β-Glucosidase improve the aroma of the tea infusion made from a spray-dried Oolong tea instant

The β-glucosidase treatment was investigated to improve the aroma of the infusion made from a spray-dried instant Oolong tea (SIOT) comparing with the infusion of the freeze-dried instant Oolong tea (FIOT). The quantitative descriptive analysis showed that the overall aroma acceptability of the SIOT infusion with β-glucosidase treatment (GSIOT) and FIOT infusion were significantly higher than that of SIOT infusion (P < 0.05). Multiple linear regression analysis showed that the intensities of floral, grassy and sweet notes were positively correlated with the overall aroma acceptability. The total contents of volatile compounds and odour active values (OAVs) in GSIOT infusion (contents: 93989.8 μg/L; OAVs: 7285.2) were the highest, followed by FIOT infusion (contents: 35882.6 μg/L; OAVs: 6495.6) and SIOT infusion (contents: 16090.4 μg/L; OAVs: 1980.1). The OAVs analysis, aroma reconstruction and omission test showed that the increases in benzyl alcohol, geraniol, (Z)-3-hexen-1-ol, methyl salicylate and (E)-β-damascenone were the major contributors to the aroma improvements resulting from the β-glucosidase treatment. This study indicates a reference for yielding high-quality tea beverages with spray-dried instant teas.