313 Indigestible dextrin from high amylose corn mutant starches.

Y. WANG, R. Kozlowski, and G. Delgado. Cerestar USA, Inc., Hammond, IN 46320.

There are many publications on enzyme-resistant starches, which are conventionally regarded as retrograded or recrystallized polysaccharides. However, there is another class of resistant starch derived through dextrinization with distinct structures and properties from those of retrograded polysaccharide, such as greater water solubility, higher molecular weight, and various glycosidic linkages. The changes of resistant starch content of five high amylose corn mutant starches (du h, du su2, amylomaize V, ae du, and amylomaize VII) during dextrinization process was studied. The starch was dextrinized at pH 2.5 and temperature ranged from 80 to 170 C. Starch was sampled every 10 min up to 180 min. Moisture, solubles, reducing sugars, carbohydrate profile and resistant starch content were determined. As the dextrinization proceeded, the moisture decreased and the solubles and resistant starch increased. The reducing sugar rose steadily to a peak of 6.5–8.5% and then dropped to 2–3%. The resistant starch did not form until the repolymerization process became predominant, which was indicated by the drop of reducing sugars after 60 min of dextrinization. On average, 20% of resistant starch was obtained after 180 min of dextrinization. The differences between mutant starches will be discussed.