Study Of Extraction Of Macadamia Integrifolia Oil And Nanoemulsion Preparation

Macadamia integrifolia is an oil-rich food containing abundant unsaturated fatty acid, which is effective in many fields such as functions of antihypertensive and adjusting blood fat. The moisture content was1.42%, oil content was74.63g/100g, protein content was9.24g/100g. It follows that Macadamia integrifolia contains high percentage of oil and is feasible to leach oil.But the domestic Macadamia integrifolia is mainly for green edible with a low added value. The oil of Macadamia integrifolia was traditionally obtained by Soxhlet extraction, it was time-consuming and would lead to decomposition of some effective components and with problems of solvent residue though the yield of Soxhlet extraction was slightly higher. Supercritical CO2extraction was screened and optimized and nanoemulsion was prepared in our study which will provide theoretical references for further study of Macadamia integrifolia oil.Five different extraction methods, solvent extraction, ultrasonic wave-assisted extraction, Soxhlet extraction, supercritical CO2extraction and subcritical extraction, were compared to extract oil from Macadamia integrifolia. Fatty acid composition, acid value, iodine value and peroxide value were determined. Given all the facts above, supercritical CO2extraction proved to be the first choice. The peroxide value was merely5.874meq/kg, the contents of palmitoleic acid(15.38%)and linoleic acid(1.55%)were increased significantly.To obtain the optimum extraction conditions of supercritical CO2extraction an orthogonal array design was employed to optimize. The optimum extraction conditions were:extraction pressure35MPa, extraction temperature50℃, extraction time90min and frequency of CO2pump16.0. The best extraction ratio was70±2%.The antioxidant activity of the extracted oil was also investigated in this experiment. The results showed that Macadamia integrifoblia oil had strong antioxidant actions on soybean oil, especially the oil extracted at the optimum condition, much stronger than0.01%BHT which would be a fine natural antioxidant.Macadamia integrifoblia oil O/W nanoemulsion was prepared. The nanoemulsion with the minimum diameter (22.13nm) would be gained at the ratio of surfactant (Tween-80):cosurfactant(olive oil):oil phase(ethanol)=9:2:1,86.4%distributing between10-30nm, spherical. The Macadamia integrifoblia oil nanoemulsion was still clarity, homogeneous and stable after the stability tests.