Spray Drying of Roselle-Pineapple Juice Effects of Inlet Temperature and Maltodextrin on the Physical Properties

A study was conducted using LabPlant SD-06 mini-spray dryer of laboratorial scale to produce spray-dried roselle-pineapple powder. Roselle calyces and pineapples were extracted under optimum condition. Three different maltodextrin DE 10 concentrations (3%, 5% and 10%) were added (w/w) as the encapsulating agent prior to spray drying. Inlet temperatures were varied at 140°C, 160°C, 180°C and 200°C respectively and the outlet temperature was fixed at 80°C. The spray-dried roselle-pineapple powder were analysed for moisture content, dissolution, water activity and hygroscopicity. The results indicated that maldodextrin concentration and inlet temperature had significant effects on the percentage of yield. Extracts with 10% maltodextrin gave the highest percentage of yield and produced less sticky film at the wall of the dryer chamber. At 180°C, juice with 10% of maltodextrin produced the finest powder. When inlet temperature and the percentage of maltodextrin increased, the moisture content and water activity decreased; its hygroscopicity and dissolution time increased.