Research on the Solubility of Soluble Starch by NaOH/ formamide/ Urea Solvent System

The optimum parameters of dissolving soluble starch in NaOH/ formamide solvent system was obtained by orthogonal experiments. NaOH/ formamide/ urea solvent system was established by introducing urea to replace part of formamide. The influence of solvent system on the structure and properties of regenerated starch was studied by the measurement of solubility, Fourier transform infrared spectroscopy(FT-IR), scanning electron microscope(SEM), polarizing microscope(POM) and X-ray diffraction(XRD). The results displayed that NaOH/ formamide/ urea solvent system could significantly promote the dissolution of soluble starch. Besides, the regenerated starch prepared by this system reached the highest solubility for 60%. And the formation of new hydrogen bonds between the solvent system and starch is the fundamental reason to the improvement of solubility. The synergistic effect of formamide and urea could promote the dissolution of starch, the solubility of regenerated starch was, therefore, better than that of single solvent system.