Posts Tagged: chilling injury
During this season, Carlos Crisosto, CE postharvest physiologist, Kearney Agricultural Research & Extension Center and the UC Davis Plant Sciences Department, is often asked how to determine maturity, as well as best practices for harvesting and storage of ‘Fuyu’ persimmons. ‘Fuyu’ persimmons completely lose their astringency before harvest and can be consumed while they are still firm. Harvest time is usually determined according to the fruit color and size. The best method of harvesting is to clip the fruit from the tree with small clippers (orange clippers), leaving the calyx attached to the fruit. It is also possible to snap the fruit from the tree but this practice is not recommended as it may injure the fruit and adjoining shoot. During harvesting and packaging, fruit must be handled carefully to avoid bruising, which can result in undesired marking as the fruit ripens. Penicillium, Botrytis and Cladosporium fungi may infect ‘Fuyu’ persimmons during storage, especially, if the skin has been damaged during postharvest handling.
‘Fuyu’ persimmons are very sensitive to chilling injury which is expressed by accelerated fruit softening, flesh browning, and translucency (jelly-like consistency) during and after storage. These symptoms appear more severe after 2-4 days at 68oF (20oC) following storage. Chilling injury is more rapid and severe at 41oF (5oC), especially, combined with ethylene exposure. Previous studies led by Dr. Kader demonstrated that exposure to 1 and 10 ppm ethylene at 68oF (20oC) resulted in accelerated softening to less than 4 pound-force ( the limit for marketability) after 6 and 2 days, respectively. Exposure to 1 and 10 ppm ethylene at 41oF (5oC) will induce fruit firmness below 4 pound-force (soft) after 15 and 8 days, respectively. Therefore, the use of 1-MCP, ethylene removal and/or exclusion of ethylene during packaging and storage at 32oF (0oC) operations is strongly recommended for maintaining quality and extending ‘Fuyu’ persimmon storage life potential.