霉变与辐照对大豆蛋白质理化性质与结构影响.pdf

现代食品科技 Modern Food Science and Technology 2015, Vol.31, No.7 霉变和辐照对大豆蛋白质理化性质和结构的影响 张振山，李晨阳，刘玉兰 （河南工业大学粮油食品学院，河南郑州 450001 ） 60 摘要：以新鲜大豆为原料制备了不同霉变程度的大豆，利用 Co-γ 射线对大豆进行了辐照处理，采用胃蛋白酶体外消化率、氨 基酸组分测定、SDS电泳和傅里叶红外变换光谱（FT-IR ）研究了霉变和辐照对大豆中蛋白质体外消化率以及蛋白质组成和结 构的影响。研究表明：大豆培养30 d 后，霉变导致大豆胃蛋白酶消化率降低23.74% ，氨基酸总量减少2.07%，大豆蛋白质二级结构 中的β-转角和无规卷曲分别增加了2.67%和4.17% ，而α-螺旋和β-折叠相应减少3.62%和3.21%。在所考察的剂量范围内（10~30 kGy ）， 辐照对新鲜大豆的胃蛋白酶体外消化率、氨基酸组成、蛋白质亚基组成没有显著影响 （P0.05 ），但对蛋白质二级结构中的α-螺旋与 β-折叠具有显著影响（P0.05 ）。霉变大豆经过γ 射线辐照处理后，氨基酸总量降低，蛋白质二级结构中的α-螺旋与β-折叠减少，无 规则卷曲增加。 关键词：大豆；霉变；辐照；蛋白质；结构 文章篇号：1673-9078(2015)7-191-196 DOI: 10.13982/j.mfst.1673-9078.2015.7.030 Effect of Mildew and γ-Irradiation on the Physicochemical Property and Structure of Soybean Proteins ZHANG Zhen-shan, LI Chen-yang, LIU Yu-lan (College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China) Abstract: Soybeans with different levels of mildew were prepared from fresh soybeans and then irradiated using cobalt-6060Co-γ rays. The effects of mildew and γ-irradiation on the in vitro digestibility, composition, and protein structure were investigated in terms of in vitro pepsin digestibility, amino acid composition, and results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS) as well as Fourier transform infrared spectroscopy (FT-IR). The results indicated that mildew on soybeans reduced pepsin digestibility and total amino acid content by 23.74% and 2.07%, respectively, after 30 d culture. Moreover, the amount of β-turns and random coils increased by 2.67% and 4.14%, respectively, while the amount of α-helices and β-sheets decreased by 3.62%