Differential Thermal Analysis of Edible Fats and Oils. I.

Abstract

Heating differential thermal analyses were carried out on four kinds of beef tallow, five kinds ofcotton seed oil and five kinds of soyban oil, all having different degree of hardening, and examinations were made on variation in the DTA curve according to the degree of hardening.1) Unhardened beef tallow #50 (I.V.49.6) showed only one broad endothemic peak but hardened beef tallow #30 (I.V.29.8) showed one peak at 49.5°C after storing at 0 or 20°C fox 1 hour, while shouldered peak appeared at 4043°C when stored for 24 and 120 hours.Beef tallow #15 (I.V.14.8) showed only one sharp endothermic peak at 56°C when stored at 0, 20 or 40°C, . and nochanges occured with changes in the period of standing. Fully hardened #0 (I.V.0.3) showed a large endothermic peak at 60°C and exothermic peak at 46°C when stored at 0 or 20°C, but the exothermic peak disappeared when stored at 40°C.2) Hardened cotton seed oi1 #80 (I.V.76.7) and #60 (I.V.60.3) showed only one broad endothermic peak because of the largea mount of liquid oil, but #40 (I.V.40.0) showed a large endothermic peak at 49°C when stored at 0°C, and another small endothermic peak at 34°C when stored at 40°C.#20 (I.V.22.5) showed a large endothemic peak at 55°C when stored at 0 or 40°C, without change according to the period of standing. #0 (I.V.2.8) showed a large endothermic peak at 61°C, with addition of an exothermic peak at 45°C when stored at 0°C.3) Hardened soybean oil #80 (I.V.81.3) also showed a broad curve as in the case of cotton seed oil, #60 (I.V.58.4) showed great variation of its curve, with less sharp peaks. #40 (I.V.38.9) showed two endothermic peaks when stored at 0 or 20°C for 1 hour, and the peak became less sharp when stored at these temperatures for 24 hours. A clear, endothermic peak sappeared at 57°C and 49.5°C when stored at 40°C but the peaks became less sharp and formed a broad peak with lapse of time.#20 (I.V.17.1) showed only one large endothermic peak, under any of the conditions tested. The fully hardened #0 (I.V.0.4) showed two endothermic peaks at 60°C and 68°C, and one exothermic peak at 51°C when stored at 0°C or 20°C for 1 or 24 hours, and the peak at 60°C disappeared when stored at 44°C for 120 hours.