| The production of conjugated linoleic acid (CLA) and its incorporation into triacylglycerides to be used in foods has recently received great interest because some intriguing physiological properties, including anticarcinogenic and antiatherogenic effects, have been attributed to this fatty acid.; A set of conditions to efficiently produce CLA by alkali isomerization of linoleic acid present in safflower oil was determined. The conversion rate was 97%, using NaOH as catalyst and propylene glycol as solvent. The resulting product, consisting of a mixture of free fatty acids containing about 74% CLA, was used to prepare structured lipids.; Enzymatic interesterification using M. miehei lipase, a sn-1, and sn-3 specific enzyme, was conducted to incorporate different levels of CLA (10, 20, 30 and 40% w/w) into triacylglycerides with different sizes of medium chain fatty acids (coconut oil and tricaprylin). Thus, specific structured lipids containing CLA predominantly in positions sn-1, and sn-3 were obtained. A fraction of each specific structured lipid was chemically interesterified to randomize the fatty acids in the triacylglycerides. Therefore, structured lipids with an ample range of compositions and molecular characteristics (i.e., chain length, unsaturation degree, and distribution of fatty acids) were produced to study the effect of these molecular parameters on the physical properties. Melting and crystallization temperatures, solid fat content, and viscosity were evaluated. Analysis of variance (ANOVA) was used to evaluate the significant effects of molecular parameters on physical properties.; In general, coconut oil-based structured lipids were solid at temperatures of 21.1°C and below; they had melting temperatures ranging from 15 to 25°C, and crystallization points from 0 to 14°C, depending upon the CLA content and distribution pattern of fatty acids. Whereas, tricaprylin-based structured lipids did not crystallize above −60°C. Therefore, no crystallization or melting points were obtained for these materials.; An increase in CLA level decreased the melting and crystallization points, and the solid fat content, but increased the viscosity. Randomization increased the melting point, but decreased the viscosity and solid fat content. Whereas, increasing in the chain length of the medium-chain fatty acids increased the melting and crystallization points, solid fat content, and viscosity. |
