Induction of Maize Starch Gelatinization and Dissolution at Low Temperature by the Hydrotrope Sodium Salicylate

Complete aqueous dissolution of starch requires the use of temperatures exceeding 100 °C. During and after cooling of the resultant aqueous solutions, starch polymers precipitate by aggregation and crystallization. Low-temperature gelatinization and dissolution of maize starch (MS) is induced, and the stability of the resultant solutions is enhanced when they contain the hydrotrope sodium salicylate (NaSal). Differential scanning calorimetry and optical microscopy evidence showed that MS gelatinization shifts to lower temperatures and that the associated enthalpy decreases with increasing NaSal concentrations. The enhanced gelatinization and dissolution are probably brought about by the association of NaSal with the more hydrophobic MS structural moieties. The minimum NaSal content of aqueous mixtures allowing full gelatinization of MS at room temperature, that is, about 11 wt %, was found to be independent of MS content (in the range 10-66.7 wt % MS).