On-line supercritical fluid extraction/enzymatic hydrolysis of vitamin a esters: a new simplified approach for the determination of vitamins a and e in food.
An on-line supercritical fluid extraction (SFE)/enzymatic hydrolysis procedure using immobilized lipase has been developed for the determination of vitamin A in dairy and meat products. Several lipases were tried, of which Novozyme 435 (Candida antarctica type B) showed the highest activity toward retinyl palmitate. There was no observed activity with alpha-tocopheryl acetate. When pressure, temperature, modifiers, flow rate, extraction time, and water content were varied, high vitamin A recovery was obtained in milk powder. Collected extracts were analyzed by reversed-phase high-performance liquid chromatography with ultraviolet and fluorescence detection without additional sample cleanup. The procedure gave reliable values of vitamin A as well as of vitamin E in other food items such as infant formula, minced pork and beef meat, and low- and high-fat liver paste. The described method is faster and more automated than conventional methods based on liquid-liquid extraction, or SFE using off-line saponification, for vitamin A and E determination. Results obtained with the new method did not differ significantly from those obtained with the other two methods mentioned above.
Department of Analytical Chemistry, Lund University, Box 124, 221 00 Lund, Sweden. charlotta.turner@analykem.lu.se
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Turner
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JW
King
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Mathiasson
D000818:Animals; D001331:Automation / Q000379:methods; D002175:Candida / Q000201:enzymology; D004224:Diterpenes; D004800:Enzymes, Immobilized / Q000378:metabolism; D004952:Esters; D005504:Food Analysis / Q000379:methods*; D005656:Fungal Proteins; D006868:Hydrolysis; D008049:Lipase / Q000378:metabolism; D008460:Meat / Q000032:analysis; D008892:Milk / Q000737:chemistry; D009862:Online Systems; D015203:Reproducibility of Results; D000084562:Retinyl Esters; D013552:Swine; D014801:Vitamin A / Q000031:analogs & derivatives* / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism; D014810:Vitamin E / Q000032:analysis*
D004224:Diterpenes; D004800:Enzymes, Immobilized; D004952:Esters; D005656:Fungal Proteins; D000084562:Retinyl Esters; D014801:Vitamin A; D014810:Vitamin E; C009166:retinol acetate; C093667:Novozyme 435; D008049:Lipase