Sensory perception and lubrication properties of milk: Influence of fat content

The sensory perception of homogenized milk with a fat content between 0.06 and 8% was correlated with its friction coefficient and viscosity. Above a threshold of 1% fat, there was a strong decrease in friction coefficient at low speeds, which is associated with shear-induced coalescence. Creamy perception was perceived only for products with the friction coefficient below 0.25 for silicone rubber at entrainment speeds lower than 200 mm s−1. Under those conditions, a linear correlation between perceived creaminess and friction was obtained at a fat content above 1%. The increased creaminess and thus decreased friction was attributed to the coalescence of fat globules on the surface of the tongue and rubber disc, respectively. At higher speeds, fused fat droplets were broken into smaller droplets (reversing coalescence) due to the high shear, thereby eliminating the correlation.