Loading...

Table of Content

    25 August 2006, Volume 34 Issue 8
    Previous Issue    Next Issue
    Chemistry & Chemical Engineering
    Performance of Chitosan-Collagen Blend M embrane as Cornea Tissue Engineering Scafold
    Wang Ying-jun Zhao Xiao-fei Lu Ling Ren Li Chen Xiao-feng Ge Jian Liu Bing-qian
    2006, 34(8):  1-5. 
    Asbtract ( 325 )   PDF (288KB) ( 523 )  
    Related Articles | Metrics

    Chitosan-collagen blend membranes used as cornea tissue engineering scaffold were prepared.and the optical performance,mechanical strength,crystallization degree,water absorption,hydrophilicity,micro.morpholo.gY and cell affinity of the scafold were tested.The results demonstrate that the chitosan and the collagen in the scaffold,which strongly interact with each other,are miscible,and that the scaffold is of a smooth and unif0m sur.face and a layer-ordered interior structure.Th e blend membrane has excellent optical transmittance and moderate wet mechanical properties.The culture of human cornea epiderm al cells on the chitosan.collagen blend membrane shows that the cells Can adhere well and proliferate onto the membrane,suggesting that the chitosan-collagen blend membrane has good cell affinity.Th e results show that chitosan.collagen blend membrane is a promising candidate material in cornea tissue engineering.

    Development of Optimization Algorithm for Synthesizing Multi-Stream Heat Exchanger Network
    Wei Guan-feng Qian Yu Yao Ping-ring
    2006, 34(8):  6-12. 
    Asbtract ( 236 )   PDF (349KB) ( 558 )  
    Related Articles | Metrics

    The synthesis of multi-stream heat exchanger network(MSHEN)is modeled as a mixed integer nonlinear programming problem (MINLP)that possesses large scale,many constraints and severe non.convexitv and nonlinearity,thus resulting in many local optima.The traditional gradient.based optimization algorithms fail to find the global optimum.In order to solve this problem,the genetic algorithm (GA)is adopted in this paper.Moreo-ver,to overcome the premature convergence and the dificulty in the appropriate determination of running parame.ters,an improved GA with diversity-maintaining operators and a multi-group evolution structure is proposed.in which the running parameters can be self-tuned and the simulated annealing algorithm is introduced during the evo.lution.Examples indicate that the adoption of the proposed algorithm helps solve the MINLP problem and guaran.tees the probability of finding the global optima in a MINLP problem.

    Adsorption/Desorption Properties of Mesoporous Silca Gel Modified th CaCl2/LiCI
    Li Xin Li Zhong Xia Qi-bi
    2006, 34(8):  13-17. 
    Asbtract ( 285 )   PDF (264KB) ( 916 )  
    Related Articles | Metrics

    In this work,mesoporous silica gel was separately modified with CaCl2,or LiCl solution.and the kinetic expenments of water vapor adsorption on the mesoporous silica gels were carried out by means of batch adsorption.The temperature program desorption(TPD)curves of water on the modified mesoporous silica gels are measured bv means of the TPD technique,and then the corresponding activation energies of water desorption are also estimated.The effects of surface modification on the hygroscopic ability of the silica gels and the desorption activation energY of water on the modified silica gels were finally discussed.Experimental results show that.in comparison with the unmodified mesoporous silica gel,the average pore diameter of the silica gel modified with CaCl2,or IACl becomes larger,and the pore volume of the modified silica gel becomes smaller. Its hygroscopic ability is improved.and the desorption activation energy of water on the modified mesoporous silica gels at a relative humiditv less than 80% in.creases.Moreover,the desorption activation energy of water on the mesoporous silica gel modified with CaCl2.is much hi gher than that on the silica gel modified by LiCl, due to the higher polarizability of Ca2+.

