Phytochemical profiles and nutritional composition of squash (Cucurbita moschata D.) from Tunisia

Abstract

Cucurbita moschata (C. moschata) is one of the vegetables used in healthy diets as well as in traditional medicine in many countries because of the nutritional and health benefits of the bioactive compounds obtainable from its seeds and fruits. The overall purpose of this study was to investigate biochemical and nutritional properties of C. moschata extracts from its pulp, fibers and seeds. The C. moschata extracts were obtained by the maceration method using four different solvents (hexane, chloroform, ethyl acetate and methanol). Total polyphenols, flavonoids, condensed tannins and nutritional composition (protein, carbohydrates and lipids) were determined in the fruit pulp, fibers and seeds. The highest carbohydrates content was established in the pulp of C. moschata with 222.2 mg/g DW and the lowest content in fiber. Moreover, proteins and lipids contents showed a significant variation between plant parts and the highest amounts were found in the pulp with 165.3 mg/g DW and 240.75 mg/g DW, respectively. The seeds are also rich in proteins (66.7 mg/g DW).On the other hand, the C. moschata pulp, fibers and seeds extracts were analyzed using LC-ESI-MS for their phenolic profiles and the identified phenolic compounds were further quantified. Moreover, the effect of the different solvents on the phenolic profiles of Cucurbita moschata was studied. The results revealed that methanol as an extraction solvent exhibited the highest amount of bioactive compounds. Comparison of plant extracts showed that the presence of phenolic compounds was diverse among fruit parts and seeds. In total, 14 flavonoids and 10 phenolic acids were identified. The predominant phenolic acids and flavonoids in fruit pulp and fibers are quinic acid, p-coumaric acid, cirsiliol and luteolin.The overall data suggested that C. moschata is a rich source of compounds with nutritious value and with a useful biological benefit. The presence of such compounds in Cucurbita moschata make them a great matrix for both industrial and therapeutic purposes.