To measure the stability of the phycocyanin isolated using the high-pressure process and hexane
separation method, the changes of the absorbance of the phycocyanin solution were measured over
time, as shown in Figure 2. The phycocyanin from the conventional extraction process had the poorest
stability because the absorbance of the phycocyanin from the conventional separation method
decreased to 0.808 after 14 days while the phycocyanin standard decreased to 0.841 after 14 days.
However, the absorbance of the phycocyanin isolated using the high-pressure process and hexane
separation method remained over 0.884 for 14 days. These data suggest that the phycocyanin isolated
using the high-pressure process and hexane separation method, compared to two other samples, was
more stable because the low temperature and high pressure extraction process effectively destroyed the
cell membrane of Spirulina platensis while minimizing the damage to the polypeptide subunits of
phycocyanin and increasing the elution of phycobiliprotein. Furthermore, the reduced chemical usage,
simple separation process, and short process time of the hexane separation method contributed to the
attainment of stable phycocyanin containing two chromophore subunit proteins intact along with a
relatively pure form. Phycocyanin with high stability and purity is expected to have an application as a
new material in the cosmetic and beauty industry.