Phenolic composition, ascorbic acid content, and antioxidant capacity of Spanish jujube (Ziziphus jujube Mill.) fruits

The interest in Ziziphus jujube is growing because it is an excellent source of nutrients and phytochemicals, and can contribute to a healthy diet. Nutritional compounds (phenolic compounds and l-ascorbic acid), and antioxidant capacity of 4 Spanish jujube cultivars were studied. Polyphenols were identified by LC-MS-QTof and quantified by UPLC-PDA-FL. A total of 25 polyphenolic compounds were identified and classified as 10 flavan-3-ols, 13 flavonols, 1 flavanone, and 1 dihydrochalcone. The content of total polyphenols (TP) ranged from 1442 to 3432 mg/100 g dry matter (dm) in fruits of the cultivars 'DAT' and 'PSI', respectively. Flavan-3-ols, the major group of polyphenols in jujube represented ∼92% of the TP content, whereas flavonols only amounted for about ∼8% each. The content of l-ascorbic acid was very high and took values in the range of 387-555 mg/100 g fresh weight (fw). Some Spanish jujube cultivars, especially 'PSI' and 'MSI', may be selected to promote the growth of cultivars with valuable nutritional and phytochemical beneficial effects on human health.