基于FTIR技术的乳清分离蛋白聚集物的二级结构表征  

Characterization of Whey Protein Isolate Aggregates Secondary Structure Based on FTIR Technology

作　　者：单杰[1] 刘雯[1] 冯金凤[2] 冯志彪[1] 

机构地区：[1]东北农业大学理学院,哈尔滨150030 [2]东北农业大学食品学院,哈尔滨150030

出　　处：《食品工业》2014年第5期156-160,共5页The Food Industry

基　　金：黑龙江省教育厅面上项目(12531007);东北农业大学人才基金

摘　　要：采用傅立叶变换红外光谱(FTIR)对乳清分离蛋白聚集物(WPI)进行了二级结构表征。首先,通过对α-乳白蛋白和β-乳球蛋白的红外原始谱图进行二阶导数求导及去卷积处理,再通过曲线拟合等操作,对蛋白的酰胺Ⅰ带进行指认,并计算出2种蛋白的二级结构相对百分含量,建立二级结构红外光谱解析方法;通过低pH热诱导聚集和酶促聚集2种方法制备WPI聚集物,将已建立的红外解析方法应用于2种聚集物的二级结构解析,结果显示,同原料乳清分离蛋白相比,制备的纤维型聚集物中β-折叠结构含量上升至50.36%、酶促聚集物中β-折叠结构含量上升至53.64%。研究结果表明乳清分离蛋白聚集物的二级结构发生了明显变化,低pH热诱导聚集物和酶促聚集物中都伴随着明显的β-折叠含量的升高,聚集产生了有序的结构。Fourier transformation inflated spectroscopy （FHR） was used to describe the whey protein isolate （WPI） aggregates secondary structure. First, based on the original infrared spectra, the approaches of second derivative spectra, Fourier self deconvolution and curve fitting were combined to assign the amide I of a-lactalbumin and β-lactoglobulin, the relative contents of secondary structure were calculated. And the infrared characterization method was established. Then whe protein isolate aggregates were prepared by two methods, heat-induced aggregation at low pH and aggregates induced by protease. WPI aggregates were analyzed by established infiared method. Compare with whey protein isolate, the β-sheet of fibrillar aggregates and aggregates induced by protease increased to 50.36% and 53.64%. The results showed that significant changes in secondary structure occurred accompanied by a significant increase in β-sheet content, and an ordered structure was produced by aggregation.

关 键 词：傅立叶变换红外光谱(FTIR) 乳清分离蛋白 聚集物 二级结构 

分 类 号：O657.33[理学—分析化学] TS201.21[理学—化学]