AIR-FLOW PRECOOLING OF INDIVIDUAL GRAPES

The forced air precooling of the individual layers of 5 kg grapes (sultana variety) was investigated in flawing air at 4 degrees C and at flow velocities from I to 2 m/s The cooling variables such as lag factor; cooling coefficient, half cooling time and seven-eighths cooling time were determined for the individual grapes in the individual layers of 5 kg, by means of the exponential decline in the dimensionless temperature at the center of the products. The results of the present study showed that the cooling variables were found to depend on the flow velocity of ail; and increasing the flow velocity of air from I to 2 mis decreased the half cooling time by 21.8% and seven-eighths cooling time by 23.6%.