Determination of vitamin A in liver and liver-containing products using narrow-bore normal, phase HPLC

Abstract

Vitamin A concentrations in livers of fattening animals and liver-containing products may reach much higher values than was assumed up to now. This effect may be caused by animal feed, which is usually supplemented with vitamins. To support this supposition, 57 liver samples of different species of animals, 97 liver sausages and 106 samples of liver-containing infant food were analysed. For isolation of retinol from the sample matrix the sample was saponified for 16 h under a nitrogen atmosphere at room temperature. Retinol was extracted from the saponification solution by using disposable cartridges. For chromatographic determination a normal-phase HPLC system using a narrow-bore analytical column and a photodiode array detector was used. It was possible to separate all-trans-retinol from other isomers. The identity of the peaks could be confirmed by recording the UV spectra.--The results of the retinol contents found in the analysed samples ranged from 11.6 to 160.7 mg/100 g in liver, from 1.4 to 31.1 mg/100 g in liver sausages and from 0.5 to 3.8 mg/100 g in infant food containing between 5 and 11% liver. By consuming liver-containing meals frequently a multiple amount of the recommended dietary intake ranging from 0.375 mg for infants to 0.8 mg for adults may be taken up. Also the recommended daily intakes of the Deutsche Gesellschaft für Ernährung can be exceeded.--The carry-over effect of daily vitamin A consumption of pigs and their liver vitamin A was investigated by parallel determination of the retinol content in the liver after slaughtering and the vitamin A content in the pig-feed during the fattening period. A clear correlation between their daily vitamin A intake and the resulting retinol content in the livers was found.

A Distinct Epidemiologic Pattern of Precancerous Lesions of Esophageal Squamous Cell Carcinoma in a High-risk Area of Huai'an, Jiangsu Province, China

“…Generally, the possible mechanism of consumption of these foods against ESCC has long been considered to be the potential immunomodulatory, anticarcinogenic, antimetastasis, and antimutagenic properties provided by high content of antioxidant micronutrients and some bioactive compounds, such as fiber, vitamin A, C, E, B vitamins, selenium, polyphenols, phytosterols, flavonoids, and isoflavones (34)(35)(36)(37). The observed protective effect of intake of animal livers is probably because livers are rich in minerals, vitamin A and B vitamins such as folate (38); meanwhile, folate, vitamin A, and its precursor b-carotene have been demonstrated to play a preventive role in various forms of cancer including ESCC (36,37,39). A study on systematic comparison of phytochemicals and antioxidant capacities of 13 classes of food legumes illustrated that the strongest oxygen radical-absorbing capacity was found in adzuki bean, followed by mung bean, and the second and sixth highest peroxyl radical-scavenging capacities were found in adzuki bean and mung bean, respectively (40).…”

Use of an experimental design to optimise the saponification reaction and the quantification of vitamins A1 and A2 in whole fish

“…The official protocol (AOAC 992.06) recommends saponification at 70°C for 25 min [9]. Different saponification protocols have been proposed to take into account the complexity of food matrices such as fortified margarine [10], other food and meat [4,9,12,[15][16][17] and biological samples [18][19][20][21][22][23] (Table 1).…”