Rosehip (Rosa canina L.), a wild fruit abundant in bioactive compounds, is susceptible to microbial spoilage post-harvest. Therefore, drying is employed to prolong its shelf-life. This research examines the impact of microwave energy intensity (2, 4, and 6 W/g) and pressure levels (10, 55, and 100 kPa) on the microwave-vacuum drying process of rosehip, focusing on antioxidant activity, ascorbic acid, total phenolic content, total colour change, energy consumption, energy and exergy efficiencies. Utilizing a genetic algorithm, the optimal conditions for drying of rosehip was identified. Results show the drying at medium pressure (55 kPa) led to a 12–24% reduction in drying time compared to low and high pressure (10 and 100 kPa). Drying at lower pressures enhanced the retention of phenolic compounds by approximately 28% during the drying process. The drying process reduced 2,2-diphenyl-1-picrylhydrazyl activity by 6.38–18.76% and degraded ascorbic acid content by 24.10–28.91%. The total colour change varied from 14.70 to 25.57, and the specific energy consumption and exergy efficiency ranged from 6.79–18.75 MJ/kg water and 2.20–7.48%, respectively. The optimal drying conditions for rosehip fruit were identified as 4.2 W/g and 45 kPa.
