Kiwifruit is native to southern China where it has been declared a National Fruit of China. Other species of Actinidia are native to India, Japan, and southeastern Siberia. Cultivation of the fuzzy kiwifruit spread from China in the early 20th century, when seeds were introduced to New Zealand by Mary Isabel Fraser, the principal of Wanganui Girls' College, who had been visiting mission schools in Yichang, China. The seeds were planted in 1906 by a Wanganui nurseryman, Alexander Allison, with the vines first fruiting in 1910.
The first commercial planting of Chinese gooseberries occurred in 1937 in New Zealand by the orchardist Jim MacLoughlin. The fruit proved popular with American servicemen in New Zealand during World War II. In 1952 MacLoughlin partnered with the New Zealand Fruit Federation to market and export the fruit in the United States market. Thanks to pioneering research into the transportability of the fruit by John Pilkington Hudson and others at the agriculture department in Wellington this was the first international export of the Kiwifruit.
Almost all kiwifruit in commerce belong to a few cultivars of Fuzzy Kiwi (A. deliciosa): 'Hayward', 'Blake', and 'Saanichton 12'.They have a fuzzy, dull brown skin, and bright green flesh. The familiar cultivar 'Hayward' was developed by Hayward Wright in Avondale, New Zealand around 1924.[14] It was initially grown in domestic gardens, but commercial planting began in the 1940s.
Hayward is the most commonly available cultivar in stores. It is a large-egg shaped fruit with a sweet flavor. Saanichton 12, from British Columbia, is somewhat more rectangular than Hayward and comparably sweet, but the inner core of the fruit can be tough. Blake has a smaller more oval fruit, and the flavor is considered inferior. The most common male pollenizer for these varietals is the Chico.
Kiwifruit can be grown in most temperate climates with adequate summer heat. Where fuzzy kiwi (A. deliciosa) are not hardy, other species can be grown as substitutes.
Kiwifruit is commercially grown on sturdy support structures, as it can produce several tonnes per hectare, more than the rather weak vines can support. These are generally equipped with a watering system for irrigation and frost protection in the spring.
Kiwifruit vines require vigorous pruning, similar to that of grapevines. Fruit is borne on one-year-old and older canes, but production declines as each cane ages. Canes should be pruned off and replaced after their third year.
The plants are normally dioecious, meaning individual plants are either male or female. Only female plants bear fruit, and only when pollenized by a male plant. One male pollenizer is required for each three to eight female vines. An exception is the cultivar 'Issai', a hybrid of Arctic Beauty and Silver Vine (A. arguta x polygama) from Japan, which produces perfect flowers and can self-pollinate; unfortunately it lacks vigor, is less hardy than most Arctic Beauties (A. arguta) and is not a large producer.
Kiwifruit is notoriously difficult to pollinate, because the flowers are not very attractive to bees. Some producers blow collected pollen over the female flowers. Generally, the most successful approach, though, is saturation pollination, where the bee populations are made so large (by placing hives in the orchards) that bees are forced to use this flower because of intense competition for all flowers within flight distance.
Firm kiwifruit ripen after a few days to a week when stored at room temperature, but should not be kept in direct sunlight. Faster ripening occurs when placed in a paper bag with an apple, pear, or banana.[18] Once a kiwifruit is ripe, however, it is preserved optimally when stored far from other fruits, as it is very sensitive to the ethylene gas they may emit, thereby tending to over-ripen even in the refrigerator. If stored appropriately, ripe kiwifruit normally keep for about one to two weeks.
Advantage of Kiwifruit
The fruit plays an important role in facilitating weight loss and promotes general health and wellness.
Owing to ant-oxidant properties, kiwi fruit is effective in protecting you against Age-Related Macular Degeneration (ARMD).
Kiwi fruit has more vitamin C than equal amount of oranges. Children fed 5-7 portions of kiwi fruit developed 44 percent less chances of being affected by wheezing as compared to those who were fed once a week, according to an Italian study published in the Thorax, an International Journal of Respiratory Medicine (BMJ group).
Another study published in the Asia Pacific Journal of Clinical Nutrition found that kiwi fruit consumption could significantly improve sleep quality in adults with sleep problems.
Eat this delicious fruit as is by peeling and slicing it or add it to a fruit salad. Use it to make chutney or blend it to prepare a chilled soup – whatever way you use it, the nutritional benefits remain the same.
Kiwifruit is the most nutrient-rich of the top 26 fruits consumed in the world today. It also has the highest density of any fruit for vitamin C and magnesiumóa limited mineral in the food supply of most affluent countries and a nutrient important for cardiovascular health. Among the top three low-sodium, high-potassium fruits, kiwifruit ranks number one, having more potassium than a banana or citrus fruits.
Based on the data published in the international scientific literature and the U.S. Food and Drug Administrationís approved legal definition of a good (>10% of the daily value (DV)) or excellent (>20% of the DV) source, kiwifruit may be classified as an excellent source of vitamin C as well as dietary fiber. By the FDA's definition, kiwifruit would also be a good source of vitamin E and potassium. Kiwifruit is low fat and contains no cholesterol.
