不同热处理条件下羊血浆蛋白体外模拟消化研究

Research on in vitro digestion of sheep plasma protein under different heat treatment conditions

中文关键词:  羊血浆蛋白  体外模拟消化  二级结构

英文关键词:sheep plasma protein  in vitro digestion  secondary structure

中文摘要:

      目的 研究不同热处理条件下羊血浆蛋白的体外模拟消化特性及其蛋白质二级结构的变化规律。方法 采用胃蛋白酶对热处理后的羊血浆蛋白进行体外模拟消化, 利用茚三酮法、十二烷基硫酸钠聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate polyacrylamide gel electrophoresis, SDS-PAGE)、表面电位(Zeta potential)及粒径、傅立叶变换红外光谱(Fourier transform infrared spectroscopy, FTIR)等表征羊血浆蛋白的水解程度及消化产物的结构特性。结果 热处理可使羊血浆蛋白消化产物水解度增加, 90℃热处理时水解度达到最大值, 热处理可产生更多的低分子量组分, 消化降解更为完全。90℃热处理时羊血浆蛋白消化产物的粒径分布单一, 聚集程度最高。70~90℃热处理组的红外光谱显示酰胺Ⅰ带向低波数方向有不同程度红移, 随着热处理程度的增加, 羊血浆蛋白消化产物中α-螺旋结构含量先增加后减少, 其余二级结构含量均无明显变化规律。结论 热处理对羊血浆蛋白体外模拟消化均有一定的促进作用, 从蛋白质变性的角度考虑, 羊血浆蛋白的热处理强度不宜超过90℃ 20 min。

英文摘要:

      Objective To study the in vitro digestion characteristics and secondary structure changes of sheep plasma protein under different heat treatment conditions. Methods The heat-treated sheep plasma protein was digested in vitro by pepsin. The hydrolysis degree of sheep plasma protein and the structure of digested product were characterized by ninhydrin method, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Zeta potential, particle size distribution and Fourier transform infrared spectroscopy (FTIR). Results The hydrolysis degree of sheep plasma protein digestion products were increased after heat treatment, and the hydrolysis degree reached the maximum value at 90℃. Low molecular weight peptides were produced and the digestion products of sheep plasma protein were degraded completely. The particle size of sheep plasma protein digestion products was unit distribution, and the aggregation degree was the highest at 90℃. The infrared spectra of 70?90℃ showed that the amide I band bathochromic-shift to the low wave number in different degrees. With the increase of heat treatment degree, the content of α-helix structure in sheep plasma protein digestion products increased first and then decreased, and there was no obvious change in the content of the remaining secondary structures. Conclusion Heat treatment can promote the simulated digestion of sheep plasma protein in vitro, and the heat treatment degree of plasma protein should not exceed 90℃ for 20 min from the perspective of protein denaturation.