糖基化卵白蛋白肽的制备工艺优化及特性与结构分析

Optimization of glycosylation process of ovalbumin peptide and its characterization and structure analysis

为改善鸡蛋清蛋白的加工特性,该文以卵白蛋白(ovalbumin,OVA)为研究对象,考察酶法与糖基化相结合的协同改性对其特性和结构的影响。以接枝度为指标,采用响应面法对OVA肽糖基化的工艺条件进行优化,并对改性前后OVA的功能特性和结构进行研究。结果表明,OVA肽糖基化的最佳工艺条件为pH 9、蛋白质量浓度8 g/100mL、OVA肽∶糖(质量比)为1∶1.5、反应时间4.5 h、反应温度65℃,在此条件下,糖基化接枝度为(35.67±0.74)%。协同改性后OVA的乳化活性指数较未改性OVA的提高了51.20 m^2/g,乳化稳定性提高了38.14%;起泡性和泡沫稳定性分别提高了121%,31.60%。SDS-PAGE结果表明,协同改性后OVA的分子质量由44.3 kDa变为45.0~97.2 kDa,傅里叶红外(FTIR)结果表明,协同改性后OVA的二级结构被破坏,葡聚糖连接到OVA肽上,部分红外吸收峰变强;扫描电镜(SEM)分析表明,协同改性后OVA的微观结构发生明显变化,由原来球状变成片状结构,排列更加紧密。

In order to improve the processing characteristics of egg albumin,effects of the synergistic modification of enzymatic hydrolysis and glycosylation on the structure properties of ovalbumin were studied.Glycosylation process of ovalbumin hydrolysates was optimized by using response surface methodology.The optimal process conditions were obtained as follows:pH 9;protein concentration 8 g/100mL;OVA peptides/saccharide ratio 1∶1.5;reaction time 4.5 h;reaction temperature 65℃.Under the above conditions,the maximum degree of grafting of(35.67±0.74)%was obtained.The results showed that the emulsifying activity index and the emulsion stability increased by 51.20 m 2/g and 38.14%,respectively.The foaming ability and the foam stability increased by 121%and 31.60%,respectively.The ovalbumin before and after the synergistic modification were characterized by SDS-PAGE,FT-IR,fluorescence spectroscopy.Results showed that,after synergistic modification,the molecular weight of ovalbumin was changed from 44.3 kDa to 45.0~97.2 kDa,FTIR result showed that secondary structure was damaged,Dextran was connected to the VOA,some wave length increased.Scanning electron microscopy(SEM)analysis showed that the microstructure of OVA modified by synergistic modification changed from spherical to lamellar structure,and was more compact.