# Rapid Green Extractions of C-Phycocyanin from _Arthrospira maxima_ for Functional Applications
## 3 Results and Discussion
### Optimization of HPH Extraction Conditions for C-PC of Arthospira Maxima  
Optimization of the HPH extraction conditions is summarized in Table 2. As shown, higher C-PC content was obtained using Na-phosphate buffer as solvent and a pressure of 1400 bar (\(\sim\)272.4 mg/g as predicted optimal value and \(\sim\)291.9 mg/g as real value). Figure 2 also represented standardized Pareto charts (Figure 2A) where non-significant variables were eliminated from the model and response \begin{table}
\begin{tabular}{l c c} \hline \hline  & \multicolumn{2}{c}{**C-PC Content (mg/g)**} \\ \hline \multicolumn{2}{c}{**Terms of the Model**} & **Estimate** & _p_**-Value** \\ \hline Constant & 120.021 & \\ A:Power & \(-\)51.8069 & 0.0000 * \\ B:time & \(-\)18.4825 & 0.0100 * \\ C:solvent & \(-\)11.8465 & 0.0938 \\ AA Power \(\times\) power & \(-\)18.512 & 0.0011 * \\ AB Power \(\times\) time & \(-\)14.5478 & 0.0003 * \\ AC Power \(\times\) solvent & 7.76572 & 0.0459 * \\ BB time \(\times\) time & \(-\)1.20219 & 0.8243 \\ BC time \(\times\) solvent & 11.3066 & 0.0043 * \\ CC solvent \(\times\) solvent & 26.9978 & 0.0000 * \\ AAB Power \(\times\) power \(\times\) time & 0.0 & 0.2485 \\ AAC Power \(\times\) power \(\times\) solvent & 0.0 & 0.5327 \\ ABB Power \(\times\) time \(\times\) time & 1.15228 & 0.8621 \\ ACC Power \(\times\) solvent \(\times\) solvent & 0.338278 & 0.9803 \\ BBC Time \(\times\) time \(\times\) solvent & 0.0 & 0.9593 \\ BCC Time \(\times\) solvent \(\times\) solvent & 4.42314 & 0.9513 \\ ABC Power \(\times\) time \(\times\) solvent & 12.1269 & 0.5056 \\ Statistics for goodness of fit of the model & & \\ R\({}^{2}\) & 0.84615 & \\ RSD & 22.885 & \\ P & 0.4008 & \\ RRSD (\%) & 3.00351 & \\ \hline \hline \end{tabular} R\({}^{2}\)-determination coefficient, RSD-residual standard deviation, _p_-value of the lack-of-fit test for the model, RRSD-residual standard deviation expressed as a percentage of the mean value of the response; * significant coefficients of the model.  
\end{table} 
Table 3: Regression coefficients (values of variables are specified in their original units) and statistics for the fit obtained by multiple linear regression. surfaces (Figure 2B). Secondly, the regression equation was also performed in the HPH method. It was adjusted to the C-PC content as the following model (2):  
\[\text{C- PC (mg/g)}=211.26+10.36\cdot\text{P}+10.96\cdot\text{S}-29.20\cdot\text{P2 }+8.37\cdot\text{P}\cdot\text{S}+47.22\cdot\text{S2} \tag{2}\]  
where C-CP is C-phycocyanin content in mg/g, P: is pressure in the bar, and S: is the solvent type (Table 4). Our results showed that after each disruption, the amounts of recovered C-PC from _A. maxima_ increased in direct correlation with a higher operating pressure, which is confirmed by what is described by [PERSON], et al. [33]. However, we also observed that the increase from 1400 to 1600 bar caused a decrease in the C-PC content of _A. maxima_. Among the cell disruption methods, HPH is one of the most promising treatments for the complete disruption of biological cells [34; 35]. Several studies report that the pressure increases the force with which the cells impact on the ring, inside valve seat, resulting in more efficient cell disruption [36]. In particular, the study performed by [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] [34] where they observed the effects of different HPH passes in the  
Figure 2: (**A**) Standardized Pareto charts for the C-PC content as response variable studied in the experimental design (grey and blue bars show negative and positive effects, respectively), and their corresponding (**B**) response surfaces using the HPH extraction technique.