Valorization of pumpkin seed hulls, cucurbitin extraction strategies and their comparative life cycle assessment

In most cases, final agricultural products such as vegetables, fruits, and cereals are associated with the industrial generation of byproducts that are usually unexploited to express all their potential value or, in the worst but common case, directly disposed of as wastes. Even after industrial processing, plant biomasses still represent an invaluable source of unique and human-useful compounds. Within the circular economy, the valorization of industrial wasted biomasses is considered an opportunity to provide new higher-value products with a concomitant solution to waste accumulation issues. In this framework, pointing to circularity, the seed hulls industrial residuals discarded as waste deriving from Cucurbita pepo L. (pumpkin) are hereby investigated to be re-entered in a circular valorization chain. After a full characterization of the biomass residual, the focus was set on cucurbitin, a biologically active non-proteic amino acid found only in the Cucurbita species. The present research investigates different water-based strategies for cucurbitin extraction and enrichment. LCA comparative analysis has been performed to evaluate the environmental impacts of the extractions and assess the most sustainable strategy to yield cucurbitin. [Display omitted] •Pumpkin seed hulls are confirmed as added-value biomass source.•The amino acid cucurbitin is extractable in water and ethanol/water solvents.•It is possible to enrich extracts in cucurbitin up to 30%.•LCA highlights non-negligible differences in relation to energy consumption.