Kaki (persimmon) - Persimmon

Japanese: カキ（柿） - かき

A deciduous tall tree of the Ebacaceae family (APG classification: Ebacaceae). The number of chromosomes is 2n = 90. It is said to have originated in China, Korea, and Japan, but it is thought to have originally been in central China. The trunk is upright and well-branched, with young branches densely covered with fine hairs. The bark of mature trees is cracked in the shape of scales. The leaves are alternate and short-stalked, short-elliptical with pointed tips, about 10 cm long, leathery, entire, and smooth and glossy. The leaves turn red in autumn. It is an insect-pollinated plant, and is polymorphic dioecious, with female plants that only bear female flowers, monoecious plants that bear female and male flowers, monoecious plants that have a mixture of female, male, and bisexual flowers, and male plants that only bear male flowers. All flowers are axillary and pale milky white. The female flowers are solitary with short pedicels and are about 2 cm in diameter. The male flowers are in cymes consisting of one or several flowers, and are 0.7 to 1 cm in diameter. All have green, 4-lobed calyxes, and a vase-shaped corolla with four lobes at the tip that are everted. Female flowers usually have 8 degenerate stamens and 8-lobed pistils. The ovary is large, with 8 locules, each with one ovule. Male flowers have 11 to 25 stamens, usually 16, arranged in two rows, inside and outside. They bloom from late May to early June, secrete nectar, and have a strong fragrance. The fruits come in various sizes, including round, elliptical, oblate, conical, and oblong conical. The skin turns yellow or yellow-red from late September to November, and sweet persimmons lose their astringency and become sweeter, while astringent persimmons remain astringent. As both sweet and astringent persimmons ripen further, the flesh turns red-orange and softens, becoming ripe, and astringent persimmons also become sweeter. The color of the fruit is due to carotene and lycopene.

[Muneo Iizuka March 22, 2021]

Cultivation history

Persimmon cultivation is oldest in China, and is recorded in the Book of Rites 2,500 years ago. In the region including Shaanxi Province in central China, the Shanglin Fu (Shanglin Fu) by the Western Han Dynasty literary figure Sima Xiangru (Shiba Xiangru) describes suitable cultivation areas, and the agricultural book Qi Min Yaoshu (Qi Min Yaoshu) from the first half of the 6th century describes the use of saplings and the method of grafting using Japanese bean rootstocks. In addition, the herbal book Jing Ben Zhou (Jing Ben Zhou) from the mid-11th century describes many varieties, including a vermilion variety. Today, persimmons are cultivated in many provinces except for cool areas and highlands such as Northeast, Inner Mongolia, and Tibet. Broadly speaking, northern varieties are cold-resistant and drought-resistant, with thin skin and pale color, while southern varieties are less cold-resistant and drought-resistant, with thick skin and dark color. There are over 200 varieties, with Maban persimmons and Judae persimmons being widely cultivated for eating raw, while Gyushin persimmons, Tsubame persimmons and Kagami persimmons are widely cultivated for processing, and dried persimmons are also exported. In Korea, persimmons are mostly cultivated in the southern part, where astringent persimmons such as Shakokushi and Seongdo persimmons are famous. Persimmons were introduced to Europe from China in the 19th century, and to America from Japan in the mid-19th century. Many were introduced to Brazil by Japanese immigrants, and both sweet and astringent persimmons are widespread.

