Department of Chemical Technology, University Colleges of Science and Technology, Calcutta University, Calcutta - 700 009, India
ABSTRACT: An attempt was made to use high-melting lowdigestible fat palmstearin as a vanaspati substitute by blending it with polyunsaturated fatty acid-rich liquid oils. This blending produced fat products of zero-trans fatty acid content and melting points below the human body temperature, so that they can be digested easily. The new blended products were fed to male albino rats (Charles Foster strain); the coefficients of digestibilities were 94.2% for palmstearin and rapeseed oil blend, 95.1% for palmstearin and sunflower oil blend, and 96.2% for palmstearin and soybean oil blend, which were somewhat better than the digestibility coefficient of conventional vanaspati (93.6%). Feeding experiments for three months showed comparable results in terms of serum lipid profiles. The blended products significantly increased the total cholesterol level but not the free cholesterol level in serum and liver of rats when compared with those of the conventional vanaspati group of rats. JAOCS 73, 617-622 (1996),
There are two distinct methodologies for making zerotrans vanaspati-like fat products, namely, interesterification
Cholesterol, digestibility, methyl ester, palmstearin, phospholipid, rapeseed oil, soybean oil, sunflower oil, total lipid, triglyceride. KEY WORDS:
Hydrogenated fats are used as edible products in such forms as shortening, cooking fat, and margarine. In India and many other countries, hydrogenated fats known as vanaspati are consumed as a substitute for ghee (anhydrous butterfat). Hydrogenated fats for the above kinds of edible uses are produced by partial and selective hydrogenation of liquid oils, such as soybean, sunflower, rapeseed, cottonseed, and rice bran oil. The hydrogenated fats are characterized by having slip melting points of 31-41 ~ and trans fatty acid contents at 30-60% levels, depending on the nature of the liquid oil. Trans fatty acids of hydrogenated fat products have been reported to contribute to several health problems, including thrombogenesis leading to coronary heart disease (1-3). Interest has grown, therefore, on production of fat products that will simulate hydrogenated fat products but will not contain trans fatty acids. Such zero-trans fat products are known in commerce as vanaspati-like fats of the unhydrogenated type. *To whomcorrespondenceshould be addressedat Departmentof Chemical Technology,Calcutta University,UniversityCollegesof Scienceand Technology,92, AcharyaPrafullaChandraRoad, Calcutta - 700 009, India. Copyright 9 1996 by AOCS Press
and simple physical blending of oils and fats. The interesterification process involving randomization requires a saturated fatty acid-rich oil or oil fraction, such as palm oil or its fraction, called palmstearin. Palmstearin is produced by fractionating palm oil by one of three different processes, namely, dry fractionation, detergent fractionation, and solvent fractionation. The yield of palmstearin varies from 20 to 30%, depending on the process of fractionation adopted. Palmstearins vary in fatty acid composition and triglyceride composition. Palmstearins contain 1-2% myristic acid, 47-74% palmitic acid, 4-6% stearic acid, 16-37% oleic acid, and 3-10% linoleic acid. Palmstearins consist mainly of the triglycerides C46 (0.5-3 mol%), C48 (12-56 tool%), C50 (34-50 mol%), C52 (5-37 mol%), and C54 (0-8 mol%) (4). While work has been done to utilize palmstearin in interesterification with liquid oils to make vanaspati-like fat products (5), and the nutritional quality of these interesterified products also has been evaluated (6), the scope of making fat products that simulate the hydrogenated vanaspati products by simple physical blending of palmstearin with liquid oils does...