    Liquid-Liquid Equilibrium for Sec-Butanol-Water-KF and Sec-Butanol-Water-K2CO3 Systems
    Xu Wen-you Zhou Xiao-yun Wang Jing-yang Liu Wen-zheng
    2006, 34(8):  18-21,26. 
    Asbtract ( 259 )   PDF (212KB) ( 486 )  
    Related Articles | Metrics

    Both the water-rich phase(water phase)and the see-butanol-rich phase(see-butanol phase)can be form ed when adding KF or K2CO3 into the see-butanol-water system.In this paper,the data about the liquid-liquid equilibrium (LLE)of see-butanol-water-KF and see-butanol-water-K2CO3systems are measured at 25℃,showing that the see·-butanol phase contains negligible salt and the water phase contains negligible see-butanol when the
    mass fraction of KF or K2CO3 in the water phase is not less than 26.38% or 28.76% ,respectively.Thus,water can be eficiently separated from the see-butanol-water system by adding KF or K2CO3 into the mixture.Moreover,a theoretical calculation of LLE data is carried out by using the Pitzer equation and the UNIQUAC equation to get the water activities respectively in the water phase and in the see-butanol phase.The calculated results are proved to be in good agreement with the experimental ones,the absolute mean deviations between the experimental data and the calculated results being 1.57% in the water phase and 0.33% in the see-butanol phase for see-butanol-wa-ter-KF system.and being 1.40% in the water phase and 0.39% in the sec-butanol phase for sec-butanol-water-K2CO3 system.

    Efect of pH Value on Exchange Equilibrium of Taurine on Anion Exchange Resins
    2006, 34(8):  22-26. 
    Asbtract ( 236 )   PDF (254KB) ( 573 )  
    Related Articles | Metrics

    The equilibrium uptakes of taurine on anion exchange resins(20 1×7 and D290)were determined by means of the static method.Th e effect of pH value of the solution on the uptake was also investigated.Then,the ion-exchange mec.hanism of taurine on the anion exchange resins was explained.The results show that the pH value of the solution greatly influences the equilibrium uptake of taurine,and that the equilibrium uptake of taurine,which increases with the pH value and reaches the maximum at pH 8 to 9,is very low in acidic solution.The ion-exchange isotherm s of taurine on the anion exchange resins indicate that,with the increase of taurine concentration of the solution.the uptake of taurine gradually increases at a low rate,and that the uptake of taurine on the 20 1×7 anion exchange resin is larger than that on the D290 anion exchange resin.

    Kinetics and Mechanism of Perkin Reaction for Synthesizing α-Furylacrylic Acid
    2006, 34(8):  27-31. 
    Asbtract ( 592 )   PDF (279KB) ( 775 )  
    Related Articles | Metrics

    The kinetics of Perkin reaction catalyzed by basic catalysts for synthesizing α-furylacrylic acid was inves-tigated by means of the ultraviolet spectr0photometry,verifying a nearly one-order total reaction for each reactant.Th e formation mechanism of acetic anhydride carbanion in the Perkin reaction for synthesizing α-furylacrylic acid was then proposed.It is concluded that acetic anhydride carbanion is obtained from the acetic anhydride with enol form . It is also concluded that the reaction rate is greatly afected by the basicity and structure of catalysts and bv the solvent’s polarity and capability of form ing hydrogen bonds as well

    Ternary Polymerization and Thermal Degradation Kinetics of N-Phenylmaleimide-Styrene-Maleic Anhydride
    Wang Zhai-rain Pi Pi-hui Wen Xiu-fang Cheng Jiang Yang Zhuo-ru
    2006, 34(8):  32-36. 
    Asbtract ( 284 )   PDF (250KB) ( 1251 )  
    Related Articles | Metrics

