The texture of many food products like margarines, pastry dough, sausages etc., is achieved by including a crystallizing triacylglycerol fraction in the lipid phase of the product. This crystalline network contains considerable amounts of saturated fatty acids, which intake has been demonstrated to raise blood cholesterol and the risk of the occurrence of cardio-vascular diseases. Therefore, the decrease of saturated fatty acids in the crystalline network would be desirable. This is not a straightforward exercise, and therefore novel alternatives for oil structuring have to be generated.
According to our findings the gelation of edible oils can be achieved by adding a mixture of oleic acid and sodium oleate at concentrations above 8 wt%. The two components individually cannot structure oil at this concentration, but their mixture, depending on the concentration, can lead to self-stand soft matter, which after storage for 20 days become transparent.. The synergistic effect of these two fillers was studied by varying their ratio and their concentration. The properties of the oleogels were evaluated using microscopy techniques (polarized microscope), rheometry, differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), small angle X-Ray scattering (SAXS) and small-angle nuclear scattering (SANS). The obtained gels were shear-sensitive and the network formation was disrupted when the temperature was higher than 35 oC, but upon cooling they regain their firmness. Moreover, addition of small amounts of water led to a change in the microstructure of the needle-like crystals and enhanced their rheological properties.
Principal investigator: Dr.
Constaninos V. Nikiforidis costas.nikiforidis@wur.nl
