork liver was 100%, the detection range was 0.10~0.88mg/kg. The qualified rate of copper in pork was 100%, the detection range was 0.23~0.87 mg/kg. The qualified rate of copper in pork liver was 50.0%, and the detection range was 4.90~78.9 mg/kg. The content of copper in 20 pig feed for fattening hog was 0.29~69.0 mg/kg and the qualified rate was 95%. It was suggested that the situation of copper remains in pork liver was not optimistic, and the copper content exceeded standard was one twentieth in pig feed.

27 Quality Analysis of Idesia polycarpa Maxim Seed Oil

GUO Hua , SHEN Quan-wei , HU Yao-chao

2012, 28(3):345-347.

[Abstract](1452) [HTML](0) [PDF 333.25 K](816)

Abstract:
Quality analysis for Idesia polycarpa Maxim seed oil was made in this paper, including the determination of acid value, saponification value, iodine value, peroxide value and the fatty acid composition, in order to provide the theory basis for Idesia polycarpa Maxim seed oil production and development. The results showed that this oil belonged to Linoleic acid- style oil because of 80.11% Linoleic acid content, and it is a kind of drying oil due to its iodine value 145.3 g I2/100g oil. It was inferred that Idesia polycarpa Maxim seed oil was a kind of healthy care cooking oil.

28 Determination of Taurine in Food Products by Amino Acid Autoanalyzer

WANG Hong-jian , ZHOU Xing-qi , FENG Zhi-qiang , ZENG Nuan-xi

2012, 28(3):348-350.

[Abstract](1516) [HTML](0) [PDF 403.30 K](724)

Abstract:
This paper introduced a method of determining Taurine in foods by using amino acid auto-analyzer, and verified this method by the precision and accuracy experiment. The relative standard deviation of the method was 0.27 % and the recovery rate ranged from 100.4 % to 102.0 %. Samples should be pretreated to prevent the interference of other amino acids. The method has high sensitivity and strong specificity, the minimum detectable level can reach 10 pmol.

29 Determination of Nutrient Elements in Litchi

KONG Fan-li , ZHANG Ming-wei , YIN Kai-dan , TAO Zheng-ping , LI Yang , KUANG Rui-bin

2012, 28(3):351-353.

[Abstract](1171) [HTML](0) [PDF 274.47 K](760)

Abstract:
In this paper, the contents of K, Ca, Na, Mg, Fe, Mn, Cu and Zn was determined in different parts of 20 different breeds of Litchi in Guangdong area, relative standard deviation of the method was between 0.2-1.9%, and recovery was between 98.1-104.2%. Comparison of the concentration and distribution of those elements was made and Q-type cluster analysis of SPSS was applied for the study of concentration and distribution of those elements in different parts of Litchi. The results showed that the elemental distribution characteristics are related to the breeds of Litchi. It had provided a reference data for the further studies and comprehensive utilization of Litchi.

30 Rapid Determination of Lead and Cadmium in Pollute Vegetable by Rhodamine 6G Colorimetry

GONG Xiao-yong , LI Qi-wan , WANG Ji-liang , HE Li-zhong

2012, 28(3):354-356.

[Abstract](1267) [HTML](0) [PDF 310.77 K](754)

Abstract:
Dry vegetable was extracted by nitric acid (1+11) and the content of lead and cadmium in sample could be simultaneously got by rhodamine 6G aqueous phase colorimetric test. The results confirmed that lead and cadmium had good linear relation in concentration range of 0.1~1.0 μg/mL and 0.01~0.1 μg/mL, respectively. The best pH value for the colorimetric system is 5.0. Compared with wet extraction, the average extraction efficiency of nitric acid for lead and cadmium were 97.47% and 96.82%, and average RSD was less than 5. Average recoveries of standard addition in six samples were 102.6% and 101.2%.

31 Determination of Phosphate Compound in Frozen Prepared Food

WU Yi , XU Hong-bin , YUAN Bo

2012, 28(3):357-359.

[Abstract](1288) [HTML](0) [PDF 289.23 K](664)

Abstract:
An ion chromatography (IC) method for the determination of phosphate compound in frozen prepared food was developed in this paper. The sample was extracted by water used ultrasonic wave washer. After protein and fat precipitation by zinc acetate and potassium ferrocyanide, the sample was analyzed by IC using conductivity detector. The RSD, precision and standard recovery of the method were >0.9990, <2% and 84.7~96.3%, respectively.

32 Rapid Detection of Atrazine Residue in Water and Corn by Colloidal Gold-based Immunochromatographic Strip

SHENG Wei , NA Yu , ZHANG Lin , LIU Bing , WANG Shuo

2012, 28(3):360-363.

[Abstract](1173) [HTML](0) [PDF 337.46 K](649)

Abstract:
An immunochromatographic strip assay using colloidal gold-labeled antibody was developed. The visual limit of detection (LOD) of the assay for atrazine in PBS was 2 ng/mL. And the results could be obtained within 10 min. Spiked tap water sample was analyzed directly by the test strip without any pretreatment and the LOD was 2 ng/mL. Meanwhile, spiked corm sample was analyzed after simple pretreatment and the LOD was 40 ng/g. The results obtained by the immunochromatographic strip assay correlated well with those determine by indirect competitive ELISA. Because of its low cost, simple operation, high specificity, fast detection and easy-to-judgment results, the strip could serve as an on-site screening of a large number of samples.

33 Optimization of the Extraction Method of Aflatoxin B1 in Moon Cake

LI Jiao , SHE Zhi-yun , LIN Yao-wen , LIU Hai-qing

2012, 28(3):364-366.

[Abstract](1314) [HTML](0) [PDF 286.98 K](715)

Abstract:
A study was conducted to optimize extraction method of Aflatoxin B1 from eight kinds of moon cake (mixed nuts, lotus seed with egg yolk, jujube paste, fruit, ham, snowy, and tuna) through ELISA. The detection results by two methods showed no significant difference except the detection in Mixed Nuts and Tuna. Better extraction efficacy was found using 50% methanol/water solution. The average recovery rate was 84.0%~114.7%. The method could improve the detection efficiency of aflatoxin B1 of moon cake.

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Volume 28,Issue 3,2012 Table of Contents