Autochthonous yeasts with β-glucosidase activity increase resveratrol concentration during the alcoholic fermentation of Vitis labrusca grape must

• 18.8% of 308 autochthonous yeasts hydrolysed grape glucosidic analogues.
• Wine-related β-glucosidase-producer yeasts were evaluated on natural substrates.
• 57% of yeasts hydrolysed natural resveratrol-glucosides of Vitis labrusca.
• Four Hanseniaspora uvarum increased free-resveratrol after alcoholic fermentation of V. labrusca.

Since red wine is the main dietary source of resveratrol, a well-known polyphenol that reduces coronary events in humans, different strategies have been employed in winery to achieve resveratrol-enriched wines. Yeasts-endowed β-glucosidase activity enhances free-resveratrol concentration in wine without modifying its composition or sensorial properties. Current assay screened 308 autochthonous yeast strains for β-glucosidase activity employing arbutin, esculin, cellobiose and piceid as substrates. The β-glucosidase-producer yeasts were evaluated in the must of Vitis labrusca Bordô grape to quantify resveratrol concentration before and after alcoholic fermentation. Fourteen yeasts increased the resveratrol concentration up to 102% without any significant difference and nine of these yeast strains also produced high ethanol contents. Four autochthonous Hanseniaspora uvarum β-glucosidase-producer strains showed adequate oenological characteristics and hydrolysed resveratrol-glucosides during the alcoholic fermentation of V. labrusca grape must.