Structural, and functional characterisation of texturized mung bean, cowpea, soy flours, and soy protein isolates for meat analogue applications

Abstract

The structural and functional properties of mung bean, cowpea, and soy proteins critically influence their suitability for texturized vegetable protein (TVP) production, yet comparative insights are limited. This study evaluates legume flours and soy protein isolate or future plant-based meat applications using low-moisture extrusion. Each material was texturized under its own optimised extrusion conditions established through targeted trials that prioritised structural integrity, expansion behaviour, and hydration performance. These conditions were refined by varying key processing parameters including barrel temperature, feed rate, water addition, screw speed and die temperature. Textured soy flour exhibited weaker structural development and retained desirable nutritional characteristics, although it showed limitations in forming strong fibrous alignment and structural integrity. In comparison, mung bean and cowpea flour-based TVPs demonstrated softer textures driven by starch gelatinisation, along with improved hydration behaviour particularly, enhanced water absorption and retention during rehydration. Soy protein isolate produced TVPs with the most pronounced fibrous structures, higher expansion ratios, and stronger protein-protein interactions under the applied extrusion conditions, resulting in superior water-holding and rehydration capacities. Overall, the findings demonstrate that underutilised legume flours particularly mung bean and cowpea have the potential to generate functional TVPs with enhanced structural properties, indicating strong potential for partial or full incorporation into plant-based meat analogue systems.