Comparative study on the extraction of macadamia (Macadamia integrifolia) oil using different processing methods

Abstract

A comparison study has been performed to analyze the chemical compositions, antioxidant activity, thermal and rheological behaviors of macadamia (Macadamia integrifolia) oils (MOs) obtained by squeezing, solvents extraction and aqueous extraction. MOs were rich in monounsaturated fatty acids (82.73–82.85%), including mainly oleic acid (60.74–61.37%) and palmitoleic acid (18.71–19.39%). The lipid compositions, tocopherol (∼36 mg/kg) and phytosterols (∼1900 mg/kg) were not significantly influenced by processing method. However, the content of squalene (261.88 mg/kg), polyphenols (39.74 mg/kg) and antioxidant capacity of MOs obtained by squeezing were significantly higher than those extracted by solvents and aqueous. Furthermore, different processing method in the thermal and spectral profiles of MOs was similar, and MOs were liquid at room temperature (25 °C). Additionally, all MOs exhibited Newtonian flow behavior. This study indicated that the pressing might be the most suitable process for extracting macadamia oil with a high antioxidant capacity and beneficial minor components.