エチレンおよび脂肪酸処理がカキ'西条'果実の熟柿化に及ぼす影響(収穫後の貯蔵・流通)  [in Japanese] Effect of Ethylene and Fatty Acid Treatment on Soft-ripening in Japanese Persimmon (Diospyros kaki Thunb.) 'Saijo' Fruit(Postharvest Physiology & Technology)  [in Japanese]

低温貯蔵したカキ'西条'果実を材料として,熟柿を安定して製造する方法の確立を目指し実験を行った.果実の軟化はヘタ近傍から始まった.この軟化開始は無処理とγ-リノレン酸100μL,エチレン100ppm48時間処理果で,それぞれ23と16,3日後に認められた.いずれの処理においても,果実は軟化開始後3日ですべて完全脱渋し熟柿となった.エチレン処理によりすべての果実は処理後6日で斉一に熟柿となった.エチレン処理は熟柿化に要する期間が最短で最も信頼できる方法と思われた.エチレン処理により果皮の着色は改善し,果実硬度は処理後直線的に低下した.また,可溶性タンニン含量は処理開始後3日から減少が始まり,6日で完全脱渋した.OOCで2から8週間貯蔵した果実はいずれもエチレン処理開始後6日に熟柿になったが,4週間以上貯蔵した場合には裂果が見られた.

To establish a stable production method for soft ripe 'Saijo' persimmon (Diospyros kaki Thunb.) fruit, the fruit were treated with fatty acids or ethylene after several weeks' storage at 0℃. Softening of the fruit first occurred in the vicinity of the calyx. Partial softening was observed at 23, 16 and 3 days after the beginning of treatment in the control, and those treated with 100μL linolenic acid and 100ppm ethylene for 48 hours, respectively. With each treatment, the fruit soft-ripened (complete removal of astringency) 3 days after partial softening. All the ethylene treated fruit soft-ripened at one time 6 days after the beginning of treatment. Ethylene treatment was found to be the fastest and the most reliable method for producing soft ripe 'Saijo'. Coloration in the ethylene-treated fruit was improved and fruit firmness decreased linearly. Soluble tannin concentration began to decrease 3 days after the beginning of treatment and astringency was removed completely on the sixth day. Fruit that was stored at 0℃ for 2 to 8 weeks and then treated with ethylene soft-ripened 6 days after beginning of treatment. When fruit were stored for longer than 4 weeks at 0℃ and then treated with ethylene, cracking occurred in the fruit during the course of soft-ripening.