Investigation of Spray-drying for Encapsulation of Antioxidant-rich Grape Pomace Extracts: a Mathematical and Experimental Approach

This study explores the use of food industry by-products, specifically grape pomace, to recover bioactive compounds and reduce environmental impact. The goal is to optimize the spray-drying process to encapsulate antioxidant-rich extracts, enhancing the stability of phenolic compounds and anthocyanins. Experiments used a 60% ethanol solution for extraction, followed by spray-drying with maltodextrins as encapsulating agents. Parameters such as inlet air temperature (120°C–200°C) and maltodextrin concentrations (0.4–0.8 w/w) were varied. Results showed maximum recovery of total polyphenols (89.2%) and anthocyanins (78.4%) at 140°C with a maltodextrin concentration of 0.6 w/w. Higher temperatures increased degradation rates, highlighting the importance of temperature optimization while the moisture content of the powders was within optimal ranges for industrial applications, with final moisture content below 4%, enhancing stability. In parallel a mathematical model was developed to predict moisture and temperature profiles, aiding in designing efficient drying protocols. This study demonstrates the feasibility of valorizing agro-industrial residues through advanced spray-drying techniques, supporting circular economy initiatives in food processing.