Recovery, chemical and rheological characterization of gum from Assyrian pulm

The extraction of gum from Assyrian palm 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 (X-1: 50-350W), extraction time (X-2: 20-90 min), and extraction temperature (X-3: 50-90 degrees 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 0.55 Pa s at a shear rate of 10 s(-1) at 20 degrees C. The viscosity of fully hydrated gum solutions decreased as temperature increase. It was found that increasing the temperature from 10 to 60 degrees C causing the viscosity to decrease about 87% at shear rate 0.1 s(-1) and 98% at shear rate 500 s(-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, 80.67 min and extraction temperature, 82 degrees C. (C) 2014 Elsevier B.V. All rights reserved.