Impact of Water Loss at Withering on Quality of Green Tea, Ruixiang

One bud and two leaves from Camellia Sinensis cv.Ruixiang, a highly aromatic cultivars suitable for processing, were used to make green tea for this study. The impact of water loss at withering on the quality of green tea was examined. Both solar and indoor natural withering methods were applied to induce the water loss. The results showed that (a) the water extract of the resulting teas decreased slowly with severity of the withering; (b) tea polyphenols changed consistently in a w-shape fashion for both withering methods; (c) the content of polyphenols was lowest in the non-withered green tea, and highest in the tea with a 5% water loss; (d) within a certain range, the more severe the withering the more caffeine and amino acids were formed a significant, positive correlation existed; (d) the ratios of polyphenols to amino acids decreased as the water loss increased; (f) the water loss had a similar impact on tea's sensory quality, i.e., increasing followed by a decline; and (g) the sensory evaluation score was the highest at 15% to 20% water loss by the natural withering, while at 25% water loss by the solar withering. Overall, the natural withering affected more significantly than the solar withering on biochemical composition and sensory quality of the green tea. Therefore, it appeared to be more desirable to wither the tea by using the natural means.