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研究蛋白酶水解制备生物活性多肽反应机制与动力学行为,基于经典的米氏方程理论,应用数学推导结合试验研究的方法,以米糠蛋白为原料,对米糠蛋白-碱性蛋白酶体系进行酶解动力学研究.考虑蛋白质单底物水解、蛋白酶失活的机理模型,构建动力学模型R=aexp[-b(DH)],其中对参数a值和b值进行确定.利用Origin 8.0软件,对推导出的公式进行拟合得到水解速率动力学模型为R=(94.754e0-0.0597s0)exp[-0.157(DH)],水解度-水解时间的动力学模型:DH =6.37ln[1+(14.88e0/s0-0.009)t].对于米糠蛋白-碱性蛋白酶模型体系,经试验拟合,并求得该体系动力学常数:酶失活常数K4为16.144 min-1,酶解反应速率常数k2为94.754 min-1. 相似文献
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比较分析碱法、胶体磨辅助碱法、超声辅助碱法、胶体磨超声辅助碱法对米糠蛋白提取率及纯度的影响。结果表明,胶体磨超声辅助碱法能够显著提高米糠蛋白的提取率,其纯度为74.27%。并以此方法中的超声功率、液料比、超声温度、超声时间为考察因素,蛋白提取率为响应值。通过Design Expert 8.0.6软件做响应面优化分析得,胶体磨超声提取米糠蛋白的最佳工艺为米糠粒径40 目、pH 9、超声功率69 W、工作时间4 s、间歇时间2 s、液料比20∶1(mL/g)、超声时间40 min、超声温度46 ℃,此条件下模型预测蛋白提取率为92.14%。经验证,实际提取率为90.84%,与模型相符。胶体磨超声辅助碱法能够显著地提高米糠蛋白的提取率,且时间短,为米糠蛋白的进一步研究提供参考。 相似文献
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A. Hebeish A. Bayazeed B. Ib. Abdel Gawad S. K. Basily S. El-Bazza 《Starch - St?rke》1984,36(10):344-349
Strongly alkaline solutions of H2O2 were found to be very unstable particularly at high temperatures. Efforts were paid to regulate the decomposition of H2O2 in these solutions by incorporation of certain stabilizers, chelating agents and surface active agents. Stabilizers consisting of MgSO4. 7H2O, anionic/nonionic wetting agent, gluconic acid and EDTA could be achieved. The action of NaOH and H202 alone or combinated with this stabilizer formulation was also investigated. The viscosity of rice starch decreased under the influence of either H202 or NaOH, indicating that the starch underwent molecular degradation. However, none of these two agents were able to cause complete dissolution of starch even at a temperature as high as 95°C. Complete dissolution could only be achieved in regulated (stabilized) alkaline solutions of H202 at 95°C. 相似文献
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稀碱法分离工艺对糯米中蛋白质提取率的影响 总被引:1,自引:0,他引:1
探讨了稀碱法分离工艺对糯米中蛋白质提取率的影响,以得到纯度较高的糯米蛋白和糯米淀粉。研究碱液浓度、温度、水料比和时间对提取率的影响,采用响应面法对工艺参数进行优化,通过软件对提取率的二次多项数学模型解逆矩阵分析,最佳提取工艺为:碱液浓度0.05 mol/L、温度45.68℃、水料比8、时间94.96 m in。在上述工艺条件下蛋白提取率为80.11%,蛋白纯度为77.53%(干基),淀粉提取率为89.61%,淀粉纯度为90.50%(干基)。 相似文献
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Alkaline extraction of Brazilian rice starch was studied. UV/Vis and fluorescence spectroscopy were employed as an innovative way for protein detection during the extraction. Moreover, the results were compared to the traditional biuret colorimetric test. In parallel, the ultrastructure of starch was monitored by small angle X‐ray scattering (SAXS) during every extraction step. A progressive reduction of the granules organization was observed, which was also detected by the loss of birefringence under polarized light. The external integrity of starch granules after complete removal of proteins was maintained, as verified by scanning electron microscopy (SEM). The size of the granules, determined by the Mie scattering method varied between 3 and 8 µm. 相似文献
