共查询到19条相似文献,搜索用时 218 毫秒
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为解决大豆蛋白胶黏剂相对分子量高、黏度大以及改性剂用量多等问题,需要制备一种由碱性蛋白酶改性的新型大豆蛋白胶黏剂,使其满足室内使用胶合板及胶合制品的要求。本研究以脱脂大豆蛋白粉为主要研究对象,碱性蛋白酶作为改性剂,探究不同酶添加量、pH、酶解温度、酶解时间对大豆蛋白胶黏剂胶合强度的影响,并通过正交试验对其工艺条件进行优化。结果表明:大豆蛋白胶黏剂适宜反应条件为碱性蛋白酶添加量10 000 U·g-1、pH9.5、酶解温度60℃、酶解时间100 min。改性胶黏剂与未改性的大豆蛋白胶黏剂相比,黏度由2 400 s降低为13 s,胶合强度由0.74 MPa提高为0.98 MPa,符合国家标准GB/T 9846—2004Ⅱ类胶合板要求。试验表明碱性蛋白酶改性大豆蛋白胶黏剂在胶合板生产领域中具有良好的应用前景。 相似文献
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不同酶解程度的大豆分离蛋白在配制酱油中的应用 总被引:1,自引:0,他引:1
以大豆分离蛋白为原料,对不同酶解程度的大豆分离蛋白在配制酱油中的应用进行了研究。首先通过单因素试验确定了酶解大豆蛋白的工艺参数,然后对添加不同酶解程度的大豆分离蛋白配制酱油的质量进行了研究,研究结果表明:酶解温度为50℃、pH为7.0、酶解时间为5h条件下的大豆分离蛋白酶解产物最适合应用到配制酱油中。 相似文献
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接枝改性大豆蛋白胶粘剂的合成及性能研究 总被引:8,自引:3,他引:5
利用疏水性单体甲基丙烯酸缩水甘油酯(GMA)接枝改性大豆蛋白以期获得耐水性较好的大豆蛋白胶粘剂.大豆蛋白(SP)经过3 mol·L-1尿素溶液预处理变性后,以GMA为接枝单体,过硫酸铵·亚硫酸氢钠(APS-NaH-SO3)氧化还原体系为引发体系,通过自由基聚合合成接枝改性大豆蛋白胶粘剂.用红外表征纯接枝物,结果表明接枝成功;研究了预处理时间、反应时间、引发剂加入量、单体加入量、反应温度对接枝改性大豆蛋白胶粘剂的粘接强度和耐水性的影响.结果说明接枝反应的确能够提高耐水性,并确定了最佳的反应条件.得出较佳的反应条件为:wsp4 g,wCM 3.39 g,WNaHSO<.3 0.2 g,WAPS:0.44 g,反应时间3 h,反应温度70℃. 相似文献
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橡胶树是重要的产胶植物,其树皮组织中的次生乳管是合成和贮存天然橡胶的主要组织。天然橡胶是从乳管中的胶乳中提炼而成,由特殊的细胞器-橡胶粒子合成。橡胶粒子为半个单位膜的球状结构,内部贮存合成的天然橡胶,外周膜上结合有多种蛋白质,这些蛋白与其执行的功能密切相关。目前对天然橡胶合成相关蛋白的研究较多,对与橡胶粒子凝集相关的蛋白研究甚少。以‘RY7-33-97’胶乳为材料,利用不同的离心速度,分级分离获取不同粒径的橡胶粒子,并进行不同程度的清洗,以Tricine-SDS-PAGE以及Western-blotting技术对橡胶粒子上结合的蛋白进行比较分析。研究结果表明,不同粒径的橡胶粒子上结合的蛋白含量存在差异。小橡胶粒子膜蛋白(SRPP)随着粒径的减小含量明显增加;而橡胶延伸因子蛋白(REF)的含量基本维持稳定,与粒径大小关系不大。存在于C-乳清中的Hev b7胶乳过敏原蛋白和3-磷酸甘油醛脱氢酶(GAPDH)与橡胶粒子有明显的结合;存在于黄色体B-乳清中的β-1,3-葡聚糖酶(Glu)、橡胶素(Hev)和几丁质酶(Chit)均能与橡胶粒子结合,但几丁质酶与之的结合能力最弱。橡胶粒子经清洗后,作为橡胶粒子的主要膜蛋白,SRPP含量随着清洗次数增加明显降低,而REF蛋白含量变化不明显,可见SRPP与橡胶粒子膜的结合紧密程度不如REF;来自C-乳清和B-乳清的凝集相关蛋白随清洗次数增加也明显降低含量。体外孵育小橡胶粒子与不同的蛋白样品,结果表明,橡胶粒子可体外结合多种不同的蛋白,其中多种蛋白都与橡胶粒子的凝集有关。本研究对不同粒径橡胶粒子上结合的凝集相关蛋白进行了初步解析,旨在为阐明橡胶树排胶机制奠定基础。 相似文献
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双酶法制备大豆降胆固醇活性肽的研究 总被引:1,自引:0,他引:1
通过比较4种酶对大豆分离蛋白的水解效果,并通过单因素及L9(34)正交试验优化其水解工艺条件,研究其最佳水解工具酶及最佳酶解参数。结果表明:木瓜蛋白酶和植物蛋白酶联合应用可作为大豆分离蛋白的水解工具酶;其最佳酶解参数为:酶解温度55℃、初始pH7.0、底物浓度12%、酶添加量8%、植物蛋白酶与木瓜蛋白酶的质量之比为1∶2,水解度可达14.20%;用双蛋白酶水解大豆分离蛋白,水解度为14.71%的产物降胆固醇活性最高,对胆固醇胶束溶解度的抑制率为61.67%。 相似文献
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M. R. Gumbmann W. L. Spangler G. M. Dugan J. J. Rackis I. E. Liener 《Plant foods for human nutrition (Dordrecht, Netherlands)》1985,35(3):275-314
In two year feeding trials, histologic changes in the pancreas of the Wistar rat were evaluated after chronic dietary exposure to raw and heated, dehulled, defatted soy flour and soy protein isolates which provided a range of trypsin inhibitor (TI) concentrations from 93 to 1271 mg/100 g diet. Also investigated was the nutritional interaction of level of dietary protein with the development of pancreatic pathology. Graded levels of TI were achieved from mixtures of raw and heated soy flour or protein isolate. Dietary protein levels were 10%, 20%, and 30%; the two higher levels obtained in some diets through casein supplementation. A total of 26 diets, including casein controls, were fed to groups of 40 male