Kiwi

“Kiwi” fruit is the name that New Zealand producers came up with for the striking, tart berry of a Chinese vine, Actinidia deliciosa, when they pioneered its international marketing in the 1970s. Several other species of Actinidia are now also cultivated, including the yellow-to-red-fleshed A. chinensis. Kiwi fruit are unusual in appearance and ripening behavior. Their thin, hairy skin doesn’t change color during ripening, and the translucent inner flesh is green with chlorophyll, with as many as 1,500 small black seeds embedded in a ring and connected to the core by white rays of vascular tissue. (There are also chlorophyllfree varieties with yellow, red, and purple flesh.) Cross-sectional slices of kiwi are thus very attractive. When harvested, kiwi fruits contain a large amount of starch. During months of storage at 32°F/0°C, the starch is slowly converted to sweet sugars. Then at room temperature they undergo a climacteric ripening that takes about 10 days. The flesh softens and the aroma becomes more pronounced, with strongly fruity esters (benzoates, butanoates) coming to dominate more delicate, grassy alcohols and aldehydes. Some kiwi varieties are rich in vitamin C and in carotenoids.