Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/12/2006
Publication Date: 1/20/2007
Citation: Fish, W.W. 2007. Novel procedure for the extraction and concentration of carotenoid-containing chromoplasts from selected plant systems. Journal of Agricultural and Food Chemistry. 55:1486-1490. Interpretive Summary: In the contemporary food industry, food supplements have become more and more prominent as a result of the increased production of prepared, processed, and convenience foods, and carotenoids are one of the classes of compounds occupying an ever-increasing role as food supplements. As more and more of the minor carotenoids receive attention for their potential health benefits and as less common sources are sought for these carotenoids, smaller and smaller quantities are encountered with which to work. It was observed that the carotenoid-containing chromoplasts of plants could be solubilized in an aqueous medium with the use of certain types of detergents. The ability to solubilize the intact chromoplasts allows their separation from insoluble cell debris, and with washing, the removal of water-soluble compounds. It was also discovered that the water-soluble organic compound, acetonitrile, effectively precipitates the chromoplasts out of the aqueous detergent solution without damaging the chromoplast membrane or the carotenoids inside and thus, effectively concentrates them. The use of these two systems in combination provides a means to extract, partially purify, and concentrate carotenoid-containing chromoplasts from selected plant systems. The concentrated chromoplasts can then be analyzed for their unique carotenoid composition. The novelty of the method is that it keeps the carotenoids inside a naturally-occurring organelle and in an aqueous milieu for much of the process, and thus provides the investigator with an alternative means to effectively concentrate carotenoids from tissues where yields are often low.
Technical Abstract: Natural sources of carotenoids for nutraceutical use are desired by the food industry as a result of the increased production of convenience and other highly processed foods. As new physiological roles are discovered for some of the minor carotenoids that are found in only small amounts in present sources, the need for discovery of new sources will amplify. Thus, a method is needed that will effectively and gently concentrate carotenoids from potential new sources for subsequent analysis. A procedure is presented by which carotenoid-containing tissue chromoplasts can be extracted and subsequently concentrated by precipitation, all in an aqueous milieu. The chromoplasts are extracted and solubilized with 0.3% sodium dodecyl sulfate (SDS) in water. The addition of a nominally equal volume of acetonitrile to the chromoplasts in SDS immediately precipitates the chromoplasts out of solution with generally >90% recovery. Carotenoids contained in the concentrated, still-intact chromoplasts can then be solubilized by organic solvent extraction for subsequent analysis. This methodology offers a means to effectively and gently concentrate carotenoids from fruit tissues where yields are often low (eg. yellow watermelon).