Recent Progress in Extraction and Structural and Functional Properties of Banana Tannins

As a subgroup of plant polyphenols, tannins have various biological activities, including antioxidant, anticancer and anti-inflammatory properties. Nowadays, tannins have been widely utilized in the food, pharmaceutical and leather industries. Bananas, one of the most widely consumed fruits in the world, are demonstrated to be rich in tannins. However, there have been few reviews of recent research on banana tannins. Most research on the extraction of banana tannins concentrates on solvent extraction, ultrasound-assisted extraction, microwave-assisted extraction and enzyme-assisted extraction. The chemical structure of banana tannins has been researched regarding their molecular mass distribution, degree of polymerization, chemical composition, structural units and linkage types. Most research on the functional properties of banana tannins focuses on their antioxidant, antibacterial, hypolipidemic and hypoglycemic activities, protective effects against pesticide-induced toxicity, metal-binding capacity and ultraviolet-absorbing capacity. Finally, future research directions are discussed, hoping to provide theoretical support for broadening the application of banana tannins in the food industry.