Analysis of reducing sugars, organic acids and minerals in 15 cultivars of jujube (Ziziphus jujuba mill.) fruits in China

Ziziphus jujuba Mill. has been used as both an edible fruit and Chinese medicine for a long time. In this study, the chemical profiles in terms of reducing sugars, organic acids, and minerals of 15 cultivars of jujube were analyzed. The reducing sugars and organic acids were measured by HPLC-UV (high performance liquid chromatography with ultraviolet detection). Minerals were detected by ICP-OES (inductively coupled plasma-optical emission spectrometry). Glucose (85.9-1005 mg/100 g FW), malic acid (120-509 mg/100 g FW), citric acid (29.4-181 mg/100 g FW), iron (5.27-12.5 mg/100 g DW), calcium (16.2-30.2 mg/100 g DW) and magnesium (51.2-70.0 mg/100 g DW) were found to be the major components in the fruits. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used, in order to classify these cultivars based on the aforementioned chemical profiles. According to the PCA, classification based on the content of reducing sugars is more reasonable and reliable than other parameters. In this classification, 15 cultivars were categorized into 6 groups.