The Impact of Drying Method on Bioactive Compounds and Microstructure of Jujube Zizyphus Lotus Leaves

Background and Aim: The leaves of Jujube Zizyphus lotus are widely used as medicine for their health benefits, particularly in China, America and the Middle East. To determine the benefits of Jujube leaves, the leaves were analysed to distinguish certain chemical compounds, examine their antioxidant activity and study their structural morphology. Materials and Methods: Conventional drying by ovens is a method of preserving nutritious foods. The drying temperature gradient of 10°C affects certain food compositions. In the case of the Jujube leaf, the increase in temperature revealed an increased extraction. Moreover, an increase in the release of polyphenols analyzed by reactive Folin method (2.5-3 mgEqAG/100g), and a small variation in antioxidant activity tested by 2,2-diphenyl-1-picrylhydrazyl method of about 80% were registered. Results: We also noticed a stability of about 3 mg/100g for flavonoids, a very low concentration 0.5 mg/g for total carotenoids, a variation between 12-45 mg/g for phyophytins, and a degradation of chlorophyll a (between 3-18) and chlorophyll b (2-8 mg/g). Conclusion: High performance liquid chromatography (HPLC) analysis showed that the Jujube tree, Zizyphus lotus, is very rich in phenolic compounds, above all Naringin, Furelique, Rutin, Quercetin, and Kaempferol.