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15 June 2009, Volume 30 Issue 12
Effects of Different Drying Processes on the Physico-chemical and Functional Properties of Banana Resistance Starch
DU Bing,CHENG Yan-feng,YANG Gong-ming*
2009, 30(12):  31-34.  doi:10.7506/spkx1002-6630-200912001
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This study aimed to compare effects of different drying processes such as hot air drying, extrusion drying, vacuum freeze drying and spray drying on retention rate, particle shape, crystal structure, iodine absorption curve, color, water absorption, water solubility of banana resistance starch. For retention and quality of banana resistance starch, vacuum freeze drying, low temperature hot air drying (50 ℃) and spray drying processes are superior to high temperature hot air drying (100 ℃). Moreover, extrusion drying caused the most obvious damage to banana resistance starch and its crystal structure, and the product color was also the deepest.

Purification and Drying of Pigment from Blackberry Fruits
ZHAO Hui-fang,LI Wei-lin,WANG Xiao-min,CUI En-hui,QU Le-wen,WU Wen-long,LU Lian-fei
2009, 30(12):  35-39.  doi:10.7506/spkx1002-6630-200912002
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After being extracted from blackberry fruits with the mixture of 1% HCl and 80% ethanol (1:99, V/V), the crude pigment was purified with macroporous adsorption resin, and then dried to powder by different processes. Moreover, we conducted the scale-up production experiment of blackberry pigment under optimized conditions. When blackberry pigment in citric acid- Na2HPO3 system at pH 3.00 was adsorbed by resin LS-300B for 5 h, and then desorbed by 70% ethanol, the best purification was achieved. Compared to vacuum and spray drying processes, freeze drying exhibited the best effect. Results of the scale-up production experiment showed that yield and color value of the blackberry pigment were 0.58% and 45.21, respectively; total anthocyanin content in the blackberry pigment was 12954.987 mg/100 g, and recovery of anthocyanin was 79.47%.

Use of Maillard Reaction for the Preparation of Food Flavor from Hydrolyzed Pork Protein
ZHAO Yan-yan,JIANG Shao-tong,CHEN Xiong
2009, 30(12):  40-42.  doi:10.7506/spkx1002-6630-200912003
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Pork protein was hydrolyzed by animal proteolysis enzyme, and then the hydrolysate was used to prepare food flavor by means of Maillard reaction. The hydrolysis and Maillard reaction conditions were optimized by orthogonal test with degree of hydrolysis and sensory evaluation score as the indicators, respectively. The optimum initial pH value, temperature, enzyme dose, and duration for hydrolysis were 7.5, 60 ℃, 0.9%, and 3 h, and under these conditions, the degree of hydrolysis was 11.56%. Under optimized conditions for Maillard reaction (pH 8.5, pork protein hydrolysate amount 60%, 120 ℃, and reaction 40 min), the product obtained had the highest sensory evaluation score, and it was of full-bodied and harmonious meat flavor.

Ultrasonic-assisted Desulfurization of Sulfited Chinese Olive
HUANG Wei1,FU Guang-liang1,LI Ai-jun2,SONG Xian-liang1,YU Xiao-lin1,YE Sheng-ying1,LUO Shu-can1,SUN Yuan-ming1
2009, 30(12):  43-47.  doi:10.7506/spkx1002-6630-200912004
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This study aimed to develop an ultrasonic-assisted desulfurization technology for sulfited Chinese olive. Effect of ultrasonic power on desulfurization rate and effects of frequency in single-frequency ultrasonic mode on desulfurization rate, L value and hardness of sulfited Chinese olive were evaluated, and desulfurization effects of single- and dual-frequency ultrasonic modes were compared. Moreover, three environmental conditions for ultrasonic treatment such as temperature, water refresh cycle and pH adjustment of deionized water were optimized using response surface analysis (RSA). The desulfurization rate presented a positive relationship with the ultrasonic power, but a negative relationship with ultrasonic frequency within the range of 25 kHz to 60 kHz. The desulfurization effects of various ultrasonic powers declined as the following order: 25 kHz > 40 kHz> 60 kHz. However, the dual-frequency ultrasonic mode (combination of any two of 25 kHz, 40 kHz and 60 kHz) did not show synergistic but only simple superposition effect. RSA indicated that under the ultrasonic parameters of 25 kHz and 250 W, the temperature, pH value and interaction between them had significant effects on the content of sulfur dioxide. The environmental conditions for ultrasonic treatment were 60 ℃, water refresh per 6 h and pH adjusted to 3.

Preparation of Heme Iron Liposomes
GE Lan,DUAN Xiang-lin,CHANG Yan-zhong*
2009, 30(12):  48-51.  doi:10.7506/spkx1002-6630-200912005
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Ethanol injection and rotary film-ultrasonic methods were applied to prepare liposomes with heme iron in this study. Heme iron content and entrapment efficiency in liposomes obtained were measured by spectrophotometry, liposome morphology was observed under optical microscope and transmission electron microscope, and phase changes in cholesterol, lecithin and heme iron were determined by differential scanning calorimetry (DSC). Results showed that the heme iron liposomes prepared by the two methods were basically identical in most indicators. The mass ratio of hemin to cholesterol to phospholipids was in range of (0.1—200): (1—10): (10—100). The liposomes obtained are uniform and big single-chamber particles with an effective diameter of 0.804μm and the maximal entrapment efficiency is 36%.

Preparation of Flavonoids and Alkaloids-rich Extract from Mulberry Leaves
LIU Jie,PAN Jian,ZHANG Wen-cheng,YANG Yi,WU Fang-rui
2009, 30(12):  52-56.  doi:10.7506/spkx1002-6630-200912006
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Objective: To develop a technique for synchronized and efficient extraction of flavonoids and alkaloids [the main component in alkaloids from mulberry leaves was 1-deoxynojirimycin (DNJ)] from mulberry leaves. Methods: The optimal pH value of acidic ethanol solution for extraction was confirmed by single factor test, and then other 4 extraction parameters were optimized by orthogonal design based on single factor test. Results: The best synchronized extraction effect of flavonoids and alkaloids was achieved under the following conditions: with ratio of 60% acidic ethanol solution at pH 2 to dry mulberry leaves powder of 10:1, duplicate extraction at 80 ℃ for 2 h. Conclusion: Orthogonal design is feasible to optimize the synchronized extraction of flavonoids and alkaloids from mulberry leaves.

Preparation of Rice Starch Microspheres
XU Zhong1,WEI Ning1,*,LI Qiang2,FAN Li-hua1
2009, 30(12):  57-60.  doi:10.7506/spkx1002-6630-200912007
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Rice starch microspheres were synthesized by inverse suspension polymerization, with epichlorohydrin as the crosslinker, Span 60 as the emulsifier and soybean oil as the oil phase. Four key factors affecting the synthesis, including starch concentration, oil/water ratio, and amounts of emulsifier and cross-linker, were optimized by orthogonal test design. Results showed that their optimal levels were 25%, 3:1, 0.5 g and 2.0 ml, respectively, and under the conditions the average particle size of the starch microspheres obtained was 13.73 μm.

Ultrasonic-assisted Enzymatic Hydrolysis of Corn Protein
LIU Zhen-chun,DENG Zi-yu,LI Hui,DUAN Xu
2009, 30(12):  61-65.  doi:10.7506/spkx1002-6630-200912008
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The present study aimed to develop a combination method of ultrasonic pre-treatment and alkaline proteasecatalyzed hydrolysis for corn protein. The ultrasonic-assisted enzymatic hydrolysis was optimized through orthogonal test design based on single factor test. When ultrasonic treatment duration, mass fractions of substrate and enzyme, and pH value and temperature for hydrolysis were 4 min, 2% and 5%, and 10.5 and 55 ℃, respectively, the maximum hydrolysis degree was achieved, reaching 61.47%. Moreover, molecular weights of products obtained at different hydrolysis time were determined by SDS-PAGE.

Extraction of Polyphenols from Pomegranate Seed
MIN Yong1,WANG Hong2,YAO Li-hua1,LIU Wei1,*,YANG Jin1
2009, 30(12):  66-68.  doi:10.7506/spkx1002-6630-200912009
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Based on single factor test, orthogonal test design was applied to optimize the extraction technology of polyphenols from crushed pomegranate seed (20 mesh). Results showed that temperature and ratio of solid to liquid had significant effects on extraction yield of polyphenols. Under optimized conditions [with 50% ethanol as extraction solvent, at the ratio of material to the solvent of 1:20 (g/ml), extracting for 2.0 h at 50 ℃], the extraction yield of polyphenols reached 12.07 mg/ g.

Ultrasonic-assisted Solvent Extraction of Total Saponins from A. trifoliatus Leaves
GAO Xia1,LI Yun-xiang1,*,CAI Ling-yun1,2,WANG Rong1,QUAN Qiu-mei1,CHEN Jiao1
2009, 30(12):  69-72.  doi:10.7506/spkx1002-6630-200912010
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In the present study, ultrasonic treatment was applied to assist the extraction of total saponins from defatted and decolorized A. trifoliatus leaves with 70% ethanol. The ultrasonic-assisted extraction technology was optimized by orthogonal test design based on single factor test. Results showed that the optimal ultrasonic power, ultrasonic treatment duration, extraction temperature and ratio of solid to liquid for the extraction of total saponins were 80% (relative value to the maximum power), 35 min, 60 ℃ and 1:10; under this condition, the extraction yield of total saponins was 16.32%, which was higher than that obtained by Soxhlet extraction.

