Exploring the causes of aroma differences in mechanically harvested tea via sensory directed analysis, targeted
Jixin Zhang1, Yuxuan Zhang1, Yanqun Jiang1
1National Key Laboratory of Tea Plant Germplasm Innovation and Resource Utilization, Anhui Agricultural University, 130 Changjiang West Road, Hefei 230036, China; School of Tea Science, Anhui Agricultural University, 130 Changjiang West Road, Hefei 230036, China.
Abstract:
Nonselective mechanical harvesting boosts late spring and summer/autumn tea utilization, but limited machine-harvested tea aroma research causes classification and processing difficulties. This study used sensory directed analysis, targeted metabolomics, and key enzyme activity assays to investigate how varying maturity levels of fresh tea leaves affect green tea aroma and processability. The results showed that bud green tea had the most pronounced floral and green aromas, while tea stems had strong sweet and roasted aromas. Based on gas chromatography-olfactometry findings, by applying modified frequency > 0.5 and odor activity value ≥1, along with aroma recombination and omission experiments, linalool, geraniol, hexanal, (E,E)-2,4-nonadienal, phenylacetaldehyde, and 2,3-diethyl-5-methylpyrazine were identified as key aroma active compounds accounting for sample aroma differences. Variations in precursor concentrations, enzyme activity, and processing conditions mainly explained these differences. This study investigates how tea maturity impacts quality and offers a scientific basis for optimizing classification and processing of machine-harvested teas.
