THE COMPONENT ACIDS AND GLYCERIDES OF ARECA-NUT (ARECA-CATECHU) FAT

Abstract

The fatty acid composition of areca-nut fat was determined by the usual ester-fractionation method, using an electrically heated and packed column for fractional distillation under high vacuum (0.2 mm.). The glyceride structure was studied by crystallization of the neutral fat from acetone and ether; the composition of each of these glyceride fractions was studied by the fractionation method and the final possible glyceride composition computed therefrom. The chief component acids are lauric (19.5%), myristic (46.2%) and palmitic (12.7%), and in the unsaturated portion oleic (6.2%), linoleic (5.4%) and hexadecenoic acid (7.2%). Minor proportions of stearic, decanoic and of unsaturated monoethylenic C12 and C14 acids are also present. The chief component glycerides are (i) 56% of fully saturated (trimyristin, dimyristins and lauromyristopalmitin); (ii) 30% of mono-unsaturated-disaturated (mainly hexadecenolauromyristin, with some oleo-(linoleo)myristopalmitins and dimyristins); (iii) 14% of diunsaturated-monosaturated (oleolinoleoglycerides, mostly oleolinoleopalmitin). The glyceride composition follows closely Hilditch's rule of widest distribution of acyl radicals in the glyceride molecules. The fully saturated glyceride content of the fat, determined separately by the method of Hilditch & Lea,1 is 53.7%. The fully saturated components are found to contain (by the fractionation method) : 19.4% of lauric, 54.6% of myristic, 19.2% of palmitic and 6.8% of stearic acids. The proportions of various acids in the fully saturated components are similar to the corresponding ones in the saturated acid portion of the whole fat.