Oral processing of meat-flavour textured soy proteins – Part I: Bolus properties and relationships with the texture profile analysis of the products

The study of food oral processing provides relevant information about the eating process. Thus, we studied the effects of oral processing of meat-flavour textured soy proteins on bolus properties and established relationships with the texture profile of the products. The soy protein concentrate was extruded under three conditions (30 % moisture/180 °C, 34 % moisture/160 °C and 38 % moisture/140 °C). The extrudates were added with salt and monosodium glutamate and then separated into two parts, one with and one without vegetable oil, thus obtaining the flavoured textured soy proteins (FTSPs). All products were subjected to texture profile analysis and in vivo assays to study oral processing. The extrusion condition at 30 % moisture/180 °C produced FTSPs with lower hardness, cohesiveness, and chewiness, which required shorter mastication times and resulted in boluses with lower moisture and a greater number of particles, which had a greater maximum Feret diameter but were less uniform (lower circularity). The addition of oil resulted in boluses with lower moisture and fewer particles, which were less uniform. Moreover, as the mastication duration increased, the number of particles increased, but the size of the particles also increased, suggesting both fragmentation and aggregation of particles phenomena during this process. In conclusion, all the study factors influenced the oral processing of meat-flavour textured soy proteins. Therefore, more studies should be conducted to obtain more information about extruded products.