Grape pomace kombucha: consumer interest and sensory characteristics

The valorization of agro-industrial waste has garnered increasing attention in recent years. Winemaking, in particular, produces substantial quantities of by-products, including wastewater, stalks, lees, pomace, and stems. This study explores the potential of grape pomace as a substrate for Kombucha production, aiming to assess consumer interest through a market study and to evaluate the beverage's organoleptic properties via sensory analysis. The Kombucha was developed by fermenting grape pomace with a symbiotic culture of bacteria and yeast (SCOBY), with variations in grape variety, sucrose concentration, and fermentation duration. Kombucha was unfamiliar to 60.0% of respondents, yet 82.5% expressed interest in a novel kombucha with health benefits. In multivariable logistic regression, higher odds of interest were independently associated with female gender (AOR = 3.99, 95% CI: 1.91–8.34), Lebanese nationality (AOR = 8.05, 95% CI: 3.67–17.68), and self-employment (AOR = 5.74, 95% CI: 1.05–31.25), whereas participants aged ≥55 years had lower odds of interest than those aged 18–30 years (AOR = 0.24, 95% CI: 0.07–0.87). Sensory evaluation showed significant formulation effects across all evaluated attributes, with the raspberry-flavored formulation receiving the highest numerical overall acceptance score and being selected as the preferred formulation by 65% of panelists. Physicochemical analyses were performed on the base fermentations and provide only preliminary insights into potential relationships between composition and sensory perception. The results support further investigation of grape pomace kombucha as a sustainable beverage derived from winemaking by-products.