Mass exchange evaluation during optimization of osmotic dehydration for Oyster mushrooms (Pleurotus sajor-caju) in salt-sugar solution

The objective of this study was to investigate the osmotic dehydration of Oyster mushrooms in salt-sugar solution at different solution concentrations, immersion times, temperatures and solution to fruit ratio to analyze the water loss, solute gain and weight reduction. Salt-sugar uptake and water transfer were quantitatively investigated during osmotic dehydration of Oyster mushrooms using response surface methodology. Experiments were conducted in a thermostatically controlled agitating incubator. With respect to water loss, solute gain and weight reduction both linear and quadratic effects of four process variables were found to be significant. For each response, second order polynomial models were developed using multiple linear regression analysis. ANOVA was performed to check the adequacy and accuracy of the fitted models. The response surfaces and contour maps showing the interaction of process variables were constructed. Applying desirability function method, the optimum operating conditions were found to be: solution temperature – 42.3° C, immersion time – 44.21 min, salt-sugar concentration – 15 %: 52.57° B and solution to fruit ratio 4.99:1. At these optimum values, water loss, solute gain and weight reduction was 41, 2.15 and 38.6 (g/100 g initial mass) respectively