Microwave-assisted Extraction of Total Flavonoids from Fruit Peels of Shatian Pomelo (Citrus grandis var. shatinyu Hort)
ZHU Yuan-ping
2009, 30(12):  73-77.  doi:10.7506/spkx1002-6630-200912011
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This study aimed to optimize extraction technology of total flavonoids from microwave-pretreated fruit peel slices of Shatian pomelo with ethanol. Two parameters of microwave pretreatment, including radiation power and duration, were optimized by single factor test, and then four parameters of extraction, including ethanol concentration, extraction temperature and duration, and solid/liquid ratio, were optimized by orthogonal test design based on single factor test. Results showed that under optimized conditions [with microwave-pretreated fruit peel slices of Shatian pomelo for 3 min at 495 W as the material and 80% ethanol as the extraction solvent, as well as the ratio between them of 1:8 (g/ml), extraction for 40 min at 70 ℃], the best extraction efficiency of total flavonoids was achieved. Triple validation experiment on the optimal extraction technology obtained showed that average extraction yield of total flavonoids was 0.99%.

Supercritical Carbon Dioxide Extraction of Almond Oil
LI Xin-hua,LI Xiao-na
2009, 30(12):  78-81.  doi:10.7506/spkx1002-6630-200912012
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Single factor combined with orthogonal test design was applied to optimize extraction technology of oil from crushed almond seeds with supercritical CO2. Range analysis for results of orthogonal test showed that effects of four key factors on extraction yield of almond oil declined in the following order: extraction pressure > extraction duration > extraction temperature > particle size of almond seed powder; the optimum extraction pressure, temperature and duration, and particle size of almond seed powder were 30 MPa, 50 ℃, 2.5 h, and 40 mesh, respectively. Under this condition, the extraction yield of almond oil was 49.85%.

Change in Selenium Content of Selenium-rich Salicornia bigelovii Torr. during Vacuum Frying
FAN You-bing1,2,ZHANG Min1,2,*,ZHOU Xiang3,CAI Jin-long3,DING Zhan-sheng1,2
2009, 30(12):  82-85.  doi:10.7506/spkx1002-6630-200912013
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Effects of pretreatment (blanching, desalting and sugaring) and vacuum frying conditions (temperature, vacuum degree and duration) on the selenium content of selenium-rich Salicornia bigelovii Torr. were studied. The results showed that 30% of selenium was lost in blanching, while desalting had no significant effect on selenium content, and sugaring may reduce the loss of selenium. Moreover, all of vacuum frying temperature, vacuum degree and duration significantly affected the selenium content. Under the condition of vacuum frying at 100 ± 20 ℃ and 0.09 MPa for 15 min, the moisture of the product reached 2% and the selenium preservation was 32%.

Establishment of Mathematical Model of Pectin Extraction from Banana Peel
QIU Li-ping1,JIANG Lu2,CHEN Qiong1,YAO Yu-jing1,WEN Qi-biao2
2009, 30(12):  86-89.  doi:10.7506/spkx1002-6630-200912014
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Deproteinized and destarched banana peel was taken as the raw material to extract pectin with HCl solution. Effects of pH of HCl solution, extraction temperature, extraction duration, solid/liquid ratio and salting-out temperature were on extraction yield of pectin were investigated by single factor test, and a mathematical model, describing pectin extraction, was established by means of Design Expert 7.0. According to the results of single factor test, the “optimal” pH of HCl solution, extraction temperature, extraction duration, solid/liquid ratio and salting-out temperature were 2.2, 85 ℃, 1.4 h, 1:3 and 70 ℃,
respectively. The mathematical model of pectin extraction was Y (%) ﹦-36.9+1.39X1+ 0.785X2-1.95X3+ 0.142X4- 0.0192X1X2 - 0.0151X1X3 - 0.0198X1X4+ 0.0289X2X3 - 0.0004X2X4+ 0.0237X3X4+ 0.386X1 - 0.0045X2 - 0.696X3 - 0.0008X4, where Y was the extraction yield of pectin, and X1, X2, X3 and X4 were the pH of HCl solution, extraction temperature, extraction duration and salting-out temperature, respectively. Variance analysis for this equation showed that the interaction between extraction temperature and extraction time presented significant effect on the extraction yield of pectin.

Formulation and Stabilization of Spirulina Oral Liquid
WANG Chen,ZHANG Yan-tao
2009, 30(12):  90-93.  doi:10.7506/spkx1002-6630-200912015
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With papain-catalyzed hydrolysate of Spirulina, ginseng concentrate (containing 1.5-1.6 g saponins /L) and pilose antler concentrate (containing 3.3-3.5 g proteins/L) as the main materials, a Spirulina oral liquid was developed. In the processing of the oral liquid, β-cyclodextrin was added in order to mask odor of Spirulina, and mixture of the above three materials was stabilized by addition of mixed thickeners (CMC-Na, xanthan gum and sodium alginate) and addition of sucrose and pH adjustment. The stabilization effect was evaluated in terms of alterations in turbidity (ΔE) of the mixture of Spirulina hydrolysate and ginseng and pilose antler and concentrates. Finally, proportions of Spirulina hydrolysate, sucrose, mixed ginseng and concentrates (1:1, V/V) and honey composing the oral liquid were optimized by orthogonal design with comprehensive sensory evaluation score as the indicator. The best formulation was obtained by mixing 40% Spirulina hydrolysate, 1.5% mixed ginseng and concentrates, 7% sucrose, 2.8% honey, 0.3% β-cyclodextrin, 0.10% CMC-Na, 0.04% xanthan gum and 0.06% sodium alginate, secondary adjusting the pH to 7.0-8.0 with NaHCO3, and final sterilizing the mixture system at 121 ℃ for 10 min. The oral liquid product obtained by this formulation was green-yellow and uniformly distributed, with good taste but without the Spirulina ordor, and demixing did not occur to the product after standing for a long time.

Microencapsulation of Flavonoids from Chaphalium affine D.Don
PAN Ming,WANG Shi-kuan,GUO Mai-xi,LIU Lu
2009, 30(12):  94-97.  doi:10.7506/spkx1002-6630-200912016
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Objective: To study the optimal preparation technology of Chaphalium affine flavonoids microcapsule. Methods: Arabia gum and β-CD were selected as the wall materials and the flavonoids extract of Chaphalium affine was microencapsulated by the method of freeze-drying. Results: The optimum ratios (m/m) of arabia gum to β-CD and wall materials to core material were 1:15 and 1:10, respectively. The best conditions for freeze-drying were as follows: condenser temperature, -40 ℃; material thickness, 8 mm; and shelf temperature, 40 ℃. The microencapsulation efficiency was higher than 90% and good embedding effect was achieved.

Preparation of Carboxymethyl- β-cyclodextrin
WANG Jin,CHEN Jun-zhi
2009, 30(12):  98-100.  doi:10.7506/spkx1002-6630-200912017
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Carboxymethyl-β-cyclodextrin (CM-β-CD) was prepared in alkaline media by nucleophilic substitution reaction of β-CD and monochloroacetic acid. Influences of reaction temperature, reaction duration and reactant ratio on substitution degree and yield of CM-β-CD were discussed. Under optimized reaction conditions (reacting for 4 h at 60 ℃ and the molar ratios of monochloroacetic acid to β-CD and sodium hydroxide to monochloroacetic acid of 8.5:1 and 2.5:1, respectively), a substitution degree of 6.06 and a yield of 46% were achieved.

Orthogonal Test Design for Optimization of the Ethanol Extraction and the Microwave-assisted Ethanol Extraction of Proanthocyanidins from Cabernet Sauvignon Grape Skin
WANG Zhu-qing,WANG Jun*
2009, 30(12):  101-106.  doi:10.7506/spkx1002-6630-200912018
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Effects of extraction duration, temperature, solid/liquid ratio and concentration of aqueous ethanol solution on yield of proanthocyanidins from Cabernet Sauvignon grape skin extracted individually with ethanol were studied by single factor test, as well as effects of microwave radiation duration, concentration of aqueous ethanol solution and solid/liquid ratio on yield of proanthocyanidins extracted with ethanol under the assistance of microwave. Based on the results of single factor test, the two extraction technologies were optimized by orthogonal test design. Under optimized conditions for individual ethanol extraction [temperature, 50 ℃; extraction duration, 55 min, solid/liquid ratio, 1:8.5 (g/ml); and concentration of aqueous ethanol solution, 55%], the yield of proanthocyanidins was 2.61%; under optimized conditions for microwave-assisted extraction [microwave radiation power, 320 W; microwave radiation duration 30 s; concentration of aqueous ethanol solution, 50%; and solid/liquid ratio, 1:13 (g/ml)], the yield of proanthocyanidins was 3.99%. When acidic ethanol solutions at pH 4.5 and 5.0 were used to extract proanthocyanidins by the two optimized technologies, the yields of proanthocyanidins were 2.67% and 4.11%, respectively, indicating that the addition of acid is favorable to increase the yields of proanthocyanidins.