It has been cultivated in Japan for a long time, and is recorded as Kaki in the Honzo Wamyo (918) and as Gaki in the Wamyoruijusho (around 931-938). According to the Engishiki (927), ripe and dried persimmons were used and cultivated at the Imperial Court. Persimmons at that time were small, so they were measured in squares. There was no distinction between sweet and bitter persimmons. The distinction between sweet and bitter persimmons did not appear until the Teiki Orai (Teikin Orai), which is thought to have been written around 1300, where it is said that kizawashi and koneri meant sweet persimmons and kaki meant bitter persimmons. Ripened persimmons and kushigaki are also recorded, and it is clear that sweet persimmons were cultivated in the Kamakura period. Zenjimaru, known as an ancient variety, was discovered by chance in the mountains in 1214 (Kenpo 2) during the reconstruction of Seishukusan Renzoin Temple in Ozenji Temple, Kakio, Kawasaki City, Kanagawa Prefecture. It was originally called Ozenjimaru, but it was a good variety for the time and became popular, so it later came to be called Zenjimaru. The Muromachi period book "Sekiso Orai" lists the differences between persimmons, hoshigaki, and kushigaki. In the second half of the 17th century, Kineri, Gosho, Fude, Shibugaki, Kizawashi, Rin, Tsurushi, and Koro appeared in the "Yoshufu-shi," and varieties, methods for removing tannins, and methods for drying persimmons were introduced, while varieties such as Kineri and Gosho appeared in the "Agriculture Encyclopedia" from around the same time. In the 18th century, varieties also increased, and in the Edo period, from the Kyoho to Genbun era (1716-1741), Mito Domain's "Goryo-nai-san" introduced Gosho, Hachiya, Mino, Yotsumizo, and Myotan, while Kanazawa Domain's "Kashu Bussan-shi" recorded 45 varieties, including Gosho, Enza, Hachiya, Hachihei, Myotan, and Saijo. The Chofu Nishu Sanbu Nii also lists 36 varieties, including Saijo, Hagakushi, and Gionbo. Thus, many of the varieties cultivated today were already in existence in the mid-18th century, and in the 19th century, the Honzo Komoku Keimo (1803), written at the end of the Edo period, listed over 200 varieties, and also conducted comparative studies of varieties with those in China. Furthermore, in the Meiji period, the Horticultural Department of the Agricultural Experiment Station of the Ministry of Agriculture, established in 1902 (Meiji 35), conducted surveys and collected superior varieties from across the country, introducing varieties such as Fuyu, Jiro, Hiratanenashi, and Yokono. Furthermore, as the Taisho and Showa periods progressed, the number of varieties increased as local varieties were identified nationwide, and according to Kikuchi Akio, the number was estimated to be between 800 and 1,000 in the early Showa period.

This specific differentiation of varieties is believed to be due to the fact that persimmons are suited to the Japanese climate, that seedlings grow well whether natural or artificial, that they can be passed down from seedling to seedling, that farmers selected them during this time, and that they were supported by the pride of "our persimmon is the best in Japan," which is why famous varieties are scattered all over the country. Modern cultivation as orchards began around the early Taisho period, and today, sweet persimmons are mainly cultivated with Fuyu and Jiro, Izu, Nishimura Wase, Hanagosho, Mizushima, Kara, and Amahyakume, while astringent persimmons are cultivated with many regional varieties such as Hiratanenashi, Aizu Mishirazu, Yotsumizo, Koshu Hyakume, Hagakure, Dojo Hachiya, Ichida Kaki, Yokono, and Gionbo. There are also completely sweet persimmons and completely astringent persimmons, and there are many variations between the two, and the difficulty of removing astringency varies. This is because the amount of astringency remaining in the flesh of the fruit varies depending on the number of seeds inside the fruit, the amount of brown spots on the flesh, and the temperature during the growing season (higher temperatures make it easier to remove astringency).

[Muneo Iizuka March 22, 2021]

Cultivation

They can be cultivated throughout Japan except Okinawa and Hokkaido. Astringent persimmons can be grown in the Tohoku region, but sweet persimmons remain astringent in cold regions, so they can only be grown commercially in Niigata and Fukushima Prefectures, and they grow well in areas where citrus fruits grow well. The soil should be clay soil or clay loam, which has strong water retention and no stagnant water. They are propagated by grafting, using Mamegaki rootstocks in cold regions and shared rootstocks (seedlings) in warm regions, but there are also Mamegaki rootstocks such as Fuyu, Jiro, and Yokono, which are incompatible for grafting, so in this case they should be grown using shared rootstocks. They are vulnerable to late frosts during the budding period. As the saying goes, "peaches and chestnuts take three years, and persimmons take eight," and it is thought that they require many years to cultivate, but they can be grown well even in residential areas if you pay attention to anthracnose and persimmon stalk beetles. For anthracnose, in addition to removing the affected areas, spray a 10x solution of lime sulfur containing a 200x solution of Klon just before germination. During growth, spray a 1500x solution of thiophanate methyl (Topsin M wettable powder) before rainfall. This also prevents powdery mildew and black spot. Persimmon stalk beetles appear twice a year, so spray a 800x solution of Sumithion emulsion four times in total, in early and late June during the first outbreak and early and late August during the second outbreak. Planting varies by variety, but 40 plants are planted per 10 ares in normal soil. Pay attention to the nature of males and females, and mix varieties that only produce female flowers with varieties that produce male flowers for pollination. Fertilizer should be 13 kg of nitrogen, 9 kg of phosphoric acid, and 13 kg of potassium for a 10-year-old field. Many varieties are alternate-bearing, so in order to make them bear fruit every year, you need to prune them every year to prevent excessive fruiting, create strong fruiting branches, and make sure they don't become deficient in fertilizer.

In 1999, the cultivation area was about 25,000 hectares, of which 10,700 hectares were Fuyu and Jiro, 2,820 hectares were sweet persimmons, and 11,300 hectares were astringent persimmons. Sweet persimmons are often cultivated in Fukuoka, Gifu, and Nara prefectures, while astringent persimmons are often cultivated in Yamagata, Fukushima, and Wakayama prefectures.