Unlike other fruits, kiwifruit has an unusually broad complement of nutrients. Most fruits tend to be high in only one or two nutrients, but kiwifruit delivers 8% DV of folic acid, 8% DV of copper, 8% DV of pantothenic acid, 6% DV of calcium and magnesium, 4% DV of iron and vitamin B6, 2% DV of phosphorus and trace amounts of vitamin A (beta carotene) and other vitamins and minerals.
Cancer
Kiwifruit has been shown to contain an antimutagenic component, helping to prevent the mutations of genes that may initiate the cancer process. The presence of glutathione may account for the reduction.
Carcinogenic nitrates are formed during the smoking or barbecuing of foods. When nitrates are ingested, a process called nitrosation can occur, in which free radicalsónitrosaminesóare formed that may lead to the formation of gastric or other cancers. Kiwi has been demonstrated to aid in the prevention of nitrosation.
In another in vitro test with cultured mammalian-cell lines, kiwifruit extract was found to inhibit melanoma, or skin cancer.
The amino acid arginine, present in kiwifruit, is being looked at by cardiologists to improve postangioplasty blood flow and actually prevent the formation (or reformation) of plaque in the arteries.
Kiwifruit is ranked as having the fourth highest natural antioxidant potentialónext to the red fruits containing high levels of beta carotene.
Lutein, an important phytochemical found in kiwifruit, has been linked to the prevention of prostate and lung cancer.
In addition to kiwifruit being recognized by the FDA as an excellent source of dietary fiber, studies indicate that it contains another not-yet-isolated compound that accelerates digestive transit time even faster than dietary fiber aloneóimportant for colorectal cancer prevention. The benefit of this laxative action is to decrease the build-up of cancer-promoting metabolites.
Kiwifruit is one of the few fruits that are green at maturity, and chlorophyll is responsible for that color. Several studies have suggested that chlorophyllin, a derivative of chlorophyll, is an inhibitor of liver carcinogenesis.
Depression
Inositol is found in kiwifruit. Recent studies have shown that inositol, because of its function as a precursor of an intracellular second messenger system, can be beneficial in the treatment of depression.
Diabetes
Inositol, a sugar alcohol naturally occurring in kiwifruit, may play a positive role in regulating diabetes. Inositol supplements may improve nerve conduction velocity in diabetic neuropathy.
Inositol plays a role in intracellular responses to hormones and neurotransmitters. It acts as a second messenger in cell signaling processes.
Eye Health/Macular Degeneration
Fourteen million American adults needlessly suffer from macular degeneration. Kiwifruit is rich in phytochemicalsóxanthophylls and especially a subcomponent, lutein. Lutein is known to accumulate in the retina of the eye. Recent USDA studies have linked these important compounds to the prevention of macular degenerationóthe leading cause of irreversible blindness in the U.S.
Kiwifruit contains a wealth of carotenoids (beta carotenes, luteins and xanthophylls); phenolic compounds (flavonoids and anthocyanins) and antioxidants, including vitamins C and E. The excellent complement of antioxidants in kiwifruit may help prevent the oxidation of the good cholesterol (HDLs).
Kiwifruit is particularly high in two amino acids: arginine and glutamate. Arginine may help promote an increase in arteriolar dilation, working as a vasodilator and improving blood flowóimportant for heart health.
The FDA considers kiwifruit a good source of vitamin E, crucial for a healthy heart.
Kiwifruit contains magnesium at 6% DV. Magnesium is thought to be in short supply in the diets of affluent countries. Poor magnesium status is associated with heart disease, myocardial infarction and hypertension.
Kiwifruit contains pectin, which has been shown to lower cholesterol.
Hypertension
Cardiologists believe the sodium-to-potassium ratio is critical for heart health. That ratio is extremely favorable in kiwifruit.
Immunity
Kiwifruit has been shown to be an immune boosterómost likely due to its extremely high vitamin C content and its complement of antioxidant compounds.
Impotence
Kiwifruit contains the amino acid arginine, a well-known vasodilator that has been used to treat impotence in men.
Physical Fitness
Kiwifruit contains a wide range of minerals (electrolytes) essential for replenishing those lost during exerciseóespecially in hot environments. It is also a naturally significant source of electrolytes for a preworkout regimen.
I
n China, a kiwi-based sport drink was designed to overcome athletic training in a hot environment, where large amounts of minerals can be lost in sweat. A 5% addition of carbohydrates to the kiwifruit juice helped to maintain a normal glucose level during exhaustive training. The sports drink was tested on Chinaís elite soccer and track teams and in a more controlled experiment on amateur athletes. The results? Subjects were able to ride a Monark ergometer longer, hematocrit increased significantly after exercise, the drink maintained blood glucose at normal levels when training lasted more than 2.5 hours without affecting insulin levels and vitamin C status of the athletes improved as measured by urinary output. Best of all, athletes said it was fragrant, tasty, refreshing and thirst quenching. It appeared to have no negative side effects (Di et al, 1990).
Stress Reduction
Kiwifruit contains a relatively high level of serotonin. Serotonin causes a calming effect in most individuals.
Weight Control
Calorie for calorie, kiwifruit is one of the most nutrient-rich fruits. You get the best balance of nutrients per calorie (the most nutrients for the fewest calories) from kiwifruit, cantaloupe, papaya and lemons.
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