Comparison of the Rheological Properties of Plant Proteins from Various Sources for Extrusion Applications.

Patrick Wittek,M Azad Emin,Goeran Walther,Heike P Karbstein

doi:10.3390/foods10081700

Patrick Wittek, M Azad Emin + Show 2 more

Open Access

https://doi.org/10.3390/foods10081700

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Abstract

Plant proteins in foods are becoming increasingly popular with consumers. However, their application in extruded products remains a major challenge, as the various protein-rich raw materials (e.g., from different plant origins) exhibit very different material properties. In particular, the rheological properties of these raw materials have a distinct influence on the extrusion process and must be known in order to be able to control the process and adjust the product properties. In this study, process-relevant rheological properties of 11 plant-based protein-rich raw materials (differing in plant origin, protein content, and manufacturer) are determined and compared. The results demonstrate distinct differences in the rheological properties, even when plant origin and protein content are identical. Time sweeps reveal not only large differences in development of viscosity over time, but also in magnitude of viscosity (up to 15-fold difference). All materials exhibit gel behaviour and strain thinning behaviour in the strain sweeps, whereas their behaviour in the non-linear viscoelastic range differs greatly. Typical relaxation behaviour of viscoelastic materials could be observed in the stress relaxation tests for all materials. Comparison of the maximum achieved shear stress, which correlates with the elastic properties, reveals an up to 53-fold difference. The results of this study could serve as a starting point for adapting raw material selection and composition to process and product design requirements and help to meet the challenge of applying plant-based proteins in food extrusion.

Highlights

Interest in the use of plant proteins in extruded foods is steadily increasing [1,2].Protein-rich raw materials from plant origin can be used either as the main ingredient, as in some meat analogues [3,4,5,6], or to increase the protein content of traditional starch-based products, such as in breakfast cereals or snacks [7,8,9].These protein-rich raw materials, i.e., flours, concentrates, and isolates, can be produced from various plants
The most commonly used raw materials in food extrusion are from soybean, wheat, and pea [10]
Recent developments have demonstrated the potential use of many other plant protein sources for extrusion applications, such as oat [11], canola [12], lupin [13], peanut [14,15,16], and hemp [17]

Summary

Introduction

Interest in the use of plant proteins in extruded foods is steadily increasing [1,2].Protein-rich raw materials from plant origin can be used either as the main ingredient, as in some meat analogues [3,4,5,6], or to increase the protein content of traditional starch-based products, such as in breakfast cereals or snacks [7,8,9].These protein-rich raw materials, i.e., flours, concentrates, and isolates, can be produced from various plants. Protein-rich raw materials from plant origin can be used either as the main ingredient, as in some meat analogues [3,4,5,6], or to increase the protein content of traditional starch-based products, such as in breakfast cereals or snacks [7,8,9]. Recent developments have demonstrated the potential use of many other plant protein sources for extrusion applications, such as oat [11], canola [12], lupin [13], peanut [14,15,16], and hemp [17] The proteins in these raw materials differ in their amino acid composition and molecular structure [18,19].

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