Set yoghurt processing with eggs as milk replacements, and improvement of texture, rheology, and microstructure by formulation design and optimisation

Eggs are suitable for the processing of set yoghurt as milk replacements, but there is no yoghurt mainly made from eggs. In the present work, production formula was designed and optimised for high-quality egg-based yoghurt processing by improving water holding capacity, aroma, texture, and taste using single factor experiment and D-optimal mixture design. Results showed that with optimised formula (whole liquid egg, 100 g; water, 180 g; sucrose, 30.89 g; diacetyl tartaric acid ester of mono(di)glycerides, 0.28 g; gelatine, 0.112 g; gellan gum, 0.14 g; and β-cyclodextrin, 0.56 g), the product showed high sensory evaluation score, fine viscosity, as well as preferable hardness and suitable fracturability. SDS-PAGE electrophoretogram indicated that the proteins in egg-based yoghurt was degraded during fermentation, which might have contributed to the improvement of gel structure and taste. Based on the SEM images, the prepared egg-based yoghurt had smoother, stronger, and more compact gel network microstructure when compared with milk-based yoghurt.