Influence of packaging on qualityretention of longans (Dimocarpuslongan) under constant andfluctuating postharvest temperatures

Abstract

Longan (Dimocarpus longan) fruit production and global exports are rapidlyexpanding. Consumer acceptance of this high value crop requires that fruit arrive inexcellent condition. Pericarp browning and fungal diseases are the main postharvestproblems for longans. Research was conducted to establish optimum storage temperaturesand packaging systems to retain fruit quality of 'Biew Kiew' longans. Averagerespiration rates for longans stored at 20 °C (61.6 mgCO2/kg/h) were about twice the rateas those stored at 10 °C (32.7 mg CO2/kg/h) and triple the rate for those stored at 5 8C(21.1 mg CO2/kg/h). Ethylene rates were below 0.4 μg·kg-1·h-1. Fruit quality and shelf lifewere greatest when stored at 10 °C. Longans held at 20 °C were unmarketable after 10 d,and fruit stored at 5 °C exhibited chilling injury (CI). After storage at 10 °C, longanspackaged in microperforated (MP) bags, clamshell (CL) containers, or Peakfresh® film(PF) had the highest visual quality ratings, lowest disease incidences, and longest shelflife when compared with fruit in Lifespan® film (LS) or fiberboard boxes. The mostpromising packages (MP, CL, PF) were evaluated further under constant 10 °C orsimulated shipping (SS) conditions with fluctuating temperatures (22 8C/10 °C/22 8C).Longans in CL containers had the highest visual quality and lowest disease incidencewhen stored at 10 °C, but there were no differences among package treatments under SSconditions. Also, sensory ratings were greatest for fruit packed in CL or PF when storedat 10 °C but all sensory scores decreased under SS temperatures. When longans werestored under fluctuating temperatures, aril texture and flavor ratings were highest forCL packages. CL, PF, and MP are suitable packages for longans stored under optimaltemperatures. However, for longans stored under SS conditions, sensory quality washighest when packaged in CL containers.