## 2 Materials and Methods
### Colour Change and TP Measurement  
The colour of the samples in each test group was analysed using a spectrophotometer (Vita Easyshade V, Vita Zahnfabrik, Bad Sackingen, Germany). First, L\({}^{*}\), a\({}^{*}\), and b\({}^{*}\) values were obtained for each sample. Measurements were taken on a white or black-and-white background, with the tip of the device perpendicular to and at the same distance from the  
\begin{table}
\begin{tabular}{c c c} \hline
**Detox Drinks** & **Compositions** & **Mean pH** \\ \hline Red & Beetroot, carrot, apple, lemon, ginger & 2.72 \\ Green & Black cabbage, spinach, lettuce, parsley, cucumber, & 3.96 \\ Orange & Carrot, orange, ginger, lemon, turmeric, grapefruit & 3.82 \\ \hline \end{tabular}
\end{table}
Table 2: Composition and pH of detox drinks.  
sample surface each time, under D65 standard lighting conditions. Prior to each colour measurement, the samples were washed with distilled water and dried with absorbent paper to eliminate any residues of the detox drinks from the sample surfaces. All colour measurements were performed at the same location and time of day. Measurements were taken at three different points, starting from the centre of the sample surface. Before each measurement, the spectrophotometer was calibrated according to the manufacturer's instructions. The colour change values (\(\Delta\)E00) between the initial measurement and those taken on days 7, 14, and 28 were calculated by applying the following CIEDE 2000 formula [21] to the obtained colour measurements:  
\[\Delta E_{00}=\left[(\frac{\Delta L^{\star}}{K_{L}S_{L}})^{2}+(\frac{\Delta C ^{\star}}{K_{C}S_{C}})^{2}+(\frac{\Delta H^{\star}}{K_{H}S_{H}})^{2}+R_{T}( \frac{\Delta C^{\star}}{K_{C}S_{C}})(\frac{\Delta H^{\star}}{K_{H}S_{H}})\right] ^{\frac{1}{2}}\]  
\(\Delta\)L, \(\Delta\)C, and \(\Delta\)H are the differences in lightness, chroma, and hue between two separate measurements. SL, SC, and SH refer to the weighting functions of colour intensity and hue.  
The following CIEDE 2000 formula was used to calculate TP (ATP00) [21].  
\[\Delta TP_{00}=\left[(\frac{L_{H^{\prime}}-L_{W^{\prime}}}{K_{L}S_{L}})^{2}+( \frac{C_{H^{\prime}}-C_{W^{\prime}}}{K_{C}S_{C}})^{2}+(\frac{H_{H^{\prime}}-H_ {W^{\prime}}}{K_{H}S_{H}})^{2}+R_{T}(\frac{C_{H^{\prime}}-C_{W^{\prime}}}{K_{C }S_{C}})(\frac{H_{H^{\prime}}-H_{W^{\prime}}}{K_{H}S_{H}})\right]^{\frac{1}{2}}\]  
The subscripts B and W in the formula correspond to the colour coordinates of black and white backgrounds, respectively. LB-LW, CB-CW, and HB-HW denote the lightness, chroma, and hue differences of the samples on black and white backgrounds, respectively. The weighting functions SL, SC, and SH adjust the total chromatic difference for variations in the chromatic difference location on B (black) and W (white) backgrounds in L*, a*, and b* coordinates.  
In both formulas, RT is the transfer function that describes the degree of interaction between colour intensity and hue differences in the blue space of the colour system. KL, KC, and KH are parametric factors used for luminance, colour intensity, and hue, respectively [22]. In this study, the parametric factors were set to 1.