Generation of short-chained granular corn starch by maltogenic alpha-amylase and transglucosidase treatment

We describe a method for permitting efficient modification by transglucosidase (TGA), from glycoside hydmlase family 31 (GH31), sequentially after the pre-treatment by maltogenic alpha-amylases (MA) from GH13. TGA treatment without MA pre-treatment had negligible effects on native starch, while TGA treatment with MA pretreatment resulted in porous granules and increased permeability to enzymes. MA -> TGA treatments lead to decreased molecular size of amylopectin molecules, increased alpha-1,6 branching, and increased amounts of amylopectin chains with the degree of polymerization (DP)<10 and decreased amounts of DP 10-28 after debranching. Wide-angle X-ray scattering (WAXS) data showed a general decrease in crystallinity except for a long term (20 h) TGA post-treatment which increased the relative crystallinity back to normal. MA -> TGA treatment significantly lowered the starch retrogradation of starch and retarded the increase of storage- and loss moduli during storage. This work demonstrates the potential of sequential addition of starch active enzymes to obtain granular starch with improved functionality.

Automated summary

The study demonstrates the potential of sequential addition of starch active enzymes, MA and TGA, to obtain granular starch with improved functionality.