Kiwifruit

Actinidia deliciosa or kiwifruit is native to southern China, and has been declared the national fruit of that country. Other species of Actinidia are also found in China and range east to Japan and north into southeastern Siberia. This species grows naturally at altitudes between 600 - 2,000 m.

The kiwifruit, often shortened to kiwi in many parts of the world, is the edible berry of a cultivar group of the woody vine Actinidia deliciosa and hybrids between this and other species in the genus Actinidia.

The most common cultivars of kiwifruit are oval, about the size of a large hen's egg (5–8 cm / 2–3 in long and 4.5–5.5 cm / 1¾–2 in diameter). It has a fibrous, dull brown-green skin and bright green or golden flesh with rows of tiny, black, edible seeds. The fruit has a soft texture and a sweet but unique flavor, and today is a commercial crop in several countries, mainly in Italy, New Zealand, Chile, Greece and France.

Kiwifruit is a rich source of vitamin C, 1.5 times the DRI scale in the USA per 100 grams. Its potassium content by weight is slightly less than that of a banana. It also contains vitamin E, and a small amount of vitamin A. The skin is a good source of flavonoid antioxidants (though it may also retain agricultural pesticides). The kiwifruit seed oil contains on average 62% alpha-linolenic acid, an omega-3 fatty acid.Usually a medium size kiwifruit contains about 46 calories, 0.3 g fat, 1 g protein, 11 g carbohydrates, and 2.6 g dietary fiber found partly in the edible skin. Kiwifruit is often reported to have mild laxative effects, due to its significant level of dietary fiber.

Raw kiwifruit is also rich in the protein-dissolving enzyme actinidin, (in the same family of thiol proteases as papain), which is commercially useful as a meat tenderizer, but can be an allergen for some individuals. Specifically, people allergic to latex, papayas or pineapples are likely to also be allergic to kiwifruit. The fruit also contains calcium oxalate crystals in the form of raphides. Reactions to these chemicals include sweating, tingling and sore mouth or throat; swelling of the lips, tongue and face; rash; vomiting and abdominal pain, heartburn; and, in the most severe cases, breathing difficulties, wheezing and collapse. The most common symptoms are unpleasant itching and soreness of the mouth, with the most common severe symptom being wheezing. Severe symptoms are most likely to occur in young children.

Actinidin also makes raw kiwifruit unsuitable for use in desserts containing milk or any other dairy products which are not going to be served within hours, because the enzyme soon begins to digest milk proteins. This applies to gelatin-based desserts as well, as the actinidin will dissolve the collagen proteins in gelatin very quickly, either liquifying the dessert, or preventing it from solidifying. However, the U.S. Department of Agriculture suggests cooking the fruit for a few minutes before adding it to the gelatin to overcome this effect.Sliced kiwifruit has long been regularly used as a garnish atop whipped cream on New Zealand's national dessert, the pavlova. It can also be used in curry.

Kiwifruit components, possibly involving vitamin E and omega-3 fatty acids from its numerous edible seeds, have potential properties of a natural blood thinner. A study performed at the University of Oslo in Norway reported consuming two to three kiwifruit daily for 28 days significantly reduced platelet aggregation and blood triglyceride levels (similar to popular mainstream aspirin therapy), potentially reducing the risk of blood clots.

Kiwifruit is a natural source of carotenoids, such as provitamin A beta-carotene, lutein and zeaxanthin.