Vc与Cu^(2+)的耦合氧化对桑葚花色苷的降解作用

Thermal degradation of mulberry anthocyanins through the coupled oxidation of Vc and Cu^(2+)

研究通过构建含Vc和Cu2+的桑葚汁模拟体系,研究这两个内源因子对花色苷的降解作用。研究表明Vc能显著促进花色苷的降解,而在果汁所含Cu2+浓度下,Cu2+对花色苷具有一定的保护作用,但当在体系中与Vc共存时,则能大大促进花色苷的降解。因此,可以得出一个花色苷被Vc和Cu2+耦合氧化的降解机制:低浓度时,Cu2+自身不催化花色苷的降解,但当有Vc存在时,它能先通过促进Vc的氧化降解,使Vc转化为对花色苷降解有显著促进作用的氢过氧化物,从而加速花色苷的降解。

In this study, we investigated the effects of Vc and Cu2＋ on the thermal degradation of mulberry anthocyanins in different model systems. The results showed that Vc can significantly promote the degradation of anthocyanins. Cu2＋ may play a protective role on anthocyanins in the concentration of the mulberry juice. However, anthocyanins degraded fast in the presence of both Vc and Cu2＋. Therefore, the results obtained allowed us to propose a coupled oxidation pathway for the degradation of anthocyanins： Cu2＋ could not promote the degradation of anthocyanins in the low concentrations, however, Cu2＋ could accelerated Vc oxidized to form hydrogen peroxide, which had a promoting effect on the degradation of anthocyanins. Thus, Cu2＋ could accelerated the degradation of anthocyanins in the mulberry juice through the coupled oxidation with Vc.