Table of Content

30 October 2007, Volume 27 Issue 5 Previous Issue    Next Issue

研究报告

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Metabolism of Xylooligosaccharides by Bifidobacterium adolescentis ZHANG Jun-hua;YONG Qiang;YU Shi-yuan 2007, 27 (5):  1-5.  Abstract ( 753 )   PDF (943KB) ( 716 )   Save Kinetics of xylooligosaccharides(XOS) metabolized by Bifidobacterium adolescentis was investigated, and the components of XOS and the main metabolites were analyzed during the metabolism. The results showed that total sugar concentration decreased from 5.00 g/L to 3.59 g/L when XOS was used as sole carbon sources for B. adolescentis after 48 h metabolism in vitro, cell concentration increased from 0.10 g/L to 0.35 g/L and the pH value decreased from 7.00 to 4.75. Xylobiose to xylopentaose were metabolized by B. adolescentis firstly when XOS was used as carbon sources, after that, arabinose was released from arabinosyl groups in XOS mixture by α-L-arabinofuranosidases from B. adolescentis during the metabolism, and then arabinose was metabolized ultimately. Free xylose was accumulated by releasing from the end chain of XOS by β-D-xylosidase from B. adolescentis. The main metabolites were lactate, acetate, propionate and butyrate. Related Articles | Metrics

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Synthesis and Property of Superabsorbent Polymers Modified by Carboxymethyl Cellulose WANG Dan;SHANG Shi-bin;SONG Zhan-qian;WANG Yu 2007, 27 (5):  6-10.  Abstract ( 732 )   PDF (780KB) ( 829 )   Save Acrylamide (AM), and [2-(methylacryloyloxy)ethyl] trimethylammonium chloride (MAETAC) were grafted onto carboxymethyl cellulose (CMC) to prepare cellulose-modified cationic superabsorbent polymers (SAP) by inverse suspension copolymerization. Factors affecting water-absorbent capacity were investigated in detail, which were found to be as follows: ratio of oil to water 2:1, dosage of Span 60 and Tween 80(3:1), 5% of water phase, pH value 4, CMC dosage 5%, content of initiator(NaHSO3,(NH4)2S2O8)2.5%, and crosslinking agent 0.5% of the weight of monomers, reaction temperature 65℃, reaction time 2 h. The cellulose-modified cationic SAPs prepared under optimum conditions were obtained which have the absorbent capacity of 657 times their own weight in distilled water and 116 times in 0.9% salt solution under optimized synthesis condition. Related Articles | Metrics

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Study on Comprehensive Extraction of Antioxidant and Essential Oil from Rosemary (Ⅱ)——One-step Extraction BI Liang-wu;ZHAO Zhen-dong;LI Dong-mei;GU Yan;WANG Jing;LIU Xian-zhang 2007, 27 (5):  11-14.  Abstract ( 576 )   PDF (609KB) ( 540 )   Save One-step extraction with polar and nonpolar mixed solvents was a method of effective comprehensive extraction for antioxidant and essential oil of rosemary (Rosmarinus officinalis L.). The method was simple on operation and was easily put into practice. The reasonable conditions of comprehensive extraction for antioxidant and essential oil of rosemary were petroleum ether-ethanol-water of volume fraction 80:15:5 as mixed solvent, 10 folds of mass fraction of mixed solvent to rosemary leaves, 3 h for extraction at 80℃. The yield of rosemary oil was 2%-3%. The constituent analysis of rosemary oil showed that the essential oil mainly contains α-pinene, 1,8-cineole, camphene, camphor, verbenone, borneol, terpinen-4-ol, limonene, and bornyl acetate. The average yield of rosemary antioxidant was 16.98%. The main active components of rosemary antioxidant were carnosic acid, carnosol, and rosmarinic acid, whose contents were 15.17%, 2.51% and 5.62%, respectively. Related Articles | Metrics

