Supercritical fluid fractionation of liquid oleoresin capsicum: Statistical analysis and solubility parameters

Supercritical fluid extraction (SFE) of liquid oleoresins (Capsicum annuum L. and Capsicum frutescens L.) was carried out in order to improve properties of oleoresins obtained by traditional processes using organic solvents. SFE allowed us to fractionate the different compounds present in oleoresins recovering both, an extract and a raffinate which can fulfill trader's needs. The aim of this work was to study the effect of pressure (140–300 bar) and temperature (313–333 K) affecting the yield and the commercial value of oleoresins extracts and raffinates, expressed in terms of parameters such as colour (SCU), pungency (SHU) and carotenoids and capsaicinoids concentration. A set of previous experiments was carried out to select the most suitable type of oleoresin and the initial ratio CO2/oleoresin which assures initial conditions in the biphasic area of CO2/oleoresin diagram to produce fractionation. A response surface methodology (RSM) was used to evaluate the effect of the factors over the variables and different linear correlations were proposed and validated to describe the responses studied. 300 bar and 333 K were selected as the best operational conditions to obtain fractionation. Finally, solubility parameters were obtained and correlated with semi-empirical models in order to obtain correlations which will be useful in subsequent stages of scaling-up.

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