    N-phenylmaleimide.styrene.maleic anhydride copolymer(NSMA)was synthesized and the structure of the copolymer was characterized using FTIR.The heat resistance and thermal degradation kinetics of the copolymer were then analyzed by means of TG,DTG and DSC techniques,with the corresponding thermal degradation mechanism being also investigated.The results illustrate that(1)the thermal degradation process of NSMA accords with the single mechanism and its initial thermal degradation temperature is 637 K;(2)the thermal degradation basical-ly ends at 761 K,the rate of which rapidly increases with the temperature from 683 to 703 K;(3)the copolymer shows a weight loss of 20% and 50% in N2 respectively at 679 and 700K,and is of a glass transition temperature of 485 K with DSC curve,(4)the apparent activation energy and pre-exponential of NSMA degraded in non-iso-therm al condition are respectively verified by Kissinger equation as 173.21 kJ/mol and 3.2939 x 1012 min-1 ;and (5)the reaction order is determined as 0．94 according to the Crane theory．

    Release-Controlling Performance of Porous Polymer M icrosphere Adsorbing Hydroquinone
    Li Lu Wen Xiu-fang Pi Pi-hui Cheng Jiang rang Zhuo-ru
    2006, 34(8):  37-40,65. 
    Asbtract ( 273 )   PDF (269KB) ( 875 )  
    Related Articles | Metrics

    Poly(styrene-divinylbenzene)(PSt-DVB)porous microspheres with a diameter of less than 1 5μm were prepared by means of the modified two-step seed swelling polymerization.Then,the adsorption and release of hy-droquinone on the produced porous microspheres were investigated an d the effects of microsphere size.pore diame-ter and adsorption capacity on the release rate were investigated in detail.Th e results indicate that both the de-crease in microsphere size and the increase in adsorption capacity result in a high release speed of hydroquinone from the microspheres,while the pore diameter has no obvious efect on the release of hydroquinone.Moreover,the concentration of hydroquinone changes little in a long period which shows that the produced PSt-DVB por0us mi-crospheres are of excellent release-controlling performance.

    Efect of Protective Colloid PVA-SH on Properties of M M A/BA Poly nler Dispersions and Their Powders
    Lin Jin-dong Chen Huan-qin
    2006, 34(8):  41-45. 
    Asbtract ( 314 )   PDF (267KB) ( 1175 )  
    Related Articles | Metrics

    Highly shear-stable copolymer dispersions with high solid contents of methyl methacrylate(MMA)and butyl acrylate(BA)were prepared using the semicontinuous emulsion polymerization,with thiol-ended poly(vinyl alcohol)(PVA-SH)as the protective colloid.FTrIR spectrum shows that PVA-SH mostly copolymerizes with MMA to form the grafting polymer PVA-g-PMMA at the first stage of the emulsion polymerization. TEM images sh0w that.when SDS(Sodium Dodecyl Sulphate)is added to the emulsion at the stage of shell formation,the particles are large in size and the PVA-SH shell is not integrated.However,when SDS is added at the stage 0f monomer droD-ping,the particles turn smaller in size and the PVA-SH shell becomes integrated. It is also indicated that the addi-tion of triethanolamine resuhs in a lower polydispersity index and an average relative molecular mass in nunaber 0f 50000 or so.Moreover,with the help of the drying assistant SiO2,the acrylic dispersions with 0. 8% t0 1.5%(mass fraction)of PVA-SH can be spray-dried into highly dispersible powders that are easy to form sec0ndary dis-persions with a particle size distribution similar to that of the original dispersion

    Synthesis and Properties of W aterborne Polyurethane Emulsion with M ul tiple M odification
    Huang Hong Xie Xiao-wei Fu He-qing Chen Huan-qin
    2006, 34(8):  46-50. 
    Asbtract ( 370 )   PDF (230KB) ( 586 )  
    Related Articles | Metrics

