The Effect of Starch Modification and Concentration on Steady-State and Dynamic Rheology of Meat Emulsions

Abstract

In this study, the effect of starch modification (NPS, native potato starch; AMS, acid modified starch; DMS, dextrinized modified starch; PGS, pre-gelatinized modified starch) and its concentrations (1, 2, 4wt%) on steady-state and dynamic rheological properties of meat emulsions were determined. Water-oil binding capacity and intrinsic viscosity of potato starch increased up to 5.07-0.90g/g, and 14.98mL/g, respectively, after modifying with pre-gelatinization method. The particle size of starches as average mean diameter ranged between 44.19μm and 293.06μm. The maximum solubility was obtained from DMS after heat treatment at 70°C being 48.22%, which means an increase about 3.06-fold in solubility as compared with NPS. The Ostwald-de Waele model was successfully used to describe the flow properties of meat emulsions (R2>0.961). While starch types did not affect the K values of emulsions (p>0.05), starch concentrations did (p<0.01). All studied emulsions exhibited non-Newtonian, pseudoplastic behavior since n values were lower than 1. Emulsion systems were characterized as weak gel-like macromolecular dispersions with storage modulus (G') much greater than loss modulus (G″). A modified Cox-Merz rule was applied by multiplying angular frequency with shift factors (α<inf>SF</inf>). Frequency dependence of complex modulus (G*) was studied to measure the strength of cross-linking protein network of emulsion systems by calculating a constant order of relaxation function (α) and concentration dependent stiffness parameter (A<inf>α</inf>). It was concluded that PGS addition improved rheological properties of meat emulsions due to higher solubility, particle size, intrinsic viscosity, water-oil binding capacity than NPS. © 2015 Elsevier Ltd.