Determination of vitamin A in liver sausage and liver tissue from slaughtered animals using HPLC

Abstract

Samples of liver sausage and liver tissue from slaughtered animals were analysed for pre-formed vitamin A. A sensitive reversed phase HPLC method with fluorescence detection was used to determine the amount of free and esterified retinol in extracts of these samples. Under our chromatographic conditions retinyl myristate and linoleate run together as do retinyl palmitate and oleate. The contents of all forms of vitamin A were expressed in milligrams of all-trans retinol per 100 g wet weight. The average concentrations of total vitamin A for turkey, pig, calf, beef, and chicken liver were 42.31, 38.15, 22.74, 14.98, and 13.22, respectively. In addition to these differences, the fatty acid composition of liver retinyl esters, as well as the amount of retinol, also varied considerably among species. Approximately 95% of the hepatic vitamin A was present as retinyl ester with retinyl palmitate/oleate as the main ester fraction. The second most abundant fatty acid in the retinyl ester fraction of calf, beef, and chicken liver was stearic acid followed by myristic/linoleic acid. An increment of retinol, however, was also found in these tissue samples. By contrast, in turkey liver the retinol fraction was increased and therefore both retinyl stearate and retinol were present in nearly equal amounts, whereas the retinyl ester fatty acids from pig liver contained relatively more myristate/linoleate and less stearate than those from liver of the other domestic animals (apparently a hallmark of pig liver). The retinol and retinyl ester pattern present in liver sausage was similar to, but not identical with, that of pig liver.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of B-Carotene Biofortified Cassava Grits (Mahihot esculenta Crantz) Based-Diets on Retinol Bioavailability and Performance of Broiler Chicks

“…The closeness in retinol content could however be due to the sufficient amount of vitamin A from the vitamin mineral premix as posited (Higdon, 2005) that conversion of β-carotene to vitamin A decreased when body store of vitamin A is high. The processing methods of grit also resulted in decreased β-carotene content of grit and resultant similarities in dietary β-carotene content except for diet 8 which had 3.33 μg/100 g. The liver retinol obtained in this study was relatively lower compared to 13.22 μg/100 g reported for the liver of chickens by Schindler et al (1987). This observed variation could thus be attributed to the differences in the age of birds.…”