Light-vibration synergy during spreading and optimized drying temperature improve machine-harvested beverage-grade green tea quality

Optimizing the flavor profile of machine-harvested beverage-grade green tea requires a delicate balance between the retention of low-boiling-point volatiles and the progression of thermal reactions. This study demonstrates that a synergistic light-vibration pretreatment combined with drying at 75 °C is a superior strategy to address this challenge. Using quantitative descriptive analysis (QDA), headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), and high-performance liquid chromatography (HPLC), we found that this protocol significantly elevated the total volatile emission to 20301.17 μg/kg. Crucially, it shifted the compositional profile toward esters and terpenes, which serve as the primary contributors to the floral and fruity notes of green tea. A total of 101 volatile compounds were identified, and nine key aroma-active constituents were screened out. These findings not only elucidate the metabolic pathways activated by light-vibration synergy but also provide a scalable and implementable technical solution for the industrial production of high-aroma, machine-harvested beverage-grade green teas.