Abstract

Plant-based meat analogs are the rising stars of the food industry as they promise to mimic the experience of eating meat without animals. They are popular due to their meat-like fibrous structures and typically obtained via high-moisture extrusion cooking. Texturization is believed to mainly take place during the solidification in a cooling die attached to the end of the extruder. However, the mechanisms behind this texturization are not fully elucidated yet. This work presents in situ studies of fiber evolution within a custom-designed extruder cooling die by small-angle neutron scattering on a length scale from 1.3 to 436 nm. The measurements demonstrated that macroscopic fibrous structures did not emerge from unfolding, elongation and orientation on molecular level. This contradicts existing hypothesis of the structuring mechanism underlying the meat-like fibers. Instead, the scattering patterns indicate the presence of densely packed protein nano-aggregates of around 40 nm consisting of globular proteins with a diameter of 9 nm. Based on that, chain-like arrangement of protein nano-aggregates, fractures of the viscoelastic mass in the flow field and sharp temperature-dependent solidification are proposed as underlying mechanisms for macroscopic fiber formation.