# Changes in Water Holding Capacity and Shear Force in Fallow Deer Muscles during Ageing
## 4 Discussion  
Generally, the ultimate pH value measured 24 h post mortem is one of the most important quality indicators in meat since it provides information not only about the physiological state of the animals and the course of postslaughter changes (glycogen depletion) but also about other technological attributes such as colour, tenderness, water holding capacity and shelf-life [1; 19]. In the present study, the pH value was measured during the ageing period to provide additional information, which might help explain changes in the water-holding capacity of fallow deer muscles. The mean value of pH24 h in SM and LTL falls in the range typical for fallow deer meat (5.4 to 6.0) [1]. It was believed that in the muscles of the venison which suffered from stress before slaughter (e.g., transport to the slaughterhouse or dog hunting), the pH value was higher compared with less-stressed animals [1]. However, currently, there is a lot of evidence that the way of slaughter doesn't affect the pH value significantly [20; 21]. This might indicate that the relation between preslaughter conditions and ultimate pH in the meat of venison is more complex than in farmed species (beef or pigs) [1]. A significant increase in pH in SM and LTL muscles along with the ageing time was noted, however, the values were still in the range for normal quality meat. A similar observation was noted by [PERSON] et al. [22] during 14 day cold storage vacuum-packed fallow deer meat from 5.56 to 5.69 in LTL muscle and from 5.54 to 5.70 in SM. However, as it was shown by [PERSON] et al. [19], the pH value of fallow deer SM and LTL muscles might remain unchanged during storage for up to 15 days. Although significant, this pH increase in the present study was too small to affect WHC. Generally, the increase in the pH value of meat tissue is related to a higher WHC due to changes in the net charge in muscle proteins [23], however, in the present study, an increase in WHC during ageing was not found. According to [PERSON] et al. [24] water-holding capacity increases with ageing time, which is indicated by lower drip and centrifugation losses. This stays in agreement with the findings of our earlier study conducted on beef, where the decrease in free water content (%) was noted during 20 days of ageing [25]. However, in the present study, there was no sig \begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline \hline  & **Ageing** & **WBC** & **FW** & **CL50** & **CL90** & **WBSF/C** & **CL/C** & **VL/C** & **WBSF/R** & **CL/R** & **VL/R** \\ \hline Ageing & & \(\mathbf{-0.38}\)* & 0.09 & \(\mathbf{0.63}\)* & \(-0.31\) & \(\mathbf{-0.53}\)* & \(0.77\)* & 0.26 & \(\mathbf{-0.65}\)* & **0.75*** & 0.20 \\ WBC & \(\mathbf{-0.38}\)* & \(\mathbf{-0.45}\)* & \(\mathbf{-0.40}\)* & \(-0.03\) & 0.04 & \(-0.28\) & -0.28 & 0.13 & \(-0.15\) & \(-0.25\) \\ FW & 0.09 & \(\mathbf{-0.45}\)* & & 0.14 & 0.14 & 0.07 & 0.26 & \(\mathbf{0.35}\)* & 0.12 & \(-0.01\) & 0.11 \\ CL50 & \(\mathbf{0.63}\)* & \(\mathbf{-0.40}\)* & 0.10 & 0.20 & \(-0.11\) & \(\mathbf{0.47}\)* & 0.17 & \(\mathbf{-0.35}\)* & **0.52*** & 0.26 \\ CL50 & \(\mathbf{-0.31}\) & \(\mathbf{-0.025}\) & 0.14 & 0.20 & 0.16 & \(-0.28\) & 0.17 & 0.14 & \(-0.19\) & 0.22 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: [PERSON]’s correlation coefficients between variables determined in the study in fallow deer meat. nificant relationship between free water content and time. In contrast, [PERSON] et al. [19] reported a decrease in free water content in SM and LTL fallow deer muscles during ageing up to 15 days postslaughter, thus an increased WHC was noted. WHC in fresh meat is related to the state of myofibrillar proteins, including cytoskeletal proteins. In post mortem, they undergo degradation, which leads to damage in connections between myofibrils and the connection of costamers to the cell membrane. This in turn enables the retention of water in the muscle cells, which would be expelled to the extracellular space as a result of myofibril shrinkage if these connections were intact.