Abstract:

Phenolic components in Lingwuchangzao jujubes (Zizyphus jujuba Mill. cv. Lingwuchangzao) during four
ripening stages (S1, green ripe; S2, representing Lingwuchangzao with red surface area of 25%–50%; S3, 50%–75%; S4,
100%) and related antioxidant activities were investigated. The contents of total phenols, total flavonoids and phenolic
compositions, and antioxidant properties including the abilities to inhibit lipid peroxidation and scavenge 2,2-diphenyl-
1-picrylhydrazyl (DPPH) and reducing power were investigated. The results showed that the content of phenolic
compounds had a significant correlation with antioxidant activities. The contents of total phenols varied from 2 996.60 to
5 801.84 μg/g and the contents of total flavonoids were in the range of 33.12 to 122.12 μg/g. Jujubes at stage S1 showed the
highest level of total phenols. The main phenolic compounds of during different ripening stages of Lingwuchangzao jujubes
were detected. The antioxidant capacity was significantly correlated with the contents of total flavonoids and total phenols
(P < 0.05). Jujubes at stage S1 exhibited the highest antioxidant activity and at stage S4 presented the lowest one. These
results showed that the extracts of Lingwuchangzao jujubes at stage S1 had high free radical scavenging activity as a potent
natural antioxidant with commercial value. The antioxidant performance of Lingwuchangzao jujubes at the green ripe stage
is better than at other ripening stages. Jujubes at the green ripe stage may be more suitable to gain natural antioxidants.

Key words: Lingwuchangzao, ripening, antioxidant capacity, phenolics