Engineering rheological properties of edible oleogels with ethylcellulose and lecithin

Addition of 1% (w/w) soy lecithin increased the shear moduli 10-fold and gel hardness 20-fold for 10% ethylcellulose (EC) oleogels. Higher lecithin addition levels or addition to gels with a higher EC concentration caused smaller increases. Similar trends were observed in the penetration force of the gels. Gels displayed thermal reversibility and a high temperature plateau at T approximate to 120-130 degrees C. Large amplitude oscillatory shear rheology demonstrated similar solid-to-fluid transitions indicating that the polymer drives elastic softening and failure of the network. However, EC oleogels differed in their resistance to flow: the addition of unsaturated lecithin promoted a more gradual thickening response compared to gels containing saturated lecithin or only EC (the last two types of gels display strong intra-cycle thickening and thinning, more indicative of brittle failure). The thickening response of EC oleogels containing unsaturated lecithin, resembles more closely that of a model edible fat (lard).