Improved textures and quality characteristics of plant-based sausages formulated with canola oil-in-water emulsions stabilized by soy protein isolate

This study aims to investigate effects of canola oil (CO) emulsions formed by soy protein isolate (SPI) on textural properties and quality characteristics of vegetarian sausages making texturized fibril soy proteins (TFSP) as the base. Results showed that at SPI contents = 12–14 wt% and CO contents = 20–40 wt%, fine stable SPI-CO emulsions (d43 = 2.85–6.94 μm) could be formed, and showed an increased binding ability by increasing component contents. Compared to the direct addition of CO, the incorporation of pre-formed SPI-CO emulsions exhibited greater improvements on TPA (texture profile analysis) attributes, shear test results, and water and fat binding capacities of TFSP-based sausages, with the one formed at SPI content = 14% and CO content = 40 wt% showing the best performance. Confocal laser scanning microscopy and dynamic rheological measurements upon temperature sweeping revealed that fine stable SPI-CO emulsion droplets (<10 μm) showed a strong affinity for TFSP due to the unfolding of protein conformation at droplet interface, and behaved as active filler participating in the network formation to reinforce TFSP-based sausage matrix. This study demonstrates that pre-emulsification of oils with SPI could be an effective way to improve textures and quality characteristics of plant-based meat products.