The Influence Of Arbutin On Inducing β-Dglycosidase From Lactobacillus Plantarum To Produce Aroma

Aroma is an important sensory quality of wine and it is mainly composed of free aroma and combination state aroma. Combination state aroma can be hydrolyzed by β-D-glucosidase and only in this way, can it be perceived by people. β-D-glucosidase is a key enzyme in the enzymatic release of these bound glycoside, but β-D-glucosidase activity of microbial source may be inhibited by extreme wine environment, such as ethanol and low pH, and weak its function in producing aroma in the process of wine making. Somebody report that, carbon source can induce β-D-glycosidase activity, but the searches about the influence of arbutin toβ-D-glycosidase activity and aroma of grape wine were less reported.In the present study, the influence of different concentrations of arbutin on β-Dglycosidase activity were detected under the two forms of cell morphology. Apart from that,the influence of pH, ethanol and glucose on enzyme activity was also analyzed. Then the abilities of the two strains to hydrolyze glycosides and fermentation were respectively evaluated with natural substrate extracted from grape. Finally, the difference of aroma of model wine inoculated XJ-14, XJ-25 or their inducible strain XJ-14-X, XJ-25-X was respectively tested by GC-MS. The main results are as follows.(1) Enzyme activity of complete cell was higher than broken cells. when the concentration of arbutin was 10g/L, the enzyme activity of β-D-glycosidase was comparatively higher, which indicated that arbutin could improve the activity of β-Dglycosidase. The optimal pH of β-D-glucosidase was 5.0. Activity of β-D-glucosidase could be inhibited by high concentration of ethanol and glucose had less influence on enzyme activity.(2) Lactobacillus plantarum induced by arbutin could hydrolyze more glucoside. The trends of OD600 and colony count of the model wine were similar before and after induced,which indicated that arbutin had less influence on the growth of the two strains in model wine.(3) The aroma content of model wine which was inoculated bacterial strain induced by arbutin is significantly higher than the control group and XJ-14-X was superior to the othersamples in terms of improving wine aroma. There were 29 species of aroma in the model wine inoculated XJ-14-X and the content of aroma was 568.81 μg/L.