    The waterborne polyurethane emulsion with multiple modification was synthesized with castor oil and tri-methylolpropane(TMP)as the cross-linkers as well as with epoxy resin and acrylate as the modification agents.The structure and properties of the modified emulsion was also characterized using Fourier Transform Infrared f fTr.IR),Gel Permeation Chromatography(GPC)and Particle Size Analyzer.The modified emulsion was then used to
    form ulate the adhesive to be used for car decoration,followed by the peel strength tests to investigate the perfor-mance of the adhesive.The results show that the materials are all broken during the tests for the adhesives between PVC(polyvinyl chloride)and polyurethane(PU),wood and leather,and that the peel strength reaches 1.66 kN/m and 1.41 kN/m for the adhesives between PU and leather,rubber and leather,respectively.It is thus concluded that the adhesive form ulated by the waterborne polyurethane emulsion with multiple modification is better than that form ulated by unmodified PU and the foreign products of the same kind.

    Efect of Ultraviolet Irradiation on Aggregation M orphology of Ionic Complementary Self-Assembly Oligo-Peptide EAK16-Ⅱ
    Ouyang Xin-ping P．Chen
    2006, 34(8):  51-54. 
    Asbtract ( 265 )   PDF (194KB) ( 565 )  
    Related Articles | Metrics

    The effect of ultraviolet irradiation on the serf-assembly aggregation morphology of ionic complementary self-assembly oligo-peptide EAK1 6-Ⅱin aqueous solution was studied using an atomic force microscopy.It is found that the ultraviolet iradiation changes the nanostructure formed by the self-assembly in the aqueous s0lution.and a variation from a fibrillar structure into a globular structure of the aggregation morphology can be caused after an ira diation with 365 nm ultraviolet for 2 h.According to the nuclear model.there draws a conclusion that the ab0ve mentioned change results from the destruction of the interm olecular forces of the assembled oligo-peptide as well as from the transition from β sheet into β turn.

    Efect of Inlet-Air Velocity Distribution on Performance of Evaporative Condenser
    Jiang Xiang Zhu Dong-sheng Tang Guang-dong Wang Nan
    2006, 34(8):  55-60. 
    Asbtract ( 320 )   PDF (302KB) ( 915 )  
    Related Articles | Metrics

    This paper investigates the inlet-air velocity distribution and its influence on the heat and mass transfer as well as the flow resistance by reasonably predigesting the physical model.In the investigation,the realizable κ-ε model.the enhanced wall treatment and the SIMPLE arithmetic for the velocity.pressure coupling are adopted.The results indicate that(1)the error between the simulated and experimental results is within the range of 1 5%;(2)when the velocity of the inlet air ranges from 1.5 to 4.5 m/s,the deviation of heat transfer duty and the pres-sure drop reach 19.3%and 9.4%,respectively;(3)when the velocity angle of the inlet air ranges from -45°to 45°the deviation of heat transfer duty and the pressure drop respectively reach 1 5.5%and 1 8.0%;and(4)the optimal velocity and velocity angle of the inlet air are 2.4 to 3.3 m/s and -15°to 20°respectively.

    Volume Shrinkage Characteristics of Porous Materials in Drying Process
    Xu Wei Ding Jing Zhao Yi Yang Xiao-xi
    2006, 34(8):  61-65. 
    Asbtract ( 273 )   PDF (228KB) ( 946 )  
    Related Articles | Metrics

    The volume shrinkage characteristics of porous materials in the drying process are investigated based on the definitions of Volume Shrinkage Coefficient and Shrinkage Isotropicity,with fresh ginger,carrot,potato and ba-nana as the drying materials.The relationship between the volume reduction of the material and the removed mois-ture is then analyzed,and the efects of the drying stream temperature and the relative humidity on the shrinkage characteristics are also discussed.Th e results show that a fast drying rate will result in great volume shrinkage,and that the microstructure of the porous materials significan tly afects the shrinkage characteristics.A dimensionless moisture difusion model is also presented in this paper for the drying of potato ,the obtained results of which accord well with the experimental ones.

