Physical Properties of Structured Fats and Fat Blends Based on the Long Chain Fatty Acids

Abstract

Enzymatic and chemical interesterification was used in preparation of structured fats without trans fatty acids. Structured fats were based on fatty acids which are not cholesterol-raising (stearic, behenic, arachidic and oleic acid). Blends of high oleic sunflower oil and fully hydrogenated erucic rapeseed oil, with molar ratio of long unsaturated fatty acids (LUFA, mainly oleic acid) to long saturated fatty acid (LSFA, mainlystearic, arachidic and behenic acid) 1.5:1; 1:1 and 1:1.5, were interesterified by alkaline and sn-1,3 enzymatic interesterification. Interesterification caused considerable rearrangement of triacylglycerol species, reduction of trisaturated triacylglycerols content and increase in monounsaturated and diunsaturated triacylglycerols, resulting in lowering the melting point, solidification point, changing in SFC profile and DSC thermograms. Greater changes in physical properties were noted after sn-1, 3 enzymatic interesterification. It has been found that it is still possible to use the enzyme Lipozyme TL IM for the interesterification of fully hydrogenated fats with high melting point. Prepared structured fat was used for the model fat blends preparation where as a liquid part was used low erucic rapeseed oil. The strength of the three-dimensional crystal network of model fat blends was monitored by means of a penetrometric test at 10 °C. Physical properties of fat blends such as melting point, solidification point, solid fat content, penetrometry increased with increasing concentration of structured fats. The increase was caused also with increasing ratio of saturated fatty acid in structured fats. Mixture of polymorphic modifications β and β´ was observed in most fat blends.