SUPERCRITICAL CARBON DIOXIDE EXTRACTION EFFICIENCY OF CAROTENES FROM CARROTS
The increasing demand for natural -carotene has resulted in efforts to find alternate extraction methods from natural sources, since conventional methods are expensive and use toxic organic solvents. In this study carrot pulp (press cake) was used as the natural source for the supercritical carbon dioxide extraction of carotenes.
Three levels of pressure (20.7, 27.6 and 43.5 MPa), temperature (40, 55 and 70C), and ethanol (0, 5, 10% wt/wt) were used as independent variables. The percentages of -, - and total carotenes extracted from the carrot pulp were determined by HPLC and spectrophotometric methods. A response surface model for yield was determined from the results.
A maximum of 99.5% of total beta-carotene was extracted in the study. Ethanol concentration was shown to be an important factor to increase the extraction yield. The maximum extraction was achieved when using the highest level of ethanol. Temperature was also important for increased extraction. Similar results were obtained for the extraction of alpha-, beta- and total carotenoids. The following equation describes the response surface model for the %extraction yield of beta-carotene:
%beta-carotene extraction = 8.456 + 0.882T - 10.765E + 0.184T*E + 1.902E^2 - 0.026T*E^2
where T= temperature (C) , E = ethanol (%). R^2 = 0.973.
The economical feasibility of SC-CO2 + ethanol extraction seems great despite high capital investment because of the high price for natural beta-carotene, the availability of inexpensive carrot pulp, and the high extraction efficiency that can be achieved.