Effect of package designing and performance parameters on the precooling of peach in the designed forced air cooling system

Postharvest technologies such as precooling process and packaging have an important effect in the storage and marketing of fruits and vegetable. Proper designing of package and determination of performance parameters of precooling process affect these technology. In this research, the various design of commercial packages as well as three levels of cooling airflow rate were studied and their effects were evaluated on the 3 4 th, 7 8 th cooling time and standard deviation of 3 4 th cooling time. According to the results, the functional parameters and the best package was selected. Increasing in the airflow rate from 1 to 1.5 L/s kgp had no significant effect on the standard deviation of 3 4 th cooling time and decreased cooling time just 11.5%. Therefore, the airflow rate of 1 L/s kgp was selected as the optimum airflow rate in which the 3 4 th cooling time and that's standard deviation were 87.74 min and 15.36, respectively. The results of precooling process of peach using the commercial packages indicated that the 3 4 th cooling time of fruit was in the range of 109.3 to 94.10 min and the standard deviation of 3 4 th cooling time were varied from 11.55 to 22.22. The two and three layers packages had the lowest cooling time, however, using of this package is not proper because of the high probability of fruit mechanical damage and heterogeneity of cooling process. Using the one layer packages in the airflow rate of 1 L/s kgp (with 101.3 and 155 min of 3 4 th and7 8 th cooling time, respectively) is advisable with modifying its tray to reduce the precooling time because of the energy consumption.