Evaluation of the protein profile and emulsifying properties of legume wastewater as emulsifier in circular food applications

The potential of legume wastewater (LWW), which is an underappreciated functional legume by-product, is explored as a sustainable emulsifier in bakery products. This research aims to advance recycling practices for LWW from pea, chickpea and soybean. The emulsifying properties of oil-in-water LWW emulsions were markedly influenced by the legume type and processing type. The emulsions of soaking and cooking water from soybeans (SS and SC) demonstrated a smaller particle size (125.4- 136.2 μm), improved emulsification capabilities, and superior stability compared to those derived from peas and chickpeas. SS and SC established a comparative scale for protein fractions of vicilin, α-legumin, and β-legumin, respectively. The emulsion of chickpea soaking and cooking water showed a significantly larger particle size (104.2-328.6 μm) and lower emulsion stability (50.4 and 55.0%) compared to pea (90.4-285.8 μm, 56.1 and 58.8%) and soybean (125.4-136.2 μm, 57.5 and 60.8%). The PC sponge cake demonstrated a harder texture compared to SC and CC, observed by its notable hardness measurement (475.76 N), which correlates directly with its protein level and the inclusion of legumin. LWW stands out for creating profitable food additives, simultaneously prompting people to view sustainable development from the perspective of the food application.