ISOLASI ALKALOID DARI TEPUNG GADUNG (Dioscorea hispida Dennst) DENGAN TEKNIK EKSTRAKSI BERBANTU GELOMBANG MIKRO

Abstract

Alkaloid constitutes the largest group among nitrogen-containing secondary metabolites. Alkaloid presents in plant and animal kingdom. Alkaloid exibits many biological and medical functions. Gadung (Dioscorea hispida Dennst) has been known for its high carbohydrate and alkaloid content. In order to utilize gadung as food source, hence the alkaloid was separated by microwave assisted extraction. Solid-liquid extraction of gadung’s alkaloid involved the selection of solvent, mass transfer process, heat transfer process and also being influenced by several process variables such as extraction time, solvent concentration, solvent-materia ratio and microwave power. Thus this research objectives were to choose the suitable solvent, study the influence of the process variables which is comprised of ethanol concentration (96%-75%), solvent-material ratio (10:1-20:1) and microwave power (100-400W) to the extraction yield, and also to develop mass transfer model of the gadung alkaloid extraction. The research was conducted in three major steps i.e raw material preparation, microwave assisted extraction of gadung alkaloid and mass transfer modelling. The solvents were chosen based on Hildebrand solubility parameter, which was predicted by group contribution methods. A pre-experiment was conducted to determine the best extraction time. The mass transfer coefficient was evaluated by using MATLAB program. The result showed that the selected solvents for microwave assisted extraction of alkaloid from gadung was ethanol-water mixture. The highest extraction yield achieved when the alkaloid was extracted using 85% of ethanol as solvent at solvent-material ratio of 12.5:1, using microwave power of 100W for 20 minutes. The final mathematical mass transfer model of the alkaloid extraction was C = 0.0008 − 0.0008.e−0.10061.t and the mass transfer coefficient was 0.10061 s-1. The model showed a good agreement with the experimental data with average absolute relative deviation of 2.96%.