Structural modification of starch using efficient α-amylases to improve its properties is an established method in the starch industry. In our previous research, the novel maltogenic α-amylase CoMA that catalyzes multi-molecular reactions has been identified. In this study, the impact of CoMA on the structure and retrogradation properties of potato starch was evaluated. CoMA cleaves internal starch chains to change the proportion of amylose and amylopectin in starch. Following treatment, visible pores and microporous on the surface of starch granules were observed from SEM analysis. CoMA modification led to increased insoluble blue complex formation and hydrolysis to shorten the outer chains, which was found to reduce the development rate of starch according to network interactions from the dynamic rheological analysis. Furthermore, maltose accumulation with water competition was also deduced to be involved in the inhibition of retrogradation. Its activities in the cleavage of internal starch granules, shortening of outer chains of starch, and maltose formation make CoMA a powerful agent for the inhibition of starch retrogradation with a very low effective dose of 0.5 mg/kg, which may find potential applications in the starch processing industry.
Keywords: Maltogenic amylase; Maltose; Retrogradation; Starch granules; Water competition.
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