Process integration for producing tocotrienols-rich oil and bixin-rich extract from annatto seeds: A techno-economic approach

Supercritical fluid extraction (SFE) coupled to low-pressure solvent extraction (LPSE) was studied for producing tocotrienols-rich oil and bixin-rich extract from annatto seeds. In the SFE step using CO2, 2.90 +/- 0.01 g oil/100 g seeds was obtained, which was composed of 14.85 wt.% delta-tocotrienol and 2.06 wt.% gamma-tocotrienol. In the LPSE step using ethanol, 11.3 +/- 0.6 g extract/100 g defatted seeds was obtained, which was composed of 30 wt.% bixin. The process integration was also evaluated in the economic viewpoint with the objective to show its feasibility in different scenarios, which included different purchasing costs of seeds, costs of plants, processing times in the SFE step, bed height to internal diameter ratios in the SFE step, solvent type in the LPSE step, and selling prices of oil and extract fractions. Among 64 scenarios assessed, the more promising one provided values of cost of manufacturing (COM) of US$ 336.96/kg oil and US$ 12.05/kg bixin extract, payback time of 0.26 year, return on investment of 389.7% and gross margin of 66.5%. For a 100 L scale plant, 4968 kg oil and 7643 kg bixin can be recovered per year using approximately 220 tons of seeds. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.