Evaporation kinetics and quality attributes of grape juice concentrate as affected by microwave and vacuum processing

In this study, grape juice was concentrated through a microwave vacuum-assisted technique. The concentrate prepared at different powers (30, 50, 80 W) and vacuum pressures (35, 70 kPa) for time intervals to optimize the processing conditions. highest evaporation rate (5.32 g/100 g min) lowest moisture ratio (0.18) were observed higher level of power (80 pressure (70 kPa). Moreover, mechanistic models used predict values ratio. Among them, Midilli (R2 = 0.999, SSE 1.970 × 10−8, RPD 0.012%) model best fits experimental values. effective diffusivity (1.69 10−14 m2/s), activation energy (1.56 W/kg), extraction yield (69.30%) possessed maximum W KPa. While had exhibited antioxidant activities (77.2%) than fresh (25.28%) 30 W. Overall results indicated that microwave-vacuum technique significantly reduced requirement.