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Study on Catalytic Cracking of Tar Derived from Biomass Pyrolysis and Gasification SUN Yun-juan;JIANG Jian-chun 2007, 27 (5):  15-20.  Abstract ( 573 )   PDF (1227KB) ( 848 )   Save Main raw material is poplar sawdust. Catalytic cracking of tar is performed in a secondary fixed-bed cracking reactor using four types of dolomite as catalyst. Operation parameters like cracking temperature, catalyst type and residence time of reaction are investigated for their influences on tar cracking and gas quality. The characters of catalysts from different areas are measured in order to seek for suitable catalyst for commercial utilization in gasification systems. The results show that higher cracking temperature and longer residence time are favourable to tar cracking. When pyrolysis temperature goes beyond 1000℃, the tar cracking rate can reach 98.99%.Dolomites from different places show obvious difference in their catalysis effect. The dolomite from Shaanxi calcined at 900℃ can have tar cracking rate up to 95.14%. The most important factor that determines cracking effect of dolomites is their specific surface area after calcination. The bigger the specific surface area the better is catalysis effect. In order to obtain high catalysis effect, dolomite with bigger specific surface area should be chosen. Related Articles | Metrics

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Antioxidant Activities of the Extractives of Larix kaempferi Carr. Fresh Needles SI Chuan-ling.;LIU Zhong;KWON D J;KIM J K;BAE Y S 2007, 27 (5):  21-24.  Abstract ( 738 )   PDF (334KB) ( 706 )   Save Seven compounds, including three flavan-3-ols, (+)-catechin (1), (-)-epicatechin (2) and (+)-gallocatechin (3), three flavonoid glycosides, isorhamnetin-3-O-β-D-glucopyranoside (4), astragalin (5) and 2″-O-rhmnosylvitexin (6), and one lignan with the trivial name cedrusin (7), were isolated for the first time from the fresh needles of Larix kaempferi C. Their structures were elucidated by chemical and spectral analysis. The antioxidant activities of the crude extracts, partitioned fractions and isolated compounds were evaluated by DPPH free radical-scavenging assay. Results suggested that EtOAc participated fraction and the three flavan-3-ols showed significantly high antioxidant potential compared with α-tocopherol and BHT, which were used as controls. Related Articles | Metrics

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Chemical Composition Characteristics of Pinus latteri Mason Rosin and Turpentine from the South of Cambodia WANG Shi-fa 2007, 27 (5):  31-36.  Abstract ( 788 )   PDF (898KB) ( 717 )   Save The chemical composition characteristics of Pinus latteri Mason rosin and turpentine from the South of Cambodia was studied using GC and GC-MS. The Pinus latteri Mason oleoresin was first separated into two fractions of rosin and turpentine oil, and they were analyzed qualitatively and quantitatively. Nine components were identified from the rosin fraction including 8(14),15-pimaradiene, sandaracopimaric acid, isopimaric acid, 8(9)-isopimaric acid, dehydroabietic acid, 8,12-abietadienoic acid, abietic acid, neoabietic acid and mercusic acid. The proportions of pimarane-type, abietane-type, and dibasic resin acids were 49.59%, 37.18% and 12.4%, respectively. The main resin acids were isopimaric acid, 8(9)-isopimaric acid, abietic acid and mercusic acid, and their contents based on rosin weight were 20.9%, 21.14%, 23.45% and 12.40%, respectively. Sixteen components in turpentine oil were determined including 13 monoterpenes, 2 sesquiterpenes, and one diterpene. Monoterpene was the main component and accounted for 99.49% of turpentine oil. The main monoterpenes were m-mentha-4,8-diene, fenchene and alloocimene, and their contents in turpentine oil were 24.01%, 29.21% and 23.71%, respectively. Related Articles | Metrics

