Remarkable improvement in the storage stability of maltodextrin through 1,4-?-glucan branching enzyme modification

Enzymatic modification is a potential approach to effectively improve the stability of maltodextrin for food and industrial applications. In this study, a 1,4-alpha-glucan branching enzyme from Rhodothermus obamensis STB05 (Ro-GBE) was used to modify maltodextrin. The transparency of the Ro-GBE-modified maltodextrin prepared under the optimal modification conditions: enzyme dosage of 100 U/g, reacting time of 12 h at 55 degrees C, and pH of 7.0, was maintained above 90% for over 30 days. In addition, the viscosity stability, retrogradation property, and freeze-thaw stability were significantly improved. Because of the constant value of the dextrose equivalent (DE), increase in alpha-1,6-glycosidic linkage ratio, and decrease in weight-average molecular mass (Mw), we believed that the glycosidic bond rearrangement played a vital role in the Ro-GBE modification. Moreover, Ro-GBE exhibited high specificity in cleaving long chains with DP >= 15 and transferring the released chains as exterior chains to form a short-clustered structure. Pearson correlation analysis revealed that the transparency stability of malto-dextrin mainly correlated with the branching degree, while the viscosity stability, retrogradation property, and freeze-thaw stability mainly contributed to the Mw of branched molecules.