先日のニュースで「柿すだれ」が取り上げられていた。「柿すだれ」とは、田舎の民家の軒先などに干し柿を作るために柿を簾のように吊るす風景をいう。以前は晩秋によく見られた光景だったが、これも温暖化の影響で2週間余り先送りされたようである。
干し柿に使われる渋柿は、もともと甘柿よりも糖度が高いのだが、干すことでシブオールと呼ばれる渋味のタンニンが水溶性から不溶性に変化（脱渋反応）し渋味が消える。水分が抜けた干し柿の糖度は甘柿の4倍ほどだと言われている。
干し柿の表面の白い粉はブドウ糖、果糖、蔗糖などの糖分が結晶化したもので、中国では柿霜（しそう）と呼ばれ、生薬として用いられている。柿には高い薬効があることから、「柿が赤くなれば医者が青くなる」という諺まであるほどだ。
柿の歴史は古く、『古事記』や『日本書紀』では「柿」が地名や人名として使われている。例えば、有名な万葉歌人の柿本人麻呂は家に柿の木があったことから「柿本」と名乗ったと言われている。
また、平安時代中期に編纂された『延喜式』では、熟した柿や干し柿が儀式や祭りの供物や天皇への菓子として使われていた。このことから、柿が古くから宮廷で栽培されていたことが窺われる。
（拙・和文英訳）
The other day, the news featured "Kakisudare" (persimmon blinds). “Kakisudare” means a scene of persimmons being hung like blinds on the eves of rural houses to make dried persimmons. Previously, this scene was often seen in late autumn, but due to the global warming, it seems to have been postponed by about two weeks recently.
Bitter (Astringent) persimmons are used for making dried persimmons, but they originally have a higher sugar content than sweet persimmons. When they are dried, the astringent tannin called shibuol changes from water-soluble to insoluble (a de-astringent reaction), making the astringent taste disappear. It is said that the sugar content of dried persimmons after the moisture has been removed is about four times that of sweet persimmons.
The white powder on the surface of dried persimmons is crystallized sugars such as glucose, fructose, and sucrose, and is called shiso (persimmon frost), and is considered a herbal medicine in China. A Chinese proverb says that as persimmons have high medicinal properties, “when persimmons turn red, doctors turn blue.”
Persimmons have a long history. In the Kojiki and Nihon Shoki, the word "kaki" (persimmon) is used as a place name and person’s name. For example, it is said that the Man'yoshu famous poet Kakinomoto no Hitomaro called himself "Kakinomoto" because he had a persimmon tree in his house.
Furthermore, the Engishiki, compiled in the middle Heian period, ripened persimmons and dried persimmons were used as offerings in ceremonies and festivals, and as sweets for the emperor. It is presumed that persimmons would have been cultivated at the imperial court since ancient times.
