The photo is of the sliced kiwi I usually eat as part of my dinner every night. I always have an apple with peanut butter, a bell pepper, a mandarin orange and a small piece of cheese. The other fruit or vegetable I vary — cherries, carrots, kiwi, etc. So, I am very familiar with the juicy sweet tartness of kiwi. I also know that kiwis are high in vitamin C and fiber. And they are so pretty! There is nothing more attractive and appetizing than sliced kiwi. Besides being good in salads, kiwis can really spice up a dessert too. Colorful sliced fruit — including kiwi — on a tart looks like a piece of art. You eat with your eyes first. And the taste does not disappoint. Let’s learn more about this versatile fruit.
According to Wikipedia, kiwifruit — commonly shortened to kiwi in North America and continental Europe — or Chinese gooseberry is the edible berry of several species of woody vines in the genus Actinidia. The most common cultivar group of kiwifruit — Actinidia deliciosa 'Hayward' — is oval, about the size of a large hen's egg: 2–3 inches in length and 1+3⁄4–2+1⁄4 inches in diameter. It has a thin, fuzzy, fibrous, tart but edible light brown skin and light green or golden flesh with rows of tiny, black, edible seeds. The fruit has a soft texture with a sweet and unique flavor. In 2018, China produced half of the world total of kiwifruit.
Kiwifruit is native to central and eastern China. The first recorded description of the kiwifruit dates to the 12th century during the Song dynasty. In the early 20th century, cultivation of kiwifruit spread from China to New Zealand, where the first commercial plantings occurred. The fruit became popular with British and American servicemen stationed in New Zealand during World War II, and later became commonly exported, first to Great Britain and then to California in the 1960s.
Etymology
Early varieties were described in a 1904 nursery catalogue as having "...edible fruits the size of walnuts, and the flavor of ripe gooseberries," leading to the name Chinese gooseberry. In 1962, New Zealand growers began calling it "kiwifruit" for export marketing, a name commercially adopted in 1974. In New Zealand and Australia, the word "kiwi" alone refers to the kiwi bird or is used as a nickname for New Zealanders; it is almost never used to refer to the fruit. Kiwifruit has since become a common name for all commercially grown green kiwifruit from the genus Actinidia. In the United States and Canada, the shortened name kiwi is commonly used when referring to the fruit.
History
Kiwifruit is native to central and eastern China. The first recorded description of the kiwifruit dates to 12th century China during the Song dynasty. As it was usually collected from the wild and consumed for medicinal purposes, the plant was rarely cultivated or bred.
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 Whanganui nurseryman, Alexander Allison, with the vines first fruiting in 1910. A New Zealand horticulturalist developed the well-known green kiwifruit in Avondale, New Zealand, around 1924. This well-known green kiwifruit was later renamed "Hayward" as a tribute to its creator, Hayward Wright.
The first commercial planting of Chinese gooseberries occurred in 1937 by the orchardist Jim MacLoughlin. He found that the vines were low maintenance and fruited well. By 1940, MacLoughlin purchased more property for Chinese gooseberry production. MacLoughlin's truck was commandeered for army use during the outbreak of war and as a result, he was forced to sell his property and enter into a shared cropping arrangement with another farmer. In 1955, MacLoughlin bought out his partner, purchasing his land back along with an additional 38 acres and planting it all in Chinese gooseberries. During the war, around 550 cases of the fruit were marketed each season with the fruit proving popular with American servicemen in New Zealand, providing the opportunity for the previously domestically consumed fruit industry to expand by exporting to an international market.
In 1952, MacLoughlin approached the New Zealand Fruit Federation who agreed to facilitate the shipping and marketing of the fruit to United States markets, this was New Zealand's first export of Chinese gooseberries. Due 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.
In New Zealand during the 1940s and 1950s, the fruit became an agricultural commodity through the development of commercially viable cultivars, agricultural practices, shipping, storage and marketing.
Species and cultivars
The genus Actinidia comprises around 60 species. Their fruits are quite variable, although most are easily recognized as kiwifruit because of their appearance and shape. The skin of the fruit varies in size, hairiness and color. The flesh varies in color, juiciness, texture and taste. Some fruits are unpalatable, while others taste considerably better than the majority of commercial cultivars.
The most commonly sold kiwifruit is derived from A. deliciosa or fuzzy kiwifruit. Other species that are commonly eaten include A. chinensis (golden kiwifruit), A. coriacea (Chinese egg gooseberry), A. arguta (hardy kiwifruit), A. kolomikta (Arctic kiwifruit), A. melanandra (purple kiwifruit), A. polygama (silver vine) and A. purpurea (hearty red kiwifruit).
