Increasing the Applications of Crocus sativus Flowers as Natural Antioxidants

Large amounts of floral bio-residues (92.6 g per 100 g of flowers) are generated and wasted in the production of saffron (Crocus sativus) spice. Progress in mechanization of saffron crop offer the opportunity to expand the uses of C. sativus flowers, beyond the spice (dried stigmas). The antioxidant potential of flowers of saffron, their separate parts (tepals, stamens, styles, and stigmas) and floral bio-residues were evaluated by 4 in vitro assays: lipid peroxidation, deoxyribose assay, Rancimat test, and Trolox equivalent antioxidant capacity. Phenolic content and crocetin ester composition were also determined. All the samples studied showed to be potential antioxidants. The highest phenolic, flavonoid, and anthocyanin contents were observed in tepals. Stamens showed lower phenolic, flavonoid, and anthocyanin contents than those of whole flowers, tepals, and floral bio-residues. Crocetin esters were not found in tepals or stamens. Stamens exhibited the most potent LOO• and OH• radicals scavenging activity, being higher than those of food antioxidant propyl gallate. Flowers of saffron, tepals, stamens, styles, and floral bio-residues showed LOO•, OH•, and ABTS•- radicals scavenging activity, while stigmas showed LOO• and ABTS•- radicals scavenging activity. All samples studied improved the oxidative stability of sunflower oil in Rancimat test. These antioxidant properties could suggest the application of this floral material as functional ingredients with the subsequent added value.