Use of legume flours and fiber for tailoring structure and texture of pea protein-based extruded meat alternatives

Abstract

The overall objective of this study was to understand texturization of pea protein isolate (PPI) using low moisture extrusion, and investigate protein interactions, functionality, and cross-linking with the inclusion of different levels of pea fiber (5-15%) and different types of starch-containing legume flours (20% chickpea flour or pea flour). PPI/ legume flour raw formulations had 18-27% lower water absorption capacity (WAC) as compared to the PPI control. However, WAC increased by 8-16% with the addition of pea fiber to a PPI/ legume flour control. Rapid Visco Analysis trends mirrored these results with peak viscosity shifting to higher temperatures with the addition of legume flour and lower temperatures with the addition of pea fiber. The role of starch in interfering with protein hydrophilic interactions and that of fiber in decoupling this effect were discussed. These interactions determined extruded textured protein properties, with more layering and denser products (174-229% higher bulk density as compared to control) observed with the addition of legume flours leading to lower water hydration capacity (WHC), as opposed to more cellular and porous microstructure (55-58% lower bulk density as compared to control) with the addition of fiber. Bulk density and WHC trends due to these porosity and layering effects impacted the instrumental texture characteristics of ground hydrated product, including hardness that increased from 475 g to 837-2334 g with the higher layering caused by starch, but decreased from 1295 g to 534-1050 g due to the porosity induced by fiber. To summarize, the use of legume flours and fiber can allow flexibility in targeting specific qualities while reducing costs and increasing sustainability of plant-based meats. PRACTICAL APPLICATION: Health, environment, and animal welfare concerns are creating a growing movement toward plant-based meat. Pea protein isolate and concentrate have become popular ingredients for texturized plant protein. Understanding of the role of starch and fiber in the structuring of textured pea protein could lead to use of legume flours and co-products of protein isolation to reduce cost and increase sustainability and nutrition of meat alternatives while targeting desired textural attributes.

Keywords: extrusion; legume flours; pea fiber; pea protein; plant-based meat; texturization.