Supercritical carbon dioxide extraction of oil and α-tocopherol from almond seeds

The objective of this study was to extract oil and tocopherols from almond seeds using supercritical carbon dioxide and to compare this extraction with a traditional solvent method. Oil and tocopherol extraction rates were determined as functions of the pressure (350-550 bar), temperature (35-50 degrees C) and CO2 flow rate (10-30 kg h(-1)), using a 10-1 vessel. The effects of matrix particle size on extraction yield were also studied and it was demonstrated that extraction yield is greatly influenced by particle size. Maximum recovery was obtained in the first 2 - 3 h of extraction at a pressure of 420 bar, a temperature of 50 degrees C and a flow rate of 30 kg h(-1) CO2. These results suggest that the elevated initial oil and tochopherol solubility is related to the increased proportion of fatty acids in the initial extract. The results were compared with those obtained when hexane/methanol was used as a solvent. (c) 2005 Society of Chemical Industry.