AMYLOLYSIS OF LARGE STARCH GRANULES FROM BARLEYS IN RELATION TO THEIR GELATINISATION TEMPERATURES

Abstract

Large starch granules, prepared from a range of barley samples, show considerable variation in their susceptibility to attack by α-amylase at 65°C. Susceptibility is not correlated with their protein content, amylose/amylopectin ratio or gelatinisation temperature as measured by loss of birefringence. It does correlate with gelatinisation as measured by swelling of the granules or their staining with Congo Red. When granular expansion is taken as the measure of gelatinisation, the more resistant starches show gelatinisation curves displaced to higher temperatures.