PROCESS SIMULATION OF PINEAPPLE JUICE SPRAY DRYING

Abstract

Pineapple juice is one of the known natural sources of bromelain, a bioactive compound beneficial to health. The dried powder has potential commercial value and is a convenient source of the juice drink. The quality of spray dried pineapple juice is dependent on the powder moisture content. Spray dried pineapple powders with low moisture contents were produced in a lab-scale spray dryer in this study.  Powder production of 25% of total solids were obtained by use of DE6 maltodextrin to solids ratio of 0.41:0.59. A heat and mass transfer model of the spray drying process was implemented in Matlab and solved to determine its predictive utility. The simulation results showed agreement with experimental data at high inlet air temperatures but widely diverged at other air temperatures. The error size in predicted product moisture varied from 73% at 165 oC to almost zero at 185 oC while that for the predicted exit air temperatures varied from about 38% to zero over the same temperature range.  Accuracy can be improved if transient heat effects, and sub models for the feed drying are included in the model.