Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2011
Publication Date: 6/15/2011
Citation: Wall, M.M., Nishijima, K.A., Keith, L.M., Nagao, M. 2011. Influence of packaging on quality retention of Longans (Dimocarpus longan) under constant and fluctuating postharvest temperatures. HortScience. 46: 917-923. Interpretive Summary: Longan (Dimocarpus longan) fruit production is rapidly expanding in Hawaii, and exports to U.S. mainland markets are increasing concurrently. Consumer acceptance of this high value crop requires that fruit arrive at their final destination in excellent condition with minimal defects. Fruit browning and decay are the main postharvest problems for longans. Research was conducted to establish optimum storage temperatures and packaging systems to manage diseases, improve fruit quality, and extend longan shelf-life. Postharvest and sensory quality was maintained, overall disease incidence minimized, and shelf-life extended when clamshell containers, microperforated packages, or modified atmosphere packaging were used in conjunction with storage at 10°C. However, clamshell containers were most suitable for retaining longan quality under fluctuating temperatures typical during shipping and handling.
Technical Abstract: Longan (Dimocarpus longan) fruit production and global exports are rapidly expanding. Consumer acceptance of this high value crop requires that fruit arrive at their final destination in excellent condition. Pericarp browning and fungal diseases are the main postharvest problems for longans. Research was conducted to establish optimum storage temperatures and packaging systems to retain fruit quality of ‘Biew Kiew’ longans. Average respiration rates for longans stored at 20°C (61.6 mg CO2·kg-1h-1) were about twice the rate as those at 10°C (32.7 mg CO2·kg-1h-1), and triple the rate at 5°C (21.1 mg CO2·kg-1h-1). Ethylene rates were below 0.4 µg·kg-1h-1. Fruit quality and shelf-life were greatest when stored at 10°C. Longans held at 20°C were unmarketable after 10 days, and fruit stored at 5°C exhibited chilling injury. After storage at 10°C, ‘Biew Kiew’ longans packaged in microperforated bags (MP), clamshell containers (CL), or Peakfresh® film (PF) had the highest visual quality ratings, lowest disease incidences and longest shelf-life when compared to fruit in Lifespan® film (LS) or fiberboard boxes. Among fruit exhibiting disease symptoms, the most frequently isolated fungal pathogen was Phomopsis sp., followed by Pestalotiopsis sp. and Colletotrichum sp. The three most promising packages (MP, CL, PF) were evaluated under constant 10°C or simulated shipping (SS) conditions with fluctuating temperatures (22°C/10°C/22°C). Fruit packaged in PF bags had the lowest weight lost (1%) among all package types, and this difference was most pronounced under SS temperatures. Longans in CL containers had the highest visual quality and lowest disease incidence when stored at 10°C, but there were no differences among package treatments under SS conditions. Also, sensory ratings were greatest for fruit packed in CL or PF when stored at 10°C, but all sensory scores decreased under SS temperatures. When longans were stored under fluctuating temperatures, aril texture and flavor ratings were highest for CL packages. CL, PF, MP are suitable packages for longans stored under optimal temperatures. However, for longans stored under SS conditions, postharvest and sensory quality was highest when packaged in CL containers.