The use of whole faba beans in emulsion gel

The faba bean (Vicia faba L.) is an economical protein source used in food and feed worldwide. It has high protein content and well-balanced amino acid composition. Since the starch fraction of faba beans causes problems in protein gelation, it hinders the use of whole faba beans for tofu production. Due to economical, ecological and nutritional reasons, it is worthwhile to develop a new way for producing whole faba bean tofu without discarding any part of faba beans. The aim of this thesis work was to produce whole faba bean glucono-𝛿-lactone (GDL) tofu by the starch amylolysis treatment and to study the impact of starch hydrolysate on faba bean tofu properties. This research investigated the changes in faba bean emulsion and emulsion gel properties with or without the starch hydrolysate. The pH and soluble protein content of faba bean suspensions with different GDL concentrations were measured. The microstructure, particle size distribution and viscosity of faba bean emulsions were studied. Moreover, the rheological and textural properties, microstructure, water holding capacity and total solid content of faba bean emulsion gels (GDL tofu) were also investigated. In addition, the contribution of different protein-protein interactive forces to the maintenance of faba bean emulsion gels was evaluated by comparing the protein resolubilization extent of the gels immersed in different reagents. Whole faba bean GDL tofu was prepared by the starch amylolysis treatment, emulsification and gelation processes. The starch hydrolysate containing faba bean emulsion gel was less elastic and more viscous than the starch-free gel. The presence of the starch hydrolysate increased the pH and viscosity of faba bean emulsions, which resulted in weakened protein-protein interactions. The starch hydrolysate significantly reduced the contribution of disulfide bonds to the maintenance of faba bean gel networks, but it increased the contribution of non-covalent interactions. In addition, the microstructure of the starch hydrolysate containing faba bean emulsion gel was not as fine and uniform as that of the starch-free gel. The presence of the starch hydrolysate lowered the water holding capacity and decreased the gel strength of faba bean tofu. All in all, the quality of the whole faba bean GDL tofu containing the starch hydrolysate was not comparable to that of the starch-free faba bean tofu, and further improvements are still required to improve its quality.