摘要
以燕麦蛋白为原料,采用木瓜蛋白酶进行限制性酶解,以制备不同水解度的酶解产物(水解度2%~7%)并深入研究其结构特性与抗氧化功能。结果表明:木瓜蛋白酶水解燕麦蛋白有助于低分子质量肽段的增加,蛋白结构发生改变,并在紫外吸收光谱和荧光光谱中得到证实;酶解后的燕麦蛋白的二级结构发生显著变化,主要表现为α-螺旋结构降低,而无规卷曲和β-转角结构增加,预示着酶解产物的抗氧化潜能;木瓜蛋白酶水解显著提高燕麦蛋白的1,1-二苯基-2-三硝基苯肼自由基清除率和金属离子螯合能力,尤其是在水解度为4%时,IC50分别为36.83μg/mL和33.42μg/mL;水解度为4%时所得的燕麦蛋白肽不仅可以延长葵花籽油的氧化诱导时间,还能提高水包葵花籽油乳液的氧化稳定性。因此,木瓜蛋白酶限制性酶解可改善燕麦蛋白的抗氧化功能,这与其结构特性的改变密切相关。
Oat protein isolate hydrolysates with different degrees of hydrolysis(DH,2%–7%)were prepared by limited enzymatic hydrolysis with papain,and their structural and antioxidant properties were investigated.Our results showed that papain hydrolysis could favor the formation of low-molecular-mass peptides,demonstrating changes in protein structure.This was further confirmed by the results of ultraviolet absorption and fluorescence spectroscopy.Also,the enzymatic hydrolysis could change the secondary structure of oat protein,as demonstrated by a decline inα-helical structure and an increase in random coil andβ-turn structures.This implied that the enzymatic hydrolysis might be beneficial to the antioxidant potential of oat protein hydrolysates.Interestingly,papain hydrolysis(particularly at DH of 4%)led to an increase in 1,1-dipheny1-2-picrylhydrazyl(DPPH)radical scavenging activity and metal ion chelating activity of oat protein hydrolysates,demonstrating half-maximum inhibitory concentration(IC50)of 36.83μg/mL and 33.42μg/mL,respectively.More intriguingly,the hydrolysate at 4%DH could not only prolong the induction period of sunflower oil,but also improve the oxidative stability of sunflower oil-in-water emulsion.Therefore,limited hydrolysis with papain could result in the improved antioxidant activities of oat protein,which was closely associated with the changes in protein structure.
作者
郑召君
王曼
李嘉欣
李进伟
刘元法
ZHENG Zhaojun;WANG Man;LI Jiaxin;LI Jinwei;LIU Yuanfa(School of Food Science and Technology,Jiangnan University,Wuxi 214122,China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2020年第20期76-82,共7页
Food Science
基金
国家自然科学基金青年科学基金项目(31901730)
江苏省自然科学基金青年项目(BK20190587)
中国博士后科学基金面上资助项目(2018M632235)。
关键词
燕麦蛋白
木瓜蛋白酶
结构特性
抗氧化
限制性水解
oat protein isolate
papain
structural properties
antioxidant activity
limited hydrolysis