The structuring of oleogels using mixed crystalline gelators was investigated as a potential means of improving the functionality of wax-based oleogels, as such systems tend to exhibit brittle mechanical flow behavior. The impact of combining white beeswax (WBX) and mixed mono- and diglycerides (MDG) were thus compared to oils structured with WBX alone using 15% structurant in high oleic sunflower oil. Mixed gelator oleogels were structured with a 2:1 WBX/MDG ratio and exhibited more desirable mechanical properties compared to those structured with WBX alone. Thermal analysis showed eutectic behavior in the mixed system, indicating independent crystallization of WBX and MDG. Microstructural analysis demonstrated smaller, clustered needles dominated the mixed WBX/MDG oleogels, while larger, singular needles were observed in oleogels structured with WBX alone. Large deformation flow profiles demonstrated the addition of MDG to the WBX crystal network increased plasticity, without compromising mechanical strength. This effect was attributed to the fact that plastic deformation mechanisms of polycrystalline materials are grain size dependent. Smaller microstructural grains are known to induce more plastic behavior, which correlated with the increased plasticity observed in the mixed WBX/MGD system. Changes in plasticity were observed during storage and could be correlated to observed changes in grain sizes. These results indicate the incompatibility between WBX and MDG impacts the microstructure of the resulting crystalline network, which has direct implications on the functional properties of the bulk material. Specifically, the ability to increase plasticity without compromising mechanical strength may have direct applications for mimicking specialty fats.
.jpg "Megan E. Govers, University of Guelph, Canada photo")