The macadamia tree (Macadamia integrifolia Maiden & Betche) produces a nut of highly commercial value, distinguishable from other nuts by its delicate flavour and oil quality. This study aimed to compare the oxidative stability of dried nuts, with the application of hot air microwave energy, in relation to conventional drying. The analyses were performed at the beginning stage (time zero), at 90 days, and 180 days of storage, to evaluate the percentage of free fatty acids, peroxide values, induction period, fatty acid composition, and tocopherol/tocotrienol content. The percentage of free fatty acids varied from 0.095 (MW1) to 0.124 (MW3) and from 0.123 to 0.148 (CVL); peroxide values (meq O2 kg-1oil) ranged from 0.77 (MW2) to 2.57 (MW1) and from 1.52 to 3.29 (CVL); the induction period (h) from 16.7 (MW2) to 13.6 (MW4) and from 11.9 to 10.6 (CVL); and the α-tocotrienol (mg 100 g-1 content from 1.75 to 2.19 (MW1) and from 2.14 to 2.19 (CVL), for microwave and conventional drying, respectively. The fatty acid composition values did not change during storage, in relation to the drying processes applied. The microwaves drying method was more efficient, regarding the macadamia nuts oxidative stability, when compared to the conventional drying method.
Macadamia integrifolia Maiden & Betche; microwave; drying