[Muneo Iizuka March 22, 2021]

The total cultivation area in 2018 was 19,100 hectares, of which 2,530 hectares were in Wakayama Prefecture, 1,800 hectares in Nara Prefecture, 1,250 hectares in Fukuoka Prefecture, and 1,240 hectares in Gifu Prefecture.

[Editorial Department, March 22, 2021]

Persimmon

The persimmon genus is found mainly in Asia and Africa, but also widely in the Americas, and belongs to the family Ebenaceae along with the genera Euclea and Lissocarpa . They are evergreen or deciduous tall or low trees, and are used widely in various ways depending on the region, including as fruit trees, timber, fish poison, dyes, medicines, etc. The fruits of the edible fruit are mainly kaki and several other species, and there are many in different regions, but the black sapote, native to Mexico, is an excellent variety.

As a material for use, ebony is widely known, and there are about 50 species. As for medicinal purposes, the dried stem of a persimmon (the persistent calyx) is called a persimmon stalk, and taking the boiled juice has been said to be effective against hiccups since ancient times, and has been considered a miracle cure. Persimmon tannins and leaves are also used as folk medicines.

[Muneo Iizuka March 22, 2021]

The Ebenaceae family, to which the genus Diospyros belongs, is also considered to be part of the Ebenaceae family in the APG classification. The Ebenaceae family is made up of about 800 species in four genera, mainly in the tropical and subtropical regions of the world, and eight species of the genus Diospyros can be found in Japan.

[Editorial Department, March 22, 2021]

nutrition

The raw fruit of the sweet persimmon contains 15.9% carbohydrates, mainly glucose (6%) and fructose (4%), 0.4% protein, 0.2% lipids, and 0.4% ash. 100 grams of flesh contains 0.12 milligrams of vitamin A (as carotene), 0.03 milligrams of _{vitamin B1} , and 70 milligrams of vitamin C, and has an energy content of approximately 60 kilocalories.

[Muneo Iizuka March 22, 2021]

Removing bitterness

The phenomenon in which the astringency of fruit is no longer felt is called "removal of astringency," and the difference between sweet and astringent persimmons depends on the timing of removal of astringency. It has been said that the astringency of persimmons is based on the solubility of shibuol in the tannin cells present in the tissue. Shibuol is thought to be a type of polyphenol called leucoanthocyanin, and if it is soluble in the fruit, it is astringent, and if it is insoluble, it is sweet due to the sugars that are naturally accumulated in the fruit. In other words, as the fruit develops, insolubilization of shibuol occurs relatively early in sweet persimmons, but in astringent persimmons, this does not occur until the persimmon becomes ripe. Sawashi persimmons are made by artificially promoting the production of acetaldehyde and other substances in the astringent persimmon, which then condense this with soluble astringent substances to make them insoluble. The sesame seeds (brown spots) in the fruit are the result of oxidation of this. The tannins in the tannin cells of a fruit that has been deastringent solidify and shrink inside the cells or outside the ruptured cells.

[Muneo Iizuka March 22, 2021]

How to make Sawashi persimmon

(1) Alcohol-based method of removing astringency In the past, this was done by using sake in sake barrels, and is therefore also known as the "tarunuki" method, but nowadays plastic bags are used. 20 kilograms of astringent persimmons are sprayed with 80 milliliters of 35% alcohol, which is then layered and packed into plastic bags, which are then sealed and boxed. After a few days, the astringency is removed and the fruit becomes sweet. At home, the stems of each fruit can be treated by soaking them in alcohol, and two stems are placed together and wrapped in newspaper, which is then placed in a thick plastic bag with as little air as possible and sealed, and left indoors for a few days to remove the astringency. Shochu or whiskey can also be used.

(2) Hot water method for removing astringency: Immerse the fruit in 45°C hot water for about 10 hours, being careful not to let it get too cold, and the fruit will become sweeter.

(3) Carbon Dioxide Removal Method: The bitterness is removed using liquefied carbon dioxide or dry ice.

Other methods for removing astringency include soaking in lime milk and heating.

