优化蛋清粉蛋白热变性条件的研究

为了降低蛋清粉蛋白高F值寡肽的生产成本以实现工业化大规模生产,本实验利用了对比分析和L9(34)正交试验设计方法,考察热变性时间、热变性温度和加酶量三个因素对蛋清粉蛋白水解度的影响,优化出蛋清粉蛋白热变性条件的最佳参数为:当底物浓度为5%,热处理温度90℃,热处理时间10min,碱性蛋白酶加酶量5%,酶解5h后蛋清粉蛋白水解度为26.68%。

喷雾冷冻干燥对鸡蛋清蛋白结构和特性的影响

为了探究喷雾冷冻干燥(Spray freeze drying,SFD)对鸡蛋清蛋白结构及功能特性的影响,将其与喷雾干燥(Spray drying,SD)蛋清粉进行对比,并通过质构仪、差示扫描量热(D S C)、傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)、低场核磁共振(LF-NMR)等对其结构及特性进行测定。结果表明:SFD粉的变性温度比SD粉低了15.7℃,表面巯基含量低42.40%;SFD粉的α-螺旋和β-折叠结构比例大,分子结构更有序,蛋白聚集程度小,从而使其乳化特性得到改善;SEM分析表明,SFD粉呈大孔隙颗粒网络结构,溶解度增大。两种蛋清粉溶解度随pH的升高均呈先下降后上升的趋势,SFD粉溶解性和乳化性明显高于SD粉(P<0.05),凝肢硬度和束缚水含量显著低于S D粉(P<0.05),保水性差,两者的起泡性无显著差异。综上所述:与SD粉蛋白相比,SFD粉蛋白在结构和部分功能特性方面发生了显著变化,尤其在溶解度和乳化特性方面更具优势。

The influence of Trichosanthin on the induction of IgE responses to ovalbumin under adjuvant-free condition

Trichosanthin(TCS) is a potent allergen in mice. It can reproducibly induce specific IgE responses in C57BL/6J mice without the help of adjuvant alum. TCS can bring out the IgE responses to ovabumin(OVA), while OVA itself could not induce IgE responses to it. How- ever, TCS only works when QVA immunization is given one day after TCS immunization. Either time lag in OVA immunization, or immunization of both antigens at the same time, or OVA immunization given first, all has no effect on the induction of IgE responses to OVA. Through analysis of the antibody specificity of hybridoma clones, it indicated that specific antibodies to TCS or OVA were secreted by independent B cell clones. The IgE antibodies showed no polyreactivity to different antigens.