Comparative Analysis of Physicochemical Characteristics, Nutritional and Functional Components and Antioxidant Capacity of Fifteen Kiwifruit (Actinidia) Cultivars—Comparative Analysis of Fifteen Kiwifruit (Actinidia) Cultivars

Physicochemical characteristics, nutritional and functional components, and the antioxidant capacity of 15 kinds of domestic and imported kiwifruit in China were studied. Kiwifruit was classified according to flesh color or species, and the differences were analyzed and compared. Results demonstrated Ruiyu had the highest sugar-acid ratio, and Hongshi No.2 was an excellent cultivar with strong antioxidant capacity. TPC (total polyphenol content) and AAC (ascorbic acid content) showed a significant positive correlation. TPC was the greatest antioxidant contributor in the DPPH and FRAP assays. The sugar–acid ratio and TFC (total flavonoids content) in red-fleshed kiwifruit were significantly higher than those in yellow-fleshed and green-fleshed ones. The composition of free amino acids had a tendency to distinguish A. deliciosa and A. chinensis, but this needs further verification. In addition, the contents of mineral elements, folic acid and L-5-methyltetrahydrofolate were also analyzed. Generally, kiwifruit contains comprehensive nutrients and has strong antioxidant capacity. Cultivar is one of the main factors affecting nutritional and functional properties and antioxidant capacity.