Determination of total phenolic, flavonoid, carotenoid, and mineral contents in peel, flesh, and seeds of pumpkin (Cucurbita maxima)

Pumpkin is an important vegetable, which has potential to be used as medicinal and functional food. Not only the pulp but also the peel and seeds of pumpkin are good sources of phytochemicals and minerals. Pumpkin peel, flesh, and seeds were dried to obtain powders, and 80% of methanolic extracts were prepared for further analyses. Among three fractions of pumpkin, higher content of total phenolics (224.61 ± 1.60-mg GAE/100-g powder) and total flavonoids (139.37 ± 1.07-mg CE/100-g powder) were recorded in pumpkin seeds as compared with peel and flesh, whereas higher carotenoids (35.2 ± 0.49 mg/100-g powder) and β-carotene (6.18 ± 0.04 mg/100-g powder) were present in pumpkin flesh extract, when compared with peel and seeds. Pumpkin flesh, as compared with peel and seeds, contained higher values of Na, K, and Fe (17.87 ± 0.22, 1592 ± 20.3, and 41.50 ± 0.45 mg/100-g powder, respectively). Valuable amount of Zn (15.21 ± 0.07 mg/100-g powder) was present in pumpkin seeds powder. Practical applications Pumpkin parts (peel, flesh, and seeds) own high nutritional significance due to the presence of total phenolics, flavonoids, total carotenoids, and appreciable amount of macroelements and microelements. Organic waste generated as a result of pumpkin processing could effectively be utilized in different food products for the development of functional and medicinal foods. Notably, pumpkin seeds are high in zinc content, and in this situation of COVID-19 pandemic, scientific community is well aware of oxidation and mediating role of zinc for activation of enzymes in the body. Phytochemicals present in pumpkin peel, flesh, and seeds can fight against antiaging and enhance immunity. These low-cost powders from pumpkin parts can be used as a potential source of functional foods and nutraceuticals in food and medicinal industries.