[Muneo Iizuka March 22, 2021]

Dried persimmon

Dried persimmons are harvested while still hard, peeled, and sweetened by drying in the sun or over a fire. They are called kushi-gaki (skewered persimmons), koro-gaki (rolled persimmons), tsurushi-gaki (hanging persimmons), etc., depending on the production method. When dried in the sun, they are dried for 3-4 weeks before being brought into the farm. The dried fruit is then kneaded to soften it, the core is removed, and it is left out of the wind for 3-4 days. It is then dried in the sun for another 3-4 days, and then brought into the farm again. If this process is repeated 2-3 times, it will become white-powdered. If this dried fruit is stored in layers with rice straw, a white powder made of glucose and fructose will spread out. Dried persimmons are often made in Fukushima, Yamanashi, Nagano, Yamagata, and other prefectures with dry air. To prevent dried persimmons from turning black, it is recommended to fumigate them with sulfur. Sulfur burns to produce sulfurous acid gas, which reacts with the water in the fruit to produce sulfurous acid. This prevents the tannins from oxidizing and browning. Fumigation with 10 grams of sulfur per cubic meter for 10 to 20 minutes is sufficient. The peeled skin is dried and used as livestock feed, or as a sweetener for pickles. Secondary processing of dried persimmons includes rolled persimmons in Tokushima and persimmon yokan in Gifu.

[Muneo Iizuka March 22, 2021]

Other uses

Persimmon tannin is made by crushing young, freshly picked fruits or Japanese bean pears, collecting the juice, allowing it to ferment naturally, and maturing it in a cool, dark place for 1-2 years until it becomes the supernatant liquid. It is used as an undercoat for lacquerware, as tannin paper, and to reinforce hemp nets for silkworm cages and hemp fishing nets. It is also used as a clarifier in the sake brewing process. The filtrate (roeki), which is fermented and maturated after the unripe fruits have fallen, is collected and called kakisu (persimmon vinegar), and is edible. Persimmons with black heartwood are called kuro gaki zai (black persimmon wood) and are prized for furniture. The wood is also used for golf club parts.

[Muneo Iizuka March 22, 2021]

Folklore

Persimmons have been cultivated since ancient times, and in addition to their practical uses, they also have a variety of folk customs related to folk beliefs. In the "Narikizeme" ceremony held in various places on Koshogatsu (Little New Year), persimmons are the main target among other fruit trees. In this question-and-answer style ritual, one person approaches the fruit tree with a saw or hatchet and asks, "Will it grow or not? If not, I'll cut it down," while making a small cut in the bark. The other person replies, "It will grow, it will grow," and applies red bean porridge to the cut. In other words, the ritual is a prayer for a bountiful harvest of persimmons, following the steps of question → threat → oath → reward, and can also be considered an event to celebrate a good rice harvest. There is also a custom in which newlyweds discuss persimmons on their wedding night in hopes of sharing in the fertility of persimmons (they are said to produce many fruits). Some legends about Kakinomoto no Hitomaro that are circulated around the country say that Hitomaro was a child prodigy who appeared under a persimmon tree, born from the tree's forks. Conversely, there is a story in the old tale "The Stepchild and the Bird" in which the corpse of a stepchild is buried under a persimmon tree, and there is also a folk belief that a supernatural spirit appears from under a persimmon tree. For these reasons, persimmons are thought to have been seen as a medium for life, or as a medium between the afterlife and this world, and not only are they given special status as food and offerings during Obon and New Year, but they are also associated with various taboos and folk beliefs. In addition to these folk customs, persimmons also appear as important elements in old tales such as "The Battle of the Monkey and the Crab," "The Brown Chestnut and Persimmon," "The Picture Wife," and "Ten Persimmons and Eleven."

[Kenzo Matsuzaki March 22, 2021]

Sweet persimmon (Jiro)
©Shogakukan ">

Sweet persimmon (Jiro)

Sweet persimmon (Nishimura Wase)
©Shogakukan ">

Sweet persimmon (Nishimura Wase)

Sweet persimmon (Fuyu)
©Shogakukan ">

Sweet persimmon (Fuyu)

Astringent persimmon (Atago)
©Shogakukan Photo by Hideyuki Asakura ">

Astringent persimmon (Atago)

Astringent persimmon (Koshu Hyakume)
©Shogakukan ">

Astringent persimmon (Koshu Hyakume)

Astringent persimmon (Saijo)
©Shogakukan ">

Astringent persimmon (Saijo)

Astringent persimmon (Tono Wase)
Persimmons on the tree are covered with bags and poured with solid alcohol to remove the astringency. They are prone to developing brown spots like sweet persimmons. ©Shogakukan ">

Astringent persimmon (Tono Wase)

Astringent persimmon (without seed)
©Shogakukan ">

Astringent persimmon (without seed)

Dried persimmon
The photo shows raw dried dried persimmons ©Shogakukan ">

Dried persimmon

Making dried persimmons
"Tsurushigaki" is a type of persimmon that is peeled and hung on a thin rope or thread to dry. Date City, Fukushima Prefecture ©Shogakukan ">

