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1.
Biol Trace Elem Res ; 81(1): 79-92, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11508334

RESUMEN

Experiments were conducted to evaluate the extent to which element binding of locust bean gum (LBG) affects the availability of calcium, iron, and zinc in the gut. Infant formula was supplemented with increasing amounts of LBG and subjected to an intraluminal digestion procedure. Element binding was measured by eliminating the complexes by twofold centrifugation. Availability of the elements was determined using a validated continuous-flow dialysis technique. Elemental content of the samples, supematants, and dialysates was analyzed with validated atomic absorption spectrometry. LBG provided small amounts of intrinsic calcium (1.13+/-0.02 mg/g) and trace amounts of iron (0.02+/-0.00 mg/g) and zinc (0.01+/-0.00 mg/g), which were strongly bound to the LBG molecule (respectively: 76.6+/-3.3%, 83.4+/-1.2%, 96.7+/-6.6%). Correlation analysis, between percent element bound by LBG after centrifugation and percent trapped after dialysis, yielded significant correlation only for the data of zinc (r = 0.93). For calcium and iron, no correlation could be demonstrated; however, for iron a similar trend was observed. These findings suggest that element binding of LBG has a major influence on the availability of zinc and maybe of iron. For calcium, other factors might also be involved, affecting availability.


Asunto(s)
Minerales/metabolismo , Polisacáridos/metabolismo , Disponibilidad Biológica , Galactanos , Humanos , Lactante , Alimentos Infantiles , Mananos , Minerales/análisis , Minerales/farmacocinética , Gomas de Plantas , Estándares de Referencia , Solubilidad , Espectrofotometría Atómica
2.
Nutrition ; 17(7-8): 614-8, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11448582

RESUMEN

Although it is accepted that dietary fiber probably is not needed in the diets of infants younger than 1 y, babies suffering from regurgitation are often fed with infant formulas thickened with considerable amounts of fiber. The effect of increasing amounts of alginic acid, locust-bean gum, and guar gum was studied from casein and whey-based infant formulas. A dialysis in vitro method with preliminary intraluminal digestion, adapted to the conditions of infants younger than 6 mo, was used. Human milk was used as the reference standard. Elemental contents of samples and dialysates were determined by atomic absorption spectrometry. Soluble dietary fiber inhibited mineral availability more in casein than in whey-based formulas. Mineral availabilities from casein- and whey-based formulas supplemented with 0.42 g of locust-bean gum/100 mL were 9.4% (0.7) and 10.4% (0.6) for calcium (P < 0.05), 0.32% (0.08) and 1.45% (0.17) for iron (P < 0.05), and 3.2% (0.2) and 5.6% (0.5) for zinc (P < 0.05), respectively. Calcium availability from the whey formula decreased in the presence of each fiber source, especially guar gum and alginic acid. Supplementing 2 g of alginic acid-based agents per 100 mL depressed calcium availability from 13.3% (1.2) to 5.3% (0.3; P < 0.05). With respect to iron and zinc, availabilities increased from 1.28% (0.28) to 6.05% (0.96; P < 0.05) and from 6.7% (0.6) to 10.2% (1.0), respectively, with the addition of 2 g of alginic acid (P < 0.05). Both gums lowered iron and zinc availabilities, and guar gum affected iron availability more severely than locust-bean gum did. Iron availabilities were 1.45% (0.17) from formula thickened with locust-bean gum (0.42 g/100 mL) and 0.92% (0.15) from formula thickened with guar gum (P < 0.05). Adding thickening agents based on soluble dietary fiber to traditional infant formulas probably affects calcium, iron, and zinc availability in various ways.


