Analysis of Quality in Shoumei White Tea from Different Tea Plant Varieties

To explore the quality and material basis of Shoumei white tea from different varieties of tea trees, in this study, Shoumei white tea made from the raw materials of Fu'an Da Bai (FA), Fuding Da Hao (FD), Meizhan (MZ) and Fengqing Da Ye Zhong (FQ) were analyzed for their quality using sensory evaluation, high performance liquid chromatography (HPLC), headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). Orthogonal partial least squares discriminant analysis (OPLS-DA) and its permutation test were used to distinguish the differences among the samples, and variables were selected based on the variable importance in projection (VIP) values and P-values. The results indicated that there were differences in both sensory evaluation and physicochemical properties among the white teas processed from the four varieties of tea trees. Each of the Shoumei white teas from the four varieties of tea trees exhibited good sensory qualities and distinct characteristics. The water extract content of the different Shoumei white teas ranged from 45.48% to 46.89%, the tea polyphenol content ranged from 16.79% to 19.96%, the caffeine content ranged from 41.34 to 56.61 mg/g, the total theaflavin content ranged from 3.31 to 8.22 mg/g, the total catechin content ranged from 143.90 to 165.62 mg/g, the non-esterified catechin content ranged from 21.55 to 36.01 mg/g, the esterified catechin content ranged from 114.14 to 134.16 mg/g, and the total free amino acid content ranged from 30.35 to 38.31 mg/g. Furthermore, differences in the content of non-volatile compounds were observed among the different tea samples. A total of 57 volatile compounds were detected in the four tea samples, with a total concentration ranging from 121.63 to 203.43 μg/g. Among them, alcohols and aldehydes accounted for the majority. Significant differences were observed among the tea samples in terms of the aroma profile, types, and concentrations of volatile compounds. OPLS-DA based on 93 compounds from the four tea samples was employed to effectively differentiate between the tea samples and identify 56 differentiating compounds (VIP>1 and P<0.05) that significantly contribute to their quality characteristics. In conclusion, different varieties of tea trees have an impact on the quality characteristics of Shoumei white tea. The findings of this study can provide data support for quality control of the four types of Shoumei white tea.