High moisture extrusion of pulses for the production of meat analogues

As animal-based foods, such as meat, have a large impact on the environment, meat analogous products, based on vegetable proteins, are now in the spotlight. The market for these products is in rapid growth, offering a great opportunity for the food industry. Meat analogous products can mimic the meat functionality, i.e. have similar product features and sensory attributes, thanks to the fibrous nature of those products. The purpose of meat analogous is to meet the needs of consumers who are aware of sustainability and nutritional issue. For this reason, pulses 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. Initially, flours fractions were characterized to understand the rheological behavior; specifically, the pasting properties (ViscoQuick, Brabender®) were studied to understand the starch and protein behaviors on heating and cooling cycles under controlled conditions. Functional properties, such as the ability to absorb and retain water and oil and the emulsifying and foaming properties, were assessed to understand the interactions of these raw materials with water and oil. Finally, mixing behavior (Farinograph, Brabender®) was studied to investigate dough resistance to shear stress. 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®). Soy protein concentrate was used as a control since it is up-to-now the most widely used raw material to produce meat analogous. Each pulse 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. 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 in order to offer consumers sustainable products with high protein content.