Valorization of red guava by-products: Nanoencapsulation of pulp carotenoids with peel and seed for a liquid dietary supplement dye

This study explored the integral use of imperfect red guava by extracting carotenoids from the pulp, employing the peel and seed as natural wall materials for nanoencapsulation. Ultrasound-assisted extraction with cereal ethanol was maximized using a 2⁴ full factorial design, yielding 31.40 ± 5.04 μg/g and an extraction efficiency of 90.90%. The extract was nanoencapsulated using poly(lactic-co-glycolic acid) (NPPLGA), guava peel (NPGP), and guava seed (NPGS), producing nanoparticles with sizes ranging from 171.50 ± 10.69 (NPPLGA) to 219.52 ± 33.98 (NPGP) nm, an acidic pH, and measurable antioxidant activity. NPGS exhibited the highest encapsulation efficiency and carotenoid content and was found to be non-cytotoxic to HT22 cells at concentrations ≤0.07 μg/mL. In a liquid dietary supplement model system, NPGS exhibited minimal changes in yellow color over 22 days of refrigerated storage (ΔE* < 2), indicating a possible application as a food dye and demonstrating a strategy for valorizing guava by-products.