Making dried persimmons

Rolled persimmon
Tokushima Prefecture ©Shogakukan ">

Rolled persimmon

Persimmon female flower
It has a short flower stalk, about 2 cm in diameter. Pale milky white flowers grow in the axillae from late May to early June. ©Shogakukan Photo by Masatoshi Hirose ">

Persimmon female flower

Persimmon fruit (Aizu Mishirazu)
Astringent persimmons have long been cultivated in the Aizu region of Fukushima Prefecture and its surrounding areas. They are shipped after undergoing a process to remove the astringency. ©Shogakukan ">

Persimmon fruit (Aizu Mishirazu)

Persimmon fruit (Koshu Hyakume)
Astringent persimmons are produced in large quantities in Yamanashi Prefecture. They are large and are often used as dried persimmons. ©Shogakukan ">

Persimmon fruit (Koshu Hyakume)

Persimmon fruit (Gose)
This sweet persimmon is said to have originated in Gose City, Nara Prefecture. It has long been known for its delicious taste .

Persimmon fruit (Gose)

Persimmon fruit (Jiro)
Sweet persimmons native to Morimachi, Shuchi District, Shizuoka Prefecture. The original trees remain within the town. ©Shogakukan ">

Persimmon fruit (Jiro)

Persimmon fruit (four grooves)
A type of persimmon cultivated from eastern Shizuoka Prefecture to western Kanagawa Prefecture. It is characterized by four grooves on the surface of the fruit .

Persimmon fruit (four grooves)

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

カキノキ科（APG分類：カキノキ科）の落葉高木。染色体数は2n＝90。原生地は中国、朝鮮、日本といわれるが、初めは中国中部であったものと考えられる。幹は直立し、よく分枝し、若枝には細毛を密生する。成木の樹皮は鱗(うろこ)状に亀裂(きれつ)を生ずる。葉は互生し短い葉柄をもち、短楕円(だえん)形で先端はとがり、長さ約10センチメートル、革質で全縁、表面は平滑で光沢がある。秋に紅葉する。虫媒花で、雌花のみをつける雌株、雌花と雄花をつける雌雄同株、雌花と雄花および両性花を混生する雌雄同株、雄花のみをつける雄株とがある多形雌雄異株性を示す。花はいずれも腋生(えきせい)し、淡乳白色。雌花は短い花柄をもって単生し、花径約2センチメートル。雄花は1個ないし数個からなる集散花序につき、花径0.7～1センチメートル。いずれも緑色の4裂片の萼(がく)をもち、花冠は壺(つぼ)状で、先端は4裂し反転する。雌花には通常、退化した8本の雄しべと8裂した雌しべをつける。子房は大きく、8子室で各室1個の胚珠(はいしゅ)をもつ。雄花には11～25本、通常は16本の雄しべがあり、内外2列に配列する。開花は5月下旬から6月上旬、蜜(みつ)を分泌し芳香が強い。果実は大小さまざまで、円、楕円、扁円(へんえん)、円錐(えんすい)、長円錐形などがある。果皮は9月下旬から11月にかけて黄ないし黄赤色となり、甘柿は脱渋(だつじゅう)して甘くなるが、渋柿はなお渋い。甘柿、渋柿ともにさらに熟度が進むと、果肉は赤橙(せきとう)色を増し、肉質が軟化し、熟柿(じゅくし)となり、渋柿も甘くなる。果色はカロチンおよびリコピンによる。

［飯塚宗夫　2021年3月22日］

栽培史

カキの栽培は中国がもっとも古く、2500年前の『礼記(らいき)』に記載がある。中国中部陝西(せんせい)省を含む地方では、前漢の文学者司馬相如(しばしょうじょ)による『上林賦(じょうりんのふ)』に栽培適地が記されており、6世紀前半の農書『斉民要術(せいみんようじゅつ)』には、ひこばえの利用とマメガキを台木とした接木(つぎき)繁殖の方法が記されている。また11世紀中期の本草書『経本草(とうけいほんぞう)』には多数の品種があり、朱色の品種も記載がある。今日では、東北区、内モンゴル、チベットなど冷涼地や高地を除く多くの省で栽培されている。大別して北方系は耐寒性、耐乾燥性があり、果皮は薄く果色は淡いが、南方系は耐寒性、耐乾燥性は弱く、果皮は厚く果色は濃い。品種は200種以上あり、磨盤柿、重台柿などは生食用、牛心柿、尖柿、鏡面柿などは加工用として広く栽培され、干し柿の輸出もみられる。朝鮮での栽培は南部に多く、舎谷柿(しゃこくし)、清道柿(せいどうし)などの渋柿が名高い。ヨーロッパへは19世紀に中国から、またアメリカへは19世紀なかばに日本から導入された。ブラジルへは日本移民によって導入されたものが多く、甘柿、渋柿ともに広まっている。