Tempering Drying Characteristics of Preserved Prunes (Jiayingzi)
LIU Wei-tao,LI Bian-sheng*,YANG Shan-shan,YU Yu-ming,RUAN Zheng,ZHU Zhi-wei
2009, 30(12):  107-111.  doi:10.7506/spkx1002-6630-200912019
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Objective: To investigate the tempering drying characteristics of preserved prunes (Jiayingzi) with different moisture contents under different tempering environments and duration. Method: Physical and chemical analysis and sensory evaluation were conducted to preserved prune samples with different moisture contents after tempering and then hot air drying. Results: All the tempering environment, drying duration and moisture content had marked effects on the drying characteristics of preserved prunes. Prolonged tempering (up to 20 h) and drying time (up to 1.5 h) resulted in efficient improvements of physical and chemical characteristics and sensory quality. Compared to natural, absolute dry and refrigerator environments, air-conditioned environment exhibited the best tempering effect. The air-conditioned and absolute dry environments resulted in the highest recovery of structure and distribution uniformity of moisture. Generally, the longer the time to temper, the higher rising rate of drying velocity. But when tempering time was over 12 h, the drying velocity did not rise significantly. Conclusion: The best tempering conditions are as follows: moisture content of preserved prune samples, 35%; tempering duration, 12 h; and tempering environment, air-conditioned environment.

Drying and Cooking Characteristics of Nutritional Engineering Cereals
CHEN Hou-rong1,2,KAN Jian-quan1,2,*,ZHANG Fu-sheng3
2009, 30(12):  112-116.  doi:10.7506/spkx1002-6630-200912020
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Drying technology plays an important role in the quality control of nutritional engineering cereals. By the means of single factor and orthogonal tests, the optimal parameters for drying nutritional engineering cereals were determined as follows: drying temperature 50 ℃, wind speed 0.4 m/s and loading amount 1.0 kg/m2. Also, the cooking technology of nutritional engineering cereals was discussed. Results showed that the taste was nice when soaking the cereals with water (1:1, m/m) for 20 -40 min, and then cooking the mixture, after cooking holding the temperature for 15-30 min.

Fresh-keeping Effects of Ultrahigh Pressure Treatment on Fresh Sea Cucumber
LI Qing-ling,SONG Ji-chang*,WU Jun-fei,LIU Bing-cheng
2009, 30(12):  117-119.  doi:10.7506/spkx1002-6630-200912021
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Effects of processing pressure, pH and pressure duration on the total bacterial count of fresh sea cucumber were investigated by single factor test, and then these factors were optimized by orthogonal test design. Moreover, fresh-keeping effects of two pressure modes, namely continuous and cycle pressure modes, were compared. The results showed that under the conditions of the processing pressure 500 MPa, pH 6.5 and pressure duration 30 min, the best sterilization effect on fresh sea cucumber was achieved, and the fresh-keeping effect of the cycle pressure mode was superior to that of another mode .

Use of Macroporous Resin for the Extraction of Red Pigments from Hibiscus sabdariffa L.
XU Li-song,MA Yin-hai*
2009, 30(12 ):  120-122.  doi:10.7506/spkx1002-6630-200912022
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Red pigments from Hibiscus sabdariffa L. were extracted with HCl solution (pH 3), and then were separated from the extract with 7 macroporous resins. According to the adsorption efficiency to the red pigments, resin HPD-100 was selected for the further study concerning adsorption and desorption conditions for achieving the best separation effect of the red pigments. Results showed that the best adsorption efficiency was achieved when pH value of the extract was 3.0, at 40-60 ℃ the HPD-100 exhibited the highest adsorption efficiency, and the time to reach adsorption equilibrium was 150 min with the adsorption efficiency of 96.90%; the best desorption effect of the red pigments was achieved by using 90% ethanol as the elution solvent. After being used repeatedly 20 times, the HPD-100 still had good adsorption capability.

Ultrafiltration Preparation of Antioxidant Peptides from Black Soybean
REN Hai-wei1,WANG Chang-qing2,*
2009, 30(12):  123-126.  doi:10.7506/spkx1002-6630-200912023
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The neutral protease-catalyzed hydrolysis products of black soybean protein isolate (BSPI) were fractionated using ultrafiltration membrane with the molecular weight cut-off (MWCO) of 10, 6 and 2 ku. Effects of 4 ultrafiltration parameters, including membrane module type, operating pressure, and pH value and concentration of BSPI peptide solution on membrane separation efficiency, as well as cleaning effects of different reagents on membrane (represented by water flux recovery, WFR), were investigated. Furthermore, hydroxyl radical scavenging activities of BSPI peptides with different MWs were assayed. The results showed that a satisfying ultrafiltration effect was achieved using modified PES flat sheet ultrafiltration membrane module under the conditions of 0.25 MPa, pH 6.5, 2% peptide concentration, and 25 ℃, and the sequential cleaning procedure with proteinase liquid and alkali solution containing SDS and NaClO led to a WFR of 95.68%. Radical scavenging assay indicated that the peptides with MWCO less than 2 ku possessed higher antioxidant capacity and the IC50 was 0.587 mg/ml.

Supercritical Carbon Dioxide Extraction of C21 Steroidal Glycosides from Cynanchum bungei Decne. Root
LU Zhi-min1,TIAN Lu1,2,*,ZHU Wei-hua2
2009, 30(12):  127-130.  doi:10.7506/spkx1002-6630-200912024
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Objective: To optimize the parameters of supercritical CO2 extraction of C21 seroidal glycosides from Cynanchum bungei Decne. root by orthogonal design. Methods: Five affecting factors such as extraction pressure, extraction temperature, extraction duration, particle size of material and 95% ethanol (entrainer) dosage were investigated by single factor test, and each factor was assigned with four levels for orthogonal design. Absorbance at 590 nm was taken to represent C21 seroidal glycoside content as the index to determine the optimal extraction conditions. Results: The Temperature, the particle size of material and the 95% ethanol dosage were the main factors affecting the extraction of C21 steroidal glycosides, while the extraction duration presented the smallest effect. The optimal extraction conditions were as follows: pressure, 30 MPa; particle size of material, 40 mesh; 95% ethanol dosage, 2.0 ml/g; temperature 55 ℃; and extraction duration 90 min.

Supercritical Fluid Extraction and GC-MS Analysis of Terpenoid Compounds from Grateloupia filicina C.Ag.
LI Na,DENG Yong-zhi*,LI Wen-quan
2009, 30(12):  131-134.  doi:10.7506/spkx1002-6630-200912025
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The extraction, purification and GC-MS analysis of terpenoid compounds from Grateloupia filicina C.Ag. were investigated in the present study. The supercritical fluid extraction conditions of terpenoid compounds from Grateloupia filicina C.Ag. were optimized by orthogonal test, and the main components in the terpenoid compounds were analyzed by GC-MS. The results of orthogonal test showed that the extraction pressure presented the most significant effect on yield of terpenoid compounds, followed by extraction duration, temperature and flow rate in turn, and the optimum extraction conditions were as follows: with flow rate of 10 L/h, extraction at 30 MPa and 40 ℃ for 2 h. By searching in NIST98 spectrum library and refering to related literature, finally 11 kinds of terpenoid compounds were confirmed from the extract of Grateloupia filicina C. Ag.

Preparation and Properties of Polysaccharide from Acipenser schrenckii Skull
HUANG Qi-lin,CHEN Ruo-wen,DING Yu-qin,XIONG Shan-bo
2009, 30(12):  135-139.  doi:10.7506/spkx1002-6630-200912026
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By the step-by-step procedure of dilute alkali extraction, trypsinase-catalyzed hydrolysis, protein removal by trichloroacetic acid, ethanol precipitation, and freeze-drying, crude polysaccharide was obtained from Acipenser schrenckii skull. The conditions of dilute alkali extraction and trypsin-catalyzed hydrolysis were optimized by single factor analysis and orthogonal test. Furthermore the prepared product was subjected to composition and structural analysis. Results showed that the optimal extraction and hydrolysis conditions were as follows: extracting crushed dry Acipenser schrenckii skull for 6 h with 3wt% alkali solution, and hydrolyzing the extract for 5 h with trypsinase dosage of 0.6%, respectively. The contents of hexosamine, hexosuronic acid, total sulfate group and N-sulfate group in the polysaccharide were 18.79%, 21.91%, 15.96% and 13.32%, respectively. Moreover, the hexosamine component in this polysaccharide was identified as galactosamine.

Determination of Sugar Content in Cherry Fruit by Visible-Near Infrared Diffuse Reflectance Spectroscopy Based on CWT and GRNN
GUO Wei-dong1,NI Kai-cheng1,SUN Xu-dong2,ZHANG Chang-jiang1,CHEN Wen-rong1
2009, 30(12):  140-143.  doi:10.7506/spkx1002-6630-200912027
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CWT - GRNN model was constructed to predict sugar content in cherry fruit by combining continuous wavelet transform (CWT) with generalized regression neural networks (GRNN). CWT was used to extract the key features, which were related to the sugar content of cherry. Three scales in the CWT domain were selected to efficiently extract the features of cherry fruit, and four feature spaces were divided according to the features of visible-near infrared (VIS-NIR) diffuse reflectance spectroscopy. Thus a feature vector, which contains twelve parameters, was input to the GRNN and the smooth factor of the GRNN was set as 0.0001. Twenty cherry samples were used to verify the performance of the CWT - GRNN model. Experimental results showed that the relative error of predicted samples was below 2%. CWT - GRNN model could be used to quickly, accurately and non-destructively predict the sugar content in cherry fruit. Also, the proposed method could be applied in control and  evaluation in fruit and vegetable industry.