    Formation and Thermodynamics of Reverse Micelle in Supercritical Carbon Dioxide
    Wen Zhen Dang Zhi Zong Min-hua Zhu Zhi-xin
    2006, 34(8):  66-69. 
    Asbtract ( 264 )   PDF (220KB) ( 474 )  
    Related Articles | Metrics

    According to the solubilization behavior of methyl orange used as a solvation probe in the multiple system mixed by supercritical carbon dioxide,surfactants and cosolvents,this paper draws a conclusion that.under the ac-tion of n-butyl alcohol,the surfactants sodium bis-(2-ethylhexyl)sulfosuccinate(AOT)and isooctyl phenol poly-ethoxylate(TX-10)can form reverse micelles in supercritical carbon dioxide.The formation of the micelles is spontaneous in therm odynamics．Specifically,for nonionic surfactant TX-1 0,the form ation of the micelles depends on the increase in entropy,while for anionic surfactant AOT,the form ation mainly depends on the increase in enthalpv at a high temperature and on the increase in entropy at a low temperature.

    Interaction Between DNA and Copper(II)Complex of 1，10-Phenanthroline and Amino Acid
    2006, 34(8):  70-74. 
    Asbtract ( 252 )   PDF (255KB) ( 496 )  
    Related Articles | Metrics

    The interactions between DNA and three complexes,namely,[Cu(phen)(L-Gly)(H2O)]•CLO4•2.5H2O(phen=phenanthroline,L-Gly=L-Glycine),[Cu(phen)(L-Ile)(H2O)](CLO4)(L-Ile=Isoleucine)and[Cu(phen)(L-Met)(H2O)](CLO4)(L-Met=L-Methionine),were investigated by means of the nu0rescence
    spectroscopy,the electronic absorption spectroscopy,the viscosity measurement and the agarose gel electrophore.sis.It is revealed by the fluorescence spectroscopy.the electronic ab sorption spectroscopy and the viscosity men.surement that the mode of the interaction between the complexes and DNA is partial intercalation.Moreover,the results of agarose gel electrophoresis indicate that all the complexes exhibit obvious pBR322 DNA cleavage activitv.Furthermore,a moderate size of the auxiliary ligand should be taken into consideration because a larger or snlaller steric hindrance of the auxiliary ligand would afect the interaction between the three designed complexes and DNA.

    Influence of Solventa Properties on Fluorescent Properties of Water-Soluble Cellulose Ethers/Eu(Ⅲ)
    Ye Jun Xiong Jian
    2006, 34(8):  75-78. 
    Asbtract ( 357 )   PDF (211KB) ( 513 )  
    Related Articles | Metrics

    The effects of solvent polarity and protonic solvent on the fluorescent properties of hydroxyethvl cellulose (HEC)/Eu(Ⅲ)，methyl cellulose(MC)/Eu(Ⅲ)and carboxymethyl cellulose(CMC)/Eu(m)complexes were investigated by fluorescent spectroscopy to reveal the interaction between the fluorescent substance and the solvent on the microcosmic level.The results show that(1)the dipole moment of HEC/Eu(Ⅲ)complex in the excited state greatly changes with the increase in the polarity of H2O/CH3OH solvent,which makes the fluorescent spec.trum of HEC.Eu(Ⅲ)complex,whose intensity depends on various factors,shifts to the long-wavelength side:(2) the Increase in the H2 concentration of H2O/HAc solvent results in a reorientation of the solvent cag es around MC/Eu(Ⅲ)complex as well as a great Stokes shift of the fluorescent spectrum due to the solvent relaxation:and(3)
    the increase in the polarity of H2O/CH3COCH3 solvent has no obvious efect on the Stokes shilt of CMC/Eu (Ⅲ)complex,but it may break the equilibrium between intra-and inter.molecular hydrogen bonds in the complexes.thus changing the structure of the fluorescent substance and the intensities of the fluorescent spectra

