乳蛋白对甜菜红苷热稳定性的影响  

Effect of Milk Proteins on the Thermal Stability of Betanin

作　　者：芦霞 胡飞[1] Lu Xia;Hu Fei(School of Food Science and Engineering,South China University of Technology,Guangzhou 510640)

机构地区：[1]华南理工大学食品科学与工程学院,广州510640

出　　处：《中国食品学报》2022年第12期94-103,共10页Journal of Chinese Institute Of Food Science and Technology

摘　　要：以甜菜红苷(Bt)为对象,采用-荧光光谱、傅里叶变换红外光谱以及圆二色谱技术分析乳清蛋白(WP)和牛血清白蛋白(BSA)与Bt作用生成的复合物中乳蛋白组分对Bt热稳定性的影响。结果表明:添加WP和BSA能有效抑制甜菜红苷的热降解作用,其中WP对甜菜红苷的保护作用优于BSA。同时,体系环境的pH值变化也明显影响甜菜红苷的热降解,在p H 5.0时甜菜红苷复合物的半衰期最长,其中Bt-WP复合物的半衰期达2.99 h。荧光光谱、傅里叶变换红外光谱以及圆二色谱分析表明,复合物中Bt组分的作用导致WP和BSA发生静态荧光猝灭,WP和BSA色氨酸残基和酪氨酸残基所处微环境的疏水性减弱,极性变强。此外,添加Bt使两种蛋白质的构象结构发生改变,酰胺Ⅰ带和酰胺Ⅱ带的特征峰位置改变,二级结构中各类构象组成发生不同程度的变化。The effects of whey protein(WP) and bovine serum albumin(BSA) on the thermal stability of betanin(Bt)at different temperatures were investigated. Fluorescence spectroscopy, circular dichroism, and Fourier transform infrared spectroscopy were used to study the interaction between WP/BSA and Bt. The results showed that WP and BSA inhibited the degradation of Bt content and the protection provided with WP was better than with BSA. Additionally, the change of p H also affected the thermal degradation of Bt. The half-life(t1/2) of the compound was the longest at p H 5.0, and the t1/2of Bt-WP was up to 2.99 h. The fluorescence analysis showed that Bt led to a static quenching of WP/BSA. Further,the interaction was a spontaneous process with electrostatic interactions being the main force. Synchronous fluorescence spectra presented alterations in microenvironment of Trp and Tyr residues of WP/BSA, respectively, upon interaction with Bt. Circular dichroism and Fourier transform infrared spectroscopy analysis indicated that characteristic peak positions of amide Ⅰ, Ⅱ band and the secondary structures of WP/BSA was changed upon conjugation with Bt.

关 键 词：甜菜红苷 复合物 热稳定性 光谱分析 作用机制 

分 类 号：TS264.4[轻工技术与工程—发酵工程]