Ultrasound can be used as an analytical technique to provide information about the physicochemical properties of foods. Measurement of the reflectance coefficient offers an intriguing means to this end. To use shear and longitudinal ultrasonic reflectance to characterize the viscosity and solids content of lipids. The viscosities of the oils were measured using a concentric cylinder viscometer and the solids content of the fats estimated by differential scanning calorimetry. At all temperatures the longitudinal reflection coefficient was linearly related to viscosity but the line for each oil was different.
Shear reflectance is a sensitive and reliable measurement of oil viscosity.
Both shear and longitudinal reflectance can be used to measure solid fat content. Ultrasonic reflectance sensors are non-invasive and require no modification of container geometry so are ideal for retrofitting to existing process equipment.