Rheological properties of a soluble self-assembled complex from starch, protein and free fatty acids

Controlled interaction among amylose, protein and free fatty acids was performed using a pasting cell installed in a rheometer resulting in the formation of a soluble high molecular weight complex. Rheological characterization of solutions of the formed complex as well as during its formation in a range of temperatures of 25–95 °C and shear conditions ranging from 2.5 to 16.7 rad/s were performed. Different fatty acids (oleic acid, linoleic, palmitic, and conjugated linoleic acids), corn starch and whey protein, in a range of protein concentrations from 3.75% to 10% were used to produce the complex. By using rheological techniques and size exclusion chromatography was found that concentration of protein, type of free fatty acid, temperature, time and shear rates, all, had a significant effect on the formation of the complex and its rheological properties. Rheological results proved that the formation of the complex starts at 75 °C but its structure set during cooling at 55 °C. Increases in the shear rates applied during the complex formation significantly reduced its viscosity. Increases in the amount of protein increased the order of the complex. Conjugated linoleic acid, a bioactive compound, was able to be incorporated in the complex but using a slower heating rate than that used for the other fatty acids.