Article Title

Analysis of Carotenoids in Grass Prawn Heads by High Performance Liquid Chromatography


The carotenoid composition in grass prawn ( Penaeus monodon ) heads was studied in this investigation to obtain basic information for any future application of the natural colorants from grass prawn heads. The red oily pigment in grass prawn heads was extracted with acetone, followed by petroleum ether (b.p. 30- 50 degrees centigrade) which was dissolved in acetone and stored overnight at minus 10 degrees centigrade. Next, the crude pigment was obtained by removal of precipitates from the cold acetone, then finally, removal of the acetone. The crude pigment was analyzed by HPLC with Sumipax OA-2000 column (5 um, 0.46 cm i.d. x 25 cm) and n-hexane/dichloromethane/ethanol(l20:17:1, v/v/v)as a mobile phase. Flow rate was set at 1.5 ml/min and the dectector was set at 470 nm. The main results are shown as follows: 1.The main carotenoids in the grass heads are composed of astaxanthin, astaxanthin monoester, astaxanthin diester, and some unidentified pigments. The relative amounts of these pigments are 36.1%, 31.5%, 17.5%, and 14.9% respectively. 2. The astaxanthin fraction was separated in to its three optical isomers: (3R, 3'R)-astaxanthin, (3R, 3'S)-astaxanthin, and (3S, 3'S)-astaxanthin. The relative amounts are 15%, 43.7%, and 41.3%, respectively, as determined by HPLC.

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