Pink shrimp (P. brasiliensis and P. paulensis) residue: Supercritical fluid extraction of carotenoid fraction

The objective of this work was to study the technical and the economical viability to concentrate the carotenoid components by means of supercritical fluid extraction (SFE) from pink shrimp processing waste. The raw material was pretreated using heat treatment, milling and drying. The SFE with carbon dioxide (CO2) was evaluated by varying the raw material moisture content, the solvent flow rate, the conditions of temperature and pressure and the use co-solvent (hexane + isopropanol solution, 50:50, and sunflower oil) at concentrations of 2 and 5%. SFE curves were modeled using well-known mathematical models from literature, and mass transfer coefficients were determined and validated through correlations with dimensionless numbers. The process cost for industrial application was also estimated. The extracts were evaluated in terms total carotenoid content, carotenoid profile, astaxanthin yield and UV-Vis scanning spectrometry. The results indicated that shrimp waste can be used for concentrating natural carotenoids. The SFE was favorable at 13.3 g/min of CO2 flow rate and at 11.210% of raw material moisture content. The Sovova [21] model best fitted in the experimental data and indicated higher influence of convection when compared to diffusion. In addition, the results from the dimensionless number correlations indicated that forced convection is more important than natural convection. The carotenoid extraction increases with enhancing the CO2 density. The highest astaxanthin yield was obtained by CO2 at 300 bar/333.15 K. The cost analysis suggested the application of a SFE unit with 2 x 400 L vessels for 25 min extraction, to treat the pink shrimp residue, as the most lucrative process design. (C) 2012 Elsevier B.V. All rights reserved.