Green preparation and evaluation of physicochemical, structural and functional properties of dietary fiber from navel orange peel

BackgroundCitrus 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.ResultsCellulase-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-1 dried weight), along with the highest soluble dietary fiber yield (2.27 g kg-1 dried weight), the best soluble dietary fiber/total dietary fiber ratio (29.64 +/- 0.17%), water holding capacity (12.48 +/- 0.44 g g-1 dried weight), swelling capacity (12.10 +/- 0.24 g g-1 dried weight) and the darkest color. Lactobacillus plantarum-fermented NOPDF exhibited the best fillibility (tap density, 0.68 +/- 0.01 g mL-1 dried weight) and strongest in vitro prebiotic activity and antioxidant properties (total phenolic content, 5.81 +/- 0.26 mg gallic acid equivalents 100 g-1 dried weight; DPPH center dot scavenging capacity, 2.21 +/- 0.01 mg Trolox equivalents g-1 dried weight).ConclusionBoth 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. (c) 2025 Society of Chemical Industry.