Measurement of astaxanthin and squalene diffusivities in compressed liquid ethyl acetate by Taylor-Aris dispersion method

Abstract

An increasing demand of consumers for natural bioactive compounds has boosted the interest of the scientific community for vegetables and fruits, with many efforts being made to identify new bioactive compounds and to develop sustainable extraction methods that preserve the compounds bioactivity. Such is the case of pressurized liquid extraction and supercritical fluid extraction using “green solvents” as supercritical CO2, ethanol, and ethyl acetate. The accurate design of these processes requires the knowledge of transport properties, namely, diffusion coefficients, D12. Astaxanthin and squalene are two bioactive compounds whose D12 values were measured in compressed liquid ethyl acetate using a chromatographic technique. For astaxanthin the D12 values were in the range × − ×− − −0.817 10 1.223 10 cm s5 5 2 1 (at 303.15–333.15 K and 1–100 bar) and for squalene they were in the range × − ×− − −1.052 10 1.822 10 cm s5 5 2 1 (at 303.15–333.15 K and 1–150 bar). The influence of tem- perature, pressure and Stokes-Einstein coordinate was studied for both systems and explained with the most relevant theories of the literature