Protein composition and physical properties of soy protein isolates and their role in structure formation during high moisture extrusion

Reducing meat consumption and shifting to a more plant-based diet in the context of climate change and health are currently hot topics. To facilitate this shift, research concerning meat alternatives and plant-based protein sources should increase. Soybeans (Glycine max) have already been used as an ingredient in meat alternatives for a long time, because of their high protein content and the presence of all essential amino acids. However, the production of soy has been associated with a negative impact on the environment in its main producing countries, because of the high rate of deforestation and transport. Therefore, locally grown soy, which will be used as the starting point of this project, has gained attention and especially for the use in newly developed meat-like food products. To obtain these products, many processing steps are conducted, such as the extraction of the soy proteins and the subsequent texturization using high moisture extrusion (HME). With a selection of locally grown soy varieties, the impact of different extraction techniques will be explored and used to produce soy protein with high quality on lab scale as well as pilot scale. The nutritional quality will be based on the macronutrient composition, amino acid composition, anti-nutritional factors, allergens and digestibility. An estimation of the functional properties will be made by measuring protein solubility and thermal stability. The knowledge of the HME technique for the texturization of soy protein, on the other hand, will be expanded by assessing the effect of the processing parameters on the micro- and macrotexture of commercially available soy isolates and/or concentrates. Finally, with the optimal processing parameters in mind, texturized products will be produced from the locally cultivated soy proteins using HME and these products will again be characterized based on their nutritional and functional properties. This will allow to link the overall protein quality obtained with the different extraction techniques with their behavior during the HME process.