Effects of Different Processing Techniques on Sensory Profile and Quality Components of Early-summer Fuding Dabai White Tea

To improve the quality of early-summer white tea, further optimize its processing technology, and explore the quality and material basis of white tea processed with different techniques. This study used fresh leaves of the 'Fuding Dabai' cultivar, harvested at the stage of one bud and two leaves, as raw materials. Based on the traditional indoor withering and combined indoor-outdoor withering, light-rolling and shaking-green treatments were introduced, respectively. Through sensory evaluation, major biochemical analyses, and determination of volatile aroma components via headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), the influence of different processing techniques on the finished tea was investigated. The sensory evaluation results indicated that the white teas processed with light-rolling and shaking-green exhibited a more refreshing, pronounced, and lasting aroma, along with a sweeter and more pleasant taste, and consequently, a superior overall sensory quality. The analysis of biochemical components demonstrated that the water extract contents of the light-rolled and shaking-greened teas were 32.19% and 34.56%, respectively, and the soluble sugar contents were 4.75% and 4.61%, respectively, both of which were significantly higher than those of the traditionally withered tea (P<0.05). The analysis of aroma components led to the detection of 1172 compounds in total, which included 408 isomers. Based on the differences in their primary functional groups, the detected aroma components were classified into 15 major categories, with terpenoids, esters, ketones, and alcohols being the most abundant. Relative odor activity value (ROAV) analysis identified dihydro-2-methyl-3(2H)-furanone, (E)-β-damascone, (E,Z)-2,6-nonadienal, (E)-2-hexenal, and 4-hydroxy-2,5-dimethyl-3(2H)-furanone as key aroma compounds. The findings demonstrate that light-rolling and shaking-green are effective techniques for enhancing the sensory and key physicochemical properties of early-summer white tea. This study provides critical data and a theoretical foundation for innovating processing techniques and achieving precise quality management.