不同温度处理对红芸豆蛋白热稳定性及结构的影响  

Effects of different temperature treatments on thermal stability and structure of red kidney bean protein

作　　者：陈振家[1] 王晓闻[1] 荆旭 梁亚萍[2] Chen Zhenjia;Wang Xiaowen;Jing Xu;Liang Yaping(College of Food Science and Engineering,Shanxi Agricultural University,Taigu 030801,China;University Hospital,Shanxi Agricultural University,Taigu 030801,China)

机构地区：[1]山西农业大学食品科学与工程学院,太谷030801 [2]山西农业大学校医院,太谷030801

出　　处：《农业工程学报》2020年第19期306-312,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：山西省重点研发计划项目(201903D11006);山西农业大学博士科研启动项目(2016ZZ06)。

摘　　要：为探究加热过程中红芸豆分离蛋白(Red Kidney Bean Protein Isolate,KPI)溶解特性和结构特性变化及评估不同温度(50~95℃)处理对KPI溶液热聚集特性的影响,该研究以不同温度处理KPI溶液为研究对象,采用热力学和光谱学对其热聚集特性进行分析。结果表明:随处理温度升高,红芸豆蛋白溶解度呈先升后降趋势,70℃时蛋白溶解度达到最高值82.68%,温度升高至95℃时,溶解度下降至65.63%;电泳结果显示,90℃处理蛋白上清液电泳图谱中出现一条分子量约为135 kDa的新条带。随温度升高,总巯基数量则呈下降趋势,游离巯基呈先升后降趋势。随温度上升,加热造成蛋白α-螺旋结构占比呈下降趋势,不规则结构占比呈上升趋势,β-折叠和β-转角变化幅度不大,而KPI内源荧光的最大发射波长呈红移趋势。研究结果为红芸豆食品热加工工艺优化和质量控制提供了理论基础。Heat is the most common physical agent that denatures proteins.Heat-induced denaturation unfolds protein structure,exposes surface hydrophobic groups and dissociates proteins into their constituent subunits.Denaturation decreases protein solubility,resulting in aggregation of the unfold molecules due to changes in functional properties,such as water absorption,gelation,foaming,and emulsification.An in-depth study was carried out to investigate the physicochemical properties and aggregation characteristics of red kidney bean protein isolate(KPI)during heating and to determine the influence of different temperatures on the thermal aggregation behavior of KPI.The protein solubility,turbidity,content of total and free sulfhydryl groups,subunit composition,and protein secondary structure of native KPI aqueous dispersions(2%g/mL)thermally treated at different temperatures(50,60,70,80,90 and 95℃)were analyzed by different detection methods and techniques.High temperature caused the dissociation and association of protein subunits leading to the formation of soluble and insoluble aggregates,which reduced the solubility of the protein to some extent and increased the turbidity of the protein solution.Results of protein concentration showed that the solubility of red kidney bean protein increased initially and then decreased with the increase of temperature.The solubility of KPI increased by more than 82%at 70℃,but decreased to 65.63%at 95℃(near denaturation temperature 93.4℃).The turbidity of the protein solution of red kidney bean increased with temperature.Results of SDS-PAGE gel electrophoresis revealed that proteins of red kidney bean tended to form macromolecule aggregates at high temperature.The protein profiles obtained from SDS-PAGE analysis performed in the absence and presence of β-mercaptoethanol were not significantly different when thermal treatment was carried out at a temperature below 90℃.A new band with a molecular weight of approximately 135 kDa appeared in the electrophoretic pattern at 90℃

关 键 词：热处理 热稳定性 溶解度 红芸豆蛋白 二硫键 二级结构 内源荧光发射光谱 

分 类 号：TS201.7[轻工技术与工程—食品科学]