Active components and antioxidant activity of thirty-seven varieties of Chinese jujube fruits (Ziziphus jujuba Mill.)

Jujube has received more and more attention due to their nutritional value and pharmacological effects. This study evaluated the quality of different varieties of jujube by comparing the main active components and antioxidant activities of thirty-seven varieties of jujube through titration, UV spectrophotometry and High performance liquid chromatography (HPLC). The results revealed that there were differences in active components and antioxidant capacity among jujube cultivars. Among the thirty-seven varieties of jujube, Qingxuyuanzao (QXYZ) had the highest contents of total phenols and flavonoids, which were 16.33 mg GAE/g DW and 41.18 mg RE/g DW, respectively, and had the highest free radical scavenging (DPPH: 29.79 mg Vc/g DW; ABTS: 50.90 mg Trolox/g DW) and reducing abilities (62.13 mg Trolox/g DW). Correlation analysis indicated that the content of total flavonoids, total phenols and phenolic acid ((+)-catechin, caffeic acid, rutin) in jujube had high positive correlation with antioxidant capacity. According to principal component analysis (PCA), the comprehensive scores of different varieties of jujube were calculated. The top five jujube varieties with comprehensive scores are 'QXYZ,' Suyuanling (SYL), Xiangzao (XZ), Dunhuangdazao (DHDZ) and Meimizao (MMZ). In this paper, the main active components and antioxidant capacity of thirty-seven jujube varieties have been studied, which provides a theoretical basis for jujube breeding and the development of active nutrients for jujube.