Asunto(s)
Calcio de la Dieta/farmacocinética , Fibras de la Dieta/farmacología , Alimentos Infantiles/análisis , Absorción Intestinal/efectos de los fármacos , Hierro de la Dieta/farmacocinética , Zinc/farmacocinética , Alginatos/administración & dosificación , Alginatos/farmacología , Disponibilidad Biológica , Calcio de la Dieta/análisis , Diálisis , Fibras de la Dieta/análisis , Galactanos/administración & dosificación , Galactanos/farmacología , Ácido Glucurónico , Ácidos Hexurónicos , Humanos , Fenómenos Fisiológicos Nutricionales del Lactante , Recién Nacido , Hierro de la Dieta/análisis , Mananos/administración & dosificación , Mananos/farmacología , Leche Humana/química , Modelos Biológicos , Gomas de Plantas , Polisacáridos/administración & dosificación , Polisacáridos/farmacología , Espectrofotometría Atómica , Zinc/análisis
3.
J Pediatr Gastroenterol Nutr ; 32(1): 54-8, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11176326

RESUMEN

BACKGROUND: Variation in the bioavailability of calcium (Ca), iron (Fe), and zinc (Zn) occurs because of interactions of food components in the gastrointestinal microenvironment. Bioavailability is preferably determined by in vivo tests, but these are expensive, labor-intensive, time consuming, and often unethical. As an alternative, in vitro methods can be used to predict bioavailability of nutrients from foodstuffs. METHODS: A continuous-flow dialysis model with preliminary intraluminal digestive phase, adapted to the gastrointestinal conditions of infants younger than 6 months, was used. Human milk was the reference standard. Ca, Fe, and Zn content of samples and dialysates after digestion were analyzed by atomic absorption spectrometry. RESULTS: Ca availability is similar in human milk (13.1%+/-0.8%), whey (13.3%+/-1.2%), and soy-based formulae (13.0%+/-1.2%; P > 0.05), and higher in casein-predominant formula (21.2%+/-0.6%; P < 0.05). Availability of Fe is highest in human milk (8.12%+/-0.27%: P < 0.05). Fe availability in whey (1.28%+/-0.28%) and soy formulae (1.48%+/-0.28%) is similar (P > 0.05), but availability is lower in casein-predominant formula (0.48%+/-0.22%; P < 0.05). Zn availability is also highest in human milk (13.1%+/-0.7%; P < 0.05). However, Zn availability is similar in whey (6.7%+/-0.6%) and casein formulae (8.5%+/-1.6%; P > 0.05), but lower in soy formula (2.3%+/-0.4%; P < 0.05). CONCLUSIONS: Our observations are in agreement with previous data from in vivo studies in term infants. This in vitro procedure is an inexpensive, simple, rapid, and reliable method that predicts the bioavailability of Ca, Fe, and Zn in foods.


Asunto(s)
Calcio/farmacocinética , Alimentos Infantiles/análisis , Hierro/farmacocinética , Micronutrientes/farmacocinética , Leche Humana/química , Zinc/farmacocinética , Disponibilidad Biológica , Calcio/análisis , Diálisis , Digestión , Femenino , Humanos , Técnicas In Vitro , Fenómenos Fisiológicos Nutricionales del Lactante , Recién Nacido , Hierro/análisis , Micronutrientes/análisis , Proteínas de la Leche/metabolismo , Leche Humana/metabolismo , Valores de Referencia , Reproducibilidad de los Resultados , Espectrofotometría Atómica , Zinc/análisis
4.
J Pediatr Gastroenterol Nutr ; 30(4): 373-8, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10776946

