Techno-economic optimization of the subcritical fluid extraction of oil from Moringa oleifera seeds and subsequent production of a purified sterols fraction

Abstract

Moringa oleifera tree is found in many tropical areas, and its seed contains up to 40% of good quality edible oil where sterols are also present. In this work a techno-economic study encompassing the coproduction of oil and sterols from M. oleifeira seeds was accomplished using the RSM-COM approach. The oil is produced by subcritical fluid extraction (SFE) while the purification of the associated sterols is accomplished by a patented technology based on distillation. Besides the expenses and investment associated to the SFE, the respective costs and investment for the preliminary drying of biomass and final separation of sterols from bulk oil were also taken into account. Under optimized extraction pressure and time of 350 bar and 1.3 h, respectively, oil cost was estimated to be 2.76 (sic) kg(oil)(-1) for a SFE unit comprising two extractors of 1 m(3) capacity. For the coproduction of sterols with 89.4wt.% purity, the minimum costs were 5.60 (sic) kg(sterols)(-1). The overall annual production under optimum conditions was 558.9 tons of oil and 1.9 tons of sterols, leading the whole integrated process to a net income of 15.87 M (sic) year(-1). In conclusion the proposed combined process is feasible, and this essay opened the way to exploit M. oleifera by subcritical fluid extraction under the scope of biorefinery premises. (C) 2015 Elsevier B.V. All rights reserved.