Microwave pre-treatment as a promising strategy to develop functional milk alternatives obtained from oil industry by-products

In the study, the microwave pre-treatment of black cumin cake (BCC) and rapeseed cake (RC) was applied for development of plant-based milk alternatives (PBMAs) with high antioxidant activity (AA), and content of bioactive compounds and minerals. Microwave power (MP = 100–800 W), time of microwave radiation (t = 1–3 min), and BCC:RC ratio (0–1) were optimized with employing of response surface methodology (RSM) based on a three-level, three-variable Box–Behnken design (BBD). RC-based beverages had higher values of antioxidant potential, total contents of phenolic compounds, carotenoids, and chlorophylls, whereas the addition of BCC increased the total content of phenolic acids and minerals in BCC-based beverages. The optimal conditions based on combination responses were MP = 800 W, t = 3 min, and BCC:RC = 0.1144. The experimental values agreed with those predicted, indicating the suitability of RSM in the preparation of PBMAs with pro-health properties.