Effect of native crystalline structure of isolated potato starch on gelatinization behavior and consequently on glycemic response. http://dx.doi.org/10.1016/j.foodres.2011.10.042

Abstract

Effect of crystalline structure of two isolated potato starches on gelatinization and glycemic response was studied. Both starches showed to possess different fine structures. Starch 1 exhibited a typical B-type X-ray diffraction pattern, while Starch 2 exhibited an X-ray diffraction pattern suggesting the presence of imperfections of the general B-type crystalline structure (peak at 5.5 degrees 2 theta was absent), hence disarraying the structure order. This difference was reflected in the gelatinization behavior and consequently in the glycemic response. Starch 2 started to melt at lower temperature than Starch 1 (e.g. T-o was 60.9 and 61.84 degrees C, respectively, to native starches), and residual gelatinization enthalpy (Delta H) of Starch 2 was always smaller than that of Starch 1 when heated at 54-65 degrees C for 10 min. Glycemic response was increased as gelatinization degree (DG) increased in starches independent from the native crystalline structure (area under curve = 2.59 x DG-75.83, R-2=0.986; maximum concentration of postprandial blood glucose=0.042 x DG-0.23, R-2=0.935). Results suggested that native crystalline structure of isolated potato starch affects the glycemic response of heated starches by affecting the gelatinization behavior. (C) 2011 Elsevier Ltd. All rights reserved.