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Study on Preparation and Properties of Copolymer from Rosin-based Crosslinking Monomer and Methyl Methacrylate LIN Ming-tao;CHU Fu-xiang;MA Li;LIU Mei-hong;Jiang Qiu-na;ZHOU Dao-bing;WANG Ji-fu;WANG Chun-peng 2007, 27 (5):  25-30.  Abstract ( 667 )   PDF (1087KB) ( 911 )   Save Acrylic rosin acid (2-hydroxyethyl acrylate) ester (ARA) was synthesized by acyl chlorination and esterification of acrylic rosin acid, which was prepared by Diels-Alder addition of rosin with acrylic acid. The composition and contents of the ester were analyzed by GC-MS. Then the copolymer of ARA and methyl methacrylate (MMA) was made by miniemulsion polymerization. Physical properties of the copolymer were characterized by means of GPC, DSC, TGA and solvent extraction. Meanwhile the comparison of properties had been done among the copolymer, MMA homopolymer and MMA copolymer. It was found that ARA was composed of esterification products of (2-HEA)-ester with pimaric acid, dehydroabietic acid, abietic acid and two isomers of acrylpimaric acid. ARA is a good crosslinking agent which can copolymerize with most vinyl monomers. The properties of solvent-resistance and heat resistance of the copolymer were improved considerably by the use of ARA. The copolymer of ARA and MMA is insoluble in acetone whose loss rate is 7.5% during acetone extraction. The TG curves is moved as a whole along the direction of high temperature. Related Articles | Metrics

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Study of Gas Chromatographic Method on Chemical Identification of Gum Rosin Variety WANG Zhen-hong;SONG Zhan-qian;SHANG Shi-bin;YE Bo-hui 2007, 27 (5):  37-43.  Abstract ( 597 )   PDF (978KB) ( 855 )   Save Rosin samples were prepared from pure Pinus massoniana Lamb. oleoresin, pure P. elliottii Engelm. oleoresin and pure P. kesiya var. langbinanensis(A. Chev.) Gaussen oleoresin. The main resin acid contents of the rosins were analyzed by GC quantitative analysis using DB-5 capillary column. Rosin type can be determined and distinguished from the content of isopimaric acid and the quantity ratio of pimaric acid/isopimaric acid. The content of isopimaric acid and the quantity ratio of pimaric acid/isopimaric acid are <2%, 8.58; 4%-5%, 1.24;≥14%, 0.24 for pure P.massoniana Lamb. rosin, pure P.elliottii Engelm. rosin and pure P. kesiya var. langbinanensis rosin respectively. Related Articles | Metrics

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Studies on Modification of Polysaccharide Gum from Gleditsia sinensis Lam. Seeds with α-Galactosidase JIANG Jian-xin;ZHU Li-wei;WANG Lei;ZHANG Wei-ming 2007, 27 (5):  44-48.  Abstract ( 424 )   PDF (967KB) ( 720 )   Save Gleditsia sinensis Lam. polysaccharides gum (GPG) and locust bean gum were galactomannan gum. Mixed gel at 1% of total polysaccharide concentration showed the gel strength maximum of 103 g/cm2 when the ratio of GPG (28.6% galactose) to xanthan was 7:3. Locust bean gum (20% galactose) is more functional and more expensive than other galactomannan gums. Investigation on removal of galactose residues from GPG by α-galactosidase to yield galactomannan similar to locust bean gum was carried out. The optimum mass fraction of substrate concentrations was increased from 3% at 37℃ to 35% at 50℃ due to increased enzymic temperature tolerance. Enzymically modified G. sinensis polysaccharides gum (EMGPG) with 20.2% galactose content showed maximum mixed gel strength of 199 g/cm2, which was higher than that of locust bean gum (193 g/cm2). The crystallinity index for EMGPG is 0.235, which is somewhat lower than that of GPG (0.297). Related Articles | Metrics

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Study on Effect of Larix olgensis var. changpaiensis Extractives on Wood Preservation LI Jian;YANG Dong-mei;SU Wen-qiang 2007, 27 (5):  49-52.  Abstract ( 594 )   PDF (719KB) ( 653 )   Save Heartwood, sapwood and bark of olga hay larch (Larix olgensis var. changpaiensis) were used as raw material to obtain extractives by extracting with C2H5OC2H5,CHCl3, (CH3)2CO, MeOH and H2O,respectively. Antibacterial activities of these extractives against Coriolus versicolor and Gloeophyllum trabeumr were investigated by filter paper method. It was found that MeOH extractives and (CH3)2CO extractives of heartwood have better inhibition effect against C. versicolor; H2O extractives of bark has better inhibition effect both against C. versicolor and G. trabeum. Wood preservation activities of these two kinds of extractives were also studied in lab, the growths of wood-inhabiting fungi in samples were observed by scanning electron microscope (SEM). The effect was compared with typical wood preservative acid-copper-chromate (ACC), the result showed that MeOH extractives of heartwood has better decay-resistance against C. versicolor, H2O extractives of bark has decay resistance against G. trabeum. Related Articles | Metrics

