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.
Turner
C
C
Department of Analytical Chemistry, Lund University, Box 124, 221 00 Lund, Sweden. charlotta.turner@analykem.lu.se
King
J W
JW
Mathiasson
L
L
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