The effect of temperature and loading rate on the rheology of butter

Abstract

Series of the indentation of the cone (60°) by the constant speed into blocks butter has been conducted. The indentation tests were performed at different speeds (1, 6 and 60 mm.min−1), and the corresponding force – displacement responses were fitted with an analytical solution to obtain the time-dependent constants and the instantaneous force–displacement response. Experiments have been performed on 18 different commercially available butters. A puncture test was performed to investigate the rheological properties of the food materials at 4 °C and at 19 °C. The indentation force decreases with the temperature. It increases with the loading rate. The recently proposed method for the indentation of the cone into viscoelastic solids have been used for our data analysis. This procedure which needs the use of the numeric methods enables to obtain stress relaxation modulus which describes the initial viscoelasticity of the tested materials.

Keywords

• butter
• cone penetrometry
• loading rate
• rheology
• relaxation modulus