Advanced Materials Research Vols. 781-784

Abstract: Four kinds of different methods was used to extract the tea polyphenols (TP) and epigallocatechin gallate (EGCG) from the fresh old age tea leaves. The extraction liquor obtained under the optimal conditions was further purified by membrane filtration, resins absorption and column chromatographic exctration (CCE). The results indicated that the concentrations of TP and EGCG respectively increased to 96.1% and 60.5% after separated by the hollow fiber membrane and resins absorption. And then, after the separation by silica gel CCE method, the EGCG concentration was more than 98%.

Abstract: A new way using cellulase as auxiliary method to extract theabrownin (TB) from Guangxi Liubao Tea was proposed in this article. Single factor and orthogonal experiments were used to analysis the best extraction condition of TB from Tea. The effects of the enzyme dose, enzymatic hydrolysis time, enzymatic hydrolysis temperature and the PH of extraction were investigated by orthogonal test. Results showed that the order of influence factors was enzymatic hydrolysis time, the PH of extraction, enzyme dose and enzymatic hydrolysis temperature. The optimal extraction conditions were determined as follows: the dosage of cellulose 20 mg/g, the enzymatic hydrolysis time 40 min, the enzymatic hydrolysis temperature 30°C,the extraction PH=4. The highest extraction ration can attach 24.503%.

Abstract: For reforming jar testing and increasing separation efficiency, separation technology of fermentation broth was studied by controlling the process of flocculation. The tried new system to be operated continuously was composed of the processes of transporting fermentation broth, flocculating the broth and separating the one. The experimental course of controlling the process of flocculation was as follows: the broth was conveyed by a pump and pipeline from fermentation pot to a mixer in which a flocculant and the broth were mixed, afterward the broth flowing from the mixer was flocculated continuously in the column, and then the flocs flowing from the column were separated from the broth by filtrating or centrifugal precipitating. The experimental results showed that the filtration rate of the broth was 65% larger and precipitation rate of the flocs in the broth was 47% larger by the novel separation technology than jar testing. The results offer important evidence not only for reforming intermittent operation into continuous operation in flocculating technology of fermentation broth, and for flocculated the broth to be separated with great efficiency by filtrating or centrifugal precipitating in industry, but also for researching the law between conditions of the separation process and micro-size of the flocs.

Abstract: Gelatin was extracted from tilapia (Oreochromis spp.) scale after decalcification. The content of protein in the gelatin was 92.5% (w/w). The amount of imino acids (proline and hydroxyproline) was 167 residues per 1000 residues. Its gel strength, melting point and degradation temperature were 271 g, 27.0 °C and 59.7 °C, respectively. Fourier transform infrared spectroscopy spectra showed that the intensity of major absorption bands in the gelatin was higher than that in bovine bone gelatin. The gelatin had visible β-component and degradation fragments.

Abstract: Natural pigments have raised a growing interest due to their extensive range of colors, innocuous and beneficial health effects. In this paper, the extraction process and stability of strawberry red pigment were studied. An orthogonal test [L₁₆(4)⁴] was applied to get the best extraction conditions. Results showed that the optimum conditions were that the extraction temperature was 65C, the solid-liquid ratio was 1:5 (g/mL), the ratio of 1.5mol/L hydrochloride to 97.5% ethanol was 3:17 (mL/mL), and the extraction time was 4.5 hours. The effects of heat treatment, oxidant, sugar and preservatives on the stability of strawberry red pigment were also discussed. The stability of strawberry red pigment was found to be affected by high temperature, hydrogen peroxide, and potassium sorbate. This study is expected to provide a basis for further research, development, and utilization of strawberry red pigment.

Abstract: The aim of this study was to optimized extraction chlorogenic acid from sweet potato leave by central composite design/response surface method (CCD/RSM). The effects of ethanol concentration, ratio of solid to liquid, and extraction time on the yield of chlorogenic acid were evaluated, and the yield of chlorogenic acid under analysis optimum condition was also forecasted. The optimized extraction conditions were as follows: extraction with a 20 fold volume of 70% aqueous ethanol solution for 2h. Under these conditions the theoretical yield of chlorogenic acid was 15.95 mg/g, and the measured value was 15.89 mg/g. This method is scientific, reasonable and feasible. It also laid a foundation for research and application of chlorogenic acid in sweet potato leaves.

