Optimisation of red pepper seed oil extraction using supercritical CO_2 and analysis of the composition by reversed-phase HPLC-FLD-MS/MS

摘要

Oil extractions from red pepper seed were performed by supercritical CO_2. Three-level Box-Behnken factorial design (BBD) from response surface methodology (RSM) was applied to optimise the main extraction conditions including pressure, temperature and concentration of modifier (ethanol). The optimum conditions were as follows: extraction pressure, 27.17 MPa; extraction temperature, 47.67 ℃; and the added concentration of modifier, 8.11 vol.%. Under the optimum conditions, the oil yield of 18.4% was obtained, which was well matched with the predicted yield. A simple, stable and sensitive method for the simultaneous determination of saturated and unsaturated free fatty acids in extracted oils using 2-(11H-benzo[a]carbazol-11-yl)-ethyl-4-methylbenzenesulfonate (BCETS) as labelling reagent with fluorescence detection has been developed. All of free fatty acids (FFA) were found to give a linear response with correlation coefficients of >0.9991. The detection limits at a signal-to-noise ratio (S/N) of three are in the range of 19.06-^1.19 fmol. This method should have powerful potential for the trace analysis of short- and long-chain FFA from edible oils, foodstuff and other complex samples.