Abstract:

The determination of molecular mass, molecular mass distribution, mean square radius of gyration and conformation using gel permeation chromatography coupled with multi-angle laser light scattering (GPC-MALLS) with refractive index detector with DMSO as the mobile phase was carried out for waxy, common, G50 (with 50% amylase content) and G80 (with 80% amylase content) corn starches. The results showed that the weight-average molecular masses (Mw) of waxy, normal, G50 and G80 corn starches were 1.416 × 108, 2.744 × 107, 1.026 × 107, 3.992 × 106 g/mol, respectively. Similarly, higher-amylose corn starch had smaller mean square radius of gyration. The conformation of waxy corn starch was compact random coil and the three others were compact globular structure in DMSO.

Key words: corn starch, gel permeation chromatography, laser light scattering, molecular mass distribution, molecular conformation