Determination of phenolic compounds in jujube peels at different maturity stages by high performance liquid chromatography.

This paper focus on the composition and distribution of phenolic compounds extracted from the peels of Chinese jujube (Ziziphus jujuba Mill. cv. Dongzao) fruits at various maturity stages. The free, ester and bound phenolic compounds were detected by the high performance liquid chromatography (HPLC) on a Waters C18 column. Gradient elution was employed with a mobile phase consisting of water-acetic acid (99∶1; A) and methanol-acetic acid (99∶1; B), a solvent flow rate of 0.8 mL/min and an injection volume of 10 μL. Phenolic compounds were identified at 280 nm. The results indicated that catechin, epicatechin and p-coumaric acid were the major phenolic compounds in the jujube peels at various maturity stages. The catechin and epicatechin were mainly free or in ester form. The p-coumaric acid was mainly in ester and bound forms in the peels of the jujube fruits.