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Study on Properties of the Cured Products of Hydrogenated Terpinene Malaic Anhydride with Epoxy Resin KONG Zhen-wu;WANG Hao;DU Yu-min;CHU Fu-xiang 2007, 27 (5):  53-56.  Abstract ( 634 )   PDF (648KB) ( 570 )   Save The properties of mechanical strength, thermal stability and electrical insulation of the epoxy resin cured with hydrogenated terpinene maleic anhydride (HTMA) and their main influencing factors were investigated. It was shown from the experiment results that the cured epoxy resin had good mechanical properties, thermal stability and electrical insulation. The mechanical property and thermal stability of cured epoxy resin were closely related to the chemical structure of hydrogenated terpinene maleic anhydride. The electrical insulation properties of epoxy resins cured with alicyclic anhydrides of different chemical structures were similar. Related Articles | Metrics

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Synthesis of Rosin Allyl Alcohol Ester CHEN Chun-hong;DUAN Wen-gui;LI Xing-ren;CEN Bo 2007, 27 (5):  57-61.  Abstract ( 572 )   PDF (857KB) ( 685 )   Save A new method for synthesizing rosin allyl alcohol ester was studied. p-Toluenesulfonic acid allyl alcohol ester was first synthesized by O-acylation of allyl alcohol with p-toluene sulfonyl chloride,using NaOH as catalyst. Then rosin allyl alcohol ester was synthesized from sodium resinate and p-toluenesulfonic acid allyl alcohol ester. By single factor experimentation, the optimal conditions for the synthesis of p-toluenesulfonic acid allyl alcohol ester were obtained as follows:n(allyl alcohol):n(p-toluene sulfonyl chloride) 3:1, reaction temperature 0℃, reaction time 3 h and the yield amounted to 89.5%. The optimal conditions for the synthesis of rosin allyl alcohol ester were found to be as follows:n(sodium resinate):n(p-toluenesulfonic acid allyl alcohol ester )1.3:1, reaction temperature 40℃, reaction time 2 h and the yield was up to 75.4%. Rosin allyl alcohol ester was analyzed and characterized by TLC, IR and GC-MS. From the experiment results it can be concluded that this new method has the advantages of short reaction time, low reaction temperature, no side-reaction due to high temperature. Related Articles | Metrics

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Preparation of Macroporous Adsorption Resin of Immobilized Tannins and Its Adsorption Behavior ZHANG Li-ping;LIU Jian;CHEN Guo-wei;QIN Zhu 2007, 27 (5):  67-72.  Abstract ( 697 )   PDF (1298KB) ( 589 )   Save Using chloromethyl polystyrene resin as matrix, a new macroporous adsorption resin of immobilized black wattle tannins(MARIT) was prepared through Mannich reaction. The condition of reaction was determined by means of orthognonal experiment. Equilibrium data for the adsorption of phenol from aqueous solution by macroporous adsorption resin as adsorbent had been obtained which were correlated with Freundlich isotherm equation. Isosteric adsorption enthalpy, adsorption free energy and adsorption entropy were calculated according to the relationship of thermodynamic function. Isosteric adsorption enthalpy was 8.95-13.41 kJ/mol, which reveals a hydrogen-bonding adsorption mechanism. Difference of adsorption properties of phenol onto MARIT from aqueous solution and cyclohexane solution, as well as difference of adsorptions of phenol, resorcinol and o-nitrophenol from aqueous solution were studied, and the results further demonstrated the hydrogen-bonding based adsorption for phenol from non-aqueous solution. Related Articles | Metrics

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Research of Liquefaction of Wood and Its Utilization for Polyurethane Adhesives ZHANG Yu-cang;CHI Qing-shan;SUN Yan-feng;TAN Feng-zhi;WU Xiong-wei;ZHANG Wen-ming 2007, 27 (5):  73-77.  Abstract ( 669 )   PDF (1208KB) ( 943 )   Save The optimum technical conditions of wood liquefaction are studied using waste wood powder with phenol as catalyst at 160℃, m(phenol):m(wood powder) 5:1,catalyst dosage 1.2 mmol/g, reaction time 6 min, the residue rate can belowered to 3.5%. New residue is originated from liquefied product under prolonged reaction time. Polyurethane adhesives prepared from liquefied wood has the tensile strength of 5 MPa, which meets the application requirement. This study provides basis for its industrial production. Related Articles | Metrics