Atomic Fluorescence Spectrometric Determination of Trace Selenium in Chinese Date
ZHANG Fu-wei,HOU Dong-yan,HUI Rui-hua
2009, 30(12):  144-146.  doi:10.7506/spkx1002-6630-200912028
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An atomic fluorescence spectrometric method was developed to determine trace selenium in Chinese date by taking 10% HCl solution as the current-carrying solution, selecting 2.0% potassium borohydride solution to enhance fluorescence intensity, and eliminating the disturbance of Pb2+, Cu2+ and Ag+ by enrichment with mercapto cotton and masking with thioureaascorbic acid. Results showed that the linear range and detection limit were 1.0-32.0 ng/ml and 0.57 ng/ml, respectively; the recovery varied from 99.0% to 106.3% and the RSD was lower than 1.71%.

Negative Ion Mode ESI-MS Analysis of Cellooligosaccharides
PENG Hong1,2,3,LIN Lu2,LIU Yu-huan1,3,RUAN Rong-sheng1,3,LIU Cheng-mei1,3
2009, 30(12):  147-149.  doi:10.7506/spkx1002-6630-200912029
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Cellotriose and cellotetraose were analyzed by electron pray ionization mass spectrometry (ESI-MS) with negative ion mode. Under the ESI negative ion mode, an adduct ion from cellotriose was [M+3H2O+Cl]- (m/z 593.5), and there were two main fragments (m/z 503 and m/z 341) in MS/MS spectrum. A proton-removing quasi-molecular ion [M-H]- (m/z 665) and an adduct ion [M+Cl]- (m/z 701.5) from cellotetrose were formed, and there were seven main fragments in MS/MS spectrum, including m/z 665 or m/z 647, m/z 545, m/z 503, m/z 485, m/z 383, m/z 341 and m/z 323.

Properties of Pigments from Black Rice and Identification of the Adulterated Black Rice
ZHONG Geng1,2,DENG Li-qing1,ZHANG Yun-fang1,ZHENG Hong-yan1
2009, 30(12):  150-153.  doi:10.7506/spkx1002-6630-200912030
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The structure and physicochemical properties of black rice pigments were described to in this study as well as the preparation of adulterated black rice. Black rice adulteration may be verified through color reaction, UV-visible spectrum and IR spectrum. The results showed that the adulterated black rice could be identified by qualitative analysis of black rice pigment. Difference in the characteristics of spectrum could also be used to identify whether the black rice were adulterated or not under some condition.

HPLC Determination of Hyperoside in Stems and Leaves of Sorbus tianschanica Rupr
YANG Ling-ling,CHANG Jun-min*,YAO Jun
2009, 30(12):  154-156.  doi:10.7506/spkx1002-6630-200912031
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Hyperoside was extracted from stems and leaves of Sorbus tianschanica Rupr with methanol and then subjected to HPLC analysis. The determination (at 360 nm) was performed on a Shim-pack VP-ODS (150 mm × 4.6 mm, 5 μm) column (25 ℃) using aceyonitrile - water (25:75, V/V) as a mobile phase at the flow rate of 1.0 ml/min. A good linearity was obtained within the range of 0.04 - 0.32 mg and the correlation coefficient was 0.9992. The average recovery for hyperoside was 99.7% and the RSD was 2.6%. The method is simple, rapid, sensitive, precise, reliable and repeatable and can be applied to the quality control of stems and leaves of Sorbus tianschanica Rupr as a kind of Chinese medicinal material.

Reversed Phase High Performance Liquid Chromatographic Determination of 7 Tetracyclines Residues in Bovine Milk
SHE Yong-xin1,2,LIU Jiang-ying3,LU Xiao-ling1,WANG Jing1,* CAO Wei-qiang4
2009, 30(12):  157-161.  doi:10.7506/spkx1002-6630-200912032
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Residues of 7 tetracyclines were extracted with 0.1mol/L EDTA-McIlvaine buffer solution (pH 3.8) from bovine milk, pretreated with 50% trichloroacetic acid solution, and then subjected to cleanup with HLB solid phase extraction (SPE) cartridge. The analysis of 7 tetracyclines residues was conducted by reverse phase high-performance liquid chromatograph on a sunfireTM C18 column (250 mm × 4.6 mm, 5 μm i.d) with methanol - acetonitrile - 0.01 mol/L oxalic acid solution as a mobile phase (gradient elution) at the flow rate of 1.0 ml/min. The results showed that the method presented a wide-range high-linearity for analyzing these tetracyclines. The peak area was positively correlated with sample solution concentration in the range of 0.05 - 1.0 μg/ml. The average recovery was 78.66% - 106% and the lowest detection limit was 0.02 μg/ml. The method is sensitive, reliable and easy-operating, and can be used for simultaneous determination of 7 tetracyclines residues in bovine milk within 14 minutes.

HPLC Determination of Sugars in “Tainong 6” Pineapple
LIU Sheng-hui1,2,WEI Chang-bin1,2,SUN Guang-ming1,2,ZANG Xiao-ping1,2,*
2009, 30(12):  162-164.  doi:10.7506/spkx1002-6630-200912033
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A method using high performance liquid chromatography (HPLC) was presented for the determination of sucrose, glucose and fructose in “Tainong 6” pineapple. The sugars in pineapple was extracted with 90% ethanol, and the determination was performed on CH-820 (Ca) column (300 mm × 7.8 mm, column temperature 90 ℃) with ultrapure water as a mobile phase at the flow rate of 0.5 ml/min using a refractive index detector. There were good linear relationships between HPLC peak area and concentrations of the three sugars with correlation coefficients not lower than 0.9998. The spike recoveries and the RSDs of precision for the three sugars ranged from 98.84% to100.3% and from 0 .59% to 0.85%, respectively. The sugar content in “Tainong 6” pineapple varied among different harvest seasons. The sucrose content in the pineapple harvested in summer (July) and autumn (September) was the highest, followed by the glucose and fructose contents in turn. Whereas the glucose content in the pineapple harvested in winter (November) was the highest, and the sucrose the lowest.

Simultaneous RP-HPLC Determination of Lactic Acid and Methyl Lactate
JIANG Shao-tong,LIU Mo,CHEN Xiao-yan,ZHENG Zhi
2009, 30(12):  165-167.  doi:10.7506/spkx1002-6630-200912034
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A reversed-phase high performance liquid chromatographic (RP-HPLC) method was developed for the simultaneous determination of lactic acid and methyl lactate. The HPLC was equipped with Purospher STAR C18 reversed-phase column and diode array detector. The mobile phase was composed of 0.005 mol/L H2SO4 solution and chromatographically pure methanol (9:1, V/V) with the flow rate of 1.0 ml/min. The injection volume was 20 μl, and the detection wavelength was set as 210 nm. This method is accurate, simple, rapid and reproducible.

Gas Chromatography-Mass Spectrometry Analysis of Aroma Components in Icing Fruits of Vitis amurensis Rupr and Its Interspecific Hybrid
NAN Hai-long1,LI Hua1,2,*,JIANG Zhi-dong1
2009, 30(12):  168-171.  doi:10.7506/spkx1002-6630-200912035
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In order to provide theoretical basis for the research and development of icing grape wine of V. amurensis Rupr, GCMS analysis was performed to aroma components in icing fruits of two V. amurensis Rupr cultivars (Shuangyou, Zuoshanyi) and one of interspecific hybrids of V. amurensis Rupr (Gongniang No.1) planted in Liuhe area in northeast China, Jilin Province. The aroma components were extracted with dichloromethane and principal component analysis was adopted. Results showed that 44 peaks were separated from the “Shuangyou” and among them 38 kinds of aroma components were identified, which accounted for 83.15% of the total content; totally 40 peaks were separated from the “Zuoshanyi” and among them 37 kinds of aroma components were identified, which accounted for 92.56% of the total content; totally 32 peaks were separated from the “Gongniang No. 1” and among them 24 kinds of components were identified, which accounted for 68.2% of the total content. The main common aroma components in the icing fruits of the 3 cultivars were 3-methyl-1-butanol, 1-hexanol, diisooctyl phthalate, and 2-methyl-1-propanol, etc. The normal ripe fruits of V. amurensis Rupr are not available for the brewing of dry wine because of their poor sugar content. However, the cold hardiness of V. amurensis Rupr is extremely strong and its fruits can freeze to crystallization at low temperature in winter, which raises not only the sugar content but also the aroma and fragrant concentration. Therefore, the icing fruits of V. amurensis Rupr can be brewed to unique and wonderful ice wine.

Acetylacetone Spectrophotometric Determination of Migration of Formaldehyde and Hexamethylenetetramine from Plastics into Food Simulants
ZHU Xiao-yan,CHEN Shao-hong,LIU Zai-mei,CAO Guo-zhou
2009, 30(12):  172-175.  doi:10.7506/spkx1002-6630-200912036
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The conditions for color reaction of acetylacetone and formaldehyde and conversion of hexamethylenetetramine (HMTA) to formaldehyde were optimized. An acetylacetone spectrophotometric method was proposed for the determination of migration of formaldehyde and HMTA from plastic to acetic acid solution. The linear range of calibration curve was 0-15 mg/L, and the detection limit for the method was 0.09 mg/L. The conversion rate of HMTA to formaldehyde was 98.3%-100% and the recovery for formaldehyde in HMTA solution was 99.5%-101%. A collaborative trial was carried out by nine laboratories to samples with formaldehyde levels of 9.93 mg/L (containing HMTA) and 7.01 mg/L (without HMTA). The repeatability limits were 0.707 and 0.112 mg/L and the reproducibility limits were 2.094 and 1.516 mg/L, respectively.

