Applicability of Hinokitiol-Added Gelatin/Konjac Glucomannan-Based Coatings for the Preservation of Fresh Fruits Cultivated in Japan

Hinokitiol (HT) is a food additive with strong iron ion chelating activity, antimicrobial activity, and ethylene biosynthesis inhibition. In this research, the effects of mixed gelatin (GE) and konjac glucomannan (KGM)-based edible coatings with HT and odorless coconut oil (OCO) on the postharvest quality of persimmon (Diospyros kaki L.f.), Japanese pear (Pyrus pyrifolia (Burm. f.) Nakai), and apple (Malus pumila Mill. var. domestica Schneid.) fruits were investigated. Fruit samples were treated with the edible coating by dipping method and physicochemical properties and disease severity caused by gray mold were determined at 25℃. The results showed that HT-incorporated coating was detrimental to persimmon quality, causing rapid softening and browning, but beneficial to pear and apple quality, inhibiting gray mold rot and ethylene production when HT at more than 1,500 mg L^-1 concentration was incorporated. However, the coating also induced browning and fermentation in pear and apple after 14 days of storage. Therefore, this HT-incorporated edible coating could be applied for short-term preservation of pear and apple at ambient temperature, but not for long-term storage or for persimmon.