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BACKGROUND The application of Pickering emulsions stabilized by food‐derived particles is of great interest, studies have focused on development of natural functional emulsifiers from agricultural byproducts. Dietary fiber (DF) has been recognizing for its excellent physiological functions. Moreover, physicochemical properties of pomelo peel DF (PDF) make it a potential emulsifier. However, pristine PDF is not suitable as emulsifier due to its compact physical structure and high hydrophobicity, which seriously limits its utilization. The objective of the study was to investigate the effects of cellulase on physicochemical properties of PDF and to illustrate the feasibility of cellulase modified PDF (MPDF) as natural functional emulsifier. RESULTS: Cellulase modification significantly improved (P < 0.05) specific surface area, water‐holding capacity/oil‐holding capacity, viscoelasticity, hydrophobicity, and pore structure while decreased crystallinity index and particle size of PDF. Emulsion could remain stable over 30 days as MPDF concentrations up to 1 wt% and oil/water ratio 3:7. The appearance stability of emulsions was not influenced by temperature (4–60 °C), pH (3.0–12.0), and ion concentration (0–200 mmol L−1) which was similar to Pickering emulsions. The mechanism of MPDF as an emulsifier was mainly attributed to the combination of Pickering effect and the three‐dimensional network. In addition, MPDF showed higher antioxidant capacity in emulsions than other classical emulsifiers. CONCLUSION: The results illustrated that MPDF has a favorable feasibility for preparation of stable Pickering‐type emulsions, which will be a practical support for application of PDF as a natural functional emulsifier and will be helpful to realize the resource utilization of DF in pomelo industries. © 2022 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

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. [Display omitted] • 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. [ABSTRACT FROM AUTHOR]