抄録
Three kinds of natural fats (palm oil, lard and tallow) and four kinds of hydrogenated fats (soy-bean oil, rapeseed oil, whale oil and fish oil), for the most useful glycerides as the edible fat and for the oil industries, and their typical S3, S2U and SU2 fractions separated by solvent crystallization were studied to find the cause which will affect to the appearance, texture and creaming quality of these margarines and shortenings by means of X-ray diffraction method, microscopic melting point method and rheological method.
It was found that the tendency of causing the grainy texture of margarines and shortenings of palm oil or lard depend upon their S3 fractions being α form under the thermal condition at which margarines and shortenings have been stored during the winter season and transformed into β form from α form without passing through β′ form, and thus β form gradually developed to a large crystal withlapse of time.
On the other hand the S3 fraction of tallow was β′ form and hydrogenated fats had scarcely contained S3 fractions thereby tended to stabilize at β′ form.
For the creaming quality it could not be investigated only from the polymorphic view, but may depend on the crystal shape or rheological property of fats.
