title: Effects of stearic acid and gamma irradiation, alone and in combination, on pasting properties of high amylose maize starch.
abstract: 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 mPas to 557 and 652 mPas 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 6 0kGy) 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.
authors.affiliation: Department of Food Science, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa; Radiation Technology Centre, Biotechnology and Nuclear Agriculture Research Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra, Ghana.
authors.forename: Fidelis C K
authors.initials: FCK
authors.lastname: Ocloo
authors.affiliation: Department of Food Science, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa.
authors.forename: Amanda
authors.initials: A
authors.lastname: Minnaar
authors.affiliation: Department of Food Science, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa. Electronic address: naushad.emmambux@up.ac.za.
authors.forename: Naushad M
authors.initials: NM
authors.lastname: Emmambux
mesh_terms: D000688:Amylose / Q000378:metabolism*; D005720:Gamma Rays; D013213:Starch / Q000378:metabolism*; D013229:Stearic Acids / Q000378:metabolism*; D003313:Zea mays / Q000378:metabolism*
chemical_list: D013229:Stearic Acids; C031183:stearic acid; D013213:Starch; D000688:Amylose
keywords: Amylose–lipid complexes; DSC; High amylose maize starch; Pasting viscosity; Pressure; WAXS