Effect of oat particle concentration and size distribution on the phase behaviour of mixtures with gelatin

The present study examines the effect of oat particle addition on the structural properties of gelatin gels. In doing so, gelatin concentration was 2% (w/w) and a variable amount of oat (0-4%, w/w) was employed. The latter came at three different particle size distributions, i.e. 28.2, 82.9, and 182.2 μm. Mechanical observations were carried out using small deformation dynamic oscillation in shear alongside thermal studies with micro differential scanning calorimetry. Scanning electron microscopy images provided tangible evidence of the changing morphology in the binary mixture with the addition of oat particles. Phase separated matrices are formed where gelatin is the continuous phase supporting the discontinuous inclusions of oat particles. There was an immediate decrease in the mechanical strength of the composite gel with the addition of oat particles, which was accompanied by a parallel drop in the enthalpy values of helical associations in gelatin. Increasing concentrations of oat with the smallest particle-size distribution are capable of disturbing rapidly the gelatin network, as compared to the larger counterparts.