不同做青与烘焙工艺对乌龙茶抗氧化能力的影响
Effect of Tumbling and Roasting on Antioxidant Capacity of Oolong Tea
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摘要: 做青和烘焙是乌龙茶加工的关键工序，与乌龙茶茶多酚的氧化程度密切相关。本研究分别采用轻做青短烘、重做青短烘、轻做青长烘、重做青长烘的不同加工方式制作成乌龙茶。实验结果表明：在相同的烘焙时间下，轻做青乌龙茶羟自由基清除能力强于重做乌龙茶，总抗氧化能力也是轻做青乌龙茶强于重做青乌龙茶；在相同的做青程度下，短时间烘焙乌龙茶羟自由基清除能力及总抗氧化能力均强于长时间烘焙乌龙茶；做青程度与烘焙时间长短对乌龙茶清除DPPH自由基能力的影响并不大，起决定性的因素是鲜叶原料的茶多酚含量，鲜叶茶多酚含量越高，其DPPH自由基清除能力越强。Abstract: Tumbling and roasting are essential operations in oolong tea manufacturing. They are both closely related to the degree of tea processed with thelight tumbling showed a higher hydroxyl free radical scavenging activity and a greater total antioxidant capacity than those with the heavy tumbling; (B) with a same tumbling treatment, the tea produced under the short roasting had a scavenging activity and a total antioxidant capacity higher than that made under the prolonged roasting; (C) neither tumbling nor roasting time exerted significant effect on DPPH free radical scavenging activity on the tea; and, (D) the determining factor on the scavenging activity of DPPH was the polyphenols content in the fresh tea leaves – the more polyphenols in the leaves would result in higher DPPH scavenging capability of the processed oolong tea. polyphenol oxidation in the tea produced. Light tumbling with short or prolonged roasting, and heavy tumbling with short or prolonged roasting were applied in the experimentation to study their effects on the antioxidant activity of the teas obtained. The results showed that (A) under a same roasting time, the
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