Fuzzy kiwifruit or Actinidia deliciosa
Most kiwifruit sold belongs to a few cultivars of A. deliciosa (fuzzy kiwifruit): '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. 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' can self-pollinate, but it has a smaller, more oval fruit and the flavor is considered inferior.
Kiwi berries
Kiwi berries are edible fruits the size of a large grape, similar to fuzzy kiwifruit in taste and internal appearance, but the thin, smooth green skin and lack of fuzz makes eating the entire fruit more pleasant. They are primarily produced by three species: Actinidia arguta (hardy kiwi), A. kolomikta (Arctic kiwifruit) and A. polygama (silver vine). They are fast-growing, climbing vines, durable over their growing season. They are referred to as kiwi berry, baby kiwi, dessert kiwi, grape kiwi or cocktail kiwi.
The cultivar 'Issai' is a hybrid of hardy kiwi and silver vine which can self-pollinate. Grown commercially because of its relatively large fruit, 'Issai' is less hardy than most hardy kiwi.
Golden kiwifruit or Actinidia chinensis
Actinidia chinensis (golden kiwifruit) has a smooth, bronze skin, with a beak shape at the stem attachment. Flesh color varies from bright green to a clear, intense yellow. This species is sweeter and more aromatic in flavor compared to A. deliciosa, similar to some subtropical fruits. One of the most attractive varieties has a red 'iris' around the center of the fruit and yellow flesh outside. The yellow fruit obtains a higher market price and being less hairy than the fuzzy kiwifruit, is more palatable for consumption without peeling.
A commercially viable variety of this red-ringed kiwifruit, patented as EnzaRed, is a cultivar of the Chinese hong yang variety.
'Hort16A' is a golden kiwifruit cultivar marketed worldwide as Zespri Gold. This cultivar suffered significant losses in New Zealand in 2010-2013 due to the PSA bacterium. A new cultivar of golden kiwifruit, 'Gold3,' was found to be more disease-resistant, and most growers have now changed to this cultivar. 'Gold3' — marketed by Zespri as SunGold — is not quite as sweet as 'Hort16A' and lacks its usually slightly pointed tip.
Clones of the new variety SunGold have been used to develop orchards in China, resulting in partially successful legal efforts in China by Zespri to protect their intellectual property.
Breeding
Often in commercial farming, different breeds are used for rootstock, fruit bearing plants and pollinators. Therefore, the seeds produced are crossbreeds of their parents. Even if the same breeds are used for pollinators and fruit-bearing plants, there is no guarantee that the fruit will have the same quality as the parent. Additionally, seedlings take seven years before they flower, so determining whether the kiwi is fruit-bearing or a pollinator is time-consuming. Therefore, most kiwifruits — with the exception of rootstock and new cultivars — are propagated asexually. This is done by grafting the fruit-producing plant onto rootstock grown from seedlings or if the plant is desired to be a true cultivar, rootstock grown from cuttings of a mature plant.
Pollination
Kiwifruit plants generally are dioecious, meaning a plant is either male or female. The male plants have flowers that produce pollen, the females receive the pollen to fertilize their ovules and grow fruit; most kiwifruit requires a male plant to pollinate the female plant. For a good yield of fruit, one male vine for every three to eight female vines is considered adequate. Some varieties can self-pollinate, but even they produce a greater and more reliable yield when pollinated by male kiwifruit. Cross-species pollination is often — but not always — successful as long as bloom times are synchronized.
In nature, the species are pollinated by birds and native bumblebees, which visit the flowers for pollen, not nectar. The female flowers produce fake anthers with what appears to be pollen on the tips in order to attract the pollinators, although these fake anthers lack the DNA and food value of the male anthers.
Kiwifruit growers rely on honeybees, the principal “for-hire” pollinators, but commercially grown kiwifruit is notoriously difficult to pollinate. The flowers are not very attractive to honeybees, in part because the flowers do not produce nectar, and bees quickly learn to prefer flowers with nectar.
Honeybees are inefficient cross-pollinators for kiwifruit because they practice “floral fidelity.” Each honeybee visits only a single type of flower in any foray and maybe only a few branches of a single plant. The pollen needed from a different plant — such as a male for a female kiwifruit — might never reach it were it not for the cross-pollination that principally occurs in the crowded colony; it is in the colonies that bees laden with different pollen literally cross paths.
To deal with these pollination challenges, some producers blow collected pollen over the female flowers. Most common, though, is saturation pollination, in which the honeybee populations are made so large — by placing hives in the orchards at a concentration of about 8 hives per 2 1/2 acres — that honeybees are forced to use this flower because of intense competition for all flowers within flight distance.
