Filtration characteristics of maize and wheat starch hydrolysates

Starch hydrolysates were prepared by one-or two-stage hydrolysis with alpha-amylase. The filtration rate of wheat starch hydrolysates was considerably lower than that of maize starch hydrolysates. Omitting the second conversion step lowered the filtration rates of wheat and maize starch hydrolysates. Increasing the incubation time or the enzyme dosage resulted in an increase of the filtration rate of maize starch hydrolysates due to the increase in the dextrose equivalent. These process variables did not influence the filtration rate of wheat starch hydrolysates. Wheat starch hydrolysates had very poor filtration characteristics: low filtration rates, almost no removal of undesired components, and obstruction of the filter cake. On the contrary, maize starch hydrolysates showed good filtration characteristics: a high filtration rate and removal of the largest part of the undesired components. On storage, wheat starch hydrolysates separated into three layers. The intermediate fraction had a higher filtration rate than the total hydrolysate. Adding small amounts of the upper or lower layers to dextrose solutions decreased the filtration rate to that of a wheat starch hydrolysate. This was due to an increase of the protein and lipid concentration.