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Response surface methodology was used to determine the optimum processing conditions that yield maximum apparent viscosity and extraction yield and consistency coefficient with minimum protein content and flow behavior index during extraction of Qodume Shirazi seed gum. Extraction temperature (25–85C), pH (4–10) and water : seed (20:1–60:1) were the factors investigated. Experiments were designed according to Central Composite Face Center Design with these three factors, including central and axial points. The response surfaces showing the interaction of process variables were constructed. Solution with 3% concentration of each gum with different extraction methods were made to evaluate the flow properties of gum extracted from Qodume seeds. The Power‐law model was successfully applied to fit the shear stress versus shear rate data of gum solution. The flow behavior indices, n, varied in the range of 0.25–0.41. The consistency coefficients, k, were in the range of 5.5–8.62 Pa·sn. Applying desirability function method, optimum operating conditions were found to be extraction temperature of 36.3C, pH of 4 and water : seed of 40:1. At this optimum point, apparent viscosity, extraction yield and protein content, consistency coefficient, flow behavior index were found to be 855.9 (mPa·s), 287.3 (g/kg), 1.27 (%), 8.27 (Pa·sn) and 0.29, respectively. PRACTICAL APPLICATIONS Growing use of hydrocolloids in food industries has brought about the need for new sources of these products. Therefore, there could be a substantial market for new source of produced gum. The aim of the present paper was to choose a suitable new source for extracting polysaccharides. Qodume Shirazi is a medicinal seed grown in the Middle East that produces a high amount of mucilage. Thus we optimized the best method for extraction of mucilage from this seed, which is important for producing gum from Qodume Shirazi and assessed the flow behavior of the gum.

Sonoinactivation of alpha-amylase from Bacillus amyloliquefacience was studied at a constant frequency of 30 kHz. The effect of sonotrode emitting face and gas content of medium on the efficiency of enzyme inactivation were investigated at different time-temperature combinations and generation of OH free radicals was also monitored. The results showed that ultrasound effectively inactivated alpha-amylase with a minimum overall inactivation rate at 50 degrees C. The tip diameter of the sonotrode and the gas content of the medium both significantly affected the rate of enzyme inactivation. The increase of tip diameter increased the effect of ultrasound on the enzyme, while the removal of dissolved gas adversely influenced the cavitational events and reduced the rate of enzyme inactivation. Calculation of the kinetic and activation parameters revealed that ultrasound decreased the activation energy, E(a), activation enthalpy, DeltaH(#), and the activation Gibbs free energy, DeltaG(#), and strongly reduced the activation entropy, DeltaS(#), down to negative values. This huge reduction in activation entropy was attributed to the different mechanisms of inactivation induced by heat and ultrasound. It is proved in this study that ultrasonically generated OH free radicals and shear forces, which arise from pulsation- or collapse of bubbles, both can destabilize the enzyme, although their contribution to the overall inactivation varies depending on the temperature and the tip diameter of the sonotrode.

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