Abstract

When creating or redesigning food product researchers need to pay special attention to textural and rheological properties. Texture is a sensory perception derived from the structure of food and is related to viscosity and elasticity. Mayonnaise is semi-solid oil-in-water emulsion with starch in its formulations when fat-reduced. Under shear forces it exhibits different types of macroscopic flow behavior, such as shear thinning, yield stress behavior, thixotropy, and viscoelasticity. One problem with the rheological characterization of mayonnaise is that it is particularly difficult to isolate and quantify individual effects. Only sensory evaluation is capable to fully detect and describe them. Hence the ability to measure and to characterize them accurately and quickly enables the food industry to set standards for quality and to monitor deterioration during storage and distribution.  Back extrusion is a method used to quantify the behavior of thixotropic fluids. The relatively short time and low cost required to conduct the test makes it a suitable technique for quality control in product development. This paper evaluates back extrusion as method to analyze mayonnaise. It is performed at 5, 25 and 40ºC in a Stable Micro Systems TA-XT2 using twelve commercial mayonnaises. The method has provided qualitative and quantitative characteristics of samples in an accurate and quick way.

Key words: Rheology, back extrusion, texture, mayonnaise.