Effect of drying methods on the quality of powdered cocoa pulp juice

Effect of drying methods, spray and freeze drying, on the physicochemical properties of the powdered cocoa pulp juices and sensory quality of the reconstituted juices were investigated. Cocoa pulp juice with added sugar and maltodextrin (total soluble solid, TSS: 34°Brix, 24±1°C) were dried respectively using Buchi Mini Spray Dryer and Labconco Freeze Drying Unit. Spray drying of cocoa pulp juice was undertaken at inlet temperature of 120°C with the feeding rate of 3.37g/ minute whereas freez-dried condition was at the temperature of -37°C under vacuum of 133x10-3 Mpa. The produced powders were evaluated with respect to water activity, color index (L,a,b) and pH. To access the organoleptic properties of spray and freeze-dried powders, reconstituted juices, (ratio juice powder to water of 1:10) were prepared and evaluated by 20 panelist in terms of color, odor, cocoa pulp flavor, sweetness, sourness and overall acceptability using 9-point hedoni c scale. Result showed that cocoa pulp juice powder produced via freeze drying was apparently more yellowish in color (L=108.65, b=7.07) compared to spray-dried powder (L=118.21, b=3.21). The pH (3.15) and water activity (0.170) of spray-dried cocoa pulp juice was significantly lower (p0.05) than the freeze-dried cocoa pulp juice viz. 3.35 and 0.245 respectively. Nevertheless, changes in the aforementioned properties were not affecting the organoleptic properties of their reconstituted juice. The panelist equally preferred both reconstituted juices.