title: Influence of medium-chain triglycerides on expansion and rheological properties of extruded corn starch.
abstract: Enhancement of product properties of extruded starch based products can be achieved by incorporating health promoting oil into the matrix. In order to achieve a preferably high expansion with a homogeneous pore structure, the expansion mechanisms have to be understood. In our study, we applied a customized twin-screw extruder set up to feed medium-chain triglycerides after complete gelatinization of corn starch, minimizing its effect on the starch gelatinization. Despite the fact, that the addition of up to 3.5% oil showed no influence on the extrusion parameters, we observed a three-fold increase in sectional expansion. Longitudinal expansion was less affected by the oil content. Rheological properties of the gelatinized starch were measured using an inline slit die rheometer. In addition to shear viscosity, we presented a method to determine the Bagley pressure, which reflects the elongational properties of a fluid. We were able to observe an increase in the Bagley pressure from about 25 bar up to 35-37 bar due to the addition of oil.
authors.affiliation: Institute of Process Engineering in Life Sciences, Section I, Food Process Engineering, Karlsruhe Institute of Technology, Kaiserstraße 12, 76131 Karlsruhe, Germany. mario.horvat@kit.edu
authors.forename: Mario
authors.initials: M
authors.lastname: Horvat
authors.forename: M Azad
authors.initials: MA
authors.lastname: Emin
authors.forename: Bernhard
authors.initials: B
authors.lastname: Hochstein
authors.forename: Norbert
authors.initials: N
authors.lastname: Willenbacher
authors.forename: Heike Petra
authors.initials: HP
authors.lastname: Schuchmann
mesh_terms: D001696:Biomechanical Phenomena; D004548:Elasticity; D005782:Gels / Q000737:chemistry; D009821:Oils / Q000737:chemistry; D016062:Porosity; D011312:Pressure; D012212:Rheology / Q000379:methods*; D033081:Shear Strength; D012995:Solubility; D013213:Starch / Q000737:chemistry*; D044366:Transition Temperature; D014280:Triglycerides / Q000737:chemistry*; D014783:Viscosity; D014867:Water; D003313:Zea mays / Q000737:chemistry*
chemical_list: D005782:Gels; D009821:Oils; D014280:Triglycerides; D014867:Water; D013213:Starch