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Studies on Extraction and Anti-oxidation Activities of Flavonoids and Polysaccharide from Melia toosendan Sieb. et Zucc. HE Liang;SONG Xian-liang;YIN Ning;JIANG Jian-xin 2007, 27 (5):  78-82.  Abstract ( 633 )   PDF (809KB) ( 760 )   Save The optimum processes of extracting flavonoids and polysaccharide in fruits of Melia toosendan Sieb.et Zucc. were studied respectively. The anti-oxidation activities of its components were measured by using ammonium persulfate/ N,N,N',N'-tetramethyl ethylene diamine system and the model of Fenton reaction. The results indicated that the optimized extraction conditions of flavonoids were: ratio of material to liquid 1:30(g:mL) using 70% (volume fraction) EtOH for 7.5 min microwave-assisted extraction. Those of polysaccharide were:ratio of material to liquid 1:15(g:mL)with four times of extraction each for 3 h. Both flavonoids and polysaccharide showed strong antioxidative activities. The scavenging effect on superoxide anion free radicals reached 76.6% at concentration of flavonoids 9.74 g/L, while that on hydroxyl free radicals reached 84.0% at concentration 12.38 g/L.The scavenging effects of polysaccharide reached 63.7% and 74.0% respectively. Related Articles | Metrics

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Secretory Expression of Trichoderma reesei XYN Ⅱ Gene in Pichia pastoris OUYANG Jia;WANG Xiang-ming;ZHANG Qing;YAN Ming;XU Lin 2007, 27 (5):  83-88.  Abstract ( 619 )   PDF (1371KB) ( 842 )   Save The gene of xylanase(XYN II) was amplified by RT-PCR from the total RNA of Trichoderma reesei Rut C-30 and sequenced. The gene comprised an open reading frame that encoded a polypeptide of 223 amino acid residues, containing a signal peptide of 19 amino acid residues. A recombinant plasmid pPIC9K-xyn II was constructed by inserting gene xyn II into Pichia pastoris secretory vector pPIC9K. Linearized pPIC9K-xyn II was transformed into P.pastoris GS115 with the method of electroporation. The recombinant strain identified by G418 selection and confirmed by PCR analysis was induced by 1.0% methanol at 28℃ to express the recombinant xylanase, the highest enzyme activity of 1.45 IU/mL was detected for 60 h incubation. The optimal pH value and temperature of the enzyme activity is 6.0 and 50℃, respectively. Related Articles | Metrics

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Study on Extraction and Antioxidant Activity of Active Constituents from Ilex latifolia Thunb. in Ningbo WANG Hong;LU Hong-ya;CHEN Jian-shu;OU Zhi-min;YI Yu;YING Guo-qing 2007, 27 (5):  89-93.  Abstract ( 565 )   PDF (713KB) ( 538 )   Save The active constituents of Ilex latifolia Thunb. were extracted by steam distillation extraction (SDE), ethanolic extraction(EE), ultrasonic wave extraction(UWE), microwave-assisted extraction (MAE), and supercritical carbon dioxide extraction (SCDE) and the extraction yields were: 0.048%, 0.011%, 0.631%, 0.522% and 0.935%, respectively. Then their constituents (10 compounds (SDE), 9 compounds (EE), 12 compounds (UWE), 9 compounds (MAE) and 20 compounds (SCDE)) were assayed by GC-MS. All active constituents showed antioxidant activity in vitro. In the assay an activity order of active constituents could be established: SCDE>UWE>SDE>EE>MAE. Related Articles | Metrics

