1 Thin Layer Drying Study on Foamed Mango Pulp

A thin layer dryer was used to dry the foamed mango pulp. The mango pulp (Totapuri variety) was foamed by the addition of egg albumen at different concentrations such as 5, 10 and 15 % and the foam was stabilized with the addition of methyl cellulose at 0.5 % concentration. The foamed pulp was dried at three drying temperatures viz., 60, 65 and 70oC with three foam thicknesses viz., 1, 2 and 3 mm in the batch type thin layer dryer. The drying time required for foamed mango pulp was lower than non-foamed pulp at all selected temperatures. The drying rate constant ‘k’ value increased with decrease in pulp thickness during drying. Biochemical analysis results showed a significant reduction in ascorbic acid, total soluble solids and β–carotene in the mango flakes dried at higher temperatures when compared to the flakes dried at 60oC. Also these biochemical changes were significantly higher in 2 and 3 mm than in 1 mm thick foam dried mango flakes. There was no significant change in other biochemical constituents such as pH, acidity and total sugar due to the increase in drying temperature and foam thicknesses. The thin layer drying study on foamed mango pulp concluded that the mango pulp treated with egg albumen (10%) and methyl cellulose (0.5%), dried at 60oC with one mm foam thickness retaine