Food preservative extracts from pumpkin by-products

Pumpkin is a vegetable widely consumed around the world, popularly known for its nutritional and pharmacological properties. Some reports in the literature reveal the rich profile of nutrients and bioactive compounds of pumpkin varieties [1,2]. However, the seeds, peels, and fibers resulting from pumpkin processing are still poorly explored by food industry. Considering the alarming scenario of losses and waste during all the food supply chain worldwide [3] and seeking to promote a more sustainable food system, the present study purposed to investigate the by-products of different varieties of pumpkin as a source of extracts with preservative capacity for food application. For that purpose, hydroethanolic extracts from the varieties “Butternut squash”, “Common pumpkin”, and “Kabocha squash” from Portugal, and “Butternut squash”, “Common pumpkin”, and “Musquée de provence” from Algeria, were evaluated in terms of their bioactivities, more specifically the antioxidant, antimicrobial, and cytotoxic capacities. All the samples presented great antioxidant capacity through two based-cell assays, namely the lipid peroxidation inhibition capacity (TBARS) and the anti-hemolytic activity (OxHLIA). Interestingly, the seeds of the common pumpkin from Algeria did not present antihemolytic properties, despite showing the strongest lipid peroxidation inhibition capacity. In fact, the seeds stood out for all the pumpkin varieties in the TBARS assay, while in the OxHLIA assay, the results were quite similar between the type of bioresidues and between the varieties. Moreover, the samples from Portugal showed greater antioxidant capacity than the Algerian ones. Regarding cytotoxicity, the effect of inhibiting non-tumor cell growth was not observed, even at the highest tested concentration of 400 μg/mL. This first validation is of great importance to prevent food safety issues. These preliminary results are the basis for future studies aiming at the valorization of these bioresidues from food industry as a great source of preservative compounds toward the replacement of synthetic additives with natural alternatives allied to health benefits, as also the promotion of a circular economy The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES to CIMO (UIDB/00690/2020); national funding by FCT, P.I., through the institutional scientific employment program-contract for C. Pereira and L. Barros contracts and A.K. Molina and M.G. Leichtweis PhD grants (2020.06231.BD and 2020.06706.BD, respectively). To FCT, P.I., within the scope of the Project PRIMA Section 2 - Multi-topic 2019: PulpIng (PRIMA/0007/2019). info:eu-repo/semantics/publishedVersion