rats. Growth rates with these diets were commensurate with protein quality and level. Mortality rates tended to be slightly greater in the higher protein diets, and rats fed only raw soy as a source of protein survived well.Two lesions, nodular hyperplasia (NH) and acinar adenoma (AA) constituted the major pathological findings in the pancreas, and the incidence rates of both were positively associated with the concentration of dietary TI. The incidences of pancreatic NH and AA compared to those of the corresponding casein control were significantly elevated in rats fed heated soy flour supplying 10% protein and the lowest level of TI investigated (93 mg/100 g diet). At low levels of TI (215 mg/100 g diet), supplementation by casein to raise the concentration of protein from 10% to 20% and 30% reduced the frequency of NH and AA. When the dose-response data for NH and AA was linearized by plotting the probit of percent incidence against log of TI concentration per gram of dietary protein, the response to soy flour and soy protein isolate was not significantly different. Numerous lesions commonly found in the aging rat were diagnosed, and modulation of their rate of occurrence by nutritional factors associated with the diets was apparent in some instances.Reference to a company and/or product named by the Department is only for purposes of information and does not imply approval or recommendation of the product to the exclusion of others which may also be suitable. 相似文献
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Youna Hemery Ulla Holopainen Anna-Maija Lampi Pekka Lehtinen Tanja Nurmi Vieno Piironen Minnamari Edelmann Xavier Rouau 《Journal of Cereal Science》2011
Wheat bran is a composite material made of several layers, such as pericarp, testa and aleurone. It could be fractionated into purified fractions, which might either be used as food ingredients, or serve as a starting material for extraction of bioactive compounds. The aim of this work was to evaluate the potential of using electrostatic separation as a way to obtain purified fractions from wheat bran. Ultrafine-ground bran obtained either by cryogenic grinding or by grinding at ambient temperature was used as starting material. The ultrafine bran was then charged by tribo-electrification and introduced in a chamber containing two high voltage electrodes, where bran particles were separated depending on their acquired charge, allowing positively and negatively charged fractions to be collected separately. The particle size distribution, microstructure and biochemical composition of the obtained fractions were studied. The charge of the particles was influenced by their biochemical composition: particles rich in highly branched and cross-linked arabinoxylans (pericarp) were separated from particles rich in β-glucan, ferulic acid and para-coumaric acid (aleurone cell walls). The testa and the intracellular compounds from aleurone were not highly charged, neither positively nor negatively. The most positively charged fraction represented 34% of the initial bran, and contained 62% of the ferulic acid present in the initial bran. The yield of the separation process was good (5.4% loss), and could be further increased. 相似文献