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Synthesis of Cinamaldehyde Glycol Acetal Catalyzed by Fe2(SO4)3/SiO2 XU Zhao-hui;LIAO Wei-lin;ZHANG Shi-jin;CHENG Lei 2007, 27 (5):  94-96.  Abstract ( 602 )   PDF (587KB) ( 670 )   Save Cinamaldehyde glycol acetal was synthesized from cinamaldehyde and ethylene glycol by using ferric sulphate-loaded silica gel (Fe2(SO4)3/SiO2) as catalyst. Factors influencing the synthesis were discussed and the optimum reaction conditions were found as follows: cinamaldehyde 0.1 mol, molar ratio of n(cinamaldehyde):n(ethylene glycol) 1.0:1.5,dosage of catalyst 2.0% of the feed stock, amount of cyclohexane 15 mL,reaction time 3.0 h. The yield can reach 83.2%. Related Articles | Metrics

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Extraction of Pigment from Molasses Alcohol Wastewater and Its Antioxidant Activity WANG Biao-shi;LI Bian-sheng;ZENG Qing-xiao;LIU Hui-xia 2007, 27 (5):  97-102.  Abstract ( 523 )   PDF (1163KB) ( 634 )   Save The extraction of pigment from molasses alcohol wastewater and its antioxidant activity were studied. The macroporous resins HPD-600 and D301-R having better effect were selected through adsorption experiments using 5 macroporous resins on the pigment. The antioxidant activity from pigment from alcohol wastewater was studied in three different systems (NO2-, O2- and DPPH·). The results showed that their antioxidant activities were better in the NO2- and DPPH· system than in the O2- system and their antioxidant activities were enhanced with the increasing of concentration. In nitrite system, the half-inhibition concentraction (IC50) of the pigment toward nitrite was about 0.75 g/L. In DPPH·system, the IC50 of the pigment toward DPPH· was about 0.07 g/L. Related Articles | Metrics

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Determination of Orientin and Vitexin in Stenoloma chusanum by HPLC REN Bing-ru;XIA Bing;LI Wei-lin;WU Ju-lan;ZHANG Han-qing 2007, 27 (5):  103-106.  Abstract ( 580 )   PDF (665KB) ( 700 )   Save A method was established for determining contents of orientin and vitexin in Stenoloma chusanum(Linn.) Ching and to measure the contents of the two flavonoids in different plants in order to evaluate this resource by HPLC. Flavonoids were obtained by ultrasonic extraction, separation was carried out on Gemini C18 column with a mixture of acetonitrile/1% phosphoric acid (volume ratio 15:85) as mobile phase at flow rate 1.0 mL/min and detective wavelength 340 nm. Orientin content showed a good linear relationship within 0.025-0.148 μg (R2=0.9995) and the average recovery was100.61%, RSD was 2.18%. Vitexin content showed a good linear relationship also within 0.035-0.207 μg(R2=0.9999) and the average recovery was 99.77%, RSD was 2.37%. The sample of the highest content is from Yunnan Qiubai which contained orientin 0.116 6% and vitexin 0.145 7%. Orientin content decreased but vitexin content increased when the plant was transplanted from Qiubai to Nanjing after one year. Plant from Qiubai is an excellent resource according contents of orientin and vitexin. Related Articles | Metrics

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Studies on Supercritical CO2 Extraction and Chemical Components of Oil from Emblica Seeds ZHAO Mou-ming;LIU Xiao-li;LUO Wei;CUI Chun;ZHAO Qiang-zhong 2007, 27 (5):  107-112.  Abstract ( 574 )   PDF (1029KB) ( 718 )   Save The technic of extracting oil from emblica (Phyllanthus emblica Linn. )seeds was studied by supercritical CO2 extraction (SCDE), and method of response surface regression (RSR) was used to optimize the extraction under various conditions for the optimum yield. Optimal conditions were: extraction pressure 19 MPa, extraction temperature 35℃ and extraction time 103 min. Under optimal conditions, the yield is 26.13%±1.4%. After esterification the oil was analyzed by GC-MS, 16 compounds have been identified and their relative contents were determined by area integration. Emblica seed oil contains an appreciable amount of unsaturated fatty acids, which make up 91.33% of the total amount of fatty acid. Main unsaturated fatty acids are linolenic acid, linoleic acid and arachidonic acid. Analyses of physical-chemical parameters showed that SCDE method is a good method which can be used industrially. Related Articles | Metrics