Maturation and harvest
Kiwifruit is picked by hand and commercially grown on sturdy support structures, as it can produce several tons per acre, 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. In the northern hemisphere, the fruit ripens in November, while in the southern it ripens in May. Four-year-old plants can produce up to 14,000 lbs per acre while eight-year-old plants can produce 18,000 lbs per acre. The plants produce their maximum at eight to ten years old. The seasonal yields are variable; a heavy crop on a vine one season generally comes with a light crop the following season.
Storage
Fruits harvested when firm will ripen when stored properly for long periods. This allows fruit to be sent to market up to 8 weeks after harvest.
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. 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.
Pests and diseases
Pseudomonas syringae actinidiae or PSA was first identified in Japan in the 1980s. This bacterial strain has been controlled and managed successfully in orchards in Asia. In 1992, it was found in northern Italy. In 2007/2008, economic losses were observed, as a more virulent strain — PSA V — became more dominant. In 2010 it was found in New Zealand's Bay of Plenty kiwifruit orchards in the North Island. The yellow-fleshed cultivars were particularly susceptible. New, resistant varieties were selected in research funded by the government and fruit growers so that the industry could continue.
Scientists reported they had worked out the strain of PSA affecting kiwifruit from New Zealand, Italy and Chile originated in China.
Production history
Kiwifruit exports rapidly increased from the late 1960s to early 1970s in New Zealand. By 1976, exports exceeded the amount consumed domestically. Outside of Australasia, New Zealand kiwifruit are marketed under the brand-name label, Zespri. The general name "Zespri" has been used for marketing of all cultivars of kiwifruit from New Zealand since 2012.
In the 1980s, countries outside New Zealand began to grow and export kiwifruit. In Italy, the infrastructure and techniques required to support grape production were adapted to the kiwifruit. This adaptation — coupled with being close to the European kiwifruit market — led to Italians becoming the leading producer of kiwifruit in 1989. The growing season of Italian kiwifruit does not overlap much with the New Zealand or the Chilean growing seasons, therefore direct competition between New Zealand or Chile was not a significant factor.
Much of the breeding to refine the green kiwifruit was undertaken by the New Zealand Plant & Food Research Institute — formerly HortResearch — during the decades of 1970–1999. In 1990, the New Zealand Kiwifruit Marketing Board opened an office for Europe in Antwerp, Belgium.
Human consumption
Kiwifruit may be eaten raw, made into juices, used in baked goods, prepared with meat or used as a garnish. The whole fruit, including the skin, is suitable for human consumption; however, the skin of the fuzzy varieties is often discarded due to its texture. Sliced kiwifruit has long been used as a garnish atop whipped cream on pavlova, a meringue-based dessert. Traditionally in China, kiwifruit was not eaten for pleasure, but was given as medicine to children to help them grow and to women who have given birth to help them recover.
Raw kiwifruit contains actinidain — also spelled actinidin — which is commercially useful as a meat tenderizer and possibly as a digestive aid. Actinidain also makes raw kiwifruit unsuitable for use in desserts containing milk or any other dairy products because the enzyme digests milk proteins. This applies to gelatin-based desserts, due to the fact that the actinidain will dissolve the proteins in gelatin, causing the dessert to either liquefy or prevent it from solidifying.
Recipe for Strawberry Kiwi Pavlova from Sunset
Ingredients
4 large egg whites (1/2 cup) at room temperature
Pinch of salt
3/4 cup plus 2 tablespoons sugar, divided
1 teaspoon distilled white vinegar or cider vinegar
1 teaspoon vanilla extract or vanilla flavoring
1 cup whipping cream
3 cups sliced strawberries (15 oz.)
1 cup sliced peeled kiwi fruit (8 oz.)
Directions
Preheat oven to 250°. Trace an 8-in. circle on a piece of parchment paper with a pencil. Place it pencil side down on a baking sheet.
Put egg whites and salt in a large, very clean bowl. Beat with a handheld or stand mixer on high speed (preferably with whisk attachment) until foamy. Gradually add 1 cup sugar, a few tablespoons at a time, beating well after each addition, until stiff, shiny peaks form (4 to 5 minutes). Beat in vinegar and vanilla just until blended.
Mound meringue onto traced circle on baking sheet, spreading to fill and mounding edges slightly higher than center.
Bake until meringue is firm and pale golden brown, about 1 1/2 hours. Crack oven door and let pavlova cool completely, about 2 hours more. Carefully remove from baking sheet and transfer to a platter (it's normal for crust to crack a little).
In a bowl, with a mixer on high speed, beat whipping cream just until soft peaks form. Turn mixer to low and beat in remaining 2 tablespoons sugar.
Just before serving, top pavlova with whipped cream, strawberries, and sliced kiwi fruit. Cut into 8 wedges.
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