Tree Age and Maturity Stage Affect Reducing Sugars, Organic Acids and Minerals in Ziziphus Jujuba Mill. Cv. Huping Fruits

Ziziphus jujuba Mill. is a fruit native to China, and widely distributed in the world for its nutritional value. In this study, Jujube Huping fruits were collected from tree with ages (5, 13, 30, 100-years old) at two different ripening stages. The results showed that the contents of reducing sugars increased with tree age except for 5 years old tree. Citric and malic acids were the predominant organic acids with the highest contents in the green stage of 100 -year-old trees (3500 mg/100 g FW) and the red stage of 13-year-old trees (4290 mg/100 g FW), respectively. There was no specific pattern for minerals affected by the tree ages. Ca (156-397 mg/kg DW), Al (144-156 mg/ kg DW), Mg (512-680 mg/kg DW) and K (7105-4617 mg/kg DW) were the main minerals in fruits. Based on Hierarchical cluster analysis and principal component analysis, the eight samples were classified into four groups: Cluster 1 (SR-5, SR-100, SG-5, and SG-13), Cluster 2 (SG-30), Cluster 3 (SR-13, SR-30), and Cluster 4 (SG -100). The study showed how the age of jujube trees affected the levels of nutrients in jujube fruits, as well as provided insights on how to grow and cultivate jujube trees of various ages.