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The properties of intracellular b-glucosidases produced from two yeast isolates identified as Hanseniaspora sp. BC9 and Pichia anomala MDD24 were characterized. b-Glucosidase from Hanseniaspora sp. BC9 was not inhibited by both 20% w/v fructose and 20% w/v sucrose and was slightly inhibited by glucose ([ 40% relative b-glucosidase activity with 10% w/v glucose). b-Glucosidase from P. anomala MDD24 was inhibited by glucose, fructose and sucrose. In the presence of 4-12% v/v ethanol, b-glucosidase from P. anomala MDD24 was stimulated in range 110-130% relative activity whereas b-glucosidase from Hanseniaspora sp. BC9 was substantially inhibited in the presence of ethanol. Finally, juice and wine of the Muscat-type grape variety, Traminette, were selected to determine sugar-bound volatile aroma release, particularly terpenes, by the activity of those b-glucosidases. The results showed that high concentration of free aroma compounds were detected from Traminette juice treated with b-glucosidase from Hanseniaspora sp. BC9and Traminette wine treated with b-glucosidase from P. anomala MDD24. The preliminary results with proposed an application of these enzymes in commercial wine production lead to more efficient of b-glucosidase from Hanseniaspora sp. BC9 in releasing desirable aromas during an early stage of alcoholic fermentation while b-glucosidase from P. anomala MDD24 is suitable at the final stage of alcoholic fermentation.

-The production and characterisation of β-glucosidase from an isolated yeast strain classified as a Pichia anomala MDD24 were studied. The result shows that cellobiose is a good inducer for extracellular β-glucosidase production and optimum concentration is 1.5 percent cellobiose in yeast peptone dextrose medium. The purified β-glucosidase from Pichia anomala MDD24 exhibited a specific activity of 614 ± 14 U mg -1 of protein and a molecular mass of 42 kDa. This enzyme was slightly inhibited by fructose and sucrose in the range of 4 to 20% (w/v). An ethanol concentration between 4 and 20% (v/v) activated β-glucosidase activity, at presence 16% (v/v) ethanol, β-glucosidases obtained maximum relative activity around 150%. The optimum pH and optimum temperature for β-glucosidase activity were 4.5 and 40 °C, respectively. Although the activity under the pH and temperature of wine production (pH 3.5-4.0 and 15-20 °C) was quite low, the enzyme was stable and the relative activities were higher than commercial enzyme under those conditions. The extracellular β-glucosidase from Pichia anomala MDD24 makes it possible to release glucosidically-bound monoterpenes, which are the major contributors to floral and fruity aromas in wines from Muscat-type varieties, at final stage of alcoholic fermentation.

Headspace solid-phase microextraction (SPME) and GC-MS were used to analyze 17 commercial French Cognac brandies (9 young and 8 well-aged, ranging in age from 3 to 55 years). Sixty-four volatiles were chosen on the basis of chromatographic separation and/or known odor importance. Chromatographic peaks were manually integrated and the peak area data analyzed using partial least-squares (PLS) regression to study relationships between volatile composition (X variables) and age (Y variable). When only those compounds with the highest significance were included and from these selected the variables (a total of 33) with the highest correlation loadings on the first two principal components, principal component 1 explained 82% of the variance of the measured compounds and 85% of the variance in age. These were considered the most important volatiles to distinguish products of different ages because young and old samples were separated along principal component 1. Norisoprenoids, terpenes, and acetate esters had weaker positive and negative loadings and were therefore left out. The PLS model could predict sample age accurately with the optimum 33 volatiles as well as with a smaller subset consisting of ethyl esters and methyl ketones.