Watermelon juice microfiltration: optimization to maximize antioxidant compounds and influence mineral content

Traditional methods for fruit juice preservation use high temperatures, which degrade beneficial compounds like vitamins and antioxidants. Membrane filtration provides a gentler alternative, preserving nutrients through mild operating temperatures. This study assessed the temperature and pressure influence on watermelon juice microfiltration, focusing on permeated flow, lycopene, sugars, phenolic compounds, and flavonoids. Using a 2² composite design with central values, optimal conditions were determined by the desirability function, with pressure at 1.0 bar and temperature at 37ºC, maximizing these response variables. Resistance to permeated flux was primarily due to fouling, with an initial 25% flux reduction. The process effectively concentrated lycopene, sugars, phenolic compounds, and flavonoids, although mineral content decreased in both concentrated and permeated juice, with potassium being the most abundant mineral. The concentrated juice showed greater mineral loss than pasteurized due to retention during microfiltration. Under optimized conditions, microbial load reduction allowed the concentrated juice a shelf life comparable to pasteurized juice (14 days). Sensory analysis showed strong consumer acceptance, with 64% of tasters expressing purchase intent. These results suggest commercial viability for the concentrated juice; moreover, its high carotenoid retention could serve as an industrial ingredient for functional foods.