Comparative study of foam mat drying kinetics of tomato pulp using a tray dryer

The experiment was conducted to study the foam mat drying kinetics of tomato pulp using a tray dryer at College of Agricultural Engineering, Bapatla. The tomato pulp was dried at 60°C. In the heat up period, the drying rates increased as the moisture content of tomato foam mats decreased from the initial moisture content to approximately 8.59g/g db. The time required for reducing the moisture content of foamed tomato pulp was less as compared to normal tomato pulp. First falling rate period, occurring between the moisture content of 5.17 and 8.59 g/g (db) corresponded to the loss of free water. At moisture contents below 0.35 kg/kg (db), a decrease in drying rate was sharper, indicating that the drying was in the second falling rate period. Drying temperatures within the experimental range of 60°C-80°C did not significantly affect the textural properties and shrinkage of foams. The drying rate of tomato pulp decreased with decreasing average moisture content.