# Rapid Green Extractions of C-Phycocyanin from _Arthrospira maxima_ for Functional Applications
## 3 Results and Discussion  
### Optimization of MW Extraction Conditions for C-PC from Arthospira Maxima  
The obtained results are summarized in Table 1. As can be seen, higher C-PC content was obtained using distilled water as solvent, a power of 100 W for 30 s. Figure 1 represents standardized Pareto charts (Figure 1A) where non-significant variables of the model were eliminated and the response surfaces on the basis of the factors selection (Figure 1B solvent was distilller water; Figure 1C power at 100 W; Figure 1D time at 30 s). The regression equation was also performed in MW technique. It was adjusted to the C-PC content as the following model (1):  
\[\mathrm{C-PC~{}(mg/g)=120.02-51.81\cdot P-18.48\cdot t-18.51\cdot P^{2}-14.55 \cdot P\cdot t+7.76\cdot P\cdot S+11.31\cdot t\cdot S+27.00\cdot S^{2}} \tag{1}\]  
where C-CP is C-phycocyanin content in mg/g, P: is power in W, t: is the extraction time in seconds, and S: is solvent type (Table 3). This confirms what is described by [PERSON], et al. [28] being that the overexposure to high heat (intense power) could damage the C-PC content in the extraction. In this way, our results showed that the C-PC content reached from _A. maxima_ was higher than other results described in microalgal phycobiloproteins having ~198.3 mg/g as the predicted optimal value by statistic software and ~215.0 \(\pm\) 5.5 mg/g as the real extracted content. For example, [PERSON], et al. [29] reported several solvents for C-PC extracting from _Arthospira platensis_ where the range was from 56.2 \(\pm\) 0.14 to 96.65 \(\pm\) 0.15 mg/g. This study was also performed with an experimental design wherethe best condition using MW extraction was at 150 W and 120 s with a value of 7.45 fold lower than our maximum content.  
Figure 1: (**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 response surfaces using the MW extraction technique. The figures represent the optimal variable responses such as: (**B**) solvent as distiller water; (**C**) power at 100 W; (**D**) time at 30 s. Data are shown as mean \(\pm\) SD, n = 3.  
For example, in two studies of fucoxanthin and phycoerythrin extraction with the MW process, [PERSON], et al. [30] and [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] [28] respectively, suggested that the increase of time or power would not have any impact on the pigment's extraction yield. It was also described by [PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] [29], that the highest content of C-PC was provided with ultrasound extraction (US) followed by MW using different solvents with \(102.98\pm 1.14\) and \(28.82\pm 1.10\) mg/g, respectively.  
This case was highlighted with 1.5% (_w/v_) aq, CaCl\({}_{2}\) as solution to C-PC extract with a value of 96.6 mg/g from _Arthospira platensis_. Therefore this technique has been proposed as an efficient and rapid process to extract antioxidant compounds or pigments from plants, oils from vegetables, allowing reduced solvent consumption and shorter extraction times, with equivalent or higher extraction yields [30; 31]. In particular, the technique by MW showed that it helped to accelerate the pigment extraction kinetics in diatoms by a few minutes and using a low volume of solvent as was studied by [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] [30]. Moreover, it has also been described as a useful technique to extract compounds from armored species or with an exopolysaccharide anchoridge envelope produced by species as _Porphyridium_ sp. where the bioactive compound extractions are troublesome [32]. Finally, the MW process was used because proteins are not degraded compared to other methods, due to their short extraction time [29].