Effects of high-pressure homogenization on thermal and electrical properties of wheat starch

To investigate the effects of high-pressure homogenization on wheat starch granules, soft wheat starch suspensions (5.0%) were homogenized at increasing pressures, ranging from 0 to 100 MPa. The structural and thermal properties of the treated starches were determined by microscopy, particle size distribution, differential scanning calorimetry, and damaged starch measurements. A laboratory-scale ohmic heating setup was used to heat homogenized starch-KCl suspensions and measure the electrical characteristics. The wheat starch was partly gelatinized after high-pressure homogenization, and the degree of gelatinization increased to 25.96 +/- 1.0% when the homogenization pressure was 100 MPa. The electrical conductivities of the treated starch-KCl suspensions increased linearly with increasing temperature during ohmic heating. The slopes of the electrical conductivity-temperature curves of the homogenized starch suspensions during ohmic heating correlated with the degree of starch gelatinization. (C) 2013 Elsevier Ltd. All rights reserved.