Supercritical carbon dioxide extraction of pelletized Jalapeno peppers

The effects of process pressure (220-500bar) and temperature (35-65degreesC) on yield and extract quality of pelletized Jalapeno peppers (Capsicum annuum L) treated with supercritical carbon dioxide (ScCO2) were studied. Compaction was inadequate when using whole air-dried pepper flakes conditioned to high moisture as raw material, which resulted in high porosity pellets and low bed densities. Thus, reference pellet samples were produced from Jalapeno pepper flakes that were finely ground and conditioned to low moisture. Pressures greater than or equal to 290 bar did not affect cumulative extraction of reference pellet samples at 45degreesC. On the other hand, the extraction rate of reference pellet samples at 360 bar increased with process temperature, as a result of increments in solubility, improvements in mass transfer properties, and/or improvements in solute desorption from the solid matrix. With regard to pretreatment, finely ground pepper samples were extracted in half the time of reference pellets (120 versus 270 min) at 360 bar and 45degreesC; increasing sample moisture prior to pelletization increased extraction yield; and decreasing particle size prior to pelletization increased extraction rate slightly. These results suggest that sample moisture is partially co-extracted by ScCO2, and that the extraction rate of pelletized Jalapeno peppers is controlled by internal mass transfer mechanisms. Chlorophyllian pigments were removed in the final stages of the extraction process. Furthermore, pigment extraction increased with process pressure at 45degreesC, and it increased slightly with process temperature at 360 bar. On the other hand, the concentration of capsaicinoids in extract samples remained constant during ScCO2 extraction. (C) 2003 Society of Chemical Industry.