Use of Charge-transfer Complexation for Spectrophotometric Determination of Theanine Contents in Tea and Tea Beverage
LIU Xiao-geng
2009, 30(12):  176-179.  doi:10.7506/spkx1002-6630-200912037
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Based on the charge-transfer complexation between tetrachlorobenzoquinone and theanine, a spectrophotometric method was developed for the determination of theanine contents in tea and tea beverage. Pure theanine could be obtained by 80% ethanol extraction and then copper salt precipitation, followed by recrystallization in absolute ethanol, and the extraction yield of theanine was over 84.6%. After theanine aqueous solution and tetrachlorobenzoquinone ethanolic solution was left to react at pH 8-9 and 50℃ for 50 min, a purplish red complex with the mole ratio of theanine to tetrachlorobenzoquinone of 2:1 was obtained. Its stability constants k (293 K) and Gibbs free energy ΔrGm (293 K) were 3.9×103 and -20.14 kJ/mol, respectively, and at working wavelength (λ = 331 nm), its apparent molar absorptivity coefficient was 1.98×104 L/ mol·cm, which obeys Beer's law in the range of 5×10-6-9×10-5 mol/L with the linear equation, A = 0.028×10-6 C - 0.02 (r = 0.9958). When the method was applied in the determination of theanine content in commercial tea and tea beverage, the results were consistent with those determined by HPLC with a recovery of 98.7%-102.6% and a relative standard deviation of 1.2%-4.2%. Altogether, this method is easy-operating and highly sensitive, and can provide accurate results.

High-performance Ion Chromatographic Determination of Benzoic Acid in Paprika Oleoresin
LIU Qiao-ru1,CHU Song-mao1,YANG Wei-chun1,ZHANG Li1,PENG Qin-long1,HE Guo-xu1,SHI Qi-zeng2
2009, 30(12):  180-182.  doi:10.7506/spkx1002-6630-200912038
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A new method using suppressed high-performance ion chromatography was developed for the determination of benzoic acid in paprika oleoresin. The analysis was performed on a Dionex Ion Pac AS11 anion exchange column (250 mm×4 mm) with an AG11 guard column(50 mm×4 mm). The mobile phase was composed of 0.22 mol/L sodium hydroxide solution, water and 50% iso-propylacohol. After gradient elution the effluent was suppressed by an anion micromembrane suppressor and measured by a conductivity detector. The samples were precipitated with potassium hexaoyanoferrate and zinc acetate solution and filtered in turn by a filter paper and a membrane (0.45 μm) to remove other components. The results showed that the linear range for benzoic acid was 5.0-500 mg/L, with a detection limit of 1.5 mg/L and the correlation coefficient of linear regression equation was 0.9997; the RSD for 10 parallel determinations was 1.98%. The method was applied in the determination of benzoic acid content in paprika oleoresin with satisfactory results, and the recoveries for benzoic acid in paprika oleoresin spiked at three different levels were in the range of 97.6%-100.3%.

Micellar Electrokinetic Capillary Chromatography Method for Direct Determination of Nipagin Esters in Food
DU Jian-zhong1, ZHANG Tian-hui1,DING Ding2,3,CAI Kang-bao1,ZHOU Zhi-lin1
2009, 30(12):  183-186.  doi:10.7506/spkx1002-6630-200912039
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This study aimed to establish a method of micellar electrokinetic capillary chromatography for direct determination of nipagin esters in food. Effects of key factors, such as concentration and pH adjustment of running buffer, separation voltage and concentration of surface active agent (SDS) as well as organic solvent addition on separation of ethyl nipagin ester, propylparaben and butyl nipagin were investigated. The results showed that under the optimized conditions as follows: running buffer, 10 mmol/L (final concentration) sodium dihydrogen phosphate-10 mmol/L (final concentration) sodium borate (pH 8.0) solution; SDS concentration, 20 mmol/L; separation voltage, 22 kV; and UV wavelength, 256 nm, these nipagin esters were completely separated within 10 min. There were nice linear relationships between their concentrations and peak area. Butyl nipagin was not detected in two commercial soy sauces by this method. Average recoveries for ethyl nipagin ester and propylparaben in the two commercial soy sauces spiked at two levels were within the recovery of 97.2%- 104% (n = 5).

Simultaneous Gas Chromatographic Determination of Captan, Folpet and Captafol Residues in Vegetable
ZHOU Yan-ming,GUAN Li,NIU Sen,HU Rui
2009, 30(12):  187-189.  doi:10.7506/spkx1002-6630-200912040
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A method using gas chromatography (GC) was presented for simultaneous determination of captan, folpet and captafol residues in vegetable. Samples were extracted with acetone and subjected to liquid-liquid extraction with n-hexane, followed by cleanup with column filled with florisil and graphitized carbon black. Finally the samples were determined by GC equipped with an electron capture detector (ECD). The limits of quantification for captan, folpet and captafol by this method were 0.005, 0.003 and 0.01 mg/kg, respectively. The average recoveries for these pesticides in cabbage, radish and eggplant spiked at 0.01, 0.05 and 0.1 mg/kg were 71.6%-100.2%, 78.6%-104.6% and 70.2%-86.9%, respectively, and the coefficients of variation were 8.5% - 12.9%, 5.1%- 11.2% and 8.7%- 13.6%, respectively (n = 5).

Real-Time Fluorescent PCR Detection of Soybean Ingredients Adulterate in Milk Powder
YUE Qiao-yun,CHEN Ding-hu,WU Zhao-hui,ZHOU Zhuo-biao,QIU De-yi*
2009, 30(12):  190-193.  doi:10.7506/spkx1002-6630-200912041
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Soybean ingredients adulterated in milk powder was firstly determined by real-time Fluorescent PCR in our study using lectin, the endogenous gene of soy-bean as a reference gene. This method provided a quick and precise way for the detection of adulteration of milk powder and also presented new insights for the market supervision and administration. After respective removal of fat and protein in milk powder with hexane and tris-balanced phenol, a high-quality DNA template was obtained using Promega Wizard genomic DNA purification kit. The experimental results indicated that the sensitivity of detecting soybean ingredients adulterated in milk powder was highly improved by using real-time fluorescent PCR method, and the PCR amplification curve and cycle numbers remained corresponding relationship with adulteration amounts of soybean ingredients in milk powder. This method can provide a rapid and accurate way for detection and analysis of the adulteration of milk powder, which can be used as a new evidence for market supervision and administration.

Elimination of Caffeine Disturbance to GC Determination of Pesticides Residues in Tea
RUI San-ya,HU Qi,CAI Lu-sha,CHEN Yun-wen
2009, 30(12):  194-197.  doi:10.7506/spkx1002-6630-200912042
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A pretreatment method of dichloromethane plus hot water(45℃)extraction followed by cleanup with Carbosil cartridge (for organophouros pesticides residues) or Florisil cartridge (for pyrethrosins residues) was developed for eliminating the disturbance of caffeine to the GC determination of pesticides residues in tea. A single laboratory validation was performed by spiking organophouros and pyrethrosins pesticides at three levels (0.2, 0.8, and 1.6 mg/kg, respectively). The results showed that the caffeine was effectively removed from tea extract by this method. The average recoveries for organophouros pesticidies were between 73% and 112.9%, the RSDs were less than 8%, and the limits of detection ranged between 0.02 and 0.002 mg/kg; for pyrethrosins, the average recoveries varied between 78.8% and 105%, the RSDs were below 9%, and the limits of detection ranged from 0.001 to 0.006 mg/kg. The accuracy, precision and limit of detection of this method for all these pesticides are in agreement with even higher than the standards set by the related Chinese and EU regulations.

Ultrasonic Extraction - High Performance Liquid Chromatography for Simultaneous Determination of 6 Common Preservatives in Imported and Exported Foods
LIN Yuan,ZHAO Tao,ZHANG Zhao-hui
2009, 30(12):  198-201.  doi:10.7506/spkx1002-6630-200912043
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An ultrasonic extraction-reversed phased HPLC method was developed for the simultaneous separation and determination of 6 common preservatives such as benzoic acid, sorbic acid, methylparaben, ethyl P-hydroxybenzoate, nipasol and butyl P-hydroxybenzoate. Samples were extracted with the mixture of water and methanol (5:95, V/V) in ultrasonic field. The gradient elution was carried out on a Supelco Discovery C18 column, with an initial mobile phase of acetonitrile-acetate buffer (pH 4.4) and at the flow rate of 1.0 ml/min. The detector wavelength was set at 254 nm. Under these conditions, the separation of the 6 components was achieved within 14 min. The linear ranges for the determination 6 preservatives by this method were from 5 to 100 μg/ml with a correlation coefficient (r) of 0.9997-1.000, and the limits of detection were 0.012-0.43 μg/ml. The average recoveries for the 6 preservatives in sample spiked at three levels (10, 50 and 100 μg/g) were 90.1%-106.3% (n = 3). The RSDs of precision and stability were 0.58%- 1.79% (n = 5) and 0.15%- 1.65%, respectively. Finally, this method was applied to analysis of these preservatives in 30 different imported and exported food samples. Altogether, the pre-treatment procedure of the developed method is simple and rapid, and the result is sensitive and accurate.

