Study of Drying Method Types on the Physicochemical Characteristics of Purple-Fleshed Sweet Potato Extract Powder

The purpose of this study was to obtain the best anthocyanin pigment extract powder from 3 types of drying process, vacuum drying, spray drying, and  freeze-drying. The duration and temperature for each type of drying process are 15 h with temperature of 40 oC, 2 h with temperature of 120 oC (inlet) and 60 oC (outlet), 24 h with temperature of -50 oC respectively. This research used the Randomized Block Design method consisting of three treatments with four replications. If there is a significant difference between treatments, the test is continued with the Duncan test. Three drying methods, namely: Treatment A = Vacuum Drying, Treatment B = Spray Drying, Treatment C = Freeze-drying. The Freeze-drying method produces the best characteristics with total anthocyanin 121.63 mg/100 g (DB), color intensity L* (brightness) 64.20, a* (redness) 65.60, b* (yellowness) 18, 52, water content 5.00%, hygroscopicity 12.87%, solubility 97.21%, dissolution time 151 seconds, pH level 2.93, yield 28.69%, and PSA 0.95 µm. Based on the experiment’s result, freeze-drying method was the most suitable parameter for physiochemistry characteristic. It has the highest amount of anthocyanin, the highest antioxidant activity, and the smallest amount of PSA (Particle Size Analyzer).