Designing starch derivatives with desired structures and functional properties via rearrangements of glycosidic linkages by starch-active transglycosylases

Abstract

Modification of starch by transglycosylases from glycoside hydrolase families has attracted much attention recently; these enzymes can produce starch derivatives with novel properties, i.e. processability and functionality, employing highly efficient and safe methods. Starch-active transglycosylases cleave starches and transfer linear fragments to acceptors introducing α-1,4 and/or linear/branched α-1,6 glucosidic linkages, resulting in starch derivatives with excellent properties such as complexing and resistance to digestion characteristics, and also may be endowed with new properties such as thermo-reversible gel formation. This review summarizes the effects of variations in glycosidic linkage composition on structure and properties of modified starches. Starch-active transglycosylases are classified into 4 groups that form compounds: (1) in cyclic with α-1,4 glucosidic linkages, (2) with linear chains of α-1,4 glucosidic linkages, (3) with branched α-1,6 glucosidic linkages, and (4) with linear chains of α-1,6 glucosidic linkages. We discuss potential processability and functionality of starch derivatives with different linkage combinations and structures. The changes in properties caused by rearrangements of glycosidic linkages provide guidance for design of starch derivatives with desired structures and properties, which promotes the development of new starch products and starch processing for the food industry.

Graphical Abstract

Keywords:

• α-glucanotransferase
• glycosidic linkages
• starch modification
• catalytic mechanism
• structure
• physicochemical properties

Disclosure statement

The authors declare a conflict of interest. L.D. is employed by CarbExplore Research BV, a company that produces and markets starch modifying enzymes, and their products.

Additional information

Funding

This work was supported by National Natural Science Foundation of China (Nos. 32130084 and 32072268), Natural Science Foundation of Jiangsu Province (BK20211581), and the International Joint Research Laboratory for Starch Related Enzymes at Jiangnan University with DTU Bioengineering.