Valorization of Papaya By-Products: Bioactive Potential of Peel and Seeds and Their In Vitro Bioavailability

Papaya (<i>Carica papaya</i> L.) processing generates by-products that can serve as sustainable sources of bioactive compounds. This study aimed to extract and characterize the bioactive compounds from the peel and seeds of different papaya varieties and evaluate their antioxidant and antimicrobial potential, as well as their behavior under simulated digestion. The results indicated that Maradol seeds possessed the highest total phenolic content and antioxidant values, demonstrating superior compositional and functional profiles, and that seed extracts overall had greater antibacterial efficacy than peel extracts, with Hawaiian seed extracts exhibiting the greatest overall inhibition. Furthermore, under simulated gastrointestinal conditions, the combined extracts from peel and seeds effectively preserved phenolics through the gastric and intestinal phases and notably enhanced the generation of acetate and propionate during colonic fermentation. These findings robustly substantiate the functional valorization of papaya by-products and suggest that selecting extracts based on their specific bioactive profiles can significantly enhance their applications as natural, functional ingredients in the food industry.