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Study on Synthesis of Linalyl Acetate under Microwave Irradiation WU Chun-hua;ZHANG Jia-yan;ZHAO Qian-rong;AN Xin-nan 2007, 27 (5):  113-116.  Abstract ( 582 )   PDF (723KB) ( 619 )   Save The technology of synthesizing linalyl acetate had been studied by using the method of interval microwave irradiation. The results showed that the optimized conditions were as follows: the ratio of acetic anhydride to linalool was 2.5:1, 4% K2CO3 was used as catalyst (based on linalool weight) under 100 W microwave, and the irradiation time was 5 h. The conversion of linalool was 76.71% and the yield of linalyl acetate was 61.48% under optimum conditions. Compared with normal methods, the technology needs shorter time and cheaper catalyst to achieve higher productivity of linalyl acetate. Related Articles | Metrics

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Aging Characterization of Straw Alkali-lignin Modified Polyurethane Film JIN Fan;FANG Gui-zhen;LIU Zhi-ming;LI Ke-fei;LI Shan-shan 2007, 27 (5):  117-121.  Abstract ( 680 )   PDF (1067KB) ( 648 )   Save The behaviors of thermal-oxidation, UV photolysis and hydrolysis of straw alkali-lignin modified polyurethane films (PUF) were tested respectively. The results show that the retain ratio of tensile strength of thermal-oxidation samples with addition of 20% lignin was enhanced from 89.3% to 132.0% comparied with pure PUF and the retain ratio of elongation was from 19.6% to 66.3%, as well as from 9.4% to 48.6% under UV for 28 d. The retain ratio of tensile strength after hydrolysis, was enhanced from 74.8% to 95.5%. However, the addtion of alkali-lignin reduced remarkably the alkali resistance of PUF. Related Articles | Metrics

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Primary Study on Methods of Preserving Eleostearic Acid ZHANG Min;CAO Yong;PENG Mi-jun;LI Song-lin;HE Yan 2007, 27 (5):  122-126.  Abstract ( 578 )   PDF (1080KB) ( 702 )   Save The methods of preserving eleostearic acid were studied, adopting content of eleostearic acid as index. Eleostearic acid was esterificated with BF3 in methanol. The content of eleostearic acid was determined by gas chromatography, and the structure is studied by infrared spectroscopy. The tests on material of container, temperature and condition of preservation have been done. The effects of antioxidant, dosage and temperature on preseration of eleostearic acid were studied through orthogonal test. The results showed that the effects of antioxidant, dosage and temperature on content of eleostearic acid are insignificant. The suitable method for preservation of eleostearic acid is using vacuum package and preserved below 25℃. Related Articles | Metrics

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Effects of Reaction Condition on the Oxidation in vitro of Epigallocatechin-3-gallate and the Formation of Its Oligomers WANG Jing;QI Xiang-yang;ZHU Xue-liang;LI Hui-hui;LIU Chuan-ju 2007, 27 (5):  62-66.  Abstract ( 578 )   PDF (991KB) ( 585 )   Save In order to control the formation condition of oxidation oligomers of flavanols, epigallocatechin-3-gallate (EGCG) was oxidized in vitro and EGCG oligomeric products (EOP) were determined by HPLC-MS analysis. The influences of temperature, pH value, mass ratio of oxidant to EGCG on the oxidation of EGCG and the formation of EOP have been discussed. HPLC-MS analysis showed that there were mainly 3 oligomers, namely product 1 m/z 911, product 2 m/z 929, product 3 m/z 911. Products 1 and 3 were dehydrodimers of EGCG, product 2 was quinone dimer of EGCG. The study of reaction condition showed that oxidation of EGCG was enhanced with increased temperature. However when temperature reached 40℃, the formation of EOP decreased after 10 min; EGCG oxidation reaction could be accelerated with increase of pH value. However, at pH value 9.0, the formation of EOP decreased after 15 min; EGCG oxidation yield was increased with increase of m(oxidant):m(EGCG). However, the formation of EOP did not have a correlated relationship. The optimum conditions of EOP formation were:temperature 25℃, pH value 7.5, m(oxidant):m(EGCG)1.5:1,oxidation time 15 min. Related Articles | Metrics