On Reductive Tendency of Sterol Contents in Edible Oils and Fats during Commercial Processing Procedures

Abstract

In order to examine the behavior of sterols during the processing procedures of oils and fats, four species of animal fat and eight species of vegetable oil were submitted to the processes of deacidification, decoloration, hydrogenation and deodorization. Samples were taken at each of these steps, analyzed for sterols, and results obtained were as follows :
1) Campesterol, stigmasterol and β-sitosterol were detected in vegetable oils and the change of their compositional ratio was nearly negligible during the processing procedures.
2) A minute quantiy of cholesterol was detected in coconut oil, palm kernel oil, palm oil and rapeseed oil. Stigmasterol was not detected in rapeseed oil and kapok oil, and a minute quantity was detected in cottonseed oil. Brassicasterol was petected in rapeseed oil.
3) Sterol content in oils and fats decreased gradually with progress in processing procedures and the decrease was marked especially in hydrogenation and deodorization processes. The rate of this decrease in vegetable oils and oils of lauric acid system was smaller than that in animal fats and palm oil.
4) Sterol content in purified oils and in purified and hydrogenated oils was characteristic to the species of oils and fats but was also affected by conditions of purification and hydrogenation. In crude oils, sterol content was the smallest in palm oil, being ca. 1mg/g, while the content in rice bran oil was larger, being ca. 20mg/g.