Effect of Tumbling and Roasting on Antioxidant Capacity of Oolong Tea
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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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