## 3 Results
### In Vitro Release Kinetics of Rhodamine B  
Figure 3A shows the kinetics of the entrapment efficiency (EE) over 3 h. As observed, the initial EE of rhodamine B is between 94% and 96% and depends on the mucilage concentration. Indeed, the initial and final EE% at 0.5% concentration is higher than the other concentrations. However, the release of rhodamine B, measured as the difference between final and initial EE or as the slope of the EE as a function of time, did not show a simple relationship with mucilage concentration. After 3 h, the EE at concentrations of mucilage other than 0.5% is significantly lower (around 93% vs. higher than 94%). When mucilage concentrations are greater than 0.5%, its swelling and hydration could allow rhodamine B to be more accessible, while when alginate concentrations are higher, the development of the egg-box structure could allow rhodamine B to diffuse easily. These suggest an optimal mucilage-alginate ratio, around 1:1, that improves EE. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Mucilage** & & & & \\
**Concentration** & **Diameter** & **Major Axis** & **Minor Axis** & \\
**(\%)** & **(cm)** & **(cm)** & **(cm)** & **Circularity** \\ \hline
0.7 & 0.24 \(\pm\) 0.015 a & 0.25 \(\pm\) 0.010 a & 0.20 \(\pm\) 0.008 a & 0.84 \(\pm\) 0.028 a \\
0.5 & 0.21 \(\pm\) 0.012 b & 0.20 \(\pm\) 0.015 b & 0.19 \(\pm\) 0.010 a & 0.85 \(\pm\) 0.007 a \\
0.3 & 0.20 \(\pm\) 0.006 b & 0.19 \(\pm\) 0.008 b & 0.17 \(\pm\) 0.007 b & 0.86 \(\pm\) 0.020 a \\
0.0 & 0.15 \(\pm\) 0.000 c & 0.15 \(\pm\) 0.001 c & 0.14 \(\pm\) 0.002 c & 0.89 \(\pm\) 0.015 b \\ \hline \hline \end{tabular} Values are presented as mean \(\pm\) standard deviation. Different lowercase letters in the same column are significantly different (\(p\leq\) 0.05).  
\end{table} 
Table 3: Shape factors for each sample with different content of mucilage and alginate. Figure 2: Shapes of the capsules obtained for the solutions at different mucilage and alginate concentrations. Even so, viscosity of the solution does not allow easy production of capsules, as observed in the loss of sphericity. Figure 3B shows that after the encapsulation process, the rhodamine B release in water was fast during the first hour and showed sustained release for the rest of the time. This could occur because the rhodamine B molecule forms a matrix with the polymers and is adsorbed on the surface, producing an unavoidable lixiviation of the molecules, as reported by [PERSON] et al. [58], indicating that the \"burst\" effect occurs during the first stage, due to superficial desorption. However, rhodamine B release is lower when a higher concentration of chia seed muclage is used, a behavior related to the solution's viscosity and the high water-binding capacity, which may block the pores on the surface; results consistent with the results reported by [PERSON] et al. [59]. However, the rhodamine B release profile also depends on different parameters such as shape, size, and type of the capsule, ionic strength, and physicochemical properties of the muclage-alginate matrix. Another explanation may be the high adsorption capacity due to the existence of nanometric fibers [7] and intrinsic microporous structure [60], which may facilitate the entrapment of small molecules. However, it is necessary to determine whether the adsorption process is governed only by intraparticle diffusion or if it is more complex and involves more than only one diffusive resistance such as surface adsorption, ion exchange, complexation, complexation-chelation, or micro-precipitation, and to analyze these phenomena with other methodologies such as those reported by [PERSON] and [PERSON] [61]. The capsule release profiles were fitted to three mathematical models to understand the rhodamine B release mechanism. The best fit was obtained with the Peppas and Sahlin model Figure 3C-F), showing good correlation coefficients (R\({}^{2}\) = 0.995 to 0.999).