Amylose depending on the temperature, starch concentration

Amylose and amylopectin are established highly branched molecules of starch with anhydroglucose units joined by glucosidic bonds and is potentially degradable by using amylases. Liquefaction of starch by using ?-amylase is primarily an important process step in the food industries to acquire different kinds of syrups that are similarly used as additives with obvious functional properties for differently processed food products. The hydrolysis/liquefaction percentages of cornstarch in the present study by the Bacillus amyloliquefaciens KU-20 ?-amylase both at 800C and 900C coupled with the addition of 5 mM of Ca2+ at pH 5.5 are shown Fig. 4 and 5. These stipulated conditions of hydrolysis were chosen based on the results of observed viscosity measurements by means of RVA, whereby the readings had been virtually stable and showed no undesirable fluctuations in the viscosity curves. The hydrolysis/liquefaction of raw-starch corn at stipulated concentrations was performed and the results show that the % of hydrolysis increased as the incubation time increases. As shown, the enzyme liquefied cornstarch with various percentages of hydrolysis, depending on the temperature, starch concentration and processing time. At 10% cornstarch slurry, the best % of hydrolysis scored was 55% each at 800C and 900C after 30min of incubation. A comparable tendency was observed for 20% (Fig. ), whereas at 30% corn starch loading and at 900C, the % of hydrolysis decreased to (50% ?). Likely, this might be a result of incomplete gelatinization of starch due to less water mobility inside the phases, which led to lower hydrolysis of the starch gel-enzyme complex or invariably, decreased enzyme stability and (undertaking) activity at this high temperature. In contrast, such decrease in activity was not observed at 800C, independent of the initial corn starch concentrations and, in this case, the final % hydrolysis remained constant at 55% in all runs, indicating that the enzyme maintained activity and stability at this temperature. This confirms the viscosity curve results obtained at 800C (Fig. 1,2 and 3) which showed similar tendency with final viscosity values < 0.01 Pa S-1, independent of preliminary set starch concentration. The attractive properties of the raw starch digesting ?-amylase in this study was its strong hydrolyzing ability on high concentrations of the uncooked starch granule. In view of its raw corn digesting ability, potentially it could have application in the food and fermentation industries.