Transformation of lignins from grape solids during alcoholic fermentation

Conversion of lignins contained in solid parts of Rkatsiteli grapes (crests, seeds, and skin) during alcoholic fermentation by wine yeast in Reader's medium was studied. Various species of wine yeast were used: Saccharomyces oviformis, S. vini Kakhuri 42, S. chodati Teliani 79, and S. uvarum Tsinandali 77. We found that lignins from solid parts of grapes are partially decomposed during alcoholic fermentation, which releases low-molecular-weight aromatic compounds into the medium. A peculiar feature of lignin decomposition during alcoholic fermentation is the formation of reduction products.