利用碱对玉米醇溶蛋白进行脱酰胺作用,研究脱酰胺后玉米醇溶蛋白的乳化特性和结构的变化,旨在探究两者之间的关系。结果表明:在试验条件下,玉米醇溶蛋白在碱-水介质环境中更容易发生脱酰胺反应。脱酰胺度(deamidation degree,DD)较高(DD=34.70%)的玉米醇溶蛋白的乳化活性和乳化稳性比低脱酰胺度(DD=0.89%)的乳化活性和乳化稳定性分别提高了244.86%和1055.85%。内源性荧光光谱扫描和紫外光谱扫描结果表明脱酰胺改变了玉米醇溶蛋白的构象,提高了分子柔性。表面疏水性荧光光谱的结果表明脱酰胺降低了表明疏水性。乳化特性的改善归功于脱酰胺降低了玉米醇溶蛋白的表面疏水性和提高了分子柔性。此研究可为开发玉米醇溶蛋白天然乳化剂提供理论参考。
In order to explore the relationship between emulsifying properties and structure changes, alkaline deamidation was chosen to modify zein. The results suggested that zein was more prone to deamidation in the alkali-water medium than various concentrations of ethanol aqueous solutions. The emulsifying activity and emulsion stability of zein with high deamidation degree (DD) (34.70%) were higher than those with low deamidation degree (0.89%) by 244.86% and 1 055.85%, respectively. The results of typical intrinsic emission fluorescence spectra and UV spectra indicated that the deamidation changed the conformation of zein, and the molecular flexibility was significantly correlated with conformation. The results of surface hydrophobic fluorescence spectrum showed that the deamidation reduced the surface hydrophobicity. The improvement of emulsifying properties could be attributed to the decrease of surface hydrophobicity and the increase of molecular flexibility of zein by deamidation treatment. It is hoped that this study could provide theoretical references for developing natural emulsifiers from zein.
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