Carboxymethylation of (1→ 6)-α-dextran from Leuconostoc spp.: Effects on microstructural, thermal and antioxidant properties

The carboxymethylated (1 -> 6)-alpha-dextran (CM-dex) was synthesized by introducing carboxymethyl groups at different degrees of substitution (DS). The resulting dex1-1, dex2-1, dex3-1, and dex4-1 products had degrees of substitution of 0.57, 0.78, 1.13, and 1.25, respectively. The dex3-1 showed the highest glass transition temperature (T-g) of 215.96 degrees C, whereas T-g of pure dextran was 149.83 degrees C. TGA results indicated that the residual loss was reduced along with the increase of DS in the high-temperature region (450-600 degrees C). Besides, the CM-dex had stronger scavenging capacity against OH radicals but lower scavenging capacity for DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals compared to that of pure dextran. The carboxymethylation of (1 -> 6)-alpha-dextran will extend the applications for modified dextran. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

By introducing carboxymethyl groups at different degrees of substitution on (1→6)-α-dextran, a series of CM-dex products were synthesized, showing potential value in applications.