The influence of sodium hydroxide on the rheological properties of pastes and gels of potato, corn and wheat starches

Abstract

The subject of the study was corn, wheat and potato starch before and after treatment with sodium hydroxide solution, with the aim to evaluate whether this solution is able to remove lipids and have any effect on the rheological properties of starch pastes and gels. Applying the DSC method, it was noted that after the treatment with the sodium hydroxide solution, the enthalpy difference of the amylose – lipids complex formation/ disruption was lower for wheat and corn starch (32.7 % and 71.9 %, respectively). In case of potato starch, complexes were detected neither before nor after the treatment. The study of the rheological properties showed that after the treatment of wheat and corn starch, their gels became softer, the storage modulus (G ′ ) decreased and the delta angle (δ) increased . At the same time, the potato starch gel had a relatively low G ′ modulus and a high delta angle even without treatment, and the treatment itself had a minor effect on its properties. DOI: http://dx.doi.org/10.5755/j01.ct.62.4.3229