Effect of industrial process conditions of fava bean (Vicia faba L.) concentrates on physico-chemical and functional properties

Fava bean (Vicia faba L.) is a promising source of proteins and has a potential in industrial food applications. Processing of fava ingredients modifies proteins and their functional properties. This study established the complexity of the relationship between fava protein-associated reactions (protein hydrolysis and aggregation), physico-chemical properties (electric charge, solubility, and intrinsic fluorescence, thermal integrity) and functional properties (foam and emulsion). For this study, an air-classified fava protein concentrate (65% w/w protein d.b.) was processed using pH (2, 4, 6.4 and 11), temperature (55, 75 and 95 °C) and duration of treatment (30 and 360 min) to produce 36 modified fava concentrates. Processing resulted in protein hydrolysis at pH < 4, and protein aggregation at pH ≥ 6.4 at temperatures above 75 °C, which influenced foaming and emulsification distinctly owing to the differences in their stabilizing mechanisms. Despite these modifications, their physico-chemical and functional properties were primarily governed by the beverage application pH. The surprising interplay shown between properties encourages the need to dive further into the different protein/non-protein reaction and interactions that can occur in fava concentrate. The functionalities of fava bean protein-rich ingredients were investigated in industrial beverage application systems (pH 4 and 7) after industrial relevant process conditions (pH: 2, 4, 6.4 and 11; temperature: 55, 75 and 95 °C, treatment duration: 30 and 360 min). Foam capacity (>100%) was very high for all ingredients at both pH applications (acidic or pH 4, and neutral or pH 7), while the foam stability changed according to the application pH. So-called foam-breakers were discovered in acidic application, while all ingredients maintained high stability in neutral applications. A similar instability was found for emulsification, since emulsion made with all ingredients in acidic application creamed immediately after production. Emulsions in neutral applications were homogenous with all ingredients, thus, emulsion capacities were equivalent to each other, but the storage stability was affected by the ingredient processing pH.