　日本での栽培も古く、『本草和名(ほんぞうわみょう)』（918）に加岐、『倭名類聚抄(わみょうるいじゅしょう)』（931～938ころ）には賀岐と記されている。また『延喜式(えんぎしき)』（927）によれば、熟柿や干し柿が利用され、宮廷でも栽培された。当時のカキの実は小さかったのか升目で量られた。また甘柿、渋柿の区別はなかった。甘柿、渋柿の区別が現れるのは1300年前後の作とされる『庭訓往来(ていきんおうらい)』以降で、樹淡(きざわし)、木練(こねり)は甘柿を、かきは渋柿を意味したといわれ、熟柿や串(くし)柿も記されており、鎌倉時代には甘柿が栽培されていたことがわかる。古い品種として知られる禅寺丸(ぜんじまる)は1214年（建保2）に、現在の神奈川県川崎市柿生(かきお)の王禅寺の星宿山(せいしゅくさん)蓮蔵院(れんぞういん)の再建に際し、山中で偶然に発見され、当初は王禅寺丸とよばれたが、当時としてはよい品種で普及し、のちに禅寺丸とよばれるようになったという。室町時代の『尺素往来(せきそおうらい)』には柿と稗柿(ほしがき)および串柿の別があげられている。17世紀後半になると『雍州府志(ようしゅうふし)』に木練、五所(ごしょ)柿、筆柿、渋柿、木醂(きざわし)柿、醂柿、鈎(つるし)柿、転(ころ)柿がみえ、品種や脱渋法、干し柿乾燥法などが紹介され、また同じころの『農業全書』には木練、御所(ごしょ)柿などの品種がみえる。18世紀になると品種も増え、江戸時代、享保(きょうほう)～元文(げんぶん)期（1716～1741）にかけて、水戸藩の『御領内産物』には御所、蜂屋(はちや)、美濃、四ツ溝、妙丹などが紹介され、金沢藩の『加州物産志』には、御所、円座(えんざ)、蜂屋、八平子(はちへいじ)、妙丹、西条など45品種が記録されている。また『長防二州産物彙』は、西条、葉隠(はがくし)、祇園坊など36品種をあげている。このように、今日栽培される多数の品種は18世紀中ごろにはすでにあり、19世紀、江戸末期の『本草綱目啓蒙(ほんぞうこうもくけいもう)』（1803）には200余品種ありとし、中国との品種の対照考察も行われている。さらに明治に入ると、1902年（明治35）に設立された農務省農事試験場園芸部は全国的に優良品種の調査と収集を行い、富有(ふゆう)、次郎、平核無(ひらたねなし)、横野(よこの)などを紹介した。さらに、大正、昭和へと進み、全国的に地方の品種が判明するにつれて品種数は増し、菊池秋雄によれば、昭和初期にはその数800～1000種と推定された。

　このような品種の特異的分化は、カキが日本の風土に適し、自然、人為を問わず実生(みしょう)個体がよく育ち、実生から実生へと代を重ねることができ、この間に農民によって選抜され、「わが家の柿こそ日本一」との誇りによって支えられてきたものと考えられ、有名品種が各地方随所に散在するのはこのためである。果樹園としての近代的栽培が始まったのは大正初期ころからで、今日、甘柿では富有、次郎を主とし、伊豆、西村早生(わせ)、花御所、水島、伽羅(から)、甘百目(あまひゃくめ)などが栽培され、渋柿では平核無、会津身不知(みしらず)、四ツ溝、甲州百目、葉隠、堂上(どうじょう)蜂屋、市田柿、横野、祇園坊など、地方特有品種の栽培が多い。なお、柿には完全甘柿と完全渋柿とがあり、両者の間に多様の変異があり、脱渋に難易の差がある。これは果実内の種子数と果肉への褐斑(かっぱん)の入りぐあいや、発育期の気温の高低（高いほうが脱渋しやすい）などにより、果肉内への渋の残留程度が異なることによる。

