不同热处理对脱脂驼乳乳蛋白结构和理化性质的影响  

Effects of Different Heat Treatments on the Structure and Physicochemical Properties of Proteins from Skimmed Camel’s Milk

作　　者：王涛 王丹琳 何静[1] 吉日木图[1,2] WANG Tao;WANG Danlin;HE Jing;JI Rimutu(College of Food Science and Engineering,Inner Mongolia Agricultural University,Hohhot 010018,China;China-Mongolia Joint Laboratory of Biopolymer Application“the Belt and Road Initiatives”,Hohhot 010000,China)

机构地区：[1]内蒙古农业大学食品科学与工程学院,内蒙古呼和浩特010018 [2]中国-蒙古生物高分子应用“一带一路”联合实验室,内蒙古呼和浩特010000

出　　处：《食品科学》2024年第24期195-201,共7页Food Science

基　　金：食品科学与工程学院“一流学科”建设基金项目(SPKJ202202)。

摘　　要：本研究探讨4种不同热处理(65 ℃/30 min(T1)、85 ℃/15 s(T2)、120℃/15 s(T3)、135 ℃/5 s(T4))脱脂驼乳蛋白的理化性质和结构变化,对驼乳蛋白粒径、Zeta电位、浊度、二级结构、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE)图谱、三级结构、表面疏水性、游离巯基和二硫键含量等指标进行分析。结果表明,随着温度升高,驼乳蛋白粒径变大,Zeta电位绝对值变小,浊度升高。热处理对二级结构和三级结构有显著影响,使驼乳蛋白的α-螺旋和β-转角相对含量减少,β-折叠和无规卷曲相对含量增多。与未加热驼乳蛋白相比,T3热处理对驼乳蛋白的粒径、Zeta电位、二级结构和三级结构影响最大。SDS-PAGE图谱显示随着加热温度升高,脱脂乳可溶性乳清蛋白条带越来越浅。激光扫描共聚焦显微镜的观察结果显示,热处理使蛋白发生了一定程度的聚集,T3和T4热处理使驼乳蛋白产生了较大的聚合物。T1和T2热处理条件下的驼乳蛋白主要通过二硫键形成聚合物,但是随着加热温度升高,T3和T4热处理条件下驼乳蛋白的二硫键断裂,形成游离巯基,驼乳蛋白内部的疏水基团暴露出来。综上,不同热处理使驼乳蛋白的结构和理化性质发生不同程度变化,这些变化对驼乳稳定性产生影响。本研究结果可为生产液态驼乳的工艺参数和产品开发提供理论参考依据。In this study,we investigated the changes of physicochemical properties and structure of defatted camel’s milk proteins with four different heat treatments(65℃/30 min(T1),85℃/15 s(T2),120℃/15 s(T3),and 135℃/5 s(T4))by measuring particle size,potential,turbidity,secondary structure,sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)pattern,tertiary structure,surface hydrophobicity,free sulfhydryl group and disulfide bond content.The results showed that the particle size of camel’s milk proteins increased,the absolute value of the zeta potential decreased,and the turbidity increased with increasing temperature.Heat treatment had a significant effect on the secondary and tertiary structures,resulting in a decrease in the relative contents ofα-helix andβ-turn and an increase in the relative contents ofβ-fold and random coil in camel’s milk proteins.T3 had the greatest effect on the particle size,zeta potential,secondary structure and tertiary structure compared with the unheated control.SDS-PAGE profiles showed that the intensities of the soluble whey protein bands gradually decreased as the heating temperature increased.Observations by laser scanning confocal microscopy(LSCM)showed that the heat treatment caused protein aggregation,and T3 and T4 resulted in the production of large protein polymers. Under the T1 and T2 conditions, protein polymers were formed mainly through disulfide bonding.However, with the increase in heating temperature, the disulfide bonds of camel’s milk proteins were broken under theT3 and T4 conditions, resulting in the formation of free sulfhydryl groups and the exposure of the hydrophobic groups ofcamel’s milk proteins. The above results indicated that the structural and physicochemical properties of camel’s milk proteinscan be changed to different degrees by different heat treatments, which in turn can affect the stability of camel milk. Theresults of this study provide a theoretical reference for the development of liquid camel’s milk products.

关 键 词：热处理 驼乳蛋白 理化性质 蛋白质结构 

分 类 号：TS252.1[轻工技术与工程—农产品加工及贮藏工程]