Ultra-performance Liquid Chromatography-Tandem Mass Spectrometry for the Determination of Carbendazim and Thiabendazole Residues in Dried Shiitake (Lentinula edodes)
LIAN Wen-hao,SU Jian-feng,JIANG Bin-wei
2009, 30(12):  202-204.  doi:10.7506/spkx1002-6630-200912044
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A method for simultaneous analysis of carbendazim and thiabendazole in dried shiitake was developed using ultraperformance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). Sample was extracted with 0.02 mol/L hydrochloric acid solution containing 20% methanol, adjusted pH to 6-8, purified with dichloromethane, dried by rotary evaporator, and dissolved in 30% methanol solution. The sample was detected by the UPLC-MS/MS, and quantified by external standard method. Results showed that the linear ranges for determination of carbendazim and thiabendazole by this method were both between 1.0 μg/L and 100.0 μg/L (R2 > 0.99); the average recoveries for the two pesticides in dried shiitake spiked at three levels (1.0, 5.0 and 10.0 μg/kg) were 78%-106%, and the RSDs were 7.9%-9.8% (n = 6); the limit of detection was 1.0 μg/kg; the method could be quickly finished in 3 min and be applied in large amount detection of samples.

Uncertainty Evaluation of High Performance Liquid Chromatographic Determination of Sodium Formaldehyde Sulfoxylate (Rongalite) in Wheat Powder and Rice Powder
WANG Hui,CAO Xiao-yan*,PENG Xin-kai,HU Zhao-hui,HUANG Jiang-nan,HE Hong-mei
2009, 30(12):  205-208.  doi:10.7506/spkx1002-6630-200912045
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A mathematical model for uncertainty evaluation and analysis of factors affected by measuring uncertainty was established according to the principles for determining of rongalite in wheat powder and rice powder by HPLC and methods for uncertainty evaluation provided by Guide to Uncertainty Evaluation in Chemistry Analysis. Uncertainty of measuring result was evaluated and described. The uncertainty of this experiment was 0.41 μg/g. The results suggest that the uncertainty of this experiment is mainly caused in process of sample treatment and associated with concentration of standard stock solution.

Ultra-performance Liquid Chromatography-Tandem Mass Spectrometry for the Determination of Benzimidazoles Residues in Apples
ZHAO Ling-jun1,YUE Hui2,GUO Dong-liang2,CUI Jin3,ZHAO Shan-cang2
2009, 30(12):  209-212.  doi:10.7506/spkx1002-6630-200912046
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Objective: To establish a method for determination of benzimidazoles residues in apples by UPLC-MS/MS. Methods: Sample was extracted with acetonitrile. After impurity removal by NaCl salting out, the sample was filtered through a membrane (0.2 μm), and injected into UPLC column. Identification was achieved by electrospray ionization in positive mode (ESI+) using multiple reaction monitoring (MRM). Results: The detection limits for carbendazim, thiabendazol, thiophanatemethyle were 0.17, 0.16, 0.07 μg/kg, respectively; the average recoveries for the three benzimidazoles in blank sample spiked at three levels (1.0, 5.0 and 10.0 μg/kg) were in the range of 89.2%-104.6%, and the RSDs were 1.7%-3.6% (n = 6). Conclusion: The method can completely meet the requirement of analysis for benzimidazoles residues in apples.

Real-time Fluorescent PCR Detection of Allergen in Sesame
MA Li-dan1,CAO Ji-juan2,GAO Hai-yan3,BA Zhong-hua1
2009, 30(12):  213-214.  doi:10.7506/spkx1002-6630-200912047
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This study aimed to develop a real-time fluorescent PCR assay for specific detection of allergen in sesame. Realtime PCR amplification was conducted to DNA fragments from 22 samples including white sesame and black sesame as well as other different samples using a primer pair and a probe specific for sesame DNA fragment. Both the black sesame and white sesame DNA fragments exhibited fluorescent signal, but others did not. Sensitivity analysis showed that 4.4×10-12g of sesame DNA with the dilution of 10-5 could be detected, and the quantitative formula was Ct = -3.472018l ln (initial copy number) + 18.851009, R2 = 0.993088, indicating that the primer pair and the probe have high sensitivity and amplification efficiency and fit with the requirements of trace detection.

Automatic Static Headspace GC-MS Analysis of Flavor Compounds in Two Jiaozhou Chinese Cabbage Varieties and Tai'an Chinese Cabbage
WU Peng1,ZHOU Tao2,KOU Li-juan1,WANG Chao2
2009, 30(12):  215-218.  doi:10.7506/spkx1002-6630-200912048
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A method using automatic static headspace GC-MS was developed for the determination of flavor compounds in Chinese cabbages. The qualitative and quantitative analysis was performed by search program of NIST mass spectral library and area normalization method, respectively. The flavor compounds in two Jiaozhou Chinese cabbage varieties (Jiaozhou No. 3 and Hongshengbai) and Taian Chinese cabbage were compared. Results indicated that 9,12-octadecadienoic acid (Z,Z)-, methyl ester and 9-octadecenoic acid (Z)-, methyl ester were the main compounds attributing to the flavor of Jiaozhou Chinese cabbage, while they were not detected in Taian Chinese cabbage. This method is proved to be fast and reliable for analyzing the flavor compounds in vegetables.

HPGPC Determination of Relative Molecular Mass of Inulin
ZHANG Ze-sheng,ZHANG Jian-ping,SHI Shen,SHI Jia-ning,ZHANG Jie
2009, 30(12):  219-221.  doi:10.7506/spkx1002-6630-200912049
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A high performance gel permeation chromatography (HPGPC) method was developed for the determination of relative molecular mass of inulin. Separation was performed on a GPC column with triple distilled water as a mobile phase at the flow rate of 0.8 ml/min and 30℃ and determination was carried out using a refractive index detector. A direct linear relationship within the range of 1.0×103-2.5×105 of relative molecular mass (r = 0.9894) was found between retention time of dextranum and lgMw. Insulins obtained from jerusalem artichoke by hot water reflux method and ultrasonic-assisted and microwave-assisted water extraction methods possessed varying relative molecular mass of 3500, 2405 and 3864, respectively. Methodology evaluation experiments revealed that the RSDs for precision, repeatability and stability were 0.24%, 0.21%, and 0.38%, respecitively, and the relative error for accuracy was around 0.4%. This method is proved to be fast, simple, sensible and repeatable.

Rapid HPLC Determination of Lambda-Cyhalothrin Residue in Foods
ZHENG Ling-ling,MOU Hai-jin*,JIANG Xiao-lu
2009, 30(12):  222-225.  doi:10.7506/spkx1002-6630-200912050
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A HPLC method was developed for the analysis of lambda-cyhalothrin residue in drinking water (from polluted rivers) and Brassica chinensis leaves. The analysis was performed on a SB-C18 column using acetonitrile-water (80:20, V/V) as a mobile phase at the flow rate of 1.25 ml/min and detection wavelength was set as 230 nm. Compared to other solvents, acetone-n-hexane (1:1, V/V) mixture exhibited the highest extraction efficiency to lambda-cyhalothrin (the highest recovery) from drinking water. Acetone-petroleum ether (1:1, V/V) mixture led to the highest recovery for lambda-cyhalothrin from ground Brassica chinensis leaves, and vortex-mixing extraction was adopted due to the highest the highest recovery for lambda-cyhalothrin as well as its time-saving contribution. The recoveries for lambda-cyhalothrin in drinking water and ground Brassica chinensis leaves spiked at three levels were in the rages of 97.93%-103.02% and 91.4%-113.9%, respectively, and the RSDs were less than 4%. This method is proved to be easily performed and time saving (within 30 min) and can be applied in the food safety detection.

Uncertainty Evaluation of Formaldehyde Content in Epoxy Phenolic Resin Coating on Internal Wall of Food Can
LIU Zai-mei,CAO Guo-zhou*,SHI Hong-lan,ZHU Xiao-yan,YUAN Wei-wei
2009, 30(12):  226-229.  doi:10.7506/spkx1002-6630-200912051
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The acetylacetone spectrophotometric method was applied to determine formaldehyde content in epoxy phenolic resin coating on the internal wall of food can. A procedure was established to evaluate the uncertainty of the determination of formaldehyde content by this method, and a mathematica1 model was set up based on the Chinese national standard GB/T 5009.69 —2003. The primary factors influencing formaldehyde content were confirmed, and the main origins of the uncertainty were proposed. The various factors of relative standard uncertainty were calculated and synthesized, and the expanded uncertainty was obtained. When the formaldehyde content was 0.0739 mg/L, the relative standard uncertainty was 0.0275, and the expanded uncertainty was 0.0041 mg/L (k = 2).