    Properties and Cross Linking Mechanism of Starches Oxidized by Sodium Hypochlorite at Low Level
    Luo Fa-xing Fu Xiong Huang Qiang Li Lin
    2006, 34(8):  79-83. 
    Asbtract ( 394 )   PDF (259KB) ( 1040 )  
    Related Articles | Metrics

    Cassava and potato starches were oxidized by sodium hypochlorite with an active chlorine content of less than 1% (mass fraction,below the same).The oxidization mechanism and the physicochemical properties of the oxidized starches were then studied,revealing that both the carbonyl content and the carboxyl content of the oxi.dized potato starch are higher than those of the oxidized cassava starch,although the carboxyl and carbonyl contents of the two oxidized starches all increase with the dosage of sodium hypochlorite. As measured by Brabender Viscog.raphy,the oxidation at low active chlorine content(≤0.3%)results in higher peak and final viscosities of the oxi.dized starch.Moreover,the absorptions at 1733 cm-1 and 1714cm-1 are observed in the FTIR spectra of the cassava and photo starches oxidized at an active chlorine content of 0.9%.which weaken or disappear when the oxida.tion is carried out at an active chlorine content of 0.1%.However.the absorption at 1 150cm-1 is strengthened. It is thus concluded that a cross linking reaction takes place between the hemiacetal hydroxyl groups of the oxidized starch and the hydroxyl groups of the adjacent starch during the low-level oxidation process.

    Mechanism of Stabilizers in Solid Lipid Microparticles
    Long Chun-xia Zhang Li-juan Liu Lei Qian Yu
    2006, 34(8):  84-88,93. 
    Asbtract ( 301 )   PDF (420KB) ( 558 )  
    Related Articles | Metrics

    The emulsion-congealing method was adopted to prepare ibuprofen-loaded solid lipid microparticles (SLM)with tristearin as the carrier.The stabilities of the SLM stabilized with different stabilizers were also investi.gated,proving that polyvinyl alcohol(PVA)and soy lecithin/bile salt are good stabilizers for the SLM system.Thestabilities of the SLM stabilized with these two stabilizers at an increasing ibuprofen content were then investigated.Experimental results show that.at an ibuprofen mass fraction of 7%,the SLM system stab ilized with soy lecithin/bile salt begins to congregate,while the one stabilized with PVA remains stab le even when ibuprofen mass fractionis up to 25% .The stabilizing mechanism of the stab ilizers was finally interpreted based on the analysis and simula-tion of the molecular structure of the stabilizer and the microstructure of the drug carrier.

    M echanism of Extraction Enhanced by Dual-Frequency Ultrasonic
    Qiu Tai-qiu Zeng Rong-hua Zhang Xiao-yan
    2006, 34(8):  89-93. 
    Asbtract ( 363 )   PDF (228KB) ( 858 )  
    Related Articles | Metrics

    A dual-frequency ultrasonic device combining both a 40 kHz ultrasonic in bath and a 25 kHz ultrasonic in horn was used to extract berberine from phellodendron.The physical model and the corresponding equations of the dual-frequency device were also proposed.The cavitation caused by the ultrasonic with different frequencies was then investigated by means of the iodine method.Results of the simulation with the proposed physical model reveal that(1)the cavitational behaviour caused by(25+40)kHz dual·frequency ultrasonic is more obvious than that caused by single-frequency ultrasonic;(2)the amount of iodine released from kalium iodid in the radiation of dual-frequency ultrasonic exceeds that in the radiation of single-frequency ultrasonic;and(3)more berberine can be ex-tracted from phellodendron in the radiation of dual-frequency ultrasonic.the yield of which being 64.1%.

