Effects of soybean β-conglycinin subunits composition on its emulsifying properties and the mechanism

In the soybean beta-conglycinin system, subunit composition has an important influence on its emulsification properties. To elucidate the mechanism of subunit action in the emulsification process, the separated and purified beta-subunit and the mixture alpha- and alpha '-subunits (referred to alpha alpha '-subunit) were remixed in varying proportions, and then the physicochemical properties and structural properties of the subunit emulsifying system were characterized. The results demonstrated that when the ratio of alpha alpha'-subunit to beta-subunit was 5:5, the subunit aqueous dispersion system exhibited a minimum particle size of 47.58 nm, a maximum solubility of 87.21%, and the emulsification stability and emulsification activity were also optimal. Scanning electron microscope (SEM) images revealed excellent cross-linking between alpha alpha '-subunit and beta-subunit, forming a protein network structure that provided a structural basis for its emulsification. The emulsion with a subunit ratio of 5:5 exhibited the highest fraction of interfacial protein adsorption of 23.43% and the largest interfacial protein concentration of 11.79 mg/m(2). Inter-subunit adsorption and emulsion formation were primarily driven by hydrophobic interactions, with the beta-subunit exhibiting a higher affinity for adsorption than the alpha alpha '-subunit. The action mechanism of the subunits in the emulsion formation was proposed as a three-stage process, including establishing an initial weak protein network structure within the aqueous dispersion, followed by developing an emulsion interface layer and ultimately culminating in forming an emulsion gel network structure. Elucidating the emulsifying mechanism at the subunit level is crucial for enhancing the theoretical framework of soybean protein emulsification.

Automated summary

In the soybean beta-conglycinin system, the subunit composition plays an important role in its emulsification properties. When the ratio of alpha alpha'-subunit to beta-subunit is 5:5, the subunit aqueous dispersion system exhibits optimal emulsification stability and emulsification activity. The formation of a protein network structure between alpha alpha'-subunit and beta-subunit provides a structural basis for its emulsification. Hydrophobic interactions primarily drive the adsorption and emulsion formation between subunits. The emulsifying mechanism involves establishing a protein network structure, developing an emulsion interface layer, and forming an emulsion gel network structure.