Influence of guar gum on granule morphologies and rheological properties of maize starch

The effect of guar gum on the microstructure and viscoelastic properties of maize starch was investigated using confocal laser scanning microscopy (CLSM) and dynamic viscoelastic measurements. CLSM showed that guar gum had little effect on the swelling behavior of starch granules during heating. It also indicated that guar gum tended to inhibit starch components from leaching out of starch granules during gelatinization, as the average molecular weight or concentration of added guar gum increased. Dynamic viscoelastic measurements showed that the mechanical loss tangent tan δ of the pastes increased with increasing concentration of added guar gum. In conclusion, guar gum inhibits starch components from leaching out of starch granules to the continuous phase of starch pastes during gelatinization, resulting in an increase in viscous characteristics in the system.