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研究不同的预处理方式对碱法提取米渣蛋白得率的影响。结果表明:分别用质量分数0.5%柠檬酸或稀释20倍的醋酸(0.875 mol/L)对米渣在25 ℃处理180 min,再用0.1 mol/L NaOH溶液提取,温度50 ℃,提取时间27 h,则蛋白提取率有较大提高;蛋白质提取率分别为84.60%和80.1%,高于未经过酸处理的米渣蛋白提取率。质量分数为0.5%柠檬酸和稀释20 倍(0.875 mol/L)的醋酸预处理的大米渣蛋白质经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析表明,用体积分数18%分离胶有利于蛋白质电泳的分离;蛋白质在提取过程中分解成小的片段,主要集中在9.5 kD和4.1 kD附近,其中4.1 kD蛋白含量较多,且用质量分数0.5%柠檬酸预处理后碱法提取的蛋白质颜色纯白鲜亮,质地细腻润滑。 相似文献
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Starch granule‐associated proteins, including granule‐bound starch synthase (GBSS), were found to be partially lost during alkaline extraction of rice starch. Variability in amount of loss of GBSS and other granule proteins was found among different rice lines. Also, part of the GBSS and other granule proteins leached out during gelatinization of the alkali‐extracted rice starch. Confocal laser scanning microscopy revealed that some protein still existed in gelatinized starch granules prepared from starch isolated using alkaline extraction. The starch that retained more GBSS and other granule proteins after alkaline extraction tended to have more protein in the isolated gelatinized starch granules, indicating that proteins resistant to alkaline extraction also tended to resist leaching during gelatinization. The study suggests that leaching of granule‐associated proteins may contribute to variations in paste properties of alkali‐extracted starches. 相似文献
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研究pH值碱性偏移(pH 11)结合热处理(50、60 ℃)对米糠蛋白结构和功能性质的影响。结果表明,pH值碱性偏移促使米糠蛋白二级结构由有序向无序转化,pH值碱性偏移结合热处理使得米糠蛋白二级结构呈现折叠-去折叠-复折叠的复杂变化,并伴随巯基氧化。pH值碱性偏移促使米糠蛋白展开,随着处理时间的延长,米糠蛋白重新聚集,热处理会加剧聚集程度。pH值碱性偏移使得米糠蛋白持水性、起泡性、泡沫稳定性、乳化性和乳化稳定性显著下降,仅持油性显著改善;随着处理时间的延长,米糠蛋白持水性、起泡性、乳化性和乳化稳定性逐渐上升,其中乳化性上升幅度最大。pH值碱性偏移结合热处理可显著改善米糠蛋白的持水性、起泡性、泡沫稳定性和乳化稳定性,同时也会降低米糠蛋白的持油性和乳化性。 相似文献
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本文着重介绍了济南市化工研究所对AKD原粉及乳液的研制、生产和开发情况,以及生产和应用过程中形成的一些观点和看法。 相似文献
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涤纶纤维分散染料碱性染色工艺,包括应用于纯涤纶织物、纯涤纶细旦织物、涤棉和涤粘织物的不同染色工艺。染色中加入碱剂MH-86,可减少低聚物的沾污,提高织物的光泽度,各项色牢度指标都比较好。 相似文献
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碱性松香施胶剂的进展 总被引:3,自引:0,他引:3
叙述了供造纸用浆内施胶系统中采用松香施胶剂的进展,本文主要内容包括:酸性松香施胶(松香皂-松香分散体),碱性松香施胶,松香施胶剂的施胶机理,碱性松香胶与传统的酸性松香胶,合成施胶剂烷基乙烯酮二聚物的比较。 相似文献
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阔叶木碱性过氧化氢机械制浆 总被引:5,自引:0,他引:5
近年来,造纸科研人员对不同化学药液预处理阔叶木机械制浆工艺的浆料性能及工艺效率的影响进行了研究。研究结果表明,碱性过氧化氢预处理比碱性亚硫酸盐和 /或冷烧碱预处理得到更高的光散射性能,更好的可漂性,相同或更高的松厚度。所有这些化学预处理都能获得较高的强度性能,如山杨和桉木浆的抗张指数都高于 40 N· m/g。就整个工艺效率来看,当游离度、强度和白度接近时, APMP工艺过程中的碱性过氧化氢预处理所制得浆的得率较高,单位能耗相当或稍低。曾有过报道,碱性过氧化氢预处理制得的浆经过很好的洗涤,浆料更为清洁,阴离… 相似文献