    Preparation and Antibacterial Property of M odified M ontmorillonite as Novel Composite Antibacterial Agent
    Tan Shao-zao Ma Wen-shi Liu Ying-liang
    2006, 34(8):  94-99. 
    Asbtract ( 473 )   PDF (322KB) ( 1043 )  
    Related Articles | Metrics

    A New kind of modified montmoriUonite was prepared by introducing Zn2+ and quaternary ammonium cations into montmorillonite via the ion exchange,which was used as an antibacterial agent.The optimal preparation conditions were also investigated,and the mass fractions of Zn and tetradecyldimethyl benzyl ammonium were 2.95% and 12.18% ,respectively.The results of XRD and TG reveal a perfect exchange of Zn2+ and quaternary ammonium cations into montmorillonite as well as an onset decomposition temperature of the quaternary ammonium cation of about 210℃.Th e investigation into the antibacterial property of the prepared composite antibacterial agent shows that the minimal inhibitory concentrations(MIC)towards E.coli,S.aureus and P. aeruginosa are no more than 300 mg/L,which shows that the antibacterial agent possesses excellent antibacterial property and rather wide antibacterial spectrum.Moreover,the composite antibacterial agent exhibits good resistance to water-its antibacte.rial property remains excellent even after a dipping in deionized water at 50℃ for 30 h.

    Food Science & Technology
    Efect of Hom ogeneous Pressure on Quality of Whipped Cream
    Zhao Mou-ming Zhao Qiang-zhong Wang Cai-hua Luo Dong-hui
    2006, 34(8):  100-104. 
    Asbtract ( 231 )   PDF (275KB) ( 898 )  
    Related Articles | Metrics

    In order to reveal the interrelation between the preparation conditions and the qualitv of whipped cream.the effect of homogeneous pressure on the size distribution of fat globules in the emulsion during the preparation of whipped cream was investigated by means of the laser light scattering instrument.The relationship between the size distribution of fat globules and the partial coalescence rate as well as foam overrun of fat during the whipping process was then analyzed with SPSS 13.0 software.The results indicate that(1)the size of fat globules increases with the homogenous pressure within the range of 20 to 60 MPa;(2)the partial coalescence of fat is acce1erated bv Increasing homogenous pressure during the whipping process;(3)the overrun of whipped cream reaches its mini-mum and max m“m alue respectively at the homogenous pressures of 60 and 50 MPa;and(4)the optimal ho-mogenous pressure for whipped cream is 40~50 MP

    Composition and Interaction of Aggregate of Peptides Derived from Soy Protein Isolates
    Yu Hong-peng Tang Chuan-he Zeng Qing-xiao Yang Xiao-quan
    2006, 34(8):  105-109. 
    Asbtract ( 328 )   PDF (306KB) ( 1043 )  
    Related Articles | Metrics

    The aggregation of the hydrolysates of soy protein isolate(sPI)induced by subtilisin protease was inves-tigated.Th e amino acid composition of the aggregates and the interaction involved in the aggregation was also dis-cussed．It is indicated by the SDS-PAGE(Sodium Dodecyl Sulphate-Polyacrylamide Gel Electropharesis)and the SE-HPLC(Size Exclusion-High Performance Liquid Chromatography)analyses that SPI is digested to small fragments with the molecular mass less than 6.5 ku,which are the major fragments involved in the aggregates.More-over,the obtained aggregates can be solubilized in buffers such as urea,guanidine hydrochloride and SDS,but can hardly solubilized in-mercaptoethanol.As revealed by the amino acid analysis,the content of the hydrophobic amino acid in the aggregates is greater than that in SPI,which suggests that(1)the hydrophobic interaction force is the major force to drive the aggregation;(2)hydrogen bonds and electrostatic forces play a role in the stabiliza-tion of the finally-formed aggregates;and(3)disulfide bonds hardly contribute to the aggregation.The mechanism 0I’the aggregation of the peptides derived from SPI induced by subtilisin protease is also discussed in this Daper in term s of the molecular structure of protein.

