Molecular mechanisms of aroma quality improvement of Enshi Yulu green tea through yellow light treatment

Light irradiation modulates aroma/color-related chemical markers of freshness. • Low-temperature yellow light yields the favorable aroma-related chemical profile. • Yellow light promotes deglycosylation of aroma precursors during spreading. • Yellow light irradiation increases the abundance of free aroma compounds. Enshi Yulu is a traditional Chinese steamed green tea characterized with pronounced green color attributes. However, relatively weak aroma characteristics restrict its development, and the mechanisms governing aroma development in steamed green teas remain insufficiently understood. This study aimed to optimize aroma development of Enshi Yulu by evaluating the effects of light spectrum and temperature during spreading. Among the result, yellow light treatment promoted aroma formation, increasing the abundance of key aroma-active compounds (35,216 vs. 26,430 ng/g in the control), and key odorants such as geraniol (12,533.28 ng/g). This effect was associated with enhanced glycosidase activity (128.4 vs. 76.72 U·h/mg protein), facilitating the hydrolysis of glycosidically bound aroma precursors and the subsequent formation of volatile aroma compounds. In addition, yellow light treatment optimally preserved chlorophyll content (1.73 vs. 1.37 mg/g), maintaining desirable green color attributes. This study provided an effective strategy for aroma quality enhancement in Enshi Yulu production. Download: Download high-res image (133KB) Download: Download full-size image