桑叶金花茶中酚类物质动态变化及其抗氧化活性

 为探讨桑叶固体双向发酵过程中水溶性酚类物质含量的动态变化及其抗氧化活性,应用三氯化铝比色法、Folin-酚法测定桑叶固体双向发酵物中水溶性总黄酮及总酚酸含量,并以清除1-1-二苯基-2-三硝基苯肼(DPPH)、2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS⁺)、铁还原能力3 个指标,评价桑叶固体双向发酵过程中体外抗氧化活性的变化情况。结果发现,随着发酵时间的延长,桑叶固体双向发酵物中水溶性总黄酮、总酚酸均呈先增加后减少的趋势。其中发酵14 d 水溶性黄酮质量分数最多为2.16 mg/g,20 d 水溶性总酚酸质量分数最多为1.48 mg/g。对于体外3 个抗氧化指标而言,整体表现为:14 d>7 d>11 d>20 d>40 d 。

Dynamic change and antioxidant activity of phenolics in the mulberry leaf and Jinhua tea

This paper aims to investigate the dynamic change and antioxidant activity of water soluble phenolic substances in mulberry leaves and Eurotium cristatum solid bi-directional fermentation process. The contents of the water soluble total flavonoids and total phenolics were measured by using AlCl₃ method and Folin-Ciocalteu method. At the same time, the antioxidant activity changes of the solid bi-directional fermentation process were evaluated by three in vitro experiments including DPPH assay, ABTS⁺ assay and ferric-reducing power assay. The results showed that during the fermentation process, the water soluble total flavonoids and total phenolics decreased after the initial increase. The water soluble flavonoid content after 14 days' fermentation was the highest, being 2.16 mg/g, and the water soluble phenolics content after 20 days' fermentation was the highest, being 1.48 mg/g. The antioxidant activity displayed an order of 14 d>7 d>11 d>20 d>40 d.