The Forced-Air Cooling System: Effect of fan speeds on the Cooling Characteristics of some Horticultural produce
Forced-air cooling in conjunction with ice can rapidly remove field heat of fresh horticultural produce, and enhance their preservation. In the current work, a forced-air cooling technique was developed, and the effect of the fan speeds (1200, 1350, and 1750 rev/min) on the cooling time, sensory properties and microstructure of three different cooled products (okra, tomato, and green bell pepper) were investigated using standard methods. The results within the experimental conditions showed that the forced-air cooling technique lowers the temperature faster, and significantly reduces the cooling time (p ≤ 0.05) of all the products when compared with the time of cooling under room cooling condition. The time of cooling the tomato from ambient (32oC) to half-cooled is 5, 6, and 8 minutes when the product is cooled using fan speeds of 1200, 1350, and 1750 rev/min, respectively. The sensory experiences evoked by various food panelists delivered pleasure in the final quality of the cooled products. In addition, the microstructures of the cooled samples were well-preserved when the machine was operated under the fan speed of 1200 rev/min. However, the results presented in this work show that forced-air cooling technique plays a significant role to postharvest preservation of horticultural produce.
Keywords: Forced-air cooling, horticultural produce, fan speeds, microstructure, preservation