DYNAMIC VISCOELASTIC PROPERTIES OF SOME COMMERCIAL SALAD DRESSINGS

Abstract

ABSTRACT A controlled stress rheometer (Carrimed CS) was used to carry out oscillatory viscoelastic experiments within the linear viscoelastic region for some commercial salad dressings: mayonnaise, reduced calorie mayonnaise and salad creams. All the mayonnaise samples exhibited higher values of maximum stress amplitude which guarantee linear viscoelasticity than either the reduced calorie mayonnaise samples or salad creams. The frequency dependencies of the storage modulus and the phase angle revealed that all the standard mayonnaise samples exhibited similar viscoelastic properties, showing a higher elasticity than the reduced calorie mayonnaise samples and these, in turn had a higher elasticity than salad creams. The absolute magnitude of the complex viscosity, |η*|, followed the power law equation with respect to frequency except for the salad creams and was compared to the steady viscosity, η. |η*|/η was related to the degree of shear destruction in the structure, which was minimum for one of the reduced calorie mayonnaise samples. The viscoelastic properties of the salad dressings studied are related to their different structures.