热加工处理对奶茶体系中茶多酚生物可及性的影响

Effects of thermal processing on the bio-accessibility of tea polyphenols in tea milk

实验采用体外模拟胃肠消化方法,结合高效液相色谱检测,探究热处理加工条件(80℃/20 min、100℃/5 min)和加热方式(蛋白与茶多酚混合加热、蛋白单独加热)对奶茶模拟体系中表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)、表没食子儿茶素(epigallocatechin,EGC)、表儿茶素没食子酸酯(epicatechin gallate,ECG)及表儿茶素(epicatechin,EC)生物可及性的影响。结果表明,消化前加入乳清蛋白会降低游离茶多酚的含量,其中EC降低12.76%最明显;乳清蛋白的单独加热处理更能降低游离茶多酚的含量,其中蛋白在100℃加热下游离茶多酚含量最少;80℃热处理体系消化前游离多酚含量均大于100℃热处理体系。热加工处理对奶茶体系中茶多酚的生物可及性存在不同程度的影响——除80℃蛋白单独加热外,其余热处理均降低EGCG的生物可及性,降低11.11%~18.38%;100℃蛋白混合加热有利于提高EGC的生物可及性,提高9.05%,且除80℃混合加热外,其余热处理方式可显著降低其生物可及性,降低24.86%~40.14%;100℃热处理方式可显著提高ECG的生物可及性,提高22.72%~28.05%;80℃加热条件可提高EC约7.24%的生物可及性,而100℃热处理方式可降低EC约47.14%的生物可及性。相同热处理下,添加乳清蛋白可提高儿茶素的生物可及性(除EGC 80℃蛋白单独加热组外)。

To explore two heat processing conditions （80 ℃/20 min, 100 ℃/5 min） and two heating methods （heating the mixture, protein alone heating） on the bioavailability of （ - ）-epigallocatechin gallate（EGCG）, （ - ）- epigallocatechin （EGC）, （ - ）-epicatechin gallate（ECG） and （ - ）-epicatechin（EC） in vitro gastrointestinal digestion by HPLC detection method. Results indicated that before digestion, the whey protein can reduce the content of free polyphenols, where the most significant decline was EC by 12.76% ; heat-treated whey protein carl reduce free tea polyphenols content, and at 100 ℃ the free polyphenol content was the lowest. The free polyphenol content before digestion in 80℃ heat treatment system was greater than that in 100℃ heat treatment system. Thermal processing treatments after in vitro gastrointestinal digestion had different effects on the bioavailability of polyphenols in tea milk. Except for 80 ℃ protein heating, the remaining heat treatments reduced the bioavailability of EGCG by 11. 11% - 18.38%. Mixed heating at 100 ℃ and 80 ℃ could improve the bioavailability of EGC by 9.05% , the remaining heat treatments significantly reduced bioavailability of EGC by 24.86% -40.14%. Mixed heating 100℃ significantly increased the bioavailability of ECG by 22.72% - 28.05%. Heating at 80℃ increased the bioavailability of EC by 7.24% , while heat treatment at 100℃ could decrease by 47. 14%. Under the same heat treatment, adding whey protein could increase the bioavailability of catechins （except for the 80℃ protein alone heating group of EGC）.