Enhancing variability in fibrous structures via geometric modifications of breaker plates in high-moisture extrusion of meat analogues

Abstract

The growing shift away from meat products is a key factor in fighting climate change. High-moisture extrusion (HME) is particularly promising in the production of meat analogues due to its capability to create fiber-like structures that mimic meat textures. However, opportunities remain for diversification to use the full potential of HME. This study highlights the potential of using breaker plates in HME to enhance the versatility of creating fibrous structures and tailoring the mechanical properties of meat analogues. For soy protein isolate, the influence of various breaker plate geometries on the development of fibrous structures is investigated, regarding hole diameter (1–2 mm), hole count (10–14), and channel length (2–4 mm). Tensile tests were conducted in transversal and longitudinal direction to obtain the anisotropy index of the extruded samples. To visualize the fibrous structure, cryo imaging and visual examination of open samples were carried out. Results reveal that breaker plates introduce a secondary structure (parallel strands) overlaying the parabolic primary structure. Achievable anisotropy (1.5–6.5) exceeded the values usually achieved in conventional extrusion. Breaker plate design affected secondary structure formation substantially. Larger hole diameters produced thicker strands with reduced anisotropy (2.9–1.5). Increasing hole number raised anisotropy (1.5–6.4) by altering strand cross-sectional shape and size, accompanied by decreased rupture tension in all directions. Extending flow channels stabilized structural properties against mass flow variations. Thus, we demonstrated that using breaker plates is capable to introduce an additional structural level, allowing for greater variability in mechanical properties.