## 4 Conclusions  
Although various physiological activities of animal placentae have been reported to date, their unfavorable flavor is a challenge that must be addressed to allow their widespread use. To perform the off-flavor removal process of sheep placenta, a novel yeast strain was successfully isolated from traditionally fermented apple vinegar. The yeast strain, _B. deamine_ kh3, was used in the fermentation of the sheep placenta, and the efficacy of reducing off-flavors was tested by sensory evaluation. In this study, the sheep placenta fermented with _B. deamine_ kh3 exhibited significantly better palatability, due to the reduction in off-flavors, compared with sheep placenta fermented with _B. bruxellensis_ or the normal sheep placenta. Although the flavor preference increased with respect to sheep placenta fermented with _B. deamine_ kh3 compared to the normal sheep placenta, a significant difference was not observed between the two groups in the sensory test using the ranking scale method. However, the preference for sheep placenta fermented with _B. deamine_ kh3 was significantly higher than that of normal sheep placenta in the sensory test using the preference scale method. Specifically, when the sheep placenta was fermented with the novel yeast strain, _B. deamine_ kh3, changes were observed in various volatile compounds (ammonia, dimethyl disulfide, 1,3-dioxolane, and 2-isobutyl-4,4-dimethyl-1,3-dioxane), which could explain the deodorizing effect and increase in flavor preference. This study proposes a good starting point for the industrial application of a new deodorization method using the novel yeast strain, _B. deamine_ kh3.  
The following are available online, Table S1: Information of 42 panels who participated in QDA of this study, Table S2: Physiological characteristics of _B.deamine_ kh3.  
Conceptualization, H.-S.C., H.-C.K. and Y.-J.K.; Data curation, K.-Y.H.; Formal analysis, H.-S.C.; Funding acquisition, Y.-J.K.; Investigation, H.-S.C., K.-Y.H., X.-Y.X. and H.-C.K.; Methodology, H.-S.C., X.-Y.X. and H.-C.K.; Project administration, K.-Y.H. and Y.-J.K.; Resources, H.-S.C. and X.-Y.X.; Software, H.-S.C. and H.-C.K.; Supervision, H.K. and Y.-J.K.; Validation, K.-Y.H. and H.K.; Visualization, H.-S.C., K.-Y.H., X.-Y.X. and H.K.; Writing--original draft, H.-S.C., H.K. and Y.-J.K.; Writing--review and editing, H.K. and Y.-J.K. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the grants from the Basic Science Research Program (2019R1A2C1010428), and the Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2018R1A6A1A03025159). We are also appreciated for the project (20202298) from Kyung Hee University, Korea.  
The study was approved by the KDRI's Institutional review board (KDRI-IRB-20496) and was performed in accordance with the fundamental spirit of the Helsinki declaration (Association, 2013) which protects the rights and interests of the subjects and complies with human test management standards as well as domestic regulations in conducting research and recording results.  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.  
No new data were created or analyzed in this study. Data sharing is not applicable to this article.  
We would like to thank all volunteers and panels who participated in this study.  
The authors declare that there are no conflict of interest.  
Samples of the sheep placenta fermented with _B. deamine_ kh3 are available from the authors.