Abstract: Postharvest white-mature Dongzao jujube (Ziziphus jujube 'Dongzao') was stored at 0 ℃, and the variations in contents of active components in peel and pulp and the antioxidant capacities were investigated. Additionally, free, esterified, glycosided, and insoluble-bound forms of phenolic acids in the peel were separated and quantified by the high performance liquid chromatography with mass spectrometry (HPLC-MS). Moreover, the antioxidant abilities of main form of the phenolic acids were evaluated, and the relationship between the content and antioxidant capacities of active constituents in the peel and pulp were analyzed. The results showed that the concentration and antioxidant activities of total phenolics,flavonoids, and ascorbic acid decreased and then increased in the pulp, while they exhibited a continuously declined trend in the peel during storage The total content of phenolics,flavonoids and anthocyanin in peel was more than that in pulp (P<0.01). The antioxidant abilities of the active compounds except of anthocyanin in peel was significantly higher than that in pulp (P<0.01). The free phenolic acids in peel were mainly catechin, eicatechin and rutin. Their content firstly increased and then decreased during storage and were significantly higher than that of other three phenolic acids. The contents of phenolic acids in esterified and glycosided forms were more than that of insoluble-bound form. The p-coumaric acid was presented mainly in insoluble-bound forms. The results indicated that free phenolic acids were the main part of the antioxidant compounds.

Key words: Dongzao jujube, storage, active constituents, antioxidant activity