RESUMEN

BACKGROUND: Regurgitation is common in infants and is usually due to gastroesophageal reflux. Often parental reassurance and dietary management by feeding thickened formulas are the only therapeutic steps necessary. Adding fibers may interfere with the absorption of micronutrients. METHODS: A continuous-flow dialysis in vitro method with a preliminary intraluminal digestive phase, modified to simulate the conditions of infants less than 6 months of age and children from 6 months of age on, was used to study the availability of calcium, iron, and zinc from thickened and nonthickened first-and second-age infant formulas. Pooled mature human milk was used as the reference standard. The elemental content of the samples and dialysate fractions of calcium, iron, and zinc after digestion was determined by atomic absorption spectrometry. RESULTS: In human milk, calcium, iron, and zinc were highly available for absorptive processes. Availability of calcium, iron, and zinc from nonthickened first- and second-age infant formulas tends to be significantly better than in the corresponding products thickened with locust bean gum. Thickening infant formulas with pregelatinized rice starch, however, does not affect the availability of calcium, iron, and zinc. CONCLUSIONS: It appears that human milk provides optimal conditions for the availability of calcium, iron, and zinc. Availability of calcium, iron, and zinc seems to lower when infant formulas are thickened with indigestible carbohydrates, whereas it does not by adding digestible carbohydrates.


Asunto(s)
Carbohidratos de la Dieta , Digestión , Reflujo Gastroesofágico/dietoterapia , Alimentos Infantiles/análisis , Fenómenos Fisiológicos Nutricionales del Lactante , Micronutrientes/análisis , Disponibilidad Biológica , Calcio/análisis , Calcio/farmacocinética , Diálisis , Humanos , Lactante , Recién Nacido , Hierro/análisis , Hierro/farmacocinética , Micronutrientes/metabolismo , Leche Humana/química , Reproducibilidad de los Resultados , Espectrofotometría Atómica , Zinc/análisis , Zinc/farmacocinética
5.
Biol Trace Elem Res ; 58(1-2): 55-63, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9363320

RESUMEN

The present study was undertaken to evaluate the in vitro availability of chemically varying forms of selenium (Se), supplemented in cow's milk. Two inorganic (selenite and selenate) and two organic (seleno-methionine [Se-Met] and seleno-cystine [Se-Cys]) Se sources were evaluated. The in vitro availability was estimated by the diffusibility of Se during simulated gastrointestinal digestion. First, the diffusibility was compared after adding a constant amount of Se as either selenate, selenite, seleno-methionine, or Se-Cys in milk samples. Se-Met and selenate were found to be significantly more diffusible than seleno-cystine and selenite under the simulated gastrointestinal conditions. The tendency for superior in vitro availability of selenate and Se-Met compared to selenite and Se-Cys was confirmed for a supplementation range of 5-40 ng/g of Se. This study suggests that the high diffusibility of selenate and Se-Met in a simulated gastrointestinal environment may contribute to their high absorption in vivo.


Asunto(s)
Digestión/fisiología , Absorción Intestinal , Compuestos de Organoselenio/farmacocinética , Compuestos de Selenio/farmacocinética , Animales , Disponibilidad Biológica , Transporte Biológico , Suplementos Dietéticos , Difusión , Tránsito Gastrointestinal , Técnicas In Vitro , Leche/metabolismo , Compuestos de Organoselenio/metabolismo , Ácido Selénico , Compuestos de Selenio/metabolismo , Selenocisteína/metabolismo , Selenocisteína/farmacocinética , Selenometionina/metabolismo , Selenometionina/farmacocinética , Selenito de Sodio/metabolismo , Selenito de Sodio/farmacocinética
6.
Int J Food Sci Nutr ; 47(6): 499-506, 1996 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8933204

RESUMEN

The availability of iron, zinc and calcium from a composed meal was studied by an in vitro method using equilibrium dialysis after simulated gastric digestion. Four different concentrations of four influencing factors (coffee, vitamin C, wheat bran and pectin) were added to the mixed meal and their effect on the relative index of availability was studied after elemental analysis by atomic absorption spectrometry. Apart from ascorbic acid, all other factors had a negative effect on availability of minerals and trace elements. Most pronounced effect, and for all three elements, was observed for the addition of wheat bran. Zinc was the trace element, which was most sensitive to increased spiking of food constituents.


