Department of Food Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark.
Faculdade de Agronomia e Medicina Veterinária, Universidade de Brasília (UnB), Campus Darcy Ribeiro, 70910-970 Brasília, DF, Brazil.
Food Chem. 2019 Dec 1;300:125134. doi: 10.1016/j.foodchem.2019.125134. Epub 2019 Jul 6.
Water soluble caffeic acid derivatives in aqueous extracts of mate (Ilex paraguariensis) showed a direct dose-dependent response, protecting protein thiols in a chicken breast meat model system when oxidation was initiated by a lipophilic radical initiator (2,2'-azobis(2,4-dimethylvaleronitrile; AMVN). In contrast, an inverse dose-dependent response was obtained when initiated by a hydrophilic radical initiator (2,2'-azobis(2-amidinopropane)dihydrochloride; AAPH), pointing toward a mechanism, where a specific concentration of water-soluble polyphenol yields optimum protection. Optimal concentrations of mate extract for the protection of thiols against radicals initiated in the lipid phase (AMVN) or in the aqueous phase (AAPH) were 0.1-0.5% and 0.01-0.1%, respectively. Green tea (Camellia sinensis) extract showed a pro-oxidative effect involving quinones from oxidation of pyrogallol-type catechins (epigallocatechin-3-gallate (EGCG), gallocatechin-3-gallate (GCG), and epicatechin-3-gallate (ECG)) and not the catechol-type catechins (catechin and epicatechin).
在由脂溶性自由基引发剂（2,2'-偶氮双（2,4-二甲基戊腈）; AMVN）引发的鸡胸脯肉模型体系中，马黛茶（Ilex paraguariensis）水提取物中的水溶性咖啡酸衍生物表现出直接的剂量依赖性响应，可保护蛋白质巯基。相比之下，当由亲水性自由基引发剂（2,2'-偶氮双（2-脒基丙烷）二盐酸盐; AAPH）引发时，得到了相反的剂量依赖性响应，表明存在一种机制，其中特定浓度的水溶性多酚可产生最佳的保护作用。马黛茶提取物的最佳浓度分别为 0.1-0.5%和 0.01-0.1%，可保护巯基免受脂相（AMVN）或水相（AAPH）中自由基的引发。绿茶（Camellia sinensis）提取物表现出一种涉及焦儿茶酚型儿茶素（表没食子儿茶素-3-没食子酸酯（EGCG）、没食子儿茶素-3-没食子酸酯（GCG）和表儿茶素-3-没食子酸酯（ECG））氧化产生醌的促氧化作用，而不是邻苯二酚型儿茶素（儿茶素和表儿茶素）。
