A study on the simplification of removal of astringency using alkohol gas and ethylene absorbent in Japanese persimon.

Research Project

Project/Area Number	60860004
Research Category	Grant-in-Aid for Developmental Scientific Research
Allocation Type	Single-year Grants
Research Field	園芸・造園学
Research Institution	Tottori University
Principal Investigator	HAYASHI Shinji Department of Agriculture, Tottori University・Professor, 農学部, 教授 (90032052)
Co-Investigator(Kenkyū-buntansha)	BANNO Kiyoshi Department of Agriculture, Tottori University・Assistant, 農学部, 助手 (80127125) TANABE Kenji Department of Agriculture, Tottori University・Assistant prof., 農学部, 助教授 (40032106)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥6,000,000 (Direct Cost: ¥6,000,000) Fiscal Year 1986: ¥2,000,000 (Direct Cost: ¥2,000,000) Fiscal Year 1985: ¥4,000,000 (Direct Cost: ¥4,000,000)
Keywords	Removal of astringency in Japanese persimon / Alkohol gas / ethylene absorbent / Heating pretreatment / ドライアイス脱渋法 / 脱渋 / 炭酸ガス / 平核無 / ポリエチレンフィルム
Research Abstract	In order to develop the simple method of removal of astringency to improve flavor and quality in the excellent astringent cultivar, 'Saizyo', of Japanese persimon grown mainly in Chugoku district, the methods of removal of astringency using alkohol gas and ethylene absorbent were investigated and established in practical technique. The outline is summarized as follows. 1. Method ; Powder alkohol generating ethyl alkohol gas, ethylene absorbent and persimon were sealed up with 50 um-thick polyethylene film bag during 3 to 7 days. 2. Proper dose of treatment ; In 'Saizyo' fruits 24 to 30 g of powder alkohol per 5 kg and 20 g of ethylene absorbent were proper dosage. 3. Temperature of treatment ; Temperature of the treatment to remove astringency are 28 to 30 ゜c during 3 days, which is the same period using dry ice, or 26 ゜c during 4 days. 6 to days were needed in ambient temperature. 4. Prevention of misture injury and improvement of fruit appearance ; To prevent fruit softening and cracking of skin because of over-moisture in the film bag and to promote coloring of fruit skin, these fruits were pretreated to heat at 30 ゜c during 12 to 24 hours. Moreover, by putting the several corgated cardboard sheets in film bag to absorb moisture the injury could almost be prevented. 5. By the above-menthioned treatments it is possible to produce excellent quality, flavor and appearance and imprrove keeping quality of 'Saizyo' fruit. Moreover, this method was intended for practical use in the persimon-growing district of Tottori prefecture from 1986.