The effects of stearic acid and gamma irradiation on pasting properties of high amylose maize starch (HAMS) were studied. Stearic acid (0%, 1.5%, and 5%) was added to HAMS, and then irradiated at 0, 30, and 60 kGy before pasting. Stearic acid increased the paste viscosity of un-irradiated HAMS from 420 mPa s to 557 and 652 mPa s for 1.5% and 5% stearic acid, respectively. This observation related well with the formation of type II amylose–lipid complexes, with melting temperatures of about 100–120 °C. Gamma irradiation (30 and 60 kGy) reduced pasting viscosity of HAMS. Pasting of gamma irradiated HAMS resulted in the formation of type I amylose–lipid complexes, with melting temperatures and enthalpies ranging from 82 to 102 °C and 0.22 to 1.85 J/g, respectively. Stearic acid addition followed by irradiation creates means of producing different types of amylose–lipid complexes from HAMS for industrial utilization.
Link: https://doi.org/10.1016/j.foodchem.2015.05.023
DOI: https://doi.org/10.1016/j.foodchem.2015.05.023
