Recovery, chemical and rheological characterization of gum from Assyrian pulm

The extraction of gum from Assyrian pulm fruit (APH) was performed by microwave-assisted extraction technique. A Box-Behnken design (BBD) was applied to evaluate the effects of three independent variables (power of microwave (X1: 50-350W), extraction time (X2: 20-90min), and extraction temperature (X3: 50-90°C)) on the extraction yield of APH. The effect of temperature and concentration on flow behavior of gum solution was studied. The viscosity of 2% APH solution was 0.55Pas at a shear rate of 10s(-1) at 20°C. The viscosity of fully hydrated gum solutions decreased as temperature increase. It was found that increasing the temperature from 10 to 60°C causing the viscosity to decrease about 87% at shear rate 0.1s(-1) and 98% at shear rate 500s(-1). The correlation analysis of the mathematical-regression model indicated that quadratic polynomial model could be employed to optimize the microwave extraction of APH. The optimal conditions to obtain the highest extraction of APH (18.19±0.26%) were as follows: microwave power, 330W; extraction time, 80.67min and extraction temperature, 82°C.