Kinetics of soursop leaves antioxidant extraction using microwave-assisted extraction

Abstract

The purpose of this research is to study the kinetics of soursop leaves antioxidant extraction using microwave-assisted extraction. The kinetics was approached by a homogeneous mechanism using the first and second-order rate law. The extraction was conducted with ethanol as the solvent (1:13 v/v) using a modified microwave oven operated at various powers (300, 450, and 600 W) for 2-10 minutes. The soursop leaves extraction with ethanol using microwave-assisted extraction obtained a maximum yield of 33.98% (with total phenol of 24.10 mgGAE/g extract) at 600 W and 8 minutes. The kinetics of soursop leaves antioxidant extraction can be quantitatively described by the homogeneous rate law, where the second-order model is better than the first one. The extraction capacity and constant rate increase as the microwave power does. At 300, 450, and 600 W, respectively, the extraction capacities were about 500, 588, and 667 mg/l and the constant rates were 8.5 x 10-4, 9 x 10-4, and 1.18 x 10-3 l/mg/min.