A Simplified Method to Estimate the Time Evolution of Oil Extraction from Different Substrates by Supercritical CO₂

A. Zinnai, F. Venturi, C. Sanmartin, G. Andrich

Dipartimento di Scienze Agrarie, Alimentari e Agro-ambientali Via del Borghetto, Pisa, Italia.

DOI: 10.4236/ajac.2012.312A124                

Abstract

To allow an easy individuation of the more suitable working conditions (temperature, pressure, flow rate, etc.) to be adopted to carry out the extraction of food grade oils from different substrates by supercritical CO₂ (Sc-CO₂), a simpli- fied kinetic approach has been introduced. This kinetic model was utilised to describe supercritical fluid extraction (SFE) of oil by Sc-CO₂ not only from seeds (sunflower, soybean and rape) but also from microalgae (Nannochloropsis sp., Schizochytrium sp. and Spirulina (Arthrospira) platensis) characterised by a lipid fraction with a high proportion of polyunsatured fatty acids (C20:5w-3; C22:6w-3; C18:3w-6). Thanks to the high affinity occurring between oil and Sc-CO₂ it was possible to introduce a simplified kinetic model able to describe the time evolution of oil extraction from substrates which deeply differ for biochemical and biophysical characteristics. Moreover the synergistic utilisation of the kinetic model introduced and of the Chrastil’s equation, allowed to predict the time evolution of oil extraction as a function of the: substrate used; amount of its fat content; mass of substrate charged inside the extractor; possible pre- treatments carried out on the used substrate; flow rate of Sc-CO₂; working conditions adopted (temperature, pressure and then Sc-CO₂ density).

Keywords

SFE; Food Grade Oils; Sc-CO₂; Microalgae; Seeds; Mathematical Model

Conflicts of Interest

The authors declare no conflicts of interest.

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