Effect of roasting pretreatment of macadamia nut (Macadamia integrifolia) kernels on the physicochemical properties and flavour of macadamia nut-based beverages.

This study investigated the influence of nut roasting pretreatment (85-145 °C, 10-30 min) on the physicochemical, sensory properties and flavour of macadamia nut-based beverages. The results revealed that roasting conditions influenced various quality parameters, with an increase in roasting temperature having a greater impact on the beverage than an extension of roasting time. Roasting at 125 °C for 20 min was identified as the optimal condition, producing beverages with higher total soluble solids content, improved stability, and superior sensory acceptability. The fatty acid compositions of beverages made from raw and roasted nuts did not differ significantly, being dominated by monounsaturated fatty acids. Moderate roasting (125 °C, 20-30 min) increased the total relative content of volatile compounds and the relative odour activity values of key ketones, enhancing the flavour of the beverage. These results highlight a new option for improving the physicochemical properties and flavour of macadamia nut-based beverages.