为提高天然红曲色素的光稳定性，利用具有严格底物专一性的谷氨酰内肽酶对大豆球蛋白（11S）进行轻度水解,分析了11S酶解后表面疏水性的变化，并将水解产物与红曲色素形成蛋白/色素复合体，对两者之间的结合特性（结合常数、结合量）和复合体的光稳定性进行了研究。研究发现，谷氨酰内肽酶对11S的表面性质及红曲色素稳定性均具有显著影响。经谷氨酰内肽酶修饰后，由于内部疏水基团的暴露，11S的表面疏水性随水解度的增加而增加，与红曲色素的结合位点也随之变多。在中性条件下，水解度为1.50%、质量分数为3%的11S与红曲色素的结合常数达到最大值，最大结合量为215.00 U/g pro。复合体经24 h光照后，红曲色素的色价保留率达90%，大大提高了红曲色素的光稳定性。

To enhance photostability of Monascus pigment, glycinin was modified via glutamyl endopeptidase (GE), which had strict substrate specificity. The surface hydrophobicity of the 11S globulin after hydrolysis was analyzed, and protein/pigment complex was produced after enzymatic modification of the 11S. The binding properties (binding constant and binding capacity) and the light stability of protein/pigment complex were investigated. The results showed that GE had a significant effect on 11S surface character and Monascus pigment photostability. Surface hydrophobicity of 11S increases with the degree of hydrolysis (DH) increased after GE modifying as the inner hydrophobic groups exposed. At pH 7.0, the binding constants of Monascus pigment and 3% (m/V) 11 S reached the maximum of 215.00 U/g pro when the DH was 1.50%. After 24 h light exposure, the protein/pigment complex had the color value retention rate of 90% which highly improved the light stability of Monascus pigment

国家自然科学基金重点项目（31130042）；国家科技支撑计划项目（2012BAD34B04）