Stability of vitamins and and in foods enriched with different sources of iron. / Estabilidade das vitaminas A e E em alimentos enriquecidos com diferentes fontes de ferro.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

The food enrichment with vitamins and minerals is a very common practice nowadays, allowing to improve the nutritional value of the food and to replace nutrients lost during the processing and or stocking. However, the added nutrients can suffer negative interaction during rack life of the food, as it happens with iron (pro-oxidant) and vitamins A and E (antioxidant). Therefore, studies on interaction and stability of nutrients as well as efficient and precise analysis are necessary to guarantee to the consumer the adequate consumption of nutrients and correct nutritional information. This study aimed to evaluate the influence of the addition of iron from different sources in the degradation of alpha-tocopherol acetate (TA) and retinyl acetate (RA) in UHT (Ultra High Temperature) skim milk and in enriched rice flour packed in packing that allows and that does not allow light crossing, as well as conventional cooking and to validate a methodology for simultaneous analysis of these vitamins. The analytic procedure consisted in the extraction of the vitamins with ethanol, followed by partition in hexane and cleaning with methanol:water (9:1). The hexane fraction was evaporated and ressuspended in ethanol. For the separation of the vitamins a C18 column was used, with eluition system for gradient, with a mobile phase composed by methanol, water and tetrahidrofurane, in a flow of 1 ml/min. The detection was made in UV s Region of 325nm and 282nm to vitamin A and E, respectively. The limits of detection varied from 1.3 ng/ml to 64.77 ng/ml, while those of quantification were 2.6 ng/ml for retinyl acetate and 129,54 ng/ml for -tocopherol acetate, respectively. Repetibility and recovery, in two addition levels for the vitamins, showed values from 4.4 to 10.5% and measures of 96%, respectively. In the rice flour, as well as in the RA enriched milk, there was no significant difference for the added iron sources, while the stability of the TA was negatively influenced by the addition of the chemical forms Fe- AQ, SF and LF in the flour and LF in the skim milk. For the flours, the used packages and the cooking process did not influence the relative loss of the studied vitamin forms. The proposed and validated methodology showed to be efficient when applied in enriched skim milk and rice flour. The concomitant enrichment of rice flour with RA and TA and Fe showed to be better with Fe-EDTA and FR and the of skim milk with Fe-EDTA and Fe-AQ.

ASSUNTO(S)

estabilidade ferro minerals iron alimentos enriquecidos enriched foods vitaminas vitamins minerais na nutrição stability

ACESSO AO ARTIGO

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