Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
Food Chem. 2014 May 1;150:341-7. doi: 10.1016/j.foodchem.2013.09.127. Epub 2013 Oct 3.
The covalent complexation between (-)-epigallocatechin gallate (EGCG) and α-lactalbumin (α-La), and the effect of EGCG on the antioxidative activity and emulsifying properties of α-La were investigated. The turbidity of a solution of 1% α-La and 0.2% EGCG decreased after 24h reaction at pH 8.0 and 60°C, less than the value of α-La alone. The interaction between α-La and EGCG at pH 8.0 was more pronounced than that at pH 6.0 or 7.0, as evidenced by the reduced amplitude of amide A, and I, and II bands of α-La by FT-IR and the increase in the total phenolic content and denaturation temperature. These results implied that EGCG was covalently linked to α-La at pH 8.0. In addition, compared with the control of α-La, α-La-EGCG complexes had significantly increased antioxidative activity. The emulsions stabilized by α-La-EGCG complexes, compared with that by α-La alone, had much smaller droplet sizes, which indicated the emulsifying property of α-La was improved.
研究了（-）-表没食子儿茶素没食子酸酯（EGCG）与α-乳白蛋白（α-La）之间的共价复合物形成，以及 EGCG 对α-La 的抗氧化活性和乳化性能的影响。在 pH 值为 8.0 和 60°C 下反应 24 小时后，1%α-La 和 0.2%EGCG 溶液的浊度降低，低于单独的α-La 值。在 pH 值为 8.0 时，α-La 和 EGCG 之间的相互作用比在 pH 值为 6.0 或 7.0 时更为明显，这可以通过 FT-IR 中α-La 的酰胺 A、I 和 II 带的幅度减小以及总酚含量和变性温度的增加来证明。这些结果表明，EGCG 在 pH 值为 8.0 时与α-La 发生了共价结合。此外，与α-La 的对照相比，α-La-EGCG 复合物具有显著提高的抗氧化活性。与单独的α-La 相比，由α-La-EGCG 复合物稳定的乳液具有更小的液滴尺寸，这表明α-La 的乳化性能得到了改善。
