*3.5. Statistical Analysis*

The data were analyzed statistically using SAS software (Enterprise Guide version 7.1; SAS Institute Inc., Cary, NC, USA). The data between non-FIR-treated control and FIR treatment groups were analyzed by one-way analysis of variance. The significance between experimental groups was evaluated using Tukey's honestly significant difference (HSD) test at a *p* < 0.05 significance level.

### **4. Conclusions**

This study studied in detail the effect of FIR on the representative health-beneficial compounds and antioxidant activities of ginseng leaves. Our results demonstrate that FIR treatment is a rapid and efficient method for producing deglycosylated bioactive compounds from ginseng leaves. FIR treatment at 180 ◦C is recommended to obtain more polyphoneols and kaempferol. However, the ideal FIR treatment temperature for producing deglycosylated minor ginsenosides, such as F4, Rg6, Rh4, Rk3, Rk1, and Rg5, is 190 ◦C. Both polyphenols and ginsenosides are compounds that are beneficial to human health, with different bioactivities that vary between individual compounds. However, with regard to the antioxidant activity of ginseng leaves, it seems to be mainly contributed by the highly accumulated polyphenols rather than ginsenosides. These findings will help the further use of ginseng leaves in health care products.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/ 10.3390/molecules27154782/s1, Figure S1. The chemical structures of analyzed ginsensides in this study. PPD, protopanaxadiol; PPT, protopanaxadiol; glc, β-D-glucose; arap, α-L-arabinopyranosyl; xyl, β-D-xylose; araf, α-L-arabinofuranosyl; Table S1. Changes of PPT and PPD ginsenoside contents (mg/g dry weight) in ginseng leaves treated to different FIR temperatures.

**Author Contributions:** Conceptualization, C.W.J. and S.H.E.; methodology, S.D. and J.R.L.; software, S.D.; validation, S.D. and S.H.E.; formal analysis, S.D. and J.R.L.; investigation, X.W. and C.W.J.; resources, C.W.J. and S.H.E.; data curation, S.D., X.W., X.M.S., and H.S.G.; writing—original draft preparation, S.D.; writing—review and editing, S.H.E.; visualization, S.D.; supervision, C.W.J. and S.H.E. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study was supported by the College Student Challenge Cup of Ludong University, Yantai, China; the New Talent Introduction Project (LY2013021) of Ludong University; and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry. This research was also funded by the National Research Foundation of Korea (NRF; Grant NRF-2022R1A2C100769511).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available in this article.

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