Apple and Grape Waste Pomace Fermentation and Co-Ferment Product Chemistry

The pomace from apple and grape processing is usually treated as waste. Nowadays, pomace has attracted increasing interest due to its potential value as a nutrient source, as a raw ingredient for fermented products, and as a health beneficial product. Hence, from the perspective of a circular economy, this study incorporated different ratios of grape pomace from ‘Frontenac gris’ and apple pomace from ‘McIntosh’ to develop novel fermented beverages. This study provides knowledge of the fundamental characteristics, fermentation dynamics, and final fermented product chemistries. The results indicated different amounts of apple and grape pomace influenced sugar content, tartaric acids, and yeast nutrients in the fermentation must. The dynamic color changes indicated that grape pomace contributed to the wine’s red color, whereas apple pomace mainly contributed to the yellow coloration in the fermented products. Apple and grape pomace also contributed differently to the phenolic compounds, ethanol, and volatile acids. Different pomace contributed different phenolic components in the final wine. This fermentation study indicated the potential application of grape and apple pomace in the wine industry.