Phytochemicals from Pumpkin (Cucurbita maxima) By-Products

Cultivated plant by-products are a worldwide environmental issue that can be revalued with benefits to human health and the environment. Pumpkin (Cucurbita maxima) is one of the most widely consumed and cultivated vegetable crops. Pumpkin by-products (leaves, seeds, and skin/peel) are almost 25% of the total pumpkin processed because only the flesh fraction is edible. Notably, pumpkin wastes are health-promoting sources of phytochemicals, such as sugars, amino acids, phenols, glucosides, terpenes, flavonoids, lignans, plant steroids, and flavonoids. In addition, pumpkin by-products can be low-cost sources of potentially important bioactive compounds, i.e., tocopherols, carotenoids, fatty acids, and vitamins. Owing to the versatility of chemical compounds present in pumpkin wastes, they can be used in food supplements, showing antidiabetic, antioxidant, anticancer, and anti-inflammatory activities. Moreover, they can be used as ingredients for functional foods, including in baking, beverages, meat, and dairy products. In addition, they can be exploited for non-food and non-health purposes, becoming natural ingredients for cosmetics, natural dyes, biodegradable packaging components, wastewater purifying agents, or bioenergy sources. This chapter contributes to a more complete understanding of pumpkin by-products, considering chemical composition, bioactivity profile, and health and non-health applications of seeds and skin/peel.