Asunto(s)
Calcio/farmacocinética , Dieta/normas , Análisis de los Alimentos , Hierro/farmacocinética , Zinc/farmacocinética , Ácido Ascórbico/farmacología , Disponibilidad Biológica , Calcio/análisis , Café/normas , Diálisis , Humanos , Hierro/análisis , Pectinas/farmacología , Espectrofotometría Atómica , Triticum/normas , Zinc/análisis
7.
Int J Food Sci Nutr ; 47(1): 75-81, 1996 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8616677

RESUMEN

The trace element selenium (Se) has been recognized to be essential for human health. The dependence of infants on milk as their principal food source, generally low in Se content, makes them more vulnerable to inadequate Se intake. The present study compared the Se availability as estimated by a simulated gastrointestinal digestion procedure, of human milk and some common ruminant milks, namely cow, goat and sheep milk. The Se availability of human milk (11.1%) was significantly higher compared to that of cow (6.8%), goat (6.2%) and sheep milk ( < 2%). Further study suggested that the Se availability may be related to the gastric digestibility of protein. The high Se availability of human milk might be attributed to the high gastric digestibility of human milk protein. It was found that removal of the milk fat fraction increases the Se availability.


Asunto(s)
Leche Humana/química , Leche/química , Selenio/análisis , Selenio/farmacocinética , Animales , Disponibilidad Biológica , Bovinos , Digestión , Electroforesis en Gel de Poliacrilamida , Femenino , Cabras , Humanos , Técnicas In Vitro , Proteínas de la Leche/metabolismo , Ovinos
8.
Biol Trace Elem Res ; 49(2-3): 151-9, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-8562283

RESUMEN

Copper (Cu), zinc (Zn), and selenium (Se) in human milk of middle-class Burundian women during the first 10 mo of lactation have been determined. Wet acid digestion, using nitric and perchloric acids, and atomic absorption spectrometric analysis have been used. Daily intakes have been calculated and proven to decrease from 0.39 +/- 0.05 (colostrum) to 0.16 +/- 0.02 (mature milk), 2.3 +/- 0.3 (colostrum), to 1.2 +/- 0.2 mg (mature milk) and 10.9 +/- 1.5 (colostrum) to 5.3 +/- 0.8 micrograms (mature milk) for Cu, Zn, and Se, respectively. Since values for this African country are nonexistent, intake levels are compared with literature data and found to be somewhat higher than those observed in other poorly nourished countries. The recommended safe and adequate daily intake for infants of 0-6 mo of age, as proposed by the National Research Council of the USA, is only met for Burundian infants < 1 mo of age. The function of copper (Cu) and zinc (Zn) as essential trace elements has been known for quite a number of years (1). Also, selenium (Se) is a trace element essential for the activity of glutathione peroxidase (2) and type I iodothyronine 5-deiodinase (3). For all three elements, an adequate intake is necessary for satisfactory infant growth and development (4). In view of the almost total lack of relevant data on Burundi (Africa), we have determined Cu, Zn, and Se in human milk of middle-class Burundian women during the first 10 mo of lactation (5). The aim of this study is to assess infants' elemental intake for this country and compare this with literature data on trace elemental intake of exclusively breast-fed infants.


PIP: Copper and zinc are essential trace elements in the human diet, while selenium is a trace element essential for the activity of glutathione peroxidase and type I iodothyronine 5-deiodinase. Infants need to consume enough of each of these elements in order to grow and develop satisfactorily. The authors investigated the levels of copper, zinc, and selenium in human milk of middle-class Burundian women during the first ten months of lactation. Wet acid digestion, nitric and perchloric acids, and atomic absorption spectrometric analysis were employed in the assessment. The daily infant intakes of copper decreased from 0.39 mg to 0.16 mg over the ten-month period, zinc from 2.3 mg to 1.2 mg, and selenium from 10.9 mcg to 5.3 mcg. The higher values were obtained through the ingestion of colostrum, while the lower values were the result of consuming mature milk. Comparison of these findings with literature data show the nutrient intake levels of these Burundian infants to be slightly higher than those observed in other poorly nourished countries. The recommended safe and adequate daily intake for infants aged 0-6 months, as proposed by the US National Research Council, is only met for Burundian infants younger than age one month.


