Preparation of W1/O/W2 Emulsion Loaded with Chenpi Extract and Its Properties Evaluation

To improve the encapsulation stability and bioaccessibility of active components in Chenpi extract (CPE), the citrus soluble dietary fiber-gelatin (CSDF-G) and polyglycerol polyricinoleate were used as emulsifiers to form a W1/O/W2 double emulsion loaded with CPE. The study also investigated the optimal parameters for producing the CSDF-G complex and the W1/O/W2 double emulsion, as well as their environmental stability and in vitro digestive properties. Results revealed that CSDF and gelatin interacted via non-covalent electrostatic forces, with the strongest combination effect at pH3.5, as the emulsification capability of complex was strongest. When the CSDF/G ratio was 3:1 (w/w), the total concentration of CSDF-G complex was 2% (w/v), and the W1/O and W2 ratios were 3:7 (v/v), the prepared W1/O/W2 double emulsion had a uniform distribution, the smallest particle size, the strongest viscoelasticity, and the encapsulation rates to polyphenol and flavonoid reached 96.82% and 90.08%, respectively. Furthermore, the emulsion W1/O/W2 generated with these parameters remained stable in pH3.0~5.0 settings with ionic strength 0~100 mmol/L and showed strong resistance to high temperatures and UV light. The dual structure of emulsions was gradually dissolved during gastrointestinal digestion, as shown by in vitro digestion. After intestinal digestion, the bioaccessibility of polyphenols in W1/O/W2 emulsion-loaded CPE was increased by 33.22% compared with that in free soybean oil-loaded CPE. In conclusion, the W1/O/W2 double emulsion prepared in this study has good potential for active ingredient delivery, and the results will provide a reference for the development of new functional Chenpi-related products.