## 3 Results and Discussion
### Antioxidant and Radical Scavenging Activities of Full-Fat Cow, Coat and Eve Yogurts

Table 4: Antioxidant activities of cow, goat and ewe yogurt preparations obtained by pH adjustment and precipitation (pHAP), ultra-centrifugation (UC), and “Clarifying Reagent” (CR), as determined by FRAP assay 1. \begin{table}
\begin{tabular}{c c c c c} \hline \multirow{2}{*}{**Yogurt**} & \multicolumn{2}{c}{**DPPH Assay**} & \multicolumn{2}{c}{**Folin Assay**} & \multicolumn{2}{c}{**Folin Assay**} \\  & **EC\({}_{50}\) (g Yogurt/L Reaction Mixture)** & **(mg Gallic Acid/kg Yogurt)** & **(mg Trolox/kg Yogurt)** \\ \cline{2-5}  & **pHAP Extract** & **pHAP Extract** & **UC Extract** & **pHAP Extract** & **UC Extract** \\ \hline Cow & 1151 \({}^{\text{\,{a}}}\)\(\pm\) 21 & 68.5 \({}^{\text{\,{aA}}}\)\(\pm\) 2.4 & 88.2 \({}^{\text{\,{aB}}}\)\(\pm\) 4.5 & 60.3 \({}^{\text{\,{aA}}}\)\(\pm\) 2.1 & 77.5 \({}^{\text{\,{aB}}}\)\(\pm\) 4.0 \\ Goat & 1169 \({}^{\text{\,{a}}}\)\(\pm\) 18 & 66.4 \({}^{\text{\,{aA}}}\)\(\pm\) 1.3 & 83.5 \({}^{\text{\,{aB}}}\)\(\pm\) 2.2 & 58.5 \({}^{\text{\,{aA}}}\)\(\pm\) 1.1 & 73.4 \({}^{\text{\,{aB}}}\)\(\pm\) 1.9 \\ Ewe & 1071 \({}^{\text{\,{b}}}\)\(\pm\) 7 & 76.2 \({}^{\text{\,{bA}}}\)\(\pm\) 1.8 & 100.3 \({}^{\text{\,{bB}}}\)\(\pm\) 2.2 & 67.1 \({}^{\text{\,{bA}}}\)\(\pm\) 1.6 & 88.1 \({}^{\text{\,{bB}}}\)\(\pm\) 1.9 \\ \hline \end{tabular}  
* Each value was expressed as mean \(\pm\) standard deviation of three replicates. Different lowercase letters in the same column represent significant differences in values (\(p<0.05\)) between cow, goat and ewe yogurts. Different capital letters in the same row represent significant differences in values (\(p<0.05\)) between pHAP and UC preparations of the same yogurt.  
\end{table} 
Table 3: Antioxidant activities of cow, goat and ewe yogurt preparations obtained by pH adjustment and precipitation (pHAP) or ultra-centrifugation (UC) procedure, as determined by DPPH and Folin assays 1.  
as in the other assays. Specifically, ewe yogurt preparation appeared to be the most active one, while those of cow and goat yogurts exhibited similar activities. This was also confirmed by the determination of scavenging capacities of cow, goat and ewe yogurt against hydroxyl radicals and superoxide anion, (Table 5). Both ewe yogurt preparations obtained by pHAP and CR exhibited the highest scavenging activity against the ROS. On the other hand, the radical scavenging activities of cow and goat preparations were similar. It is remarkable to note that each CR yogurt preparation exhibited much higher antioxidant and scavenging of ROS activities than the respective pHAP and UC yogurt extracts (Tables 4 and 5). \"Clarifying Reagent\" dissolves both proteins and fat [21,22], indicating that these components are potential contributors to the antioxidant and scavenging capacities of yogurt. All the above are consistent with the product composition as ewe yogurt contained higher levels of both protein and fat than cow and goat yogurts (Table 1). To assess the relation of protein content on the antioxidant potential of the yogurts, cow, goat and ewe pHAP yogurt extracts were analyzed for their protein and total sulfhydryl groups concentration (Table 6). As expected, the protein content of the three extracts examined followed the order ewe > cow = goat in both Lowry and Bradford assays. In addition, the total sulfhydryl groups content followed the same order. During the preparation of yogurt pHAP extract (pH adjustment at 4.0 and centrifugation followed by pH adjustment at pH 7.0 and centrifugation) a large amount of proteins are precipitated and removed. Consequently, the current results indicate that ewe yogurt pHAP extract contains more soluble peptides/proteins and peptides/proteins containing sulfhydryl groups than pHAP cow and goat yogurt extracts.