Abstract: A new method for producing seedless watermelon seedlings was studied in this paper. Grafting branches breeding (GBB) and grafting seedling breeding (GSB) of seedless watermelon (Citrullus lanatus (Thunb.) Matsum and Nakai) cultivar Mi Tong was grafted onto No.1 of E-zhen, commercial hybrids. Seed breeding (SB) self-plants were used as control. The effect of different methods on watermelon fruit yield and quality was tested. The results showed that fruit yield was positively influenced by GBB when compared with the control. Detrimental effects were not determinated on fruit qualities such as fruit index, fruit weight and sugars on grafted plants. Moreover, GBB reduced the cost of producing seedless watermelon seedlings. Therefore, the grafting technique of using branches for scion was feasible, simple and efficient in the progress of seedless watermelon development.

Abstract: Guar gum is a highly viscous water soluble heteropolysaccharide obtained from guar seed endosperm portion. Partially hydrolyzed guar gum (PHGG) is low in viscosity and has the healthy benefits as the dietary fiber. In this study, the effect of amount of acidolysis agent, ethanol content, acidolysis temperature and time on the acidolysis degree of guar gum was investigated by using the solvent method. The thermal properties were characterized by the idifferential scanning calorimeter and thermogravimetric analyzer, respectively. It was showed that the better conditions for preparing PHGG were: acidolysis temperature 40°C, acidolysis time 4h, ethanol mass concentration 61%, respectively. The freeze-thaw stability, expansion capability decreased after guar gum was partially hydrolized by hydrochloric acid. The onset temperature, end temperature and peak temperature of PHGG all increased, but its melting enthalpy and thermal stability were reduced, compared with those of guar gum.

Abstract: Nowadays, public concern over food safety, especially the potential health risk to humans cause by the high levels of pesticide residues, has increased. In general, people usually refrigerate fresh vegetable in order to keep their freshness intact for longer duration of time. Very few research studies have investigated the correlation between refrigerated vegetables and degradation of pesticide residue. Gas chromatography was used to conduct dynamic analysis of pesticide degradation in off-season vegetables, which are kept in cold storage conditions. Cowpea and balsam pear samples were extracted with acetonitrile. The resultant extracts were purified in SPE column filled with cleanert pesticarb. Thereafter, the eluant extracts were determined through gas chromatography coupled with μECD. Matrix-matched calibrations were analyzed through GC-ECD, where in the limits of quantification varied between 0.0005 and 0.0026mg/kg. The linear coefficients of correlation varied between 0.9916 and 0.9997. Recoveries on cowpea and balsam pear were in the range 74.7%~98.8%. Based on the residue dynamics study, the half-lives of the five pesticides in cowpea were as follows: chlorpyrifos: 247d, chlorfenapyr: 407d, bifenthrin: 462d, cyhalothrin: 346d, and cis-cypermethrin: 315d. In balsam pear samples, the half-lives of the five pesticides were as follows:chlorpyrifos: 150d, chlorfenapyr: 187d, bifenthrin: 433d, cyhalothrin: 266d, and cis-cypermethrin: 210d. The residue of five pesticides in cowpea and balsam pear underwent slow degradation in cold storage conditions. In this study, the findings serve as important reference data, which can be used by the concerned state authorities in formulating the limit of pesticide residue in food.

Abstract: Extraction of citric acid from aqueous solutions with tertiary amine, dissolved in mixtures of kerosene and phase modifier have been studied as a function of exaction yield at different phase modifier volume fraction, temperatures, stirring speed and exaction time. The optimal experimental conditions of extraction were obtained: reaction temperature 303K, reaction time 3 min, the kerosene volume fraction 20%, and 45% 1−octanol as phase modifier, stirring speed 450rpm/min. Under these conditions, the extraction yield could reach 75%. The complex of citric acid and tertiary amine was a surfactant that makes surface tension decrease. The composition of the citric acid complex is (R₃N) · (H₃A). The formation of complex was exothermic reaction that the standard enthalpy change and standard entropy change are obtained: ΔH^θ=-10.17kJ/mol, ΔS^θ=-11.86J/(mol·K).