Wyniki wyszukiwania - Biblioteka Nauki

1

Heme iron in meat as the main source of iron in the human diet

100%

Buzala M. , Slomka A. , Janicki B.

Journal of Elementology

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2016

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tom 21

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nr 1

EN

Iron is a trace element involved in many cardinal metabolic processes of almost all living organisms. It is well known that iron participates in oxygen transport as well as it is a cofactor in many fundamental enzymatic and nonenzymatic processes. Accordingly, disturbances of iron homeostasis can cause serious clinical consequences. In humans, dietary iron can enter the body in two main forms: heme and nonheme. The former is a component of many hemoproteins (including myoglobin, hemoglobin, cytochromes b and c) and is easily absorbed in the duodenal enterocytes. Red meat is an excellent source of heme iron, while the less bioavailable nonheme form is found in large amounts in milk products and vegetables. For this reason, consumers of meat have a better iron status than vegetarians and vegans. The aim of this paper was to discuss the role of heme iron in the human diet. Heme iron found in muscle protein should be supplied to humans to prevent iron deficiency, which can lead to anemia. It is easily absorbed by the human body and its main source is red meat. In addition, heme iron, which is mainly found in myoglobin in meat, contributes to the desirable bright red color and to the most undesirable brown color of meat. Both heme and nonheme iron are catalysts of lipid oxidation in meat. This process lowers the nutritive value through oxidation of polyunsaturated fatty acids, which produces an undesirable flavor and aroma. The present review is focused on the role of heme iron, which is mainly found in meat and is the principal source of iron in the human diet.

2

Evaluation of the content and the potential bioavailability of iron from fortified with iron and non-fortified food products

84%

Suliburska J. , Krejpcio Z. , Kolaczyk N.

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tom 10

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nr 2

EN

Background. Fortified food products contain usually higher amounts of certain nutrients. However, the information about the nutritional quality of such products is limited. The objective of this study was to determine the content and the release of iron from fortified and non-fortified food products available on the Polish market. Material and methods. A group of 29 fortified with Fe and non-fortified food products, such as cereal products (16) and confectionaries (13), were purchased from local market between October and November 2009. The content of Fe in these products, as well as the amount of Fe released in enzymatic digestion in vitro was determined by the flame atomic absorption spectrometry method. Results. It was found that most of the fortified with Fe food products had significantly higher amount and the potential bioavailability of this element in comparison with the non-fortified analogues, however the content of Fe determined analytically not always matched the values declared on the label. Conclusions. Products fortified with Fe appear to be better sources of potentially bioavailable Fe in comparison with the non-fortified analogues.

PL

Wstęp. Produkty wzbogacane zawierają zwykle większą ilość składników odżywczych. Niewiele jest jednak informacji dotyczących jakości odżywczej tego rodzaju żywności. Celem pracy było określenie zawartości żelaza oraz jego potencjalnej biodostępności z produktów wzbogaconych i niewzbogaconych w żelazo dostępnych na rynku polskim. Materiał i metody. Materiałem do badań było 29 produktów spożywczych różnych producentów, dostępnych w handlu detalicznym. Zakupiono je w okresie od października do grudnia 2009 roku. Badaniami objęto dwie grupy wzbogacone i niewzbogacone w żelazo: przetwory zbożowe (16 produktów) oraz wyroby cukiernicze (13 produktów). Próbki poddano trawieniu enzymatycznemu w warunkach in vitro. Zawartość żelaza w preparatach oraz supernatancie po trawieniu określono metodą AAS. Analizę statystyczną wykonano z wykorzystaniem programu komputerowego Statistica 7.0. Wyniki. Stwierdzono, że znacząca większość badanych produktów wzbogacanych w żelazo charakteryzowała się istotnie większą zawartością i uwalnianiem tego pierwiastka, w porównaniu z ich odpowiednikami niewzbogaconymi. Oznaczona analitycznie zawar tość żelaza nie zawsze była zgodna z ilością podaną na etykiecie. Wnioski. Produkty wzbogacone w żelazo wydają się być lepszym źródłem potencjalnie dostępnego żelaza niż produkty niewzbogacone w ten składnik.

3

Influence of iron sources in the nutrient medium on in vitro shoot multiplication and rooting of magnolia and cherry plum

84%

Sokolov R. S. , Atanassova B. Y. , Iakimova E. T.

Journal of Horticultural Research

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2015

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tom 23

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nr 2

4

Wplyw skladnikow pokarmowych na wchlanianie zelaza

67%

Grajeta H.

Bromatologia i Chemia Toksykologiczna

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2006

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tom 39

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nr 2

111-119

5

Acquisition of iron by enterococci: some properties and role of assimilating ferric iron reductases

67%

Lisiecki P. , Mikucki J.

Polish Journal of Microbiology

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2006

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tom 55

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nr 4

EN

Ferric iron reductases activities have been occurred in 91% of investigated enterococci strains. Maximum activity occurred with coenzyme NADH as the reductant and the presence of cofactor FMN was necessary. Mg(II) ions has not stimulated reductases activity. Treatment of cells with proteolytic enzymes had not effect on iron reduction. The whole cells and cell fraction - cytoplasmic membrane and cytoplasm showed Fe(III) - reducing activity. The highest specific activity was associated with cytoplasm. The activity in cytoplasmic membrane was not related to iron concentration in the growth medium. In cytoplasm the activity was stimulated after growth in low-iron medium. Ferric iron reductases of enterococci characterized the broad substrate specificity. The iron in form of ferric ammonium citrate, lactoferrin and ferrioxamine B were the best iron sources for enterococcal ferric iron reductases.