Abstract
The emulsification properties of eggs allow them to readily mix with fats and oils. Moreover, their heat-induced gels have specific soft textures. However, to the best of our knowledge, the effects of adding fats and oils to liquid egg during the cooking process have not been studied so far. In the present study, we investigated the effects of heat on the rheological properties of two types of liquid egg mixtures, one with milk fat cream and the other with rapeseed oil, and their heat-induced gel structures and textures. We found that the dynamic linear viscoelasticity measurements at 10°C were relatively uniform for the liquid egg-milk fat cream mixture and highly variable for the liquid egg-rapeseed oil mixture, while those at 80°C were highly variable for the former and relatively uniform for the latter. When liquid egg was heated with milk fat cream or rapeseed oil in an omelet-like form, the resulting gel showed a porous structure, as evidenced by scanning electron microscopy. Texture measurements and sensory evaluations demonstrated that heat-induced liquid egg gel with milk fat cream exhibits vulnerable properties. Thus, the addition of milk fat cream or rapeseed oil to liquid egg altered its rheological properties, both during heating as well as during the formation of the heat-induced gel structure, and generated a unique, vulnerable, and flexible, texture.
