Enzyme-catalyzed synthesis of hydrophobically modified starch

The reaction of starch and alkyl or alkenyl ketene dimer and starch gave a novel type of hydrophobically modified starch. The reaction was facilitated with the use of an enzyme, which gave products with higher degrees of substitution (DS) at lower temperatures. The starch used included maltodextrin, amylose, cationic starch, and pre-gelatinised starch, with molecular weights ranging from several hundreds to several millions. The DS of the products could be controlled by varying the reaction conditions, such as the amount of enzyme used, the reaction temperature, the concentration of the reactants, and the reaction solvent. This hydrophobically modified starch had improved properties as compared to the original starch and may be used as a thickener or an emulsifier.