Harnessing Grape Pomace, a Multifunctional By-Product from the Wine Industry for High-Value Salad Dressings

Grape pomace (GP) has gained attention for its potential to be valorized into functional foods due to its rich composition of bioactive compounds. In this work, GP has been exploited to develop plant-based mayonnaise alternatives and salad dressings. The influence of the water-to-oil ratio, percentage content of GP, lecithin, and vinegar on the viscosity and physical stability of the obtained emulsions have been investigated by the Design of Experiments. Two formulations, one high-oil (70%) and the second high-water (60%), were further studied for their potential applications. The selected samples were subjected to an accelerated stability test (60 °C for 21 days) to verify the influence of GP on oxidation protection. The high-water sample, combined with 8% GP, showed lower primary (peroxide value < 20 mEq O₂/kg fat) and secondary oxidation (anisidine value < 55) parameters than the high-oil sample, highlighting the GP antioxidant activity. The phenolic profile of all samples by HPLC was also determined. Lastly, a sensory analysis was conducted, showing the highest overall acceptability for the oil-rich sample. The obtained results contribute to highlighting the potentiality of GP in the formulation of healthy foods, adopting the zero-waste approach for the full exploitation of this underutilized resource.