Aroma enhancement of instant green tea infusion using β-glucosidase and β-xylosidase.

β-Glucosidase and β-xylosidase were investigated for their ability to improve the aroma of instant green tea. The aroma and corresponding contributors were analyzed by sensory evaluation, gas chromatography-mass spectrometry, and odor activity value. Their specific contributions to aroma attributes were further examined by aroma reconstruction and omission experiments. The β-glucosidase treatment significantly enhanced floral and grassy notes, on account of the increases of geraniol, nonanal, and cis-3-hexen-1-ol, and weakened the caramel note, attributable to the increases of nonanal, cis-3-hexen-1-ol, geraniol, methyl salicylate, and decanal. The co-treatment with β-glucosidase and β-xylosidase further enhanced the grassy note, with further increase in nonanal and cis-3-hexen-1-ol, and further weakened the caramel note, with additional increase in nonanal, cis-3-hexen-1-ol, methyl salicylate, and decanal. The synergistic action of β-glucosidase and β-xylosidase provides new clues to the production of instant green tea infusions with high aroma quality.