Creation of Oleogels by utilizing Lipid Whisker Crystals

Efforts to achieve a sustainable food supply must be implemented urgently to overcome global food insecurity. Alternative foods made from soybeans and other plant-derived materials, of which alternative meats are most typical, have been attracting attention as a means to provide a sustainable food supply without causing further environmental damage. However, most plant-based meats lack "juiciness", which is associated with the encapsulation of oil droplets in the network of plant-based protein fibers, starch, etc. Therefore, the development of a novel manufacturing technology that can overcome the serious problem of inadequate "juiciness" of plant-based meats is strongly desired.

Oleogels have strong potential to overcome the serious problem of inadequate "juiciness" of plant-based meats. An oleogel is a structure in which a small amount of solid fats (gelling agent), such as vegetable wax, forms a solid-particle network structure that can maintain a large amount of liquid oil. However, it is quite difficult to manufacture wax-based oleogels with high stability.

Recently, we have succeeded in the manufacture of oleogels with low concentrations of triacylglycerol as the gelling agent by controlling growth temperature [1]. Particularly, it has also been demonstrated that gelation occurs with only 0.5 wt% gelling agent when fully hydrogenated hard palm mid-fraction (FHHPMF), of which 1,3-dipalmitoyl-2-stearoylglycerol (PSP) is a major component, is used as a gelling agent. Moreover, this oleogel composed of PSP had a characteristic elongated fibrous shape when observed under a dark-field microscope. In material science, such elongated fibrous crystals are well-known as whisker crystals. In this presentation, we demonstrate that elongated fibrous crystals composed of PSP are whisker crystals by using transmission electron microscopy (TEM). We will also discuss the growth direction of whisker crystals by analyzing the diffraction images.

 
[1] N. Oishi et al., Food Structure 37, 100333 (2023).