OSA improved the stability and applicability of emulsions prepared with enzymatically hydrolyzed pomelo peel insoluble fiber

Insoluble fibers are not commonly used as emulsion stabilizers because of their compact physical structure and strong hydrophilicity. In this study, pomelo insoluble fibers (PISFs) prepared via cellulase hydrolysis and cellulase hydrolysis followed by octenyl succinic anhydride esterification were used as emulsifiers. The fabricated fibers are denoted as MPISF and OMPISFs, respectively. Unlike MPISF, the OMPISFs with different degrees of substitution (i.e., OMPISF(I) and (II)) increased in the ζ-potentials and contact angles but decreased in the oil-water interfacial tensions to different degrees. Furthermore, an 0.5 wt% OMPISF(II) content was required to prepare a stable non-creaming emulsion, whereas the corresponding MPISF and OMPISF(I) contents were 0.75 wt%. The OMPISF(II)-stabilized emulsions did not undergo creaming after three freeze-thaw treatment cycles. Therefore, the properties of the OMPISF(II)-stabilized emulsions were superior to those of the MPISF- and OMPISF(I)-stabilized emulsions. Additionally, the final amount of free fatty acids released by the OMPISF(II)-stabilized emulsion was 13.3% lower than that released by the MPISF-stabilized emulsion during simulated gastrointestinal digestion. During lipid oxidation processes, the amounts of lipid hydroperoxide and thiobarbituric acid reactive substance produced in the OMPISF(II)-stabilized emulsion were 41.3% and 40.0% lower, respectively, than those in the MPISF-stabilized emulsion. OMPISFs improved the emulsion properties by increasing the oil–water interface stability, forming more solid three-dimensional structures, and promoting electrostatic repulsion between emulsion droplets. These findings indicate that pomelo peel dietary fiber is a promising emulsifier with excellent application potential for the preparation of emulsion stabilizers. • Dual modification of OSA and cellulase endowed PISF an excellent emulsibility. • Freeze-thaw, digestion and oxidative stability of emulsions were improved by OSA. • Higher DS provide emulsions with higher stabilization and application properties. • Improved network, interface layer and electrostatic value were the main mechanism. • This study facilitates the development of utilization of pomelo peel as emulsifier.