BACKGROUND: Citrus fruits are an important source of dietary fiber. However, on the one hand, traditional preparation methods of citrus fiber rely on chemical hydrolysis, resulting in unavoidable environmental contamination and nutrients loss. On the other hand, citrus fiber usually requires modification due to its low soluble dietary fiber content. Therefore, we explored green preparation methods of citrus fiber, and evaluated the impact of high-speed homogenization alone or combined with cellulase hydrolysis, Trichoderma viride or Lactobacillus plantarum fermentation on the physicochemical, structural and functional properties of dietary fiber derived from navel orange peel. RESULTS: Cellulase-hydrolyzed navel orange peel dietary fiber (NOPDF) had better water solubility and oil holding capacity but lower thermal stability. In contrast, T. viride-fermented NOPDF demonstrated the best thermal stability and glucose adsorption (4.62 ± 0.06 mmol g CONCLUSION: Both modification methods of T. viride or L. plantarum fermentation could significantly improve the physicochemical, structural and functional properties of NOPDF, and offer a valuable approach for utilizing navel orange peel in the functional food industry. © 2025 Society of Chemical Industry.