Effect of fatty acids on the rheological behaviour of maize starch dispersions during heating

The pasting of 15% maize starch dispersions in the presence of myristic, palmitic or stearic acid anions, was monitored by on-line measuring parameters, such as torque development, pasting temperature, viscosity exhibited and granule swelling. The results indicated that the fatty acid chain length played a significant role in altering the rate of the gelatinization process. The flow behaviour of heated, at 75, 85 and 98 °C, 10% maize starch dispersions was examined at these temperatures, in the presence of the above mentioned fatty acids. It was shown, that the viscosity exhibited by the starch dispersions was greatly influenced by the fatty acid chain length, the temperature of heating, the addition of acid prior or after heating to the starch system and the state of fluid motion of the sample on testing. Certain mechanisms were proposed to occur in order to explain the behaviour of starch systems during pasting as well as during heating especially in the presence of compounds, which interact with starch components.