## 3 Results and Discussion
### The Changes of C-PC Contents in the Extracts Under Various Storage Conditions
Interestingly, in other work, the cleavage of the C-PC by methanolysis was also found to be first-order kinetics with 33 (1/h) and 0.29 (1/h) of breaking \(\alpha\) and \(\beta\) subunits of C-PC [29], implying that \(\alpha\) subunit was more easily detached out of intact C-PC compared to \(\beta\) subunit. However, these rate constants seemed to be different from this work because the cleavage model in this work was only considered by a simple two steps of breaking down \(\alpha\) and \(\beta\) subunit by adding methanol, not naturally decreased by the effects of temperature and light, which was very different from our experimental conditions and purpose. Nevertheless, some of those results could also give an insight of breaking the structure of C-PC intentionally or naturally. It was also confirmed that both cases of our results and the other work revealed that the pattern of breaking the C-PC would follow mostly first-order kinetics, even though under the condition of simultaneous exposure of high temperature and light, the cleavage of C-PC followed second-order kinetics. Therefore, results of this work first found that the decrease of C-PC in the extract showed first-order kinetics in storing with no light and second-order kinetic with light, implying that the residual contents of the C-PC were continuously decreased until the end of the storage under no light condition, while the amounts of C-PC were substantially dropped at the first period of storage with light and slowly decreased at latter periods of storage, compared to the cases with no light even at the same temperatures. In particular, it can be expected that the stability of C-PC should be more affected by the initial storage temperature in the case of being exposed to light. Besides the kinetic analysis of decreasing C-PC contents in the extract, it can also be expected that the stability of C-PC should be closely related to temperature, since temperature was found to be a most important factor in long term storage. To understand this relationship, the Arrhenius model in the form of Equation (3) in Materials and Methods, was employed, as shown in Figure 6.  
As a result of fitting the rate constants in Table 1 to Equation (3), two activation energy values were calculated as 4045.02 (kJ/mol) and 4298.93 (kJ/mol) for the cases of no light and with light, respectively, along with 0.9986 and 0.9984 of regression coefficient, showing that the decrease C-PC contents in the extracts was considered to fit well with the Arrhenius relationship, too. In general, the activation energy of breaking the C-PC was found to be higher for the case of exposure to light than that of no light, which corresponded to the results that the decrease of residual contents of C-PC followed second-order kinetics, as shown in Table 1. Therefore, these results could provide useful information in the industrial fields of managing the C-PC, where long term storage would be inevitable. Figure 6: Arrhenius plot of the rate constants of decreasing C-PC contents at 4 \({}^{\circ}\)C, 25 \({}^{\circ}\)C and 40 \({}^{\circ}\)C with light and no light.