Microwave Assisted Extraction of Avocado Oil from Avocado Skin and Encapsulation Using Spray Drying

The aim of this work was to extract the avocado oil from avocado skin. This oil was used to prepare the emulsion and encapsulation using spray drying. For the oil extraction, the efficiency of microwave assisted extraction (MAE) and soxhelt method was evaluated. The results indicated that MAE at 600 W for 15 min using 2-methyltetrahydrofuran gave the highest yield percentage. The emulsion preparation of avocado oil from MAE was prepared using the wall materials of maltodextrin and the Hi-Cap. The combinations of maltodextrin and Hi-Cap showed 100% stability for 24 hours, with no phase separation. The viscosity of the emulsions was reported at 11.00-13.00 mPa·s. The droplets mean diameter was between 2.05 to 2.08 µm. The microencapsulation of avocado oil was performed in a laboratory scale spray dryer. The encapsulation efficiency of three combinations of wall materials (F1 to F3) was valued of 60-80% which indicated that the increase on maltodextrin content, when combined to Hi-Cap, led to lower encapsulation efficiency. For particle characterization, the moisture content was 1.10-1.35 % and the bulk density was 0.35-0.37 g/cm3. Therefore, the proportion of wall materials had significant influence on the emulsion properties and on the encapsulation efficiency of avocado oil.