Thermal Analysis of Raw Egg

Abstract

A raw egg was analyzed by the differential thermal analysis (DTA). Consequently, the egg yolk showed a single endothermic peak, which began about 69°C, had a center at 81°C, and was over about 90°C. The base line slanted a little at 60°C. The egg white was separated into a thick white and a thin one. Although their thermograms were different, they had the same two endothermic peaks. The one was called the first absorption peak, which began from about 61°C, had a center at 65°C, and was over about 70°C. The other was called the second absorption peak, which began from about 73°C, had a center at 79°C, and was over about 84°C. The phase transition was observed together with the first absorption of the thin white, but was not observed in the thick one. The thin one was thermodynamically in a state of equilibrium to the 13% glycerol aqueous solution under 60°C and its properties were similar to those of an aqueous ovalbumin solution. Since the thermogram of the thick one added 3% NaCl resembled closely to that of the thin one, it was considered that the thin one was equivalent to the thick one whose phase had been changed.