## 3 Results and Discussion
### Colour and Moisture Contents of Spray-Dried Anthraquinone-Loaded Casein Micelles  
The color of a food product is the principal factor determining its quality attributes and consumer preferences. The color measurements of spray-dried controlled casein micelles (CMs) and anthraquinone-loaded casein micelles (CMAQP, CMFDP, CMWLAG) determined using CIE \(L^{*}\)\(a^{*}\)\(b^{*}\) system are given in Table 1.  
In general, the lightness of controlled casein micelles (CMs) \(L^{*}\) was 96.88 \(\pm\) 0.66, and a significant decrease (\(p\) \(<\) 0.05) was observed in anthraquinone-loaded casein micelles (CMAQP), where \(L^{*}\) was 82.85 \(\pm\) 0.69 (Table 1). This significant decrease in the luminosity of CMAQP may have been caused by the early stage of the Maillard reaction depending upon anthraquinone being encapsulated, which might act as a catalyst and could modify the reaction pathway during spray-drying [39]. Throughout the early stage of the Maillard reaction, the Schiff bond formation occurs between amino acids of casein micelles and sugars of anthraquinones to produce protein-bonded Amadori products, as reported previously [40] and these are less brown and are most stable. This has been confirmed by encapsulation efficiencies and zeta potential measurements. Similarly, the parameter \(a^{*}\) in anthraquinone-loaded casein micelles increased significantly from \(-\)0.13 \(\pm\) 0.0 to 5.52 \(\pm\) 0.32 (CMAQP) with spray-drying, which was also an indication of Maillard reaction as reported previously in liquid milk and infant formula [41]. The parameter \(b^{*}\) increased from 3.51 \(\pm\) 0.81 (CM control) to 10.81 \(\pm\) 0.44 showing an increase in yellowness after spray-drying which suggested an increase in yellow components of the color that is consistent with a decrease in \(L^{*}\) and visual assessment (Table 1). The CMFDP showed \(L^{*}\), \(a^{*}\) and \(b^{*}\) with an average value of 79.75 \(\pm\) 1.37, 7.7 \(\pm\) 0.53, and 9.44 \(\pm\) 0.25, respectively. The advanced stage of the Maillard reaction may have caused a decrease in lightness during spray-drying, depending upon the nature of the sample  
\begin{table}
\begin{tabular}{p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt}} \hline \hline
**Sample** & \begin{tabular}{c} **Moisture** \\ **(\% in Dry** \\ **Weight)** \\ \end{tabular}  & **pH** & \(L^{*}\) & \(a^{*}\) & \(b^{*}\) & \ \begin{tabular}{c} **C** \\ **(Chrom)** \\ \end{tabular}  & \(H^{*}\) & \(\Delta E\) & \begin{tabular}{c} **Visual** \\ **Observation** \\ \end{tabular}  \\ \hline CM Control & 5.11 \(\pm\) 0.61 \({}^{\text{b}}\) & 7.30 \(\pm\) 0.00 \({}^{\text{a}}\) & 96.88 \(\pm\) 0.66 \({}^{\text{a}}\) & \(-\)0.13 \(\pm\) 0.02 \({}^{\text{d}}\) & 3.51 \(\pm\) 0.81 \({}^{\text{c}}\) & 3.50  
being encapsulated. The parameter \(a^{\star}\) in CMFDP changed significantly after spray-drying with an average value of 4.79 \(\pm\) 0.07, respectively, which reflects more significant redness. The yellowness \(b^{\star}\) changed CMFDP and was highest in CMWLAG with an average of 22.32 \(\pm\) 0.29. The CMWLAG showed lightness with an average value of 73.03 \(\pm\) 0.58. The lowest \(L^{\star}\) was due to the formation of a brown pigment called melanoidins produced as a result of the final stage of the Maillard reaction [42] and the highest \(b^{\star}\) corresponds to increased redness and increased yellowness of the spray-dried Aloe vera powder [43] as compared to casein micelles. These results agreed to the previous studies, where curcumin-doped casein micelles were prepared through spray-drying [44] and a decrease in lightness and an increase in yellowness indicated the browning process as depicted by visual assessment. Chroma (\(C^{\star}\)) values are indicative of overall saturation which varies from dull at low chroma values to vivid color at high chroma values [45]. The controlled casein micelles possess a chroma value of 3.50 \(\pm\) 0.80, indicating very low color saturation, so the powder appears white [44].