不同凝固剂对大豆分离蛋白分子间作用力及蛋白质二级结构的影响  

Effects of Different Coagulants on Intermolecular Forces and Secondary Structure of Soybean Protein Isolate

作　　者：戴意强 刘小莉[1] 吴寒[1] 尹丽卿 周剑忠[1] 董明盛[2] 夏秀东 DAI Yiqiang;LIU Xiaoli;WU Han;YIN Liqing;ZHOU Jianzhong;DONG Mingsheng;XIA Xiudong(Institute of Agricultural Product Processing,Jiangsu Academy of Agricultural Sciences,Nanjing 210014,China;College of Food Science and Technology,Nanjing Agricultural University,Nanjing 210095,China)

机构地区：[1]江苏省农业科学院农产品加工研究所,江苏南京210014 [2]南京农业大学食品科学技术学院,江苏南京210095

出　　处：《食品工业科技》2021年第12期89-94,共6页Science and Technology of Food Industry

基　　金：江苏省科技计划项目(BE2019355);国家自然科学基金项目(31501460)。

摘　　要：为探究盐类凝固剂和酸类凝固剂在诱导大豆蛋白凝固过程中对分子间作用力和蛋白质二级结构的影响,本文以大豆分离蛋白(SPI)为研究对象,分析了不同凝固剂对大豆蛋白凝固过程中pH、表面疏水作用力、游离巯基(SH)、Zeta电位、α-螺旋、β-折叠、β-转角和无规卷曲的变化规律。结果表明:盐类凝固剂和酸类凝固剂均能降低SPI溶液的pH,其终点pH分别为6.08~6.14和5.25~5.58。与仅热处理的SPI溶液相比,加入凝固剂会导致SPI溶液中蛋白质表面疏水作用力和游离SH含量的增加,Zeta电位降低。在加入凝固剂后的0~45 min内,SPI的表面疏水作用力呈现先增加后降低的趋势,游离SH含量逐渐降低;酸浆处理的SPI溶液Zeta电位显著高于其他凝固剂(P<0.05),为9.19~9.90 mV。此外,盐类凝固剂会导致SPI的α-螺旋和β-转角转变为β-折叠,酸类凝固剂则会破坏SPI中β-折叠。特别地,添加酸浆的SPI的α-螺旋比例介于乳酸和盐类凝固剂之间,而β-转角比例介于乳酸和醋酸之间。To study the changes of intermolecular forces and secondary structure of soy protein induced by MgCl2,CaSO4,lactic acid,acetic acid,GDL and fermented soy whey,the effects of different coagulants on the pH value,surface hydrophobicity,free sulfhydryl group(SH),Zeta potential,α-helix,β-sheet,β-turn and random coil during SPI tofu processing were analyzed,while the SPI was used as the research object.Both salt coagulants and acid coagulants could reduce the pH values of SPI solution,and the final pH value was 6.08~6.14 and 5.25~5.58,respectively.Compared with heated SPI solution without coagulant,the addition of coagulants caused increases in the surface hydrophobicity and free SH content,and a decrease in Zeta potential in SPI solution.The surface hydrophobicity of SPI induced by coagulants increased first and then decreased,and free SH content decreased at 0~45 min.The Zeta potential of SPI solution added with fermented soy whey was significantly higher than that of other coagulants(P<0.05),ranging from 9.19 mV to 9.90 mV.In addition,salt coagulants induced a shift ofα-helix andβ-turn intoβ-sheet of soy proteins,and acid coagulants destroyedβ-sheet of SPI.In particular,the SPI added with fermented soy whey hadα-helix ratio between lactic acid and salt coagulants,andβ-turn ratio between lactic acid and acetic acid.

关 键 词：大豆分离蛋白 凝固剂 分子间作用力 蛋白质二级结构 

分 类 号：TS214.2[轻工技术与工程—粮食、油脂及植物蛋白工程]