Effects of β-Glucosidase and α-L-Rhamnosidase on the Aroma of Instant Green Tea Infusion

Abstract:

Instant tea is the most important value-added tea product；and enzyme biotechnology is an important approach to improving the aroma of instant tea. To investigate the effect of β-glucosidase and α-L-rhamnosidase on the aroma profile of instant green tea infusion，sensory evaluation，gas chromatography-mass spectrometry（GC-MS） and OAV were used to analyze the instant green tea infusion and after enzyme-treated. Sensory evaluation and GC-MS analysis showed that the caramel and sweet notes were significantly in instant green tea infusion；the floral，sweet and grassy notes were significantly enhanced，caramel notes was reduced，cis-3-hexenol，geraniol，hexanol methyl salicylate and benzaldehyde were significantly increased by treated β-glucosidase；the caramel note were reduced by treated α-L-rhamnosidase；the notes of grass and sweet were further enhanced，and the contents of cis-3-hexenol and methyl salicylate were further increased by treated binding of β-glucosidase and α-L-rhamnosidase.OAV analysis found that 3-methylbutanal，2- methylbutanal，2-ethylfuran，limonene and nonanal were main aroma contribution component in instant green tea infusion；cis-3-hexenol，methyl salicylate，geraniol and furfural were main aroma contribution component by treatment with β-glucosidase；the main aroma contribution components was no significant effect by treatment with α-L-rhamnosidase；the OAV of cis-3-hexenol was further increased by treatment with β-glucosidase and α-L-rhamnosidase. These studies showed that β-glucosidase has significant effect on the aroma profile of instant green tea infusion and two enzymes have synergism to enhance green note，which provides a technological reference for improving the aroma quality of instant tea based foods.