**4. Conclusions**

In this study, the ethyl acetate extract of *Nervilia fordii* (NFE) possessing excellent antioxidant activity was first obtained, followed by encapsulation into a PVA/PVP nanofiber with high encapsulation efficiency. FTIR-ATR, TGA and XRD analysis confirmed the presence of hydrogen bonding interactions among different components and their miscibility at the molecular level. The prepared nanofiber still exhibits good antioxidant activity by inhibiting the primary oxidation products of fish oil, in particular, it was more effective than the non-encapsulated NFE. These results suggested that nanoencapsulation by electrospinning is an effective way to stabilize NFE and improve its antioxidant activity. Hence, the PVA/PVP/NFE nanofiber could be a promising antioxidant packaging material for fatty food preservation.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/ 10.3390/foods10081728/s1, Figure S1: Response surface and corresponding contour plots of three factors on the DPPH radical scavenging activity, Table S1: Factors and levels in BBD, Table S2: Analysis of variance (ANOVA) for the experimental results of BBD.

**Author Contributions:** P.W. experimental design, methodology, data curation, formal analysis, investigation, methodology, writing—original draft, writing—review and editing; T.-G.H. conceptualization, methodology, data curation, writing—review and editing; Y.W. experimental design, methodology, data curation, formal analysis; K.-E.L.—data curation; W.-P.Q.—data curation; Z.- L.H.—formal analysis; H.W. (Hong Wang) funding acquisition; H.W. (Hong Wu) supervision, project

administration, writing—review and editing. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Natural Science Foundation of China, gran<sup>t</sup> number 32001631, Guangdong Basic and Applied Basic Research Foundation, gran<sup>t</sup> number 2020A1515110190 and the National Natural Science Foundation of China, gran<sup>t</sup> number 31671852.

**Acknowledgments:** Authors acknowledge Ke-er Li, Wei-peng Qiu and Zhi-lin He for providing the electrospun fiber mat for experiments.

**Conflicts of Interest:** The authors declare no conflict of interest.
