Comparative study of microwave assisted and conventional osmotic dehydration of apple cubes at a constant temperature

a) Aims: To study the effects of microwave power (MWP) and different solution concentration (sucrose) on mass transfer kinetics and quality parameters of apple cubes (15 mm) at temperature (45 +/- 1 degrees C) during microwave assisted osmotic dehydration (MWOD), and comparison with conventional osmotic dehydration (COD) and non-linear regression analysis to validate the best model based on R-2 and RMSE. B) Methods: MWOD was carried out in different concentrations of sucrose solution (40, 50, 60 degrees Brix) with MWP (10, 20, 30% of maximum power (700W)) at temperature (45 +/- 1 degrees C). Finally, the finish drying of the osmosed samples is carried out in tray drier (8 h at 70 +/- 0.2 degrees C). c) Results: MWOD is a better process in increasing the moisture loss (ML), color change (Delta E), chroma while combating solids gain (SG) and hue angle as compared to COD. Henderson and Pabis model showed the best fit of the three. d) Conclusions: Because of the least SG, MWOD can be used for the formation of dried products used in various dishes like apple cake, apple pie, etc with lower sugar content that may be beneficial for the sugar patients. Microwaves should be preferably used at low MWP (<30%) and can be used for the preservation of fruits such as Pears.