Characterization of lipid compositions, minor components and antioxidant capacities in macadamia (Macadamia integrifolia) oil from four major areas in China

Macadamia is rich in lipids and considered as a source of high-quality oil. In this study, fatty acids, triacylglycerols, minor components and antioxidant activities of macadamia oils (MOs) from four cultivated regions (YN: Yunnan Province; GZ: Guizhou Province; GX: Guangxi Province; GD: Guangdong Province) in China were systematically analyzed by modern chromatography (Gas chromatography, high performance liquid chromatography, inductively coupled plasma mass spectrometry and ultraviolet spectroscopy). The analysis indicated macadamia oil enriched in unsaturated fatty acids (UFA), including 62.4%–65.6% oleic acid and 11.4%–17.3% palmitoleic acid. Among the four cultivated regions, the MO from YN exhibited the highest contents of UFA (85.0%) and palmitoleic acid. In addition, the minor components and antioxidant activities of MO from four cultivation areas showed a significant difference, which GX-MO had the highest contents of α-tocotrienols (58.9 mg/kg) and phytosterols (2310.4 mg/kg), while GZ-MO was rich in squalene (626.7 mg/kg) and YN-MO had the highest levels of polyphenols (71.0 mg GAE/kg) and antioxidant capacity. Based on the correlation analysis, the polyphenols and α-tocotrienols had a remarkable contribution on the antioxidant activities of MO. Furthermore, the cultivation areas of MO can be distinguished according to the analysis of hierachical cluster analysis and principal components. Our studies offer a potential guidance for the identification of MO and its application in food industry.