Asunto(s)
Lactancia Materna , Cobre/administración & dosificación , Leche Humana/química , Selenio/administración & dosificación , Zinc/administración & dosificación , Adulto , Disponibilidad Biológica , Burundi , Estudios de Cohortes , Cobre/análisis , Femenino , Humanos , Lactante , Recién Nacido , Lactancia , Leche Humana/metabolismo , Selenio/análisis , Zinc/análisis
9.
J Trace Elem Electrolytes Health Dis ; 8(3-4): 129-43, 1994 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-7599503

RESUMEN

Various factors, that probably influence the blood selenium concentration level of people residing in a given geographical area are discussed. The literature is screened for the effects of age, gender, smoking and drinking habits, race, state of lactation, environmental exposure and medical treatment. The differences are mostly found to be small on the absolute scale, with only nutrition seeming to be a major factor.


Asunto(s)
Selenio/sangre , Envejecimiento/sangre , Ingestión de Alimentos/fisiología , Exposición a Riesgos Ambientales , Femenino , Hábitos , Humanos , Lactancia/sangre , Masculino , Embarazo , Factores de Riesgo , Caracteres Sexuales
10.
J Trace Elem Electrolytes Health Dis ; 8(3-4): 225-8, 1994 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-7599518

RESUMEN

Selenium levels in venous and capillary whole blood of children were assessed by direct graphite furnace atomic absorption spectrometry. Selenium data obtained for both blood samples did not differ statistically (p > 0.05). Capillary blood may therefore be used as an alternative to venous blood, which is more difficult to obtain from children. Whole-blood selenium data for children in the Antwerp region (Belgium) were compared with literature data for children from other countries.


Asunto(s)
Capilares/fisiología , Estado Nutricional , Selenio/sangre , Bélgica , Niño , Preescolar , Estudios de Evaluación como Asunto , Humanos , Valores de Referencia , Venas
11.
Z Lebensm Unters Forsch ; 199(4): 251-4, 1994 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-7839732

RESUMEN

The dietary selenium (Se) intake in Belgium has been re-evaluated. Duplicate meal collection, wet acid destruction and flow injection hydride generation atomic absorption spectrometry were used as techniques. The daily intake ranged from 28.4 micrograms (Liège, Walloon part of the country) to 61.1 micrograms (Vilvoorde, central part of the country). Compared with intakes recently published for other countries, the actual Belgian value corresponds to intermediate ranges of Se intake.


Asunto(s)
Dieta , Selenio/administración & dosificación , Bélgica , Hospitales Militares , Hospitales Universitarios , Humanos , Espectrofotometría Atómica
12.
J Trace Elem Electrolytes Health Dis ; 8(2): 99-109, 1994 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-7881284

RESUMEN

Serum selenium levels of 160 healthy Greeks were determined by Zeeman-effect background-corrected atomic absorption spectrometry. Mean value for 101 men (70.7 +/- 16.2 micrograms/L) tended to be higher, but not statistically significant, compared to the mean value for 59 women (64.9 +/- 14.7 micrograms/L). When the subjects were divided into various age groups there appeared to be some increase as a function of age. Compared to the extensive literature data on serum Se levels for various countries healthy Greeks proved to be at the lower concentration range. The scarce, but conflicting literature data on serum Se values for Greeks is discussed.