Multi-residue Determination of 32 Pesticides in Tea by Gas Chromatography-Mass Spectrometry
DONG Jin-bin1,WANG Jin-hua2
2009, 30(12):  230-232.  doi:10.7506/spkx1002-6630-200912052
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The present study developed a method for the determination of 32 pesticide residues (17 organophosphorus, 4 pyrethroids, 8 organochlorines, acetochlor, triadimefon and paclobutrazol) in tea by GC-MS. Pesticide residues were extracted from ground tea with acetonitrile in an ultrasonic filed and purified on a graphitized carbon black column, and then determined by gas chromatography with electron ionization mass spectrometric detection in the selected ion monitoring (SIM) mode. The external standard method was adopted for quantification. The recoveries for the 32 pesticides in tea spiked at three levels ranges from 48.2% to121.9%, with the RSDs of 0.2%-18.3%, and the detection limits for these pesticides by the method were 0.001 -0.02 mg/kg. This method is rapid, sensitive, and accurate, and its various technical indexes meet the detection requirement of pesticide residues in tea samples.

Immunocapture-Universal Primer PCR Detection of Salmonella sp. in Foods
ZHANG Ti-yin,HUANG Xiao-rong,ZHENG Jing,SHAO Bi-ying,HUANG Chang-jiao,
2009, 30(12):  233-236.  doi:10.7506/spkx1002-6630-200912053
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An immunocapture-universal primer polymerase chain reaction (PCR) (IC-UPPCR) method was developed by combining the floride ion-selective electrode method with classical PCR assay for detection of Salmonella sp. in food and its sensitivity and specificity were investigated. It was feasible to establish a universal primer PCR technology was by designing specific primers from conserved regions of bacterial 16S ribosomal RNA genes. The sensitivity of the IC-UPPCR to detect Salmonella sp. was 2 × 102 CFU/ml and the specificity was 100% without any false negative or positive cases. The results demonstrate that the IC-UPPCR is a simple, rapid, highly sensitive and specific method for the detection of Salmonella sp. in the foods and suitable for detection of Salmonella sp. in a large number of food samples.

Improvement of the Animal Feeding Stuffs — Determination of Trypsin Inhibitor Activity of Soybean Products (ISO 14902:2001)
SHI Yan-yu1,LIU Jin-hua2,PANG Xiao-yang1,LIU Jun-hui1,*
2009, 30(12):  237-240.  doi:10.7506/spkx1002-6630-200912054
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A spectrometric method has been established and announced by ISO for determining trpsin inhibitor activity of soybean-based animal feed. The method, however, has several defects, which restrict its application and popularization. Therefore this study aimed to improve this method to achieve rapid and accurate determination of trpsin inhibitor activity of soybean-based food products such as soybean milk powder, etc. The improvement mainly focused on sample preparation. The results showed that the determination results were basically identical when sample was crushed to particle sizes of 80 and 100 mesh, higher than those of the samples with the particle size less than 80 mesh. Removal of fat from sample and filtration of the prepared trpsin inhibitor solution had no significant effects on determination result. The optimal extraction effect of trpsin inhibitor from sample could be achieved by stirring the mixture of the sample and distilled water for 30 min. The improved method has high accuracy and precision, and is time-saving.

GC-MS Analysis of Chemical Components of Essential Oil from Lepidium meyenii Grown in Xinjiang Area
JIN Wen-wen1,WANG Qing-fang2,LI Shuo1,WANG Li-mei1,YU Long-jiang1,*
2009, 30(12):  241-245.  doi:10.7506/spkx1002-6630-200912055
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Objective: To analyze the chemical components of essential oil from Xinjiang maca (Lepidium meyenii) and discuss the change law of main chemical components in extraction process. Methods: Essential oil was extracted from Xinjiang maca by steam distillation, and then was subjected to chemical component analysis by gas chromatography-mass spectrometry (GCMS). In addition, two key factors, such as extraction duration and buffer solution concentration, influencing main chemical components were discussed. Results: A total of 32 components were identified and their relative content was 1.72%. The main components were clearly confirmed as benzyl isothiocyanate and benzyl nitrile. Moreover, at different buffer solution concentrations, the main components of the extracted essential oil differed according to GC-MS analysis. Conclusion: The GCMS method can be used to the rapid identification and quality analysis of introduced maca, and the buffer solution concentration should be strictly controlled in the extraction process of essential oil.

Comparative Study of Detection of Norovirus in Oysters by RT-PCR, RT-Seminested PCR and RT-LAMP
LI Dan,TANG Qing-juan,LI Zhao-jie,WANG Yu-ming,XUE Yong,XUE Chang-hu*
2009, 30(12):  246-250.  doi:10.7506/spkx1002-6630-200912056
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Reverse transcription polymerase chain reaction (RT-PCR), RT-seminested PCR and reverse transcription loopmediated isothermal amplification (RT-LAMP) assays were compared to detect norovirus in oysters. All the three assays targeted the highly conserved capsid N-terminal/shell (N/S) domain of norovirus with specific primers. Although one-step RT-PCR presented more apparent results than two-step approach, it still had the limitation in eliminating inhibitors contained in food matrix, and both RT-seminested PCR and RT-LAMP showed significantly higher specificity and sensitivity than RT-PCR. However, the operation of RT-seminested PCR is tedious and time-consuming. In comparison to other two approaches, the amplification program of RT-LAMP is simple, and the reaction time is short. Without special apparatus needed, RT-LAMP can be performed under isothermal condition and the results may be visually ascertained by a simple color reaction using SYBR GreenⅠdye. Therefore, RT-LAMP is of great potential to become a valuable method for rapid detection of norovirus in oysters.

GC-MS Analysis of Chemical Constituents of Volatile Oil from Fruits of Canarium pimela Leenh.
GUO Shou-jun1,YANG Yong-li1,HUANG Jia-hong1,XIE Qiu-ling2,SHE Jian-bao1,HUANG Miao-feng1
2009, 30(12):  251-253.  doi:10.7506/spkx1002-6630-200912057
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Essential oil from fruits of Canarium pimela Leenh. was extracted by steam distillation and analyzed by capillary GC-MS method combined with computer retrieval. More than 43 peaks were isolated and 41 compounds were identified, which accounted for 97.8% of the total essential oil. The relative percentages of these compounds identified were determined by GC area normalization method. The main chemical components were 1-methyl-2-(1-methylethyl)-benzene, D-limonene, α- Phellandrene, α-pinene, hexanoic acid, hexanal, caryophyllene, caryophyllene oxide, 1-pentanol, 1-hexanol, β-phellandrene, copaene, α-humulene, 2-pentyl-furan, nonanal, cadinene, (-)-spathulenol and decahydro-1,4a-dimethyl-7-(1-methylethylidene)- [1R-(1α,4aβ,8aα)]-naphthalenol, which accounted for 85.88% of the total essential oil.

Application of Quantum Dot Labeling to Development of Immunochromatographic Test Strip for Rapid Detection of Ractopamine
ZHANG Guo-hua,LAI Wei-hua,XIONG Yong-hua,CHEN Yuan
2009, 30(12):  254-257.  doi:10.7506/spkx1002-6630-200912058
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The quantum dot labeling technique was applied to the development of immunochromatographic test strip for rapid detection of ractopamine. Four steps were involved in the procedure of preparation of the strip, including the preparation of antigen and antibody against ractopamine, the production of quantum dots, and the installation and testing of the strip. The detection limit for ractopamine by this strip was 3 ng/ml, and the detection could be finished within 10 min. Apart from being time-saving, the strip is easy to perform and relatively inexpensive. It is therefore ideally suited for on-site testing of ractopamine.

Immunoassay Determination of Tartrazine
REN Li-song1,2,LU Shi-ying1,ZHOU Yu1,Guo De-jun1,LI Yan-song1,MENG Xian-mei1,LIU Zeng-shan*
2009, 30(12):  258-261.  doi:10.7506/spkx1002-6630-200912059
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Tartrazine was coupled separately with bovine serum albumin (BSA) and ovalbumin (OVA) by 1-ethyl-3-(3- dimethylaminopropyl) carbodiimide (EDC) to prepare complete antigens. Then hybridoma cell lines secreting monoclonal antibody (McAb) against tartarzine were obtained by immunization of BALB/C mice with prepared BSA- tartarzine and then fusion between SP2/O myeloma cells and splenocytes from the immunized mice, and the McAb against tartarzine was prepared. Finally, an indirect competitive ELISA method was established for determination of tartrazine. The regression equation was y =-40.134x + 133.46, with a determination coefficient of 0.9692. The limit of detection was 0.36 μg /L. Compared to the widely used methods such as TLC and spectrophotometric assay, this new method is found to be time-saving, easy to perform, highly specific and sensitive. It was suitable for the determination of tartarzine-containing samples in large quantity.

