Study on the antioxidant activities and compositions of macadamia nuts oil from different extraction methods

Kernel oil was extracted by different extraction methods from dried macadamia nut ( aqueous extraction, solvent extraction, compression process) . Firstly, the basic physicochemical properties were analyzed. And then, physicochemical properties, active components, fatty acid composition and the infrared characteristics of macadamia nut oil with different extraction methods were analyzed.To evaluate the oxidation induction time and free radical scavenging capacity, the antioxidant capacity of macadamia nut oil with different extraction methods was determined. The results showed that the basic physicochemical properties ( peroxide value, acid value, saponification value, iodine value) of the oil extracted by the three methods all conformed to the national edible oil standard, and compression process was found to be the best process for extracting oil with a favorable quality characteristics compared to aqueous extraction and solvent extraction. Higher total phenolic acid content ( ( 41.82 ± 0.73) mg/100 g) , unsaturated fatty acid content ( 83.67%) and oxidation induction time ( ( 13.87 ± 0.37) h) were obtained with compression process, also the DPPH scavenging capacities ( 46.70%) of this group was the highest.The infrared spectrum showed that the macadamia nut oil from different extraction methods had the characteristic absorption of the nut oil, extraction method had no effect on its molecular structure.The quality analysis of macadamia nut oils extracted by different methods could lay a theoretical foundation for the extraction of high quality macadamia nut oil, as well as provide a reference for the industrial production of macadamia nut oil.