EXTRACTION OF ANNATO SEED PIGMENT BY SUPERCRITICAL CARBON-DIOXIDE

Operating pressures ranged 3000-7000 psi and temperatures 40-55-degrees-C. Maximum solubility of pure bixin was 0.003 and of annatto seed pigment 0.26 mg/g CO2. Analyses of annatto seed pigment from supercritical carbon dioxide extractions showed only alpha- and beta-bixin present. Only bixin was extracted from mixed samples consisting of bixin and norbixin. No thermal degradation product was detected in samples extracted within the temperature range we used. Increased temperature resulted in increased pigment/g CO2 at all pressures. Isothermal increases in pressure did not increase pigment/g CO2. Efficiency of annatto pigment extraction was increased in the presence of an oil.