Firstly, high concentration of ethanol was essential for effective
extraction of red pigments. The content of carotenoids colorants in
extracted solution are increased very quickly with ascending concentrations of ethanol from 60% to 90%. Then it changed smally
with ethanolic concentrations increasing. The content of colorants
in extracted solution of 90% ethanol was about 92.6% of that of 95%
ethanol. Though 90% ethanol as solvent may be viable for the
production of red pigments from FRPs, 95% ethanol was still
selected as the optimal extraction solvent of red pigments from
FRPs in this work.