High moisture extrusion of pulses for the production of meat analogues

As animal-based foods have a large impact on the environment, meat analogous products, based on vegetable proteins, are now in the spotlight. Meat analogous is generally produced through extrusion cooking, which is a cost-effective method to produce desirable fibers that can mimic the meat’s functionality. Generally, concentrated soy protein is used as raw material however this leads to allergy problems, maintenance of biodiversity, and the protein extraction process involves the use of a large quantity of water, solvent, and energy. For this reason, pulses (or their fractions) could play a key role thanks to both nutritional and health-promoting features, together with their low environmental impact. This work is aimed at understanding the aptitude of pulse flours (chickpea, red lentil, fava bean, and yellow pea) to be transformed into meat analogous. Specifically, the fractions rich in proteins obtained by air fractionation were used. Pulse flours and protein-enriched fractions were characterized to understand the rheological behavior (mixing and pasting properties using Farinograph® and ViscoQuick®) and the functional properties, such as the ability to absorb and retain water and oil and the emulsifying and foaming properties. Then, pulse fractions were subjected to high moisture extrusion process (~50% hydration and temperature up to 100°C) in a TwinLab-F 20/40 twin-screw extruder (Brabender®). Each pulse flour and its protein-enriched fraction showed peculiar functional and rheological properties, which allowed to predict the behavior of the material during the extrusion. For example, samples showing the highest torque stresses at the farinograph test led to the formation of a product with better characteristics. Differences in functional and rheological properties resulted in products with different features. Specifically, the products obtained from the extrusion of red lentil tended to expand at the end of the process creating, consequently, a heterogeneous structure characterized by the presence of air bubbles. However, red lentil performed well through Textured Vegetable Protein (TVP) extrusion. Chickpea led to a product characterized by a different appearance compared to the conventional meat analogous (i.e based on soy proteins), specifically, it was not possible to distinguish the typical fibers of the reference product. On the contrary, products from fava bean and yellow pea presented similar characteristics to the reference. In conclusion, fava bean and yellow pea could successfully be used to produce meat analogous to offering consumers sustainable products with high protein content.