Nutritional composition and bioactive potential of watermelon seeds: a pathway to sustainable food and health innovation

Watermelon (Citrullus lanatus), belonging to the Cucurbitaceae family, is a globally cultivated fruit with significant commercial value. While the fleshy part is eaten for its taste and nutritional benefits, the seeds are generally thrown away as waste, although they harbour high nutritional and bioactive contents. Watermelon seeds are rich in proteins, fats, vitamins, and minerals, and they also contain bioactive compounds such as phenolic acids, flavonoids, and carotenoids. This review seeks to investigate the proximate composition of watermelon seeds, novel techniques employed in the extraction of bioactive compounds and the various facets of therapeutic applications of these seed bioactivities, such as antioxidant, antimicrobial, antimutagenic, hypoglycaemic and anti-inflammatory properties. The effects of these seeds are assessed based on the pharmacological mechanisms underlying their therapeutic actions. Also, this review discusses the potential of using watermelon seeds and their components in the food industry as valuable functional foods and in the cosmeceuticals and nutraceuticals industries. These include health-enhancing food supplements, cosmetics, and newly developed edible products for human consumption. However, there are some issues related to its composition, yield, and safety profile that impede its optimum use. In particular, this paper highlights the sustainability problems, suggesting that converting agricultural waste into such by-products could lead to a circular economy and improve human welfare.