发酵小米体外胃肠消化特性及抗氧化活性

以小米酸肉中辅料小米为研究对象,分析辅料小米餐后血糖变化及模拟胃肠消化过程中消化率、粒经变化及抗氧化活性的变化.结果 表明:随餐后时间的延长,血糖值在0～30 min时先增加,大于30min迅速降低,餐后240 min时血糖值为22.79 dl/mg基本稳定,与300 min时血糖值23.42 dl/mg无显著差异(p...     

两性离子催化剂的研究进展

两性离子催化剂按照配体的结构特征和金属元素种类可分为两性离子茂金属配合物、非茂前过渡以及后过渡金属两性离子配合物三大类。两性离子茂金属配合物根据阴离子在配体上所连接区域的不同又可以分为Girdle型、Bridge型和Ring型三种。本文对各类两性离子配合物的合成方法、结构特征和催化反应活性进行了归纳总结,发现两性离子催化剂对催化烯烃聚合表现出较好的活性,而非茂的两性离子配合物不仅是良好的烯烃聚合催化剂,还可以催化多种类型的小分子反应。作为一种新型高效的单组份活性催化剂,目前,有关两性离子催化剂的应用研究还有很多未知的领域有待开发,尤其是在小分子的活化、催化领域。     

凝胶过滤色谱法测定3 种不同来源多肽的相对分子质量分布

目的：建立凝胶过滤色谱法测定多肽（如大豆肽、白蛋白多肽、羊胎盘多肽）的相对分子质量分布的方法。方法：采用TSK-GEL G2000SWXL色谱柱（300 mm×7.8 mm,5 μm）、流动相为乙腈-水-三氟乙酸（15∶85∶0.07,V/V）、流速0.6 mL/min、柱温30 ℃、进样体积10 μL、检测波长220 nm。结果：在相对分子质量189.1～12 355之间,相对分子质量对数与保留时间呈线性关系,相关系数为0.995 6,方法精密度、重复性、稳定性良好,准确度高。结论：本方法操作简便快速、灵敏度高、重复性好,适用于多肽类物质相对分子质量分布的检测。     

血管紧张素转化酶抑制剂体外活性检测方法的改进及应用

通过测定不同缓冲体系、氯离子浓度、酶底物比等对血管紧张素转化酶（ACE）活力测定反应体系的影响，建立了适用于食源性ACE抑制剂体外活性检测的分析方法，并分析了该方法的可靠性。测定方法条件为：浓度为200mmol／LNaCl的Tris—HCl缓冲体系．反应温度37℃，检测342nm波长下吸光值在7min内的连续变化；用已知的ACE抑制剂Captopril对方法进行检验。并将其应用于乳蛋白质不同酶水解产物ACE抑制活性的测定。     

酶法制备啤酒废酵母生物活性肽的工艺条件研究

以啤酒废酵母为原料,经木瓜蛋白酶酶解、分离、纯化、干燥等工序制得啤酒废酵母活性肽。试验通过单因素及响应面分析方法确定了木瓜蛋白酶对废酵母的最佳酶解条件为:酶解温度57.78℃,pH 7.05,酶用量3.03%.酶解后多肽得率可达到52.13%。     

SOME REASONS WHY HIGH GRAVITY BREWING HAS A NEGATIVE EFFECT ON HEAD RETENTION*

Our aim was to examine the effect of high gravity brewing on head retention with respect particularly to the effect of high gravity brewing on hydrophobic polypeptide levels. High gravity brewed beer had poorer head retention values when compared to a similarly brewed low gravity beer. Analysis of hydrophobic polypeptide levels in both high gravity wort (20° Plato) and low gravity wort (10° Plato) produced using a lauter tun, revealed that the high gravity wort contained 8% less hydrophobic polypeptide than the low gravity wort (undiluted basis). Analysis of hydrophobic polypeptides throughout the brewing process for these 10°P and 20°P brews demonstrated that the hydrophobic polypeptide content decreased, especially during the kettle boil and fermentation. Furthermore, the high gravity brewed beer suffered the greatest loss, leaving the final beer with approximately 40% less hydrophobic polypeptides than the low gravity beer. Brewing at 10°P and 20°P using a mash filter demonstrated that these filters can improve the head formation and stability of the resultant beers at sales gravity. However, the low gravity beer still produced a more stable foam (Rudin value 93 s) when compared to the high gravity beer (Rudin value 83 s). The mash filter slightly increased the hydrophobic polypeptide extraction. It is concluded that the mash filter produced higher hydrophobic polypeptide levels in the final beers, as well as having a positive effect on reducing the levels of foam negative compounds such as fatty acids in the wort, and therefore slightly improved head retention values .     

雄蚕蛾蛋白制备功能性多肽酶解条件优化研究

以水解度(DH)和肽得率为指标,分别考察温度、pH值、底物浓度、加酶量对碱性蛋白酶酶解雄蚕蛾蛋白制备功能性多肽的影响,通过二次回归正交旋转组合设计确定碱性蛋白酶酶解反应的最佳优化参数为:温度64.5℃、pH9.36、底物浓度4.46%、加酶量6660U/ml、反应时间300min。在此条件下,酶解液水解度达到21.65%、肽得率达到34.81%。