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Using dimethyl sulfoxide (DMSO) as a solvent, the polyacrylonitrile/soy protein isolate/polyurethane (PAN/SPI/PU) blend solutions
and wet-spun fibers were prepared. The rheological properties of the PAN/SPI/PU solution were investigated. Investigations
of the structure and properties of the PAN/SPI/PU fibers involved Fourier transform infrared, enzymatic hydrolysis, scanning
electron microscopy, mechanical properties, dye adsorption, contact angle, and moisture regain measurements. The results showed
that all PAN/SPI/PU solutions possess pseudoplastic properties, and there are opposite effects of SPI and PU in the PAN/DMSO
solution. The apparent viscosity, the amount of non-Newtonian fluid and the extent of structuralization of the PAN/DMSO solution
increase with the addition of SPI, whereas these features all decrease with the addition of PU. The biodegrability, the absorption
of acidic dye and the moisture regain increase with the proportional increase in weight of SPI in the fiber blend. 相似文献
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A Box-Behnken design (BBD) was used for optimization of enzymatic hydrolysis of waste cotton fibers in order to obtain finest
cellulose particles. The effect of three factors including hydrolysis time (h), substrate concentration (g/l) and enzyme loading (%) were investigated. The median size of the hydrolyzed particles was defined as the response function
of the design. Results of BBD were subjected to analysis of variance (ANOVA) and a quadratic polynomial equation was developed
for predicting the particle size. According to the fitted model, the optimal conditions i.e. hydrolysis time, substrate concentration
and enzyme loading were suggested as 175 h, 5 g/l and 2.3 %, respectively. The suspension prepared under optimum conditions was subjected to ultrasonic treatment, and the
resulted stable suspension of cellulose nanoparticles was characterized. It was found that these nanoparticles are spherical
and most of them are in the range of 40–90 nm. The enzymatic and ultrasonic treatments caused an increase in the crystallinity
and a decrease in the degree of polymerization of cotton. 相似文献
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花生蛋白碱性蛋白酶水解物对血管紧张素转化酶抑制作用的初步研究 总被引:6,自引:0,他引:6
分别以碱性蛋白酶Alcalase和中性蛋白酶Neutrase对花生分离蛋白进行水解.制备花生分离蛋白水解物.并测定不同水解时间所得产物对血管紧张素转化酶(ACE)的抑制活性。未水解的花生分离蛋白没有ACE抑制活性.用中性蛋白酶Neutrase水解所得的水解物显示弱ACE抑制活性。然而,碱性蛋白酶Alcalasc水解物具有很强的ACE抑制活性.水解0.5h时水解物活性最高,其半抑制浓度为(IC50)0.56mg/mL。本研究表明,当用碱性蛋白酶Alcalase水解时,花生分离蛋白是生产ACE抑制肽的良好蛋白质来源,花生分离蛋白碱性蛋白酶Alcalase水解物可作为具有降压功能的功能食品添料。 相似文献
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以大豆分离蛋白为试验材料,优化糖基化大豆分离蛋白制备工艺并研究经过葡萄糖处理对大豆分离蛋白溶解度、凝胶强度、乳化性以及热稳定方面的影响。结果表明:糖基化大豆分离蛋白最佳制备工艺为反应温度69.49℃、反应时间46.64 min、糖的添加量10.64%,凝胶强度最高为76.03;在相同p H下,经葡萄糖处理后的大豆分离蛋白溶解度较大,沉淀较少,而未糖基化的大豆分离蛋白沉淀量增加。糖基化处理的大豆分离蛋白乳化稳定性(emulsifying stability,ES)和热稳定性均有所增强。糖基化改性过程可显著提高大豆分离蛋白的溶解性和乳化性能,这为拓宽其在食品工业中的应用提供了理论基础。 相似文献