Functional and nutritional properties of faba bean (Vicia faba) isolates and their application in food

Replacing protein from animal sources with protein from plant sources is driven by cost, health and environmental factors. Vicia faba is a potential source of alternative protein as it contains good amount of protein, carbohydrate, fibre and micronutrients. However, the presence of the anti-nutritional compounds vicine and convicine have limited its utilisation in food. The aim of the project was to prepare protein isolates from Vicia faba and apply them to the preparation of beef patties. Four food grade extraction conditions at different pH (7.6 or 10) and temperature (6°C or 20°C) were used to extract Vicia faba isolate with a total yield ranging from 26.6 to 30.2 %, and a protein content ranging from 32.5 to 42.7%. Proteins in Vicia faba isolates were characterised by SDS-PAGE and confirmed by LC-MS analysis to be mainly legumin, vicilin and favin. The highest protein content (42%) and lowest vicine and convicine (<0.5%) content were found in isolate extracted at pH 7.6 at room temperature. The isolate also contained starch (5%) and fibre (19%). The proximate composition and functional properties were affected by pH and temperature. All Vicia faba isolates were shown to have good water holding (1.4 to 1.6 g/g) and fat holding capacity (1.1 to 1.3 g/g). Emulsifying and foaming properties were also observed. Heat-induced gelled was observed in all Vicia faba isolates at 12% and 20% w/v. Their functional properties were compared with commercial protein isolates (soy, pea, hemp and faba) and significant differences were found between samples. The best isolate was chosen for the application in beef patties based on the protein composition, quality with low vicine and convicine content. The addition of 20% of Vicia faba isolate to beef mince improved product yield significantly compared to 100% beef patties. The utilisation of faba bean to partially replace meat could contribute towards reducing the cost of nutritious food, and reduce burden on health and the environment.