Hydrocooling rates of Barhee dates at the Khalal stage

Abstract

The objective of the current study was to determine cooling rates for Barhee dates at the Khalal stage using a batch type hydrocooling technique. Crushed ice mixed with water was circulated within an insulated tank using a 0.5-kW water pump. The temperatures of the ice–water mixture and the dates were monitored and recorded at equal time intervals (1 min). The cooling curves are presented and the half-cooling and seven-eighths cooling times were calculated using linear regression equations fitted for the different size of dates and different initial temperature of the product. The seven-eighths cooling times ranged from 6.18 to 10.23 min. Small sized fruit cooled faster compared to larger ones. However, the difference in size only explained a relatively small fraction of the differences in calculated cooling times. The hydrocooling process with an ice–water mixture was found to be a very effective method to pre-cool dates in order to extend their shelf-life and maintain their quality during distribution.