## 3 Results and Discussion  
### The Changes of C-PC Contents in the Extracts Under Various Storage Conditions  
First, Figure 1 was to compare HPLC chromatograms of the C-PC in the extracts from ultrasonic extraction process treated under two extreme storage conditions such as 4 \({}^{\circ}\)C without light (a) and 40 \({}^{\circ}\)C with light (b) after two month exposure. As a control, initial concentration of C-PC in the extract obtained from ultrasonic extraction process (UE) in Figure 1c was estimated as 10.5 (mg/mL), and the amounts of which were found to be similar to other results from a low temperature ultrasonic process and solvent extraction processes [26]. However, after two month storage, there was significant differences between the C-PC contents in two extracts such as 9.41 (mg/mL) of C-PC at 4 \({}^{\circ}\)C with no light and 1.13 (mg/mL) of C-PC at 40 \({}^{\circ}\)C with light as shown in Figure 1a,b, respectively. It was confirmed that, in storing the UE extract at 4 \({}^{\circ}\)C without light, less than 10.39% of initial content of the C-PC was decreased even for two months, which tells that C-PC stored at low temperature was very stable. However, at high temperature of 40 \({}^{\circ}\)C with the illumination of the visible light, more than 89.34% of the C-PC was destructed after two months storage. Therefore, these results clearly proved that the storage conditions must be absolutely critical for a long-term storage of the C-PC. Moreover, the dissociation of the C-PC was much severely accelerated at high temperature associated with the light, which was first found in this work. Therefore, Figures 2 and 3 were to more comprehensively illustrate the effects of storage temperatures on the breakage of C-PC in the extract by being associated with the effect of the light for two month of long-term storage experiment. Figure 1: High-performance liquid chromatography (HPLC) chromatograms of C-phycocyanin (C-PC) in the _Spirulina platensis_ extract treated under the conditions stored at 4 \({}^{\circ}\)C with no light (**a**) and at 40 \({}^{\circ}\)C with light (**b**) compared with the initial C-PC in the extract as a control (**c**) and a standard C-PC (**d**). Figure 2: The residual concentration of C-PC in the _Spirulina platensis_ extract at three different temperatures with no light for two months of storage. First, Figure 2 was to compare the decrease of C-PC at three different storage temperatures for two months storage without light. At 4 \({}^{\circ}\)C storage, only ca. 10.39% drop of C-PC contents in the extract was observed after two months of storage, compared to the initial content at the first day of storage, while 25.81% of initial concentration was decreased at 25 \({}^{\circ}\)C and ca. 47.53% at 40 \({}^{\circ}\)C even with no light. These results clearly indicated that the stability of C-PC was greatly decreased at higher temperature and it should be stored at below room temperature at least. Similar results of significant destruction of the C-PC at over 40 \({}^{\circ}\)C of high temperature were reported elsewhere [20; 21]; however, there was no report on the effect of temperature for long-term storage, such as more than two months, in this work. Therefore, this result would be first realistic data of representing the stability of C-PC in many experiments. The results of Figures 2 and 3 showed the changes of the amounts of C-PC in the UE extract at three different storage temperatures with light for two months. The patterns of decreasing the contents of C-PC were different from those without light even at same temperature. The final residual concentrations of C-PC in the extract were also much lower being exposed to light than the cases without light as shown in Figure 2: 4.42 (mg/mL) with light vs. 9.41 (mg/mL) without light at 4 \({}^{\circ}\)C, 2.15 (mg/mL) vs. 7.79 (mg/mL) at 25 \({}^{\circ}\)C and 1.13 (mg/mL) vs. 5.51 (mg/mL) at 40 \({}^{\circ}\)C, respectively.