drying-based kaki de-astringing
process / process-kaki-drying-deastringing
はく皮乾燥・干し柿による脱渋
Astringency removal that occurs as peeled fruit hangs in a well-ventilated place to dry naturally; it is also the production process for dried persimmons. Sulfur fumigation may precede drying to improve color.
On this page (8 sections)
Reading the bitterness
Dried persimmons are made by peeling astringent persimmons, hanging them in a well-ventilated place, and allowing astringency to diminish during natural drying. An account of a dried-persimmon factory says peeled fruit is fumigated with sulfur before sun-drying and finishing as a product. Another source notes that many astringent cultivars can be eaten when dried but do not readily lose astringency through deastringency treatment. Drying is thus presented as a distinct use route from treatment for eating the fresh fruit.
In a 1992 experiment by Inari and Tomoeda using 'Hachiya' persimmons harvested in Gifu Prefecture in November 1987, drying and astringency removal were compared under 3 conditions: standard fumigation with 20 g sulfur burned for 20 minutes, a doubled treatment with 40 g for 60 minutes, and no fumigation. The untreated fruit lost astringency fastest, in about 1 week. More sulfur meant more days, but even the doubled treatment lost astringency in 3 weeks, with only slight astringency remaining. During drying, alcohol dehydrogenase (ADH) activity was not detected in any group, whereas pyruvate decarboxylase (PDC) activity was present in all groups; PDC was therefore inferred to participate in drying-related deastringency.
A separate study of dried persimmon chips used trained-panel descriptive sensory analysis on 40 cultivars finished by hot-air drying, rather than traditional natural hanging. It measured bitterness as one taste attribute alongside sweetness, sourness, and saltiness, and identified bitterness, together with astringency, crispness, skin toughness, fibrousness, and sourness, as factors tending to lower consumers' preference rankings. Numerical bitterness intensities are not given in the main text and appear only in supplementary figures and tables.
Sources for this overview
柿の脱渋に関する一考察(第2報) タンニンの不溶化及びそれに関与する酵素活性の変動
Checked for this overview: Used as evidence for the opening explanation that dried persimmons lose astringency during drying. / Used as evidence for measured deastringency speed and PDC and ADH activity under 3 sulfur conditions.
Checked for this overview: Used as evidence for the statement that astringent cultivars do not readily lose astringency through deastringency treatment.
Checked for this overview: Bitterness was described as a negative preference driver in hot-air-dried persimmon chips.
Follow the connections
Hoshigaki (dried persimmon) →is prepared by→ drying-based kaki de-astringing
drying-based kaki de-astringing →is documented as having→ bitterness →can be measured separately …→ astringency
Structured claims — open a section to read each claim's confidence, evidence and limits
Sensory (1)
Scope: Layer: food. Chips from 40 persimmon cultivars; trained-panel descriptive analysis (4 taste attributes calibrated at 4 reference-concentration levels) and a PLSR regression model of preference rankings from more than 100 consumers.
Note: This source used hot-air drying, unlike the traditional peeled-fruit natural drying (sometimes with sulfur fumigation) addressed by the existing claim. Mean numerical bitterness intensity is not given in the main text, only in supplementary figures (Supplemental Figure S4), so the verbatim quotation is limited to the qualitative description.
Show data
process-kaki-drying-deastringing —is_documented_as_having→ sensation-bitterMechanism and receptors (1)
Scope: 'Hachiya' persimmons (grown in Gifu Prefecture), harvested in November 1987.
Note: Inari & Tomoeda (1992).
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process-kaki-drying-deastringing —has_currently_proposed_mechanisms→ "In making dried persimmon (hoshigaki), the usual practice is to fumigate the peeled persimmon with sulfur, to make the color beautiful, and then sun-dry it. In an experiment comparing a standard batch burning 20 g of sulfur for 20 minutes, a double-dose batch burning 40 g for 60 minutes, and an untreated batch, the untreated batch de-astringed fastest (in 1 week); the more sulfur used, the more days de-astringing took, but even the double-dose batch de-astringed in 3 weeks (with a slight astringency remaining). During drying, ADH activity was not detected in any batch, while PDC activity was present in every batch, from which it was inferred that PDC is involved in de-astringing by drying."How processing and cooking change it (1)
Note: Dried persimmon (hoshigaki) made from astringent persimmon is a processed product that makes use of the fact that de-astringing proceeds in the process of peeling and drying the fruit. Based on the description of a dried-persimmon (hoshigaki) workshop in Inari & Tomoeda (1992), and on the statement of Yamada et al. (2012), 「多くの渋ガキ品種は、干柿にすれば食用とはできるが、脱渋処理をしても容易に脱渋しない」 (in translation: “many astringent persimmon cultivars can be made edible as dried persimmon (hoshigaki), but do not readily de-astringe even with de-astringing treatment”).
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ingredient-hoshigaki —is_prepared_by→ process-kaki-drying-deastringing