Asunto(s)
Selenio/sangre , Adulto , Europa (Continente) , Femenino , Grecia , Humanos , Masculino , Persona de Mediana Edad , Valores de Referencia , Espectrofotometría Atómica
13.
Z Lebensm Unters Forsch ; 197(4): 342-5, 1993 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8249477

RESUMEN

The present study evaluates the application of an in vitro digestion procedure for estimating the selenium (Se) availability from cow's milk. The results obtained by this in vitro method indicate that only a small portion (< 10%) of milk Se can be estimated as available. The available fraction of whole milk (4.7%) was significantly lower compared to the Se availability of skim milk (7.3%). Investigations on the methodology of the in vitro method indicate that the portion of total potentially available Se, determined as total dialysable Se, increases simultaneously with protein digestibility along with the digestion process. Therefore it is concluded that protein digestibility might largely influence the Se availability from milk.


Asunto(s)
Leche/química , Selenio/farmacocinética , Animales , Disponibilidad Biológica , Electroforesis en Gel de Poliacrilamida , Estudios de Evaluación como Asunto , Valor Nutritivo , Selenio/análisis
14.
Sci Total Environ ; 136(1-2): 49-76, 1993 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-8211111

RESUMEN

Daily dietary intake of copper, zinc and selenium for different population groups in Burundi, Africa, has been determined, using different sampling strategies, by atomic absorption spectrometry. Recommended daily intakes (RDA, National Academy, USA) are met for copper and zinc. For selenium, especially the rural population risk a deficiency as observed with a daily intake of 17 micrograms. The importance of different types of food in daily intake is discussed. Legumes proved to be an important source of copper, while for selenium fish contributes in a large part in dietary intake. Calculated total daily intakes are compared with intakes recently published for other countries.


Asunto(s)
Cobre/análisis , Dieta , Análisis de los Alimentos , Selenio/análisis , Zinc/análisis , Burundi , Conducta Alimentaria , Femenino , Humanos , Masculino , Población Rural , Selenio/sangre , Oligoelementos
15.
Z Lebensm Unters Forsch ; 196(6): 536-9, 1993 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8328219

RESUMEN

The selenium (Se) distribution in sheep's milk is reported. Skim milk was found to contain the major part (98%) of total milk Se. The Se distribution over casein and whey protein fractions depends on the separation method used, but irrespective of these methods, skim milk Se is mainly associated with the casein fraction (> 68%). Approximately 11%, 4% and 17% Se is removed by dialysis (molecular mass cut-off 10-12 kDa) from skim milk, casein and whey respectively, indicating a major association of Se with milk proteins. This observation is confirmed through Se analysis of individual caseins and whey proteins isolated through ion-exchange chromatography and gel filtration. Se concentrations of the different isolated milk proteins show considerable variations (caseins, 304-750 ng Se/g; whey proteins, 241-806 ng Se/g).


Asunto(s)
Caseínas/química , Proteínas de la Leche/química , Leche/química , Selenio/análisis , Animales , Precipitación Química , Cromatografía en Gel , Cromatografía por Intercambio Iónico , Electroforesis en Gel de Poliacrilamida , Femenino , Ovinos , Ultracentrifugación , Proteína de Suero de Leche
16.
Z Lebensm Unters Forsch ; 196(3): 236-8, 1993 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-8465609

RESUMEN

The present studies were undertaken to characterize selenium distribution in egg white. Ion-exchange chromatography fast protein liquid chromatography (FPLC) and flow injection atomic (absorption) spectrometry (FIAS) were used to separate egg white proteins and to determine the selenium content of different fractions. After purification, nine different proteins were identified with sodium dodecyl sulphate-polyacrylamide gel electrophoresis and 56% of the total selenium content was found to be associated with ovalbumin-1 and -2 (+/- 500 ng/g), which is the main protein in egg white. Flavoprotein was determined to be the richest selenium-containing protein (1800 ng/g). The selenium content of the other proteins (lysozyme, conalbumin, globulins and ovomucoid) ranged from 359 to 1094 ng/g.


Asunto(s)
Proteínas del Huevo/química , Selenio/análisis , Animales , Cromatografía por Intercambio Iónico , Electroforesis en Gel de Poliacrilamida , Flavoproteínas/análisis , Flavoproteínas/química , Ovalbúmina/análisis