POSTHARVEST TREATMENT OF TROPICAL COMMODITIES FOR QUARANTINE SECURITY, QUALITY MAINTENANCE, AND VALUE ENHANCEMENT
Location: Tropical Crop and Commodity Protection Research
Title: Postharvest practices for managing the quality of longans and rambutans
Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 21, 2010
Publication Date: November 1, 2010
Citation: Wall, M.M., Nishijima, K.A., Keith, L.M., Nagao, M.A. 2010. Postharvest practices for managing the quality of longans and rambutans. Acta Horticulturae. 880: 473-480.
Interpretive Summary: Consumer acceptance of longans and rambutans requires that these high value fruit arrive at their final destination in excellent condition with minimal defects. Research was conducted to integrate preharvest disease control methods with postharvest practices to manage diseases, improve fruit quality, and extend the shelf-life of longans and rambutans. The main fungal pathogens of longans and rambutans were identified, preharvest applications of registered fungicides were studied for disease control, and optimum postharvest temperatures and packaging systems were established.
Longan (Dimocarpus longan) and rambutan (Nephelium lappaceum) are two important specialty fruit crops grown in Hawaii. Increased export of these fruits to U.S. mainland markets is necessary to accommodate a rapid expansion in production. Consumer acceptance of these high value crops requires that fruit arrive at their final destination in excellent condition with minimal external and internal defects. Research was conducted to integrate preharvest disease control methods with postharvest practices to manage diseases, improve fruit quality, and extend the shelf-life of longans and rambutans. The main pathogens of longan and rambutans were isolated and identified as Lasmenia, Colletotrichum, Pestalotiopsis and Phomopsis. In vitro sensitivity of these pathogens to registered fungicides was established, and Serenade® (a patented strain of Bacillus subtilis) was 100% effective at all test concentrations. However, when Serenade® was applied as a preharvest field treatment, it did not control postharvest diseases or improve quality for rambutans or longans. In postharvest studies, optimum storage temperatures and packaging systems were established. Package treatments included microperforated bags, clamshell containers, Peakfresh® film, and Lifespan® film. For longans, the sensory quality was maintained, overall disease incidence minimized, and shelf-life extended when microperforated packages or clamshell containers were stored at 10°C. The modified atmospheres (15% CO2 and 7% O2) inside Peakfresh® packages adversely affected longan flavor. Rambutans stored in the clamshell, microperforated bag, or Peakfresh® packages had higher visual quality ratings and lower disease incidences when stored at constant 10°C compared to simulated shipping temperatures. Rambutans held under simulated shipping temperatures in microperforated bags or clamshells had disease incidences that were 2-3 times higher than when stored at constant 10°C. Rambutans stored in Peakfresh® packages had the best overall quality ratings and lowest disease incidence, but lowest flavor ratings.