Comparison of the nutritional properties and biological activities of kiwifruit (Actinidia) and their different forms of products: towards making kiwifruit more nutritious and functional.

The nutritional properties and biological activities of kiwifruit and their different products made from same raw kiwifruit were investigated. Compared with the more common Hayward variety, three new kiwifruit varieties, namely Qinmei, Hongyang and Huayou, showed better nutritional properties and biological activities. After processing into different products, the nutritional properties and biological activities of kiwifruit changed substantially but still showed a correlation with the variety's characteristics. Processing kiwifruit into juice, wine and vinegar retained a higher vitamin C and polyphenol content than dried slices and jam and demonstrated better biological activities, while dried slices and jam provided more mineral elements than the three liquid products. In addition, the fermentation products wine and vinegar showed a similar nutritional composition that were present at a higher concentration than in juice, which indicated that fermentation helps in the dissolution of nutrient substances, while the thermal processing products dried slices and jam showed a similar nutritional composition. Consuming original kiwifruit supplies a more comprehensive nutritional composition than from any kiwifruit products.