Abstract
This research aimed to the study the effect of drying on total phenolic compounds, antioxidant activities and physical properties of palm sugar. The vacuum drying was operated at the temperature of 40, 50 and 60 oC for 3, 4 and 5 h. It was found that vacuum drying at 60 oC for 5 h gave the lowest moisture content of 0.98% (wet basis). The highest phenolic content of palm sugar dried at 40oC for 3 h was 16.29 mg of gallic acid equivalents/mg (dry weight). The drying condition of palm sugar at low temperature yielded higher phenolic content than that of high temperature. The antioxidant activity of dried palm sugar determined by 2, 2 - diphenyl-1- picrylhydrazyl (DPPH) scavenging activity and ferric reducing antioxidant power (FRAP) showed the highest value of 59.34% and 1.11 µmol/g of sample at the drying of 40oC for 3 h. These values were positively correlated to total phenolic compounds. The dried palm sugar had lowest water activity (aw) and solubility time of 0.31 and 31.66 sec when operated at the drying of 60 oC for 5 h. Based on the results of these studies, the drying condition of palm sugar at 40oC for 3 h delivered the highest total phenolic content and antioxidant activities of dried palm sugar.
