Jujube fruit: A potential nutritious fruit for the development of functional food products

Jujube (Ziziphus Jujuba Mill.) has been eaten as a fruit and nutraceutical food in China for thousands of years. Recent phytochemical and pharmacological studies have shown that the polysaccharides are one of major biologically active components of the jujube fruit and have various biological effects, including immunomodulatory, antioxidant, antitumor, hepatoprotective, and hypoglycemic activities, and gastrointestinal-protective effects. Although the extraction and purification of jujube polysaccharides are tedious processes, including different steps of liquid- and solid-phase separation, the polysaccharides have been structurally characterized. However, the relationships between the structures and activities of the jujube polysaccharides are not well established. The purpose of the present review is to appraise the previous and current literature on the extraction, purification, structural characterization, and biological activities of jujube polysaccharides. This review should provide a useful bibliography for the further investigation, production, and application of jujube polysaccharides in functional foods and therapeutic agents.