## 4 Conclusions  
The present study demonstrated that supplementing ewes' diets with either processed or unprocessed orange peels has no adverse effects on the quality characteristics of the resulting yoghurt compared to those made from milk produced by ewes fed a conventional diet. Notably, the inclusion of unprocessed orange peels (UOP) resulted in yoghurt with higher protein and fat content than those from ewes fed processed orange peels (POP), while fat nutritional indices remained consistent across all treatments. Antioxidant activity differed only in the POP group when measured as total phenolic content. Differences were observed in colour parameters, such as redness (a*), yellowness (b*), and colour saturation (Chroma); however, Lightness (L*) and the whiteness index--key indicators of consumer perception--remained unaffected. Textural analysis revealed that yoghurt from ewes fed UOP was firmer, more cohesive, and stickier during the first two weeks of storage. Taste panel evaluations showed no significant differences in flavour across treatments, with all yoghurt samples receiving an overall acceptability score above 4. Instrumental assessments of sensory attributes, such as colour, texture, viscosity, and syneresis, confirmed stability throughout storage.  
These findings highlight the practical potential of incorporating orange peels--both processed and unprocessed--as a sustainable secondary feed ingredient in dairy production. Their use could reduce feed costs, enhance milk composition, and contribute to circular economy practices in the dairy industry. However, certain limitations of this study should be acknowledged. As this research was conducted under controlled experimental conditions, large-scale trials in commercial dairy farms would help validate the practical feasibility of incorporating orange peels into ewe diets. Future studies should explore both their suitability within various feed formulations and their effects on other dairy products, such as cheese and butter, to expand their potential applications in the dairy industry.  
Conceptualization, E.K.; methodology, E.K. and P.M.; formal analysis, Z.B.; investigation, E.K., Z.B., G.P., S.M., E.M.B., V.P. and M.-A.K.; resources, E.K.; data curation, E.K. and G.P.; writing--original draft preparation, E.K., S.M., E.M.B. and M.-A.K.; writing--review and editing, E.K.; supervision, E.K.; project administration, E.K.; funding acquisition, E.K. All authors have read and agreed to the published version of the manuscript.  
This research was funded by EU PRIMA Program for Research, Technological Development and Demonstration under grant agreement n\({}^{\circ}\)2013 (Turn food industry by-products into secondary feedstuffs via circular-economy schemes-NEWFED, [[https://newfeed-prima.eu/](https://newfeed-prima.eu/)]([https://newfeed-prima.eu/](https://newfeed-prima.eu/))).  
This study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of the University of Western Macedonia (protocol code 23/2023 and 25 October 2022 date of approval) for studies involving humans.  
Informed Consent Statement: Informed consent was obtained from all subjects involved in this study.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
**Acknowledgments:** The authors are grateful to [PERSON] (Department of Product and Systems Design Engineering, University of Western Macedonia, Campus Kila Kozani, GR50100 Kozani, Greece) for producing the containers used for colour and texture analyses.  
**Conflicts of Interest:** The authors declare no conflicts of interest. The funders had no role in the design of this study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.