Supercritical fluid extraction of red pepper (Capsicum frutescens L.)

The aim of this work was to assess supercritical fluid extraction (SFE) of red pepper (Capsicum frutescens L.) oleoresins. The influence of pressure, and superficial velocity of supercritical CO2 at 313 K, on the Capsicum frutescens oleoresins yield and capsaicinoids content was studied. The central composite, non-factorial design was used to optimise the extraction conditions, using the Statistica, version 5 software (Statsoft). The results were compared with those obtained when n-hexane was used for the extraction of red pepper oleoresin in a Soxhlet apparatus. At 10 min of extraction time an optimal value of the yield was determined (5.2% (w/w)) for pressure of 21.5 MPa and superficial velocity of 0.071 cm s−1. An optimum value for the yield in capsaicinoids (0.252% (w/w)) occurred at 20.5 MPa and 0.064 cm s−1. The extract of the supercritical fluid process obtained at 21.5 MPa, 0.074 cm s−1 of CO2 superficial velocity during 10 min was chosen, in order to perform a sensorial analysis. Selected extract was suspended in extra virgin olive oil (0.7% acidity) at three capsaicinoids contents (0.0006% (w/w), 0.0011% (w/w) and 0.0015% (w/w)) and analysed in terms of pungency, aroma, taste and after taste. Commercial red pepper flavoured olive oil (0.0011% (w/w) capsaicinoids) was used as reference. Panel preferred taste of the olive oil added with extract that contains 0.0006% (w/w) of capsaicinoids. At this concentration SFE extract did not influence olive oil colour.