HPLC Analysis of Variation of Total Flavonoids Content during Processing of Eucommia staminate Flower Tea
BAI Xi-ting,ZHU Wen-xue,LUO Lei,FAN Jin-ling,XIANG Jin-le
2009, 30(12 ):  262-265.  doi:10.7506/spkx1002-6630-200912060
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A HPLC method was proposed to analyze the variation of total flavonoids content during processing of Eucommia staminate flower tea. Samples were extracted using 50% methanol solution-concentrated sulfuric acid (20:1, V/V) and cleaned up using ethyl acetate. The HPLC analysis was performed on a Kromasil-C18 column (4.6 mm × 250 mm, 5 μm) with methanol- 0.4% phosphoric acid (60: 40, V/V) as the mobile phase at the flow rate of 1.0 ml/min, and the column temperature and the detection wavelength were set as 25℃ and 360 nm, respectively. The external standard method was applied to quantification using quercetin as the reference substance. There was a good linear relationship between HPLC peak area and quercetin concentration in the range of 0.05-0.55 g/L. The average recovery for quercetin in spiked Eucommia staminate flower tea was 98.82% with a RSD of 0.96%. The method is convenient, accurate and can be applied in the quantitative determination of total flavonoids in the processing of Eucommia staminate flower tea. The fixation resulted in the fall of content of total flavonoids, while the following primary and advanced frying led to the gradual rise. Through the procedures of fixing, primary frying and advanced frying, the content of total flavonoids in fresh Eucommia staminate flower was elevated by 25.88%.

Effects of Maturity on Near Infrared Spectral Detection of “Nanguo” Pears
LI Dong-hua1,JI Shu-juan1,*,SHIGEFUJI Kazuaki2
2009, 30(12):  266-269.  doi:10.7506/spkx1002-6630-200912061
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The present study investigated the difference in internally chemical component contents of “Nanguo” pears with different maturities, established NIR models of sugar degree and acidity of “Nanguo” pears with different maturities, explored the difference in properties of these models, and discussed the effects of maturity change on NIR analysis for “Nanguo” pears. The results showed that there was significant difference in sugar degree and acidity between “Nanguo” pears harvested on Sep. 13 and Sep. 7, but not between “Nanguo” pears harvested on Sep. 10 and Sep. 7. All the correlation coefficients of the models were over 0.9, and the correction RMS errors were less than 0.5. The analysis for prediction ability of the models showed that the applicability of the model for harvest on Sep. 13 was higher than that of other models, indicating the significant change in maturity enlarges the range of chemical component contents of calibration samples and improves the applicability of models.

Simultaneous Determination of Nine Kinds of Phthalates Multiresidues in Food Packaging Materials by HPLC-ESI-MS/MS
XU Li-guang1,LI Zhuo-kun1,DING Tao2,XU Chuan-lai1,*,SHEN Chong-yu2,MA Wei1,WANG Li-bing1XU Li-guang1,LI Zhuo-kun1,DING Tao2,XU Chuan-lai1,*,SHEN Chong-yu2,MA Wei1,WANG Li-bing1
2009, 30(12 ):  270-275.  doi:10.7506/spkx1002-6630-200912062
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A HPLC-ESI-MS/MS method was developed for the qualitative and quantitative of nine kinids of phthalates multiresidues in food packaging materials HPLC-ESI-MS/MS. Samples were extracted using acetonitrile. The analytes were separated using 0.1% fomic acid-methanol system as the mobile phase with a linear gradient elution program , and determined by a tandem mass detector. The mean recovery for each analyted ranged from 65.28% to 98.33%, with the relative standard deviations from 5.35% to 11.22%, and the limits of detection were about 5-20 ng/ml.

Effects of 1-Methylcyclopropene and Chlorine Dioxide on Preservation of Xinjiang Flat Peaches
XIAO Li-mei,ZHONG Mei,WU Bin,GUO Fu-yang,WANG Ji-de
2009, 30(12):  276-280.  doi:10.7506/spkx1002-6630-200912063
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The qualities of Xinjiang flat peaches treated with 1.0 μl/L 1-MCP, 1.0 μl/L ClO2 and 1.0 μl/L 1-MCP + 1.0 μl/L ClO2 storage were studied during both room temperature (23-25 ℃) and cold (4-5 ℃) storages. The results showed that all treatments were able to decrease the release of ethylene as well as the respiration rate of the peaches. The reductions in firmness and contents of vitamin C and titratable acid were effectively retarded and the incidence of decay was decreased. Among the three treatments, the third one showed significantly higher inhibitory effect than the former two. Combination of low temperature storage and pretreatment with 1.0 μl/L 1-MCP + 1.0 μl/L ClO2 can effectively extend the shelf-life of Xinjiang flat peaches.

Color Stability of Juice Concentrates of 6 Pear Species during Storage at 4℃
YANG Fu-chen,WANG Ran,WANG Feng-wu,ZHAO Yu-jun,HUANG Guo-qing,LI Wen-xiang,WANG Cheng-rong*
2009, 30(12):  281-284.  doi:10.7506/spkx1002-6630-200912064
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The color stability of the juice concentrates that were prepared from 6 pear species was studied during the storage at 4 ℃. During the storage of the 6 pear concentrates, the browning degree and the total color aberration elevated gradually, the content of reducing sugar changed slightly, the content of amino nitrogen showed a decreasing trend, the soluble phenol and protein reduced gradually, and no obvious change in pH was found. The difference of color and its related indexes among 6 pear juice concentrates were obvious-the pear concentrates prepared from Dangshansu pear, Kuerle fragrant pear and Laiyangchi pear showed a higher browning degree compared to Zhongxiang pear, Huangjin pear, and Qiu pear. The concentrate prepared from Kuerle fragrant pear displayed higher soluble phenol content, and that prepared from Zhongxiang pear had higher protein content. The concentrate of Dangshansu pear exhibited the highest pH (above 4.9) and that of Laiyang pear showed the lowest pH (4.4-4.5) during the storage. The peaks of 5-HMF content of concentrates prepared from Dangshansu pear and Laiyangchi pear appeared at the fourth month and those of other species appeared at the third month.

Effects of Methyl Bromide Fumigation on Storage Quality of Apple and Mangosteen
ZHANG Fan-hua,LIU Bo,WANG Yue-jin*
2009, 30(12):  285-288.  doi:10.7506/spkx1002-6630-200912065
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This study discussed the effects of methyl bromide fumigation at different dose on the storage quality of apple and mangosteen at 20 ℃. The results showed that the fumigation treatment could inhibit respiration during the treatment and reduce the water loss. However, no significant influence was observed in the flesh hardness and the changes of color were fastened. No significant effect was found on the contents of total soluble sugar in both the two fruit varieties while the total acidity of apple increased and that of mangosteen had no obvious change.

Effects of Green Tea Extract on Preservation of Chilled Mutton
QIAO Jin-ling1,HU Yong-jin2,CAO Zhen-hui1,GE Chang-rong1,*
2009, 30(12):  289-292.  doi:10.7506/spkx1002-6630-200912066
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To extend the limited shelf life of chilled mutton, which is one of the main obstacles hindering the further development of chilled meat, the effects of different concentrations of green tea extracts on the shelf-life of chilled Guishan goat meat were assessed in the present study. The results showed that the 2%, 4% and 6% green tea extracts could significantly inhibit the growth of intestinal flora, Pseudomonas and total bacteria, and the accumulation of the total volatile basic nitrogen (TVB-N) and thiobarbituric acid reactive substances (TBARs). Furthermore, the L*, a* and b* values as well as the sensory evaluation score of samples treated with 2% and 4% green tea extracts were higher than those of the control. These results suggest the high potential of using green tea extracts to enhance the freshness and quality of chilled meats.

Fermentation Production of Tomato Wine
LIU Dian-feng1,2,ZHU Xue-wen2,ZHANG Zhi-xuan2,ZHAO Yang-ling2,
2009, 30(12):  293-296.  doi:10.7506/spkx1002-6630-200912067
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Tomato juice, wine yeast (Angel brand) and sucrose were taken the main materials to develop a wine. The fermentation technology was optimized by orthogonal test design based on single factor test. Under the optimized conditions of main fermentation temperature of 24 ℃, inoculation quantity of wine yeast of 0.2 g/L, and initial sugar content of 28%, the highest alcohol degree was achieved. When the above parameters were 22 ℃, 0.4 g/L and 24%, respectively, the sensory evaluation score of wine product obtained was the highest. The wine product had not only high nutritive value and elegant flavor, but also health function.

Brewing of Semi-sweet Yellow Rice Wine with Purebred Yeast
MAO Qing-zhong
2009, 30(12):  297-299.  doi:10.7506/spkx1002-6630-200912068
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This study compared the fermentation performances of 5 purebred yeast strains that were applied to brewing of semi-sweet yellow rice wine. Strain No.1 and No.2 were selected due to the bigger weight loss and the higher alcohol yield as well as the production of taste similar to that of traditional semi-sweet yellow rice wine. Then an orthogonal test design was conducted to optimize the brewing technology of semi-sweet yellow rice wine. The results showed that under the optimized conditions of Dongfeng rice wine addition of 112.0%, water addition of 25.0% and inoculation quantity of strain No.1 of 10.73%, the biggest weight loss and fermentation indexes were achieved.

Brewing of Fruit Vinegar of Berberis nummularia Bge. and Formulation of Its Beverage
DI Xiang,WUERNISHA Xahidin,GONG Yu-ting,ABDULLA Abbas*
2009, 30(12 ):  300-302.  doi:10.7506/spkx1002-6630-200912069
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Berberis nummularia Bge. fruits were taken as the raw material to produce vinegar by the means of liquid fermentation. Then the fruit vinegar, honey and citric acid were blended to develop a compound beverage. The fruit vinegar had full-bodied and unique flavor and proper sour taste. The optimal formula for the fruit vinegar beverage was as follows: water 100 ml, fruit vinegar 9 ml, citric acid 0.1 g, and honey 12 g. The beverage product obtained was clear and refreshing.