ABSTRACT
Hog plum juice powder was obtained from its juice under optimized condition by spray drying with juice: maltodextrin ratio at 2:1, 4:1 and 6:1 (v/w) basis. The inlet temperature and feed rate were varied between 120 to 175 °C and 8 to 14 mL/min. The effect of variables i.e. maltodextrin level, temperature and feed rate on the physicochemical properties and total phenolic content were studied. Moisture content, hygroscopicity, bulk density, water activity and total phenolic content of the powder were significantly affected by inlet temperature and maltodextrin level. However feed rate showed no any significant effect on the bulk density of the powder. An increase in inlet temperature and maltodextrin level reduced the total phenolic content in the spray dried powder. Morphological study showed that at high inlet temperature the spray dried powder were of smooth surfaces however, at low inlet temperature majority of the particles were of shrivelled surfaces. Spray dried hog plum juice powder made with 3.9:1 juice: maltodextrin, processed at 171 °C inlet temperature and at 8 mL/min feed rate had less hygroscopicity, water activity, moisture content and potent TPC content. Storage temperature significantly affected the TPC and DPPH free radical scavenging activity of the powder. Refrigeration temperature was found to be more effective to reduce the losses of TPC and DPPH free radical scavenging activity during storage. Colour acceptability of the refrigerated sample was comparatively more than to the sample stored at room temperature.
