The contribution of polysaccharides to the foaming and emulsifying properties of aquafaba

Aquafaba is the cooking water remaining after legumes cooking. Its foaming and emulsifying properties are attributed to the diffusion of proteins to the cooking water. However, the solubilization of carbohydrates from these polysaccharide-rich matrices may also contribute to these functionalities, which can be modulated by salts during cooking. Based on this hypothesis, this study aimed to elucidate the relationship between polysaccharides composition and the foaming and emulsifying properties of aquafaba prepared using distilled water and 0.25% (w/v) aqueous solutions of sodium chloride, sodium acetate, or sodium bicarbonate. Carbohydrate concentration increased throughout the cooking process, reaching a plateau after 3 h. The highest carbohydrate concentration was achieved with sodium bicarbonate (65 g/L), resulting in an aquafaba enriched in glucose-rich polysaccharides (5.2 g/L), mainly gelatinized starch, as well as cellulose as part of cell wall debris. The use of sodium chloride and sodium acetate also resulted in aquafaba with higher carbohydrate content (36 g/L) than that obtained using water alone (30 g/L). This increase resulted from higher solubilization of pectic polysaccharides (2.2-2.7 g/L) and the glycosidic moieties from arabinogalactan-proteins (0.3-0.5 g/L). Starch and cellulose were found to be positively correlated with aquafaba foam stability, acting as stabilizers via Pickering-like mechanisms. Higher concentrations of these polysaccharides were also found to enhance the firmness of the emulsions formed. These findings highlight the relevance of polysaccharides for aquafaba foaming and emulsifying performance.