## 3 Results and Discussion
### Analysis of Adulterated Milk and the Influence of Temperature
However, the variation between the diluted samples (0% and 97.9%), at various times, measured at the \(10^{1}\) Hz frequency was not influenced by temperature (16 \({}^{\circ}\)C = 12.6 times; 28 \({}^{\circ}\)C = 12.1 times; and 37 \({}^{\circ}\)C = 12.6 times). However, at a frequency of \(10^{6}\) Hz the temperature was influenced, with a slight increase in temperature variation up to 37 \({}^{\circ}\)C (16 \({}^{\circ}\)C = 13.0 times; 28 \({}^{\circ}\)C = 13.7 times; and 37 \({}^{\circ}\)C = 14.6 times). It is worth noting that for the higher frequency of \(10^{6}\) Hz (\(2.3\times 10^{6}\) Hz) this variation is more noticeable (16 \({}^{\circ}\)C = 7.3 times; 28 \({}^{\circ}\)C = 8.8 times; and 37 \({}^{\circ}\)C = 10.0 times). When considering the percentage of water in the milk sample and the frequency, a difference in bioimpedance behaviour was observed with increased frequency (Figures 8-10 and Table 4). The bioimpedance variations between 0% and 50% water in milk at frequencies of \(10^{1}\) and \(10^{6}\) Hz were reduced, with little influence of temperature: 16 \({}^{\circ}\)C = 1.5/1.6 times; 28 \({}^{\circ}\)C = 1.5/1.6 times; and 37 \({}^{\circ}\)C = 1.2/1.6 times, respectively. This behaviour is observed for all frequencies in between this interval. For calculations considering higher percentages of water, 50% and 97.9%, a large variation with higher temperatures was observed: 16 \({}^{\circ}\)C = 8.5/8.0 times; 28 \({}^{\circ}\)C = 8.3/8.4 times; and 37 \({}^{\circ}\)C = 10.4/9.0 times (\(10^{1}/10^{6}\) Hz), respectively. It is interesting to note that at the frequency \(2.3\times 10^{6}\) Hz and the lower percentages of water in milk (0% and 50%), the variation profiles were similar to the other frequencies (1.6 times for all temperatures). However, at the higher percentages  
\begin{table}
\begin{tabular}{l l l l l l l} \hline \hline \multicolumn{1}{c}{**Dilution**} & \multicolumn{6}{c}{**Temperature**} \\ \hline \multirow{2}{*}{**(\% \(V/V\))**} & **16 \({}^{\circ}\)C** & & **28 \({}^{\circ}\)C** & & **37 \({}^{\circ}\)C** & \\ \cline{2-7}  & **AC** & **\(\mathbf{R^{2}}\)** & **AC** & **\(\mathbf{R^{2}}\)** & **AC** & **\(\mathbf{R^{2}}\)** \\ \hline
00.0 & \(-\)0.025 & 0. (50% and 97.9%) the variation was reduced by half and was influenced by temperature (16 \({}^{\circ}\)C = 4.5 times; 28 \({}^{\circ}\)C = 5.3 times; and 37 \({}^{\circ}\)C = 6.2 times). Also, paying attention to the percentage of water in the milk sample only, it can be seen that at dilutions greater than 75% water, the inclination of the reduction of bioimpedance was more accentuated with the increase in frequency and the behaviour remained similar between the tested temperatures of 16 \({}^{\circ}\)C (0%: AC = 0.03 and \(R^{2}\) = 0.32; 75%: AC = 0.05 and \(R^{2}\) = 0.41; 97.9%: AC = 0.82 and \(R^{2}\) = 0.95), 28\({}^{\circ}\)C (0%: AC = 0.02 and \(R^{2}\) = 0.39; 75%: AC = 0.04 and \(R^{2}\) = 0.47; 97.9%: AC = 0.54 and \(R^{2}\) = 0.94) and 37 \({}^{\circ}\)C (0%: AC = 0.02 and \(R^{2}\) = 0.39; 75%: AC = 0.04 and \(R^{2}\) = 0.47; 97.9%: AC = 0.53 and \(R^{2}\) = 0.89) (Figures 8-10 and Table 4). Also, in Figures 8-10 the behaviour of the frequency profile along the milk dilutions is represented. Linearity, with slight growth, is noted at all analysed frequencies up to the milk samples with 75% water. From this, a sharp increase in impedance values occurs. The behaviour of distilled water at 16 \({}^{\circ}\)C was the same as that of adulterated milk samples, with a reduction in impedance value of 5.6 times between the frequencies 10\({}^{1}\) and 10\({}^{6}\) Hz. Considering the frequency of \(2.3\times 10^{6}\) Hz, the reduction was even higher, rising to 13.8 times. The highest impedance value was obtained at frequency 10\({}^{1}\) Hz (8748.39 \(\Omega\)) and the lowest at \(2.3\times 10^{6}\) Hz (634.62 \(\Omega\)). In Figures 8-10, the behaviour of the phase \(\theta\) of impedance at different temperatures and with increasing frequency is also represented.