Refractometric investigation of butter and margarine

Abstract

In this study the refractive indices (RI) of 11 types of butter and margarine have been measured at \(\lambda = 632.8\,{\rm nm}\) by using a specially designed laser refractometer. Refractometric data have been obtained for five different temperatures: 25, 30, 32, 35, and 40 °C. The temperature gradients \(({\frac{{{\rm d}n}}{{{\rm d}t}}})\) have been found for each of the given butters or margarines. The density of the samples has been determined picnometrically at t=40 °C. Refractometric analysis of four mixtures of cow butter with margarine, palm fat, and lard fat has been performed.