Viscoelastic properties of table margarine prepared from lipase-catalyzed transesterified mixtures of palm stearin and palm kernel olein

A controlled-stress rheometer was used to evaluate dynamic viscoelastic (VE ) performance of an experimental table margarine prepared from a transester ified palm stearin (PS):palm kernel olein (PKO) mixture (40:60 ratio) using Rhizomucor miehei lipase as' the biocatalyst. Comparison was made using a commercial fable margarine made of palm oil and palm kernel oil. The experi ments were carried out over a period of three months with the margarines ke pt at 20 and 30C. Elastic parameters such as elastic moduli (G'), viscous m oduli (G "), complex viscosities (eta*) and tan delta were determined as fu nctions of frequency and storage period The experimental table margarine ex hibited larger linear viscoelastic (LVE) regions than the commercial margar ine, indicating a move elastic and firmer structure than the commercial pro duct. Similarly, the frequency dependencies of the storage moduli and tan d elta also revealed that the experimental table margarine samples exhibited a higher elasticity than its commercial counterpart. For both samples, the values of G' were higher than G " at any given frequency. The ratio of the absolute complex viscosities (\eta*\) compared to the steady viscosity (eta ) shows that the commercial samples showed the lowest destruction due to st eady shear compared to the experimental samples. Trans fatty acid (FA) cont ent was found to be higher in the commercial (1.6%) than the experimental m argarine (0.2%).