Edible flower powders of three Cucurbita species: Insights into metabolomic profiling and phytonutritional properties

Abstract

This study assessed nutritional composition, antioxidant activity, and untargeted metabolomic profiles of pumpkin flower powders from three Cucurbita species: Cucurbita pepo (CPP), C. maxima (CMX), and C. moschata (CMS). CPP had the highest Calcium content (1.44 g/100 g), and zeaxanthin content (380.06 mg/100 g), while CMS contained the highest levels of iron (0.14 g/100 g), magnesium (0.56 g/100 g), phosphorus (0.69 g/100 g), and protein content (26.91 g/100 g). Highest carotenoids such as Trans-β-carotene (334.89 mg/100 g) and cis-β-carotene (20.92 mg/100 g), and lower oxalate (70.14 mg/100 g) were recorded in the flower powders of CMS, contributing to the highest antioxidant power (FRAP) (66.62 mM TE/g).

Lysine (1.30 g/100g), phenylalanine (1.16 g/100 g), and oxalate content (109.96 mg/100 g) were the highest in CMX. Antioxidant assays showed that CMX had the highest ABTS scavenging activity (0.34 mg/mL; IC₅₀). UPLC-Q-TOF-MS identified 49 metabolites in the flower powders, mainly phenolic compounds (68%), as well as iridoids, carbohydrate derivatives, and fatty acid and derivatives. Differential analysis revealed 27 regulated metabolites between CMS vs CPP, 16 of which were upregulated in CMS, primarily flavonoids and phenolic acid derivatives. KEGG pathway analysis showed flavonoid-related metabolic pathways contained the most differential metabolites. The study showed that pumpkin flower powders exhibited species-dependent differences in nutritional composition, antioxidant potential, and metabolomic profiles. CMS had higher protein content and antioxidant capacity, while CPP and CMX provided distinct mineral and carotenoid profiles. These findings highlight the potential of Cucurbita flower powders as functional food ingredients.