Differential Chemical Constituents in Liangye Roasted Green Teas Made of Different Cultivars

Objective Biochemical constituents of varieties of the famed Liangye Roasted Green Tea from Wuping were compared in relation to their sensory quality.

Method Liangye Roasted Green Teas made by using the leaves plucked from Fuyun 6, Meizhan, Wuniuzao, and Longjing 43 tea bushes were chemically analyzed by UPLC, and the brewed teas evaluated by a sensory panel.

Results The Wuniuzao tea was rated by the panel with the highest score among all. It was followed by Meizhan and Longjing 43. Biochemical composition analysis found that the content of water extracts was significantly higher in the green tea made by Meizhan than others (P<0.05), and the content of tea polyphenols was significantly higher in the green tea made by Meizhan and Wuniuzao than the other two varieties (P<0.05). While the total amino acid content of Wuniuzao tea was the highest, but the ratios of ester catechin/non-ester catechin and polyphenol/amino acids as well as the index of catechin bitter taste the lowest, of all. On amino acids, the theanine content of 8.971-14.942 mg·g⁻¹ in Fuyun 6 and aspartic acid of 1.854-2.506 mg·g⁻¹ in Wuniuzao were significantly higher than those in the others (P<0.01); and glutamate of 1.690-2.244 mg·g⁻¹ in Meizhan and Wuniuzao significantly higher than that in the other two varieties (P<0.05). The sensory scores on the teas positively correlated with the water extract content (R=0.65) as well as the ratios of polyphenol/amino acids and ester catechin/nonester catechin (P<0.05), but negatively with the index of catechin bitterness index of the various teas.

Conclusion The sensory evaluation on the brewed teas indicated that Wuniuzao tea bushes yielded the roasted green tea with the most desirable drinking quality among the four tested cultivars.