Production of cellulose nanocrystals from waste Phellinus igniarius substrate by enzymatic hydrolysis-centrifugal fractionation method: Construction of a bioactive substance delivery system

To achieve the conversion of waste Phellinus igniarius substrate into functional foods, we employed enzymatic hydrolysis-centrifugal fractionation method to extract highly uniform spherical cellulose nanocrystals (CNCs, 14–28 nm) from the waste Phellinus igniarius substrate. These CNCs were used to construct an emulsion delivery system for carotenoids and polyphenols. We utilized biphasic fluorescence staining and Cryo-SEM to visually confirm the adsorption of CNCs at the interface. Furthermore, interfacial shear rheology was applied to perform time-, frequency-, and strain-dependent analyses. These methods provided direct, dynamic, and quantitative evidence that the CNCs rapidly adsorb at the oil-water interface and form a solid-like film dominated by elastic behavior (G′ > G″). This conclusively demonstrates that the emulsification mechanism follows a Pickering-type stabilization. Stabilized emulsions exhibit excellent storage and environmental stability, effectively delaying the degradation of bioactive compounds while preserving their antioxidant activity. In vitro simulated digestion experiments demonstrated that the Pickering mechanism of the CNC-stabilized emulsion offers the advantage of retarding lipid digestion. The bioaccessibility of the four encapsulated bioactive compounds, namely β-carotene, lutein, zeaxanthin, and dihydroquercetin, reached 46.19 ± 1.20 %, 44.66 ± 0.56 %, 40.72 ± 1.17 %, and 38.97 ± 1.16 %, respectively. This study successfully established a bioactive compound delivery system, enabling the conversion of waste Phellinus igniarius substrate into functional food.