Optimization of Aqueous Enzymatic Microwave Assisted Extraction of Macadamia Oil And Evaluation of Its Chemical Composition,Physicochemical Properties,and Antioxidant Activities

This study presents the green and effective aqueous enzymatic process assisted microwave extraction (AEME) to preparate macadamia nut oil (MNO). The conditions of the extraction process are optimized (extraction temperature 50 °C, extraction time 64 min, enzyme concentration 1.60% (w/w), and irradiation power 450 W). An oil yield of 58.09 ± 0.63% is achieved under these optimal conditions. The scanning electron micrograph (SEM) analysis of nuts before and after extraction illustrates that AEME promotes the emancipation of oil stored within the organelles. Gas chromatography-flame ionization detector (GC-FID) analysis reveals the fatty acid compositions of MNOs obtained by AEME and the Soxhlet extraction (SE) are similar and mainly dominated by monounsaturated fatty acids beneficial to human health which is higher in MNO than in any other known food. Moreover, gas chromatography-mass spectrometry (GC-MS) analysis reveals higher amounts of more odoriferous oxygenated terpenes is present in the MNO extracted by AEME in comparison with SE. The physicochemical properties of AEME oil are more excellent than those of SE oil. Moreover, AEME oil exhibits superior antioxidant capacities. In conclusion, green AEME gives relatively satisfactory yield and better retains the fragrance and functionality of MNO. Practical Applications: The present study provides a green extraction method and valuable data for the process design as well as industrial scale-up applications. In addition, compared to the nonsustainable and environmentally nonfriendly traditional method, AEME preserves the initial composition of the flavor substances and enhances the extraction of healthy beneficial compounds in MNO. Therefore, AEME oil can be used to develop functional edible oils or even in medicinal, cosmetic, and pharmaceutical preparations.