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| Authors: | S. Chatelain-Mercado, D. Castillo-Animas, C. Pelayo-Zaldívar, J. Jacuinde-Guzmán, F. Rivera-Cabrera, F. Díaz de León-Sánchez, L.J. Pérez-Flores |
| Keywords: | cooling curves, cooling times, postharvest, lychee |
Abstract:
Scientific literature indicates that cooling is an important postharvest operation to preserve the quality of lychees.
In order to evaluate the effect of two cooling methods on lychees, a forced-air cooler and immersion hydrocooler prototypes were designed and constructed.
Both equipments were compact in design to facilitate handling and transportation to the field but with enough capacity to cool adequate sizes of samples for experimental work.
The forced-air cooler included a double-sided wall chamber insulated with polystyrene foam and was equipped with mechanical refrigeration, and systems to force cold air through fruit boxes and to keep high relative humidity (RH). In addition to a double wall polystyrene foam insulated container and a mechanical refrigeration system equipped with a submerged evaporator coil, the immersion hydrocooler, included a water recirculation system to keep a uniform water temperature.
Cooling tests were conducted in two producing areas of Mexico, using lychees ‘Brewster’ in two stages of maturity and two average fruit sizes.
In both cases cooling curves were obtained and 7/8 cooling time was determined.
Results indicated that cooling times were comparable with those obtained with commercial equipment, the temperature inside the chambers was uniform during the entire cooling process and RH above 95% was obtained in the air cooler operating at 1°C.
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