## 2 Materials and Methods
### Milk Collection and Yoghurt Production  
Animals were milked twice a day. For yoghurt production, milk from each group (evening and morning milk) was collected separately in designated tanks in the milking parlour and then combined into a single container per group. Milk from the evening and morning milking within the same group was thoroughly mixed. Shortly after the morning milking, approximately 10 L of milk from each group was transported under refrigerated conditions on the same day. The distance between Paralimni Giannitsa (milking parlour) (40\({}^{\circ}\)45\({}^{\prime}\)5.0904\({}^{\prime\prime}\) N 22\({}^{\circ}\)27\({}^{\prime}\)10.9548\({}^{\prime\prime}\) E) and Florina (laboratory) (40\({}^{\circ}\)46\({}^{\circ}\)56.2764\({}^{\prime\prime}\) N 21\({}^{\circ}\)24\({}^{\prime}\)35.388\({}^{\prime\prime}\) E) is approximately 120 km, with an average travel time of 90 min. Upon arrival at the laboratory, the milk was poured through an aluminium milk strainer equipped with a filter paper (disk filters for cans, \(\mathcal{O}\)170 mm, Albert Kerbl GmbH, Buchbach, Germany) suitable for milk aimed for human consumption to remove large debris, such as bedding, hair, and soil parts, and placed in the refrigerator. The milk was also examined for the presence of antibiotic residue to ensure its suitability for yoghurt production. The EcoTest Easy MRL \begin{table}
\begin{tabular}{c c c c} \hline  & & **Diet** & \\ \cline{2-4}
**Ingredient (g/kg)** & **Control** & **UOP** & **POP** \\ \hline Corn grain & 300 & 300 & 300 \\ Barley grain & 200 & 200 & 200 \\ Wheat grain & 200 & 120 & 120 \\ Soyabean meal & 110 & 110 & 110 \\ Sunflower meal & 150 & 120 & 120 \\ Orange peels & 0 & 110 & 110 \\ Limescale & 5 & 5 & 5 \\ Monocalcium & 5 & 5 & 5 \\ phosphate & Salt & 5 & 5 \\ Vitamin and & 25 & 25 & 25 \\ mineral premix & & & \\ \hline \end{tabular} UOP = Unprocessed orange peels; POP = Processed orange peels.  
\end{table} 
Table 1: Ingredient composition of the experimental diets. (Acquanegra Cremonese, Italy) was employed for this analysis. The examination for the presence of antibiotic residue was precautionary, since the milk was obtained from the flock raised at HAO-Demeter, where information on all veterinary interventions was known. The milk was pasteurised (85-90 \({}^{\circ}\)C for 30 min), then cooled to a temperature range of 40-45 \({}^{\circ}\)C in an ice bath. When it reached approximately 42 \({}^{\circ}\)C, the starter culture was prepared [23]. During milk cooling, the effectiveness of pasteurisation was evaluated by the rapid alkaline phosphatase test using the Lactognost test kit (Heyl Chemisch-pharmazeutische Fabrik GmbH & Co. KG, Berlin, Germany) [24]. For the first batch of yoghurt production, a commercially available traditional yoghurt made from sheep's milk was used as the starter culture. For the subsequent three batches, a yoghurt sample from the previous batch served as the starter culture. The starter culture was prepared by diluting sheep milk yoghurt into the milk at a concentration of 3% \(w/v\), similar with the culture percentage used in the study by [PERSON] et al. [25]. To ensure a more uniform dilution, the starter culture was first mixed with a small portion of pasteurised milk (approximately 200 mL). This mixture was then incorporated into the remaining milk through gentle stirring. The resulting mixture was transferred into designated containers based on the type of analysis. For proximate composition, titratable acidity, pH, and syneresis by gravity, 125 mL transparent PET (polyethylene terephthalate) containers with lids were used. Sensory evaluation samples were prepared in similar but smaller size (70 mL) containers. Fatty acid composition, total phenolic content, and antioxidant profile samples were placed in 50 mL plastic centrifuge tubes with lids. Samples destined for viscosity determination were placed in 300 mL transparent PP (polypropylene) containers (beakers) with lids.