Design of a continuous type dryer for the drying kinetics study of foamed and non-foamed mango pulps.
Rajkumar P., Kailappan R., Raghavan G. S. V., Viswanathan R., Orsat V.
Author Affiliation: Department of Food and Agrl. Process Engineering, Agricultural Engineering College and Research Institute, Tamil Nadu Agricultural University, Coimbatore, India.
Applied Engineering in Agriculture 23 : 509-515
Abstract : A continuous type dryer was designed for drying of foamed mango pulp at 0.30 kg/h w.b. over the 0.40-m2 surface area of the dryer belt. The pulp contained 10% egg albumen as a foaming agent and 0.5% methyl cellulose as a stabilizing agent. The dryer was operated with air heated to 60°C and one mm foam thickness. Batch studies using similar conditions demonstrated that the foamed mango pulp could be dried to 5.07% w.b. in 40 min when the foam was spread to a mat density of 0.52 kg/m2 w.b. Similarly, non-foamed pulp could be dried to 6.03% w.b. in 100 min when the pulp was spread to a mat density of 1.01 kg/m2. When the dryer was operated in continuous mode at a residence time of 35 min and a mat density of 0.52 kg/m2 w.b., the foamed mango pulp dried rapidly compared to the batch conditions, giving a final moisture content of 5.02% w.b. Biochemical changes were less for foamed drying compared to non-foamed drying.