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

Abstract

Enzymatic modification is a potential approach to effectively improve the stability of maltodextrin for food and industrial applications. In this study, a 1,4-α-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 °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 α-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 maltodextrin mainly correlated with the branching degree, while the viscosity stability, retrogradation property, and freeze–thaw stability mainly contributed to the Mw of branched molecules.