Abstract:[Objective] The aim of the study is to explore the suitable roasting temperature for macadamia nuts. [Method] Macadamia nuts were roasted at 140, 160, and 180 ℃ for 5 min, respectively. The changes in volatile substances, total phenols, total flavonoids, and antioxidant capacity were determined. [Result] Macadamia nuts mainly contained six kinds of fatty acids: arachic acid, arachidonic acid, oleic acid, linoleic acid, palmitic acid, and palmitoleic acid. Unsaturated fatty acids, mainly linoleic acid and palmitoleic acid, accounted for more than 83%. Roasting temperature had no significant effect on the relative content and composition of fatty acids in macadamia nuts. After roasting treatment, the mass fraction of total phenols and the mass concentration of total flavonoids, as well as the antioxidant activity of macadamia nuts were increased, indicating that roasting improved the biological activity and antioxidant activity of macadamia nuts. Higher roasting temperature increased the mass fraction of total phenols and the mass concentration of total flavonoids in macadamia nuts, and improved their antioxidant capacity. Macadamia nuts roasted at high temperatures produced Maillard reaction products and lipid peroxidation products. It was found that roasting at 160 ℃ for 5 min resulted in a higher relative content of aroma substances in macadamia nuts, imparting a desirable roasted aroma. In addition, the relative molecular weights of macadamia protein were about 50 000 and 40 000. The stability of macadamia nut protein was better after roasting at 160 ℃. [Conclusion] Roasting at 160 ℃ for 5 min can better improve the sensory and nutritional qualities of macadamia nuts.
