Non-thermal shearing effect on gluten conformation for plant-based anisotropic structures

Abstract

Wheat gluten manipulation to obtain fibrillar structures is a promising approach for elaborating meat analogs on large or small scales. Alternatively to extrusion, mild methods can save energy and avoid sensory attributes/protein degradation. This study aimed to evaluate low-temperature shearing to create gluten-based fibers, assessing the material structure as a function of processing intensity. The effect of the non-thermal shearing length (up to 10 min) and added mechanical energy (up to 565.5 J/g) applied on a highly hydrated wheat gluten-based matrix was investigated in terms of density, exudation, secondary protein structure (FTIR), protein network attributes (confocal laser scanning microscopy), elongation attributes, morphology (SEM), and anisotropicity of cooked matrices. The progression of the shearing process was associated with the development of β-sheet secondary structures (26 % to 50 % predominancy), higher elongation attributes, raw matrix density, and anisotropicity of cooked matrices. Higher protein vessel length and width were associated with the formation and stacking of β-sheets. Exudation, cooked matrix density, and endpoint rate were associated with higher α-helices content (lowered from 39 % to 11 % of predominancy) and lower shearing-added energies. A principal component analysis of the entire dataset confirmed these observations, and the morphology revealed the evolution of the matrix organization during the shearing process. These results underscore the potential of mild-temperature shearing of a highly hydrated gluten-enriched matrix to alter the protein conformation, opening possibilities for controlling fiber structure development, valid for new foods such as meat analogs.