    Efect of Transglutaminase on Properties of Cast Films from Food Proteins
    Jiang Yan Wen Qi-biao Tang Chuan-he Yang Xiao-quan
    2006, 34(8):  110-115. 
    Asbtract ( 339 )   PDF (329KB) ( 997 )  
    Related Articles | Metrics

    The effect of transglutaminase(TGase)treatment on the properties of the cast films from several food proteins including soy protein isolate(SPI),sodium caseinate (NaCN),gelatin,whey protein concentrate (WPC),wheat gluten(WG)and peanut protein isolate(PPI)were investigated.The results indicate that TGase treatment of the film-forming solutions significantly increases the tensile strengths of WG,SPI,NaCN and gelatin films respectively by 36.2% ,17.7% ,13.1% and 25.6% (P≤0.05),enhances the surface hydrophobicities of NaCN-SPI,WPC,WG and gelatin films respectively by 216.1% ,116.9% ,30.5% ,26.4% and 2.4% (P≤0.05),and results in the decrease in the water content,the total soluble matter and the transparency for all films.Also，it leads to an increase in the elongation at break by 16.3% ,72.6% and 172.3% respectively for gelatin,NaCN and WPC films,and a decrease in the elongation at break by 7.5% and 36.2% respectively for SPI and WG films.Moreover,a cross-linking induced by TGase iS finally confirm ed by SDS-PAGE analysis.

    Anti-Aging and Immune Regulation Efects of Peptides Derived from Big-Head Carp(Aristichthys nobilis)Protein
    Li Lin Zhao Mou-ming Wang Wei Wu Min-zhi Xie Guo
    2006, 34(8):  116-120. 
    Asbtract ( 218 )   PDF (287KB) ( 899 )  
    Related Articles | Metrics

    The a6ng mice models were induced by D-galactose(D-gal)to reveal the anti-aging effect of the pep.tides derived from big-head carp protein on the index of immune apparatus and the phagocytic functions of phago-cytes as well as on the content of malonadehide(MDA),the activities of superoxide dimutase(SOD),glutathi-one peroxidase(GSH-Px)and monoamine oxidase-B(MAO-B)in the liver,brain and blood serum of mice.The activities of Ca2+ -Mg2+ -ATPase and Na+ -K+ -ATPase in myocardial mitochondria were also determined.The re-suhs indicate that the peptides derived from big-head carp protein can greatly decrease the MDA content in mice liver and brain and the activities of MAO-B in mice brain(P<0.01),increase the activities of anti-oxidative enzymes SOD and GSH-Px,and significantly afect the activities of Ca2+ -Mg2+ -ATPase and Na+ -K+-ATPase in mvo-cardial mitochondria.Moreover,the peptides can also enhance the phagocytic functions of phagocytes in aging mice (P<0.01).All these imply obvious anti-aging and immune regulation effects of the peptides on the senile mice in-duced by D-gal.

    Influence of Double Enzymolysis on Bitterness of Soybean Oligo-Peptide
    Tao Hong Liang Qi Zhao Mou-ming
    2006, 34(8):  121-124. 
    Asbtract ( 359 )   PDF (224KB) ( 1288 )  
    Related Articles | Metrics

    Although soybean oligo-peptide possesses various physiological functions,its application to food engi-neering is restricted due to the bitterness caused by the enzymolysis of soybean isolate protein.In order to solve this problem,a single enzyme Promatex and the bi-enzyme Promatex/Favourzyme were respectively used to hydrolyze soybean isolate protean,and the influence of hydrolysis method on the bitterness of soybean oligo-peptide solution was investigated with the degree of hydrolysis and the length of the peptide chain kept constant.The results indicate that the adoption of the bi-enzyme Promatex/Flavourzyme can greatly decrease the bitterness of the soybean oligo-peptide solution and markedly shorten the processing period.

    Contents
    2006, 34(8):  0. 
    Asbtract ( 26 )  
    Related Articles | Metrics
News
More>>
Featured Article
More>>
Most Read
More>>
Most Download
More>>
Most Cited
More>>
Links
More>>