Viscoelastic Characterisation of High Protein Ice Cream: Predicting Tactile Sensory Properties via Time–Concentration Superposition and Large Amplitude Oscillatory Shear (LAOS) Rheology

In the present work we report on the exploration of time concentration superposition principle (TCS) and non- linear dynamic rheology (LAOS) as useful instrumental tools for predicting tactile sensory modalities of ice cream at serving temperature ( 14 ◦C). Three common tactile sensory properties of ice cream i.e., resistance to scooping (scoopability), creaminess and gumminess were assessed in high protein formulations differing in their protein to fat ratio (φP/F =0.9 to 4) and protein source (milk protein concentrate (MPC) vs whey protein isolate- sodium caseinate (WPICAS) 1:1 blend). The complex viscosity – angular frequency data obeyed the TCS principle with the calculated shift factors reflecting effectively the compositional profile of ice creams i.e., ac ∝ φP/F 1.16 and φP/F 2.23, bc ∝ φP/F1.27 and φP/F1.75 for MPC and WPICAS fortified systems. LAOS assessment revealed a clear impact of protein type and φP/F on the shearing deformation of ice creams. MPC fortification and decrease in the φP/F enhanced the shear flowing ability of the ice creams. In all cases, the onset of shear stiffening and thickening behaviour was observed at shear stresses below the flow point, which indicates gel-like or colloid glass-like structures. According to partial least squares regression analysis, the TCS parameters (ac and bc), damping factor (tanδ) and the shear strain (γf) and elastic modulus (log Gʹ f) at flow point were determined as the most important parameters predicting tactile sensory modalities on large deformation (spooning) such as scoopability, creaminess and gumminess.