Recovery of Aromatic Aglycones from Grape Pomace Winemaking By-Products by Using Liquid-Liquid and Pressurized-Liquid Extraction

The potential of winemaking grape pomace by-products as a source of glycosidic aroma precursors that under enzymatic hydrolysis might release aroma compounds has been evaluated. Two different extraction methodologies, liquid-liquid and pressurized liquid extraction (LLE and PLE) were employed. Solid phase extraction (SPE)-GC-MS analysis of the hydrolyzed LLE glycosidic extract revealed 22 aroma compounds belonging to different chemical families (terpenes, C13 norisoprenoids, vanillines, etc.). Response surface methodology was employed to study the effect of the most significant PLE experimental variables (temperature and solvent composition) on the extraction of aromatic aglycones. The parameters of the model were estimated by multiple linear regressions. Most of the aroma compounds showed an adequate fit to the calculated model (18 compounds from 22 with R (2) > 0.8). The application of the optimized PLE conditions (50 % of ethanol in the hydroalcoholic solution) and 90 A degrees C showed higher extraction yield of aglycones when comparing with the extraction yield obtained by LLE.