The effect of extrusion parameters on meat analogs produced from durum wheat and pea proteins

Defatted durum wheat cake is the solid by-product derived from the durum wheat oil extraction, and the dry-fractionation process to produce a protein-rich ingredient has been proposed as a technological strategy to valorise it. Considering the strong interest in alternative protein ingredients and plant-based meat, dry- fractionated durum wheat cake (DWC) could be extruded to produce low-moisture meat analogs. In order to produce a structure that could imitate meat, the setup of the different extrusion parameters must be optimized. Thus, the aim of this research was to produce low-moisture meat analogs from DWC in combination with pea protein isolate (25:75 w:w), studying the effect of extrusion parameters (screw speed, moisture content, and pH of the melt), on the physicochemical textural properties of the products. To reach this objective, a response surface methodology approach was used. The results revealed that the pH of the melt and the screw speed had a major influence on the water holding capacity (WHC) and water solubility index (WSI) of the extrudate. In particular the WHC increases and the WSI decreases by increase the screw speed and the pH of the melt. According to the texture profile and sensory analysis, hardness decreased significantly (P < 0.05) with increasing screw speed indicating the presence of a more puffed structure. These findings demonstrate that dry-fractionated durum wheat cake protein can be recovered to produce meat analogs and adjustment of extrusion conditions could significantly modify the physicochemical and textural properties of the final product.