The role of non-Saccharomyces species in releasing glycosidic bound fraction of grape aroma components--a preliminary study.
OBJECTIVE
The purpose of the study was to evaluate the effect of beta-glycosidase activity in wine yeasts in releasing terpene glycosides from grape juice.


RESULTS
Glycosidase activity was screened in 160 yeasts by testing their ability to hydrolyse arbutine on agar plates. Only non-Saccharomyces species exhibited beta-glycosidase activity. Enzyme activity, based on hydrolytic activity on p-nitrophenyl-beta-glycoside, was mainly located in the whole cell fraction, with smaller amounts in permeabilized cells being released into the growth medium. The hydrolysis of glycosides was determined by HRGC-MS, confirming the role of yeast in the liberation of monoterpenols, especially linalool and geraniol.


CONCLUSIONS
The results indicate the potential of microbial beta-glycosidases for releasing flavour compounds from glycosidically-bound, non-volatile precursors, with significant implications for wines made from less aromatic grapes.


CONCLUSIONS
This study confirms the role of non-Saccharomyces species in enhancing wine aroma and flavour, suggesting that the future lies with controlled use of mixed cultures in winemaking.
Mendes Ferreira
A
A
Food Science Department, Universidade de Trás-os-Montes e Alto Douro, 5001 Vila Real, Portugal.
Clímaco
M C
MC
Mendes Faia
A
A
D001104:Arbutin / Q000378:metabolism; D000440:Butanols / Q000378:metabolism; D005285:Fermentation; D006026:Glycoside Hydrolases / Q000378:metabolism*; D006027:Glycosides / Q000096:biosynthesis* / Q000737:chemistry; D009850:Oman; D000439:Pentanols / Q000378:metabolism; D010843:Pichia / Q000201:enzymology*; D019685:Rosales / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013729:Terpenes / Q000737:chemistry / Q000378:metabolism
D000440:Butanols; D006027:Glycosides; D000439:Pentanols; D013729:Terpenes; C040507:isobutyl alcohol; D001104:Arbutin; C029683:isopentyl alcohol; D006026:Glycoside Hydrolases