ENHANCING THE EXTRUSION PROCESS RESPONSES AND PHYSICAL AND TECHNO-FUNCTIONAL PROPERTIES OF FAVA BEAN PRODUCTS THROUGH PREPROCESSING

Preprocessing techniques before extrusion-cooking can reduce antinutrients in legumes, such as fava beans. However, they can also alter their structure and composition affecting properties of industrial interest. This study aimed to evaluate the impact of three preprocessing techniques [soaking (S), soaking and reconstitution (SR), and soaking and dehulling (SD)] on the extrusion process responses and the physical and techno-functional properties of extruded fava bean (var. Verde) products. Samples were cooked in a twin-screw extruder and compared with a control (C) of extruded fava bean flour without preprocessing. According to the results, preprocessing increased the protein and crude fat levels of raw flours while reducing their dietary fiber. It also favored a reduction in particle size, especially in SR and SD samples (<841µm), enhancing their exposure and susceptibility to extrusion-cooking. Consequently, the torque and specific mechanical energy of processing decreased by up to 36% and 33%, respectively, compared to C. Processing enhanced the expansion (SEI) and porosity of the extrudates, decreasing their density and hardness compared to C. The best values were obtained for SD extrudates, with SEI=5.8, density=1.31g/cm3, and hardness=46.58N. Color was also impacted: S and SR extrudates exhibited light brown and green hues, whereas SD colors leaned towards light yellow. Preprocessing also improved the techno-functional properties of the extruded flours, increasing their water absorption and solubility index, oil retention and foaming capacity and stability. The best results were observed in SD, however, S and SR formed more stable emulsions. Preprocessing led to specific changes in the viscosity behavior of the extruded flours. S and SR generated less viscous pastes at room temperature and during heating, whereas SR produced more viscous and heat-resistant flours. In conclusion, preprocessing before extrusion can enhance the process and product attributes of fava beans, producing valuable ingredients for developing more nutritious and sustainable products.