Techno-functional Properties of Fava Bean (vicia Faba L.) Pod Flour as a Function of the Drying Process

The by-product of fava bean processing, mainly the pods, accounts for more than 70% by weight of the vegetable, with the consequent problem from an economic and environmental point of view. Thinking of its richness in nutritional and bioactive compounds, proposing an integrated zero-waste process for the recovery of fava bean pods as a powdered food ingredient would contribute to a healthy, intelligent and sustainable diet. Freeze-drying (FD) can be proposed as the most appropriate reference method when dehydrating raw materials of plant origin, with thermolabile and oxidation-sensitive compounds. However, if the major bioactive compound is not vitamin C, but phenols, e.g., as is the case in fava bean pods, this benefit may not be as evident. Hot air drying (AD) is one of the most common methods of food preservation and significantly cheaper than FD. In any case, techno-functional properties of the powder should also be considered. As such a powdered product, it must respond to adequate flowability. In addition, its use as a food ingredient must allow for an adequate capacity for interaction with water and oil. This study compares different techno-functional properties of the powder obtained by applying both drying processes, at 45°C, 50°C and 55°C. The drying temperature had practically no effect on most of the properties analyzed. AD allowed to obtain a product with a larger particle size and lower interparticle porosity than FD, which led to a slightly lower hygroscopicity, better flowability and wettability, and also higher emulsifying activity and emulsion stability, despite a lower oil retention capacity. These results allow us to recommend, among the studied methods, AD at 55ºC as the quickest process to obtain a fava bean POD flour with adequate technofunctional properties.