Effect of fat on non-linear rheological behavior of processed cheese spreads using coupled amplitude-frequency sweeps, Fourier Transform-Chebyshev polynomials method, sequence of physical processes, and quantitative network analysis

Abstract

The nonlinear rheological behavior of high and low-fat cheese spreads was investigated at strains between 0 and 1000% using 4 different methods. The first method consisted of frequency sweeps at selected strains where the strain sweep was stopped, and a frequency sweep was conducted immediately in the linear viscoelastic region. Secondly, the strain sweep was analyzed with the FTC method in the non-linear region. The third method used SPP to create Cole-Cole plots to quantify elastic and viscous transient moduli throughout the oscillation cycle. Lastly, quantitative network analysis was done on SEM images relating non-linear rheological properties to progressive structural changes in the casein network. The coupled amplitude-frequency sweep method along with SEM and network analysis help elucidate the relationship between the non-linear rheological behavior and microstructure. High-fat samples showed a denser network in SEM images. G’ and G” were higher at small strain amplitudes (<10%) but high-fat samples decayed faster at higher strains (10–1000%). Both formulations recorded shear-thinning and strain-stiffening behavior in the nonlinear region.