M.Sc. (Food Science) student Department of Food and Human Nutritional Sciences, University of Manitoba Winnipeg, Manitoba, Canada
Meat analogues are gaining popularity because of environmental, religious and ethical concerns associated with industrial meat production. Plant-based meat analogues are products with texture, taste and appearance that resemble meat products and can sustainably fulfill future protein-rich food demand. High moisture extrusion cooking is widely used to produce meat analogues on an industrial scale, with one of the main challenges being the fibrous texture of the product that mimics muscle meat. To address this challenge, two novel solutions are proposed: (1) manipulation of extruder long cooling die temperature, and (2) physical blowing agent-assisted extrusion cooking, neither of which has been systematically investigated so far. In this study, the effects of cooling die temperature (35, 50 and 65°C) and nitrogen gas (as a physical blowing agent) injection pressure (0, 1 and 2.5 bar) on the physical properties (texture and density) and three-dimensional microstructure of soy protein meat analogues were investigated. The hardness and chewiness values of meat analogues significantly (p < 0.05) decreased while the degree of texturization increased with a decrease in cooling die temperature. Compared to no nitrogen gas injection, gas injection at 2.5 bar pressure resulted in a significant (p < 0.05) decrease in meat analogue density, making its texture softer, less gummy and chewy. X-ray microtomography analysis proved that a higher number of bubbles were present in the nitrogen-injected meat analogues which were responsible for the changes in the meat analogue’s physical properties. This research has shown the potential of these two novel approaches, i.e., cooling die temperature manipulation and physical blowing agent assisted extrusion, on protein texturization during high moisture extrusion cooking, providing new avenues to improve several textural attributes of meat analogues.