Researchers at the Braganza Polytechnic Institute have found that the non-edible portions of pumpkin carry substances with strong antioxidant and antimicrobial properties. The study was published in Molecules.
While pumpkin flesh is widely used, the by-products—which may contain valuable polyphenols, polyunsaturated fatty acids, minerals, and carotenoids—are often discarded or underutilized. In a new investigation, chemists examined the content and effects of biologically active compounds present in the fibers, seeds, and skins of several Algerian and Portuguese pumpkin varieties.
Eight flavonoids were identified in pumpkin byproducts, with the shell showing the highest concentrations, reaching up to 9.4 mg per gram. Seeds were also found to be rich in antioxidant compounds.
All Portuguese pumpkin samples demonstrated antibacterial activity against foodborne pathogens. The extracts inhibited organisms such as Yersinia enterocolitica and Aspergillus fumigatus, while a pumpkin from Algeria showed activity against Staphylococcus aureus and Aspergillus fumigatus. Importantly, at the highest concentration tested (400 µg/mL), none of the extracts harmed pig liver cells.
These results underscore the value of transforming pumpkin by-products into usable materials for multiple industries, including cosmetics and pharmaceuticals. By reclaiming and repurposing these by-products, producers can add value, reduce waste, and support product development across sectors that rely on natural bioactive compounds. The research supports a broader approach to food processing that looks beyond the edible portion to unlock health-promoting ingredients in the entire pumpkin and its residues. Attribution: Braganza Polytechnic Institute; Molecules