Acidified dough processing of faba bean protein concentrates: A pathway to enhanced ingredient functionality

The application of lactic acid fermentation to improve the nutritional, functional and sensory properties of plant protein ingredients is gaining considerable interest. In this study, we hypothesised that dough formation and acidification by addition of lactic acid per se can modify the techno-functional properties of faba bean protein concentrate (FPC). FPC was formed into a dough, acidified using lactic acid and incubated at 37 °C for 18 h to mimic conditions during lactic acid fermentation. Texture analysis revealed a higher hardness for the acidified dough of 421.1 ± 8.4 g compared to 106.3 ± 8.6 g for the non-acidified dough. Results showed a more open and disrupted protein network of the acidified dough, shifts in protein secondary structure, and differences in structural domains, with the acidified dough exhibiting a population of tightly bound protons of 87.5 % ± 1.6 % compared to 22.0 % ± 3.2 % for the non-acidified dough. Dispersing the doughs in water (5 % w/w protein) and adjusting the pH to 4.4, 6.4 or 7.0 enabled screening of their techno-functional properties. Similar protein solubilities of the dispersions were found at pH 4.4 (9.7 ± 0.3–10.6 ± 0.3 %). At pH 7.0, however, both the non-acidified dough (66.7 ± 1.1 %) a well as the acidified dough (59.8 ± 0.3 %) exhibited decreased protein solubility compared to the control (72.5 ± 0.1 %). Moreover, emulsion stability, foaming, and gel formation relative to the direct use of FPC were strongly pH dependent. Dough formation and acidification offer a promising strategy for enhancing the potential of plant-based ingredients and pave the way for the development of fermented legume dough-based ingredients.