Schnitzenbaumer raw starch digesting ?-amylase used inSchnitzenbaumer raw starch digesting ?-amylase used in

Schnitzenbaumer et al.,(2013) defined the “end-point of liquefaction as the curve point at which the consistency after gelatinization is equal to the minimum consistency before gelatinization”. In all the examined initial starch concentrations with the addition of both enzyme and Ca2+, the RVA amylographs showed smooth viscosity curves during the liquefaction process with substantial flowability characteristics (shear thinning flow behavior index of <0.01 Pa. S-1). These results indicated that Ca2+ is required for the stability and activity of the examined enzyme. Despite the remarkable signal noise reported in the literature during such investigations, the method used in this study showed good reproducibility in three parallel runs with a coefficient of variation (CV=?). The results also indicate that good mixing (shear rate) of the substrate and heat transfer in the presence of raw starch digesting ?-amylase (RSD?-A) can generate faster and complete starch liquefaction in a short period of time at the examined temperature profiles. To date, this has not been reported. The shear thinning flow behavior index of <0.01 Pa. S-1 observed in this study eliminates viscous -associated problem which has been observed during gelatinization processes and thus, allows efficient mixing and pumping of hydrolysate. The distortion of curves reading in form of a '' hump'' that was observed after 5min of hydrolysis/liquefaction, occurred in all examined starch concentrations at 900C without the addition of Ca2+ ion. This could be a result of initial peripheral hydrogel-enzyme complex formation caused by slow liquefaction of the complex during progression. Alternatively, the formed complex may affect the smash or torque, which invariably changed the curve reading during the process. Nevertheless, the final viscosity profiles (readings) at the end of liquefaction was smooth with a relatively low viscosity in all tested runs, independent of the initial corn starch concentration (Fig. xxx). In all the tested initial starch concentrations with the addition of Ca2+, the rheological amylographs showed smooth viscosity curves during the liquefaction process with substantial flowability characteristics (viscosity). This mode of liquefaction can also lead to the design of a good reactor system and ultimately can reduce costs in terms of energy input by 20-30% compared to the conventional method by high-temperature-cooking (jet cooking) above atmospheric pressure. This energy input during jet cooking has been the rate-limiting economic factor in the conventional two-stage gelatinization and liquefaction of starch. The attractive (attractiveness) properties of the raw starch digesting ?-amylase used in this study was its strong hydrolyzing power on high concentrations of the starch granule. In view of its raw corn digesting ability, it could have potential application in the food and fermentation industries.