Abstract:[Objective] This study aims to explore the major quality characteristics and volatile components of Zhenghe white tea. [Method] Three representative samples of Baimudan tea and two samples of Shoumei tea were chosen and studied by sensory evaluation, physicochemical analysis, microbial determination, and gas chromatography-mass spectrometry (GC-MS). [Result] Baimudan tea samples showed a tip aroma and a fresh and mellow taste, and the leaf residue bud was tender or stout. Shoumei tea samples exhibited a pure aroma and a rich taste. The mass fractions of water and water extracts of all the samples met the requirements of the national standards White Tea (GB/T 22291—2017) and Quality Requirements for Product of Geographical Indication—Zhenghe White Tea (GB/T 22109—2008). The results of partial least squares-discriminant analysis (PLS-DA) showed that free amino acids, tea polyphenols, water extract, and caffeine were the main physicochemical components to distinguish between Baimudan tea and Shoumei tea. Pathogens were detected in none of the samples, while there were differences in the total plate count and mold count, which were lower in Shoumei cake tea and higher in Baimudan 3 (BMD3). The analysis of volatile components showed that the volatile components of Baimudan tea were mainly composed of alcohols and ketones, conferring Baimudan tea with a sweet, floral, and tip aroma. In addition, geraniol, linalool, and linalool oxide II had higher relative content in Baimudan tea. The volatile components of Shoumei tea were mainly composed of alcohols, ketones, and esters, which endowed Shoumei tea with a floral, medicinal, and woody aroma. Additionally, Shoumei tea had higher relative content of methyl salicylate, dihydroactinidiolide, and β-lonone. The results of principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed that the volatile components were significantly different between Baimudan tea and Shoumei tea. Specifically, Baimudan tea had a strong and pure aroma, while Shoumei tea had a light aroma and a dull taste. [Conclusion] This study can provide references for the flavor characteristic and safety evaluation of Zhenghe white tea.