［飯塚宗夫　2021年3月22日］

栽培

沖縄と北海道を除く日本全土で栽培できる。渋柿は東北地方でもよいが、甘柿は寒冷地では渋が残るため営利栽培は新潟と福島県までで、柑橘(かんきつ)類がよくできる地帯によいものができる。土壌は、保水力が強く停滞水のない埴土(しょくど)ないし埴壌土がよい。繁殖は接木により、寒地ではマメガキ台、暖地では共台(ともだい)（実生苗）を用いるが、マメガキ台には富有、次郎、横野などのように接木不親和の品種もあり、この場合は共台による。萌芽(ほうが)期の晩霜に弱い。「モモ、クリ三年、カキ八年」といわれるように、栽培は長年月が必要と考えられているが、一般宅地内でも、炭疽(たんそ)病やカキヘタムシなどに注意すればよくできる。炭疽病には病斑(びょうはん)部切除のほか、発芽直前に「クロン」200倍液を加えた石灰硫黄(いおう)合剤10倍液を散布する。発育中には降雨前にチオファネートメチル剤（「トップジンM」水和剤）1500倍液を散布する。これらによって、うどん粉病、黒星病なども防止できる。カキヘタムシは年2回発生するので、1回目の発生期の6月上旬と下旬、2回目の発生期の8月上旬と下旬に計4回、「スミチオン乳剤」800倍液を散布する。植え付けは品種による強弱はあるが、普通の土壌で10アール当り40本植えとし、雌雄の性質に注意し、雌花だけをつける品種には、授粉用として雄花をもつける品種を混植する。肥料は10年生圃場(ほじょう)で窒素13キログラム、リン酸9キログラム、カリ13キログラムとする。多くの品種が隔年結果性をもつので、毎年実をつけさせるには、結実しすぎないように毎年剪定(せんてい)し、強い結果枝をつくり、また、肥料不足にならないようにすることで解決できる。

　1999年（平成11）の栽培面積は約2万5000ヘクタール、そのうち富有、次郎で1万0700ヘクタール、そのほかの甘柿が2820ヘクタール、渋柿が1万1300ヘクタールとなっている。甘柿は福岡、岐阜、奈良県に、渋柿は山形、福島、和歌山県でよく栽培される。

［飯塚宗夫　2021年3月22日］

　2018年（平成30）の栽培面積は1万9100ヘクタール、そのうち和歌山県が2530ヘクタール、奈良県が1800ヘクタール、福岡県が1250ヘクタール、岐阜県が1240ヘクタールとなっている。

［編集部　2021年3月22日］

カキノキ属

カキノキ属の植物はアジア、アフリカを主とし、アメリカ大陸にも広く分布し、ユウクレア属Euclea、リッソカルパ属Lissocarpaとともにカキノキ科に属する。常緑または落葉性の高木ないし低木で、果樹のほか用材、魚毒、染料、薬用などのほか、地方ごとにさまざまな用途があり、きわめて広く利用される。果実を食用とする種類は、おもなものはカキのほか数種で、地域的には多数あるが、そのなかではメキシコ原産のブラックサポテは優れた種類である。

　用材としてはコクタンが広く知られ、約50種ある。また薬用としては、カキのへた（宿存花萼(かがく)）を乾燥したものを柿蒂(してい)といい、煮汁を服用すると古来えつき（しゃっくり）に効くといわれ、特効薬とされてきた。柿渋や葉も民間薬として用いられている。

［飯塚宗夫　2021年3月22日］

　カキノキ属が属するカキノキ科EbenaceaeはAPG分類でもカキノキ科とされる。カキノキ科は、世界の熱帯・亜熱帯を中心に4属800種ほどが知られ、日本にはカキノキ属8種がみられる。

［編集部　2021年3月22日］

栄養

甘ガキの生果実中には、ブドウ糖（6％）、果糖（4％）を主とする炭水化物15.9％、タンパク質0.4％、脂質0.2％、灰分0.4％を含み、果肉100グラム中にビタミンAをカロチンとして0.12ミリグラム、B₁を0.03ミリグラム、Cを70ミリグラム含み、熱量は約60キロカロリーである。

［飯塚宗夫　2021年3月22日］

脱渋

果実の渋味が感じなくなる現象を脱渋(だつじゅう)といい、甘と渋の差は脱渋の早晩による。柿果の渋味は、組織中に存在するタンニン細胞中のシブオールの可溶性に基づくといわれてきた。シブオールはポリフェノールの一種であるロイコアントシアンであると考えられ、これが果実内で可溶性の状態にあれば渋く、不溶性であれば本来果実内に蓄積されている糖類により甘い。つまり、果実の発育に伴って、甘柿ではシブオールの不溶化が比較的早くからおきるが、渋柿では熟柿(じゅくし)になるまでおきない。さわし柿は、渋柿の果実中に人為的にアセトアルデヒドなどの生成を促し、これと溶解性の渋味物質とを縮合させて不溶性にしたものである。果実内のごま（褐斑(かっぱん)）はこれが酸化したものである。脱渋した果実のタンニン細胞のタンニンは、細胞内または破裂した細胞外で凝固、収縮している。

