钙离子对酪蛋白胶束结构影响的光谱学研究(英文)

Spectroscopic Investigation of the Influence of Calcium Ion on the Structures of Casein Micelles

综合运用动态光散射光谱、荧光光谱和高效液相-紫外光谱法检测钙离子对酪蛋白胶束结构的影响。外源添加的钙离子的浓度从0增加至12mmol·L-1的过程中,酪蛋白胶束的外源ANS荧光强度和浊度一直增大,但是其体积平均直径和胶束的多分散指数是一直下降。同时,当外源添加的钙螯合剂(柠檬酸根)离子的浓度从0增加至12mmol·L-1的过程中,酪蛋白胶束的外源ANS荧光强度和浊度一直减小,但是酪蛋白胶束的体积平均直径、胶束的多分散指数和胶束的稳定性是增大的。因此,在对酪蛋白胶束的结构影响方面,钙离子和柠檬酸根离起到了相反的作用。研究证实,外源钙离子可以有效地调节酪蛋白胶束的结构,进而改善其功能特性。

The effects of calcium ion on the structural properties of casein micelles in the course of heat treat- ment were synthetically examined by non-structure-invasive spectrometry. The hydrophobicity, reflected by extrinsic fluorescence （ANS fluorescence）, was positively correlated with the concentration of the calcium ion, within the range of 0 to 12 mmol . L-1. Meanwhile, the turbidity and stability of casein micelles also increased with the growth of calcium concentrations. However, opposite results were observed for hydrodynamic diame- ter and polydispersity index. Compared with the calcium ion, the calcium-chelator （citrate） has an opposite effect on the structural characteristics of casein micelles. Within the calcium concentrations range of 0 to 12 mmol ~ L-1 , the hydrophobicity, stability and turbidity were negatively correlated with the concentration of the calcium ion, nevertheless, opposite results were observed for hydrodynamic diameter and polydispersity in- dex. All the results indicate that the calcium ion could be used to modify the structures of casein micelles dur- ing heat heatment.