Development, modeling and simulation of extraction and purification of bixin from annatto seeds (Bixa orellana L.)

Abstract

To extract and purify bixin from annatto seeds, a new process based on alkaline extraction, partition with an aqueous two-phase system (ATPS) and acid precipitation was developed on a SuperPro Designer v. 7.0® simulator. To implement the model, data of seed leaching, liquid extraction in an ATPS and acid precipitation were determined experimentally. The seeds were leached using alkaline saline solutions and a face-centered factorial design (FCD) was applied to investigate the effects of salt concentration, pH and temperature on the yield of the dye extraction. The highest yields were obtained with potassium phosphate 20 wt%, at 298.15 K and pH 9.0. The extract was then purified using ATPS composed of potassium phosphate (14 wt%) pH 9.0 and polyethylene glycol 1500 mol/L (14 wt%). Norbixinate preferentially partitioned to the top phase (Kp = 210.2). The acid precipitation demonstrated that, as the pH decreases, the concentration of norbixin salt in the top phase decreases. The process simulation with 1 ton of annatto seeds showed that the plant has the capacity to produce more than 1900.00 kg/year of the main product (88% of norbixin). The selling price ($ 2400/kg) was the most sensitive parameter of the sensitivity analysis.