［飯塚宗夫　2021年3月22日］

さわし柿の作り方

(1)酒精脱渋法　昔は酒樽(さかだる)に清酒を用いて脱渋していたため樽抜(たるぬき)法ともいうが、今日ではビニル袋を用いている。渋柿果実20キログラムに対し、35％の酒精80ミリリットルを噴霧し、これをビニル袋に層状に詰めて密閉し、箱詰めにする。数日で脱渋し甘くなる。家庭では1果ごとにへたの部分を酒精に漬けて処理し、2個ずつへた部をあわせて新聞紙に包み、これを厚手のビニル袋内に空気を少なくして密閉し、数日室内に置くと脱渋する。焼酎(しょうちゅう)またはウイスキーを用いてもよい。

(2)温湯脱渋法　45℃の温湯に果実を浸漬(しんし)し、冷えないように注意して十数時間保つと甘くなる。

(3)炭酸ガス脱渋法　液化炭酸ガスやドライアイスなどを用いて脱渋する。

　このほか石灰乳浸漬法、火熱法などでも脱渋する。

［飯塚宗夫　2021年3月22日］

干し柿

渋柿を堅いうちに収穫して皮をむき、天日や火力で乾燥させて甘くしたものが干し柿である。製造法によって串(くし)柿、転(ころ)柿、つるし柿などとよぶ。天日乾燥では、3～4週間乾燥したのちに取り込み、乾果をもんで柔らかくする芯(しん)切りをし、3～4日風に当てずに置く。その後さらに3～4日天日乾燥をして、また取り込む。これを2～3回繰り返すと白粉を帯びる。この乾果を稲藁(いねわら)と交互に層状に蓄えると、ブドウ糖や果糖からなる白い粉がふいてくる。空気の乾燥している福島、山梨、長野、山形県などで多くつくられる。干し柿の黒変を防ぐには硫黄(いおう)薫蒸を行うとよい。硫黄が燃えて亜硫酸ガスができ、これが果実内の水と反応して亜硫酸ができる。これによりタンニンの酸化褐変を防ぐ。硫黄は1立方メートル当り10グラム、10～20分の薫蒸でよい。むいた皮は乾燥して家畜の飼料とするほか、漬物などの甘味源とする。なお、干し柿の二次加工として徳島の巻柿、岐阜の柿羊羹(ようかん)などがある。

［飯塚宗夫　2021年3月22日］

その他の利用

柿渋は、もぎたての若い果実やマメガキをつぶして搾汁を集め、これを自然発酵させ、1～2年冷暗所で熟成させてできた上澄み液である。漆器の下塗り、渋紙に利用し、蚕座の麻網や麻製漁網などの補強に用いた。また、清酒醸造過程の清澄剤として用いられる。落下した未熟果を集め、発酵熟成させた濾液(ろえき)を柿酢(かきす)とよび、食用とする。柿材のなかで心材の黒いものを黒柿材(くろがきざい)とよび、家具に珍重される。また、材はゴルフのクラブの部品ともする。

［飯塚宗夫　2021年3月22日］

民俗

カキは古くから栽培されてきただけに実用として用いられるほか、民間信仰とかかわる多様な民俗をもっている。小正月(こしょうがつ)に各地で行われる「成木責(なりきぜ)め」でも、他の果樹のなかではカキが主たる対象となっている。問答形式をとるこの儀礼は、1人が鋸(のこぎり)や鉈(なた)を手にして果樹に向かい、「成るか成らぬか、成らねば伐(き)るぞ」と問いかけながら樹皮にすこし傷をつけ、他の1人が「成ります成ります」と答えてその傷に小豆粥(あずきがゆ)を塗るものである。すなわち、問いかけ→威嚇→誓約→報酬という手順を経てカキの実の豊穣(ほうじょう)を祈るもので、さらに敷衍(ふえん)させてイネの豊作を予祝する行事とみなすこともある。カキの豊穣性（実が多くなるという）にあやかろうと、新婚夫婦が初夜の床でカキについて問答する習俗もみられる。また、各地に流布する柿本人麻呂(かきのもとのひとまろ)伝説のなかには、人麻呂はカキの木の下に出現した神童で、カキの木の叉(また)から生まれたと伝えるものもある。これとは逆に、継子(ままこ)の死体をカキの木の下に埋めるという話が昔話の「継子と鳥」のなかで語られており、さらにはカキの木の下から妖怪(ようかい)が現れるといった俗信もある。こうしたことからカキは、生命を媒介する、あるいは他界と現世とを媒介する存在としてとらえられていたとも考えられ、盆や正月の食べ物、供え物として特別視されているばかりでなく、さまざまな禁忌や俗信を伴っている。なお、このような民俗のほかにも、昔話の「猿蟹合戦(さるかにがっせん)」や「茶栗柿(ちゃくりかき)」「絵姿女房」「柿十(かきとお)と十一(じゅういち)」などのなかで、カキは重要な構成要素として登場している。

［松崎憲三　2021年3月22日］