Combined effect of pH and temperature on the stability and antioxidant capacity of epigallocatechin gallate (EGCG) in aqueous system

文献类型: 外文期刊

第一作者: Xu, Yong-Quan

作者: Xu, Yong-Quan;Xu, Yong-Quan;Yu, Peigen;Zhou, Weibiao;Zhou, Weibiao

作者机构:

关键词: EGCG; Thermal degradation; Epimerization; Kinetic modelling; Antioxidant capacity

期刊名称:JOURNAL OF FOOD ENGINEERING ( 影响因子:5.354; 五年影响因子:5.144 )

ISSN: 0260-8774

年卷期: 2019 年 250 卷

页码:

收录情况: SCI

摘要: The stability of ( - )-epigallocatechin gallate (EGCG) in an aqueous system with a pH range of 2.2-8.0 was investigated at temperatures ranging from 25 to 165 degrees C. Within these ranges, the stability of EGCG decreased with increasing pH and temperature. The lowest (1.06 x 10(-7)s(-1)) and highest (8.83 x 10(-2)s(-1)) degradation rate constants were obtained at pH 3 and 25 degrees C, and pH 8 and 135 degrees C, respectively. Epimerization rate constants between EGCG and ( - )-gallocatechin gallate (GCG) both increased with increasing temperature and pH. However, the rate of epimerization from EGCG to GCG was found to always be higher than that of GCG to EGCG. To further evaluate the effects of pH and temperature on catechins, antioxidant capacity analysis was conducted on thermally processed EGCG solutions using DPPH and ABTS assays. Changes in the total antioxidant capacity of samples after thermal treatments under various pH values were found to be insignificant.

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