The extraction of essential oil from sandalwood (santalum album) by microwave air-hydrodistillation method

Oil from sandalwood is commonly obtained by a conventional distillation process which requires great energy, significant amount of solvents, and quite a long process time. Therefore, the use of new 'green technique' for extracting essential oil with minimum/low energy, solvents, and time need to be considered. One extraction method which has been succesfully developed is microwave hydrodistillation method. This research employs a method developed from microwave hydrodistillation, that is microwave air-hydrodistillation for optimizing the extraction of essential oil. The purpose of this study is to examine the effect of the presence and absence of additional air flow to the microwave hydrodistillation method. The material used in this study includes sandalwood powder. The extractions by microwave hydrodistillation and microwave air-hydrodistillation methods were done on the power of 600W; the ratio of the raw material to be extracted and the solvent was 0.05 g mL^-1 and the extraction time was 120 minutes. In the extraction by microwave air-hydrodistillation, the rates of air flow used were 0.1, 0.5, 1.5, 3.0, and 5.0 L/min. The results of the research show that the extraction of sandalwood oil by microwave air-hydrodistillation is faster and produces higher yields and recovery accumulation compared to the extraction by microwave hydrodistillation method. The testing of the physical properties of the sandalwood oil indicates that essential oil obtained by microwave hydrodistillation and microwave air-hydrodistillation has the same quality (refractive index and specific gravity). Further, the testing of the chemical properties of the sandalwood oil shows that essential oil obtained by microwave air-hydrodistillation has better quality (flavor) compared to the oil obtained by microwave hydrodistillation.