Hydrolysis of acetylated starches with a thermostable alpha-amylase

The hydrolysis of acetylated starches with different subsitutions degrees was conducted with an enzyme active at 90 degrees C. The extent of degradation was evaluated by colorimetric and chromatographic methods. With slightly acetylated starches, 100% of the substrate was fragmented and the main product obtained was maltose. The classification of these different substrates according to their percentage of biofragmentation was the same with two methods. With highly acetylated starches, the degradation was lower and the decomposition products are mainly maltose, maltotriose and pentaose. The classification of the different substrates was also the same with the two methods. Moreover, the values of the kinetic parameters confirmed these classifications.