Hydraircooling: A New Precooling Method with Special Application for Waxed Peaches1

Abstract A new technique, termed hydraircooling , was evaluated for precooling fruit of peach ( Prunus persica (L.) Batsch) packed in DU-ALL or similar type containers. Cooling rate was determined with respect to air and waterflow. Waterflow rates of 3.63 and 5.44 ml/minute were tested at each of 4 airflow rates (1070, 2140, 3210 and 4280 ml/second). Half-cooling times, with respect to airflow, ranged from 0.460 to 0.348 hour on top and 0.672 to 0.451 hour on the bottom of the container at 3.63 ml/minute waterflow. At the 5.44 ml/minute waterflow, respective half-cooling times ranged from 0.470 to 0.328 hour on top and 0.511 to 0.249 hour on the bottom. The peaches in these tests were 6.35 cm in diameter. In tests to compare hydraircooling with forced-air precooling, using 7 cm diameter peaches, respective half-cooling times were 0.433 hour compared to 0.516 hour on top and 0.523 hour compared to 0.731 hour on the bottom at an airflow of 2140 ml/second and a waterflow in the hydraircooler of 3.63 ml/minute. Cooling rate increased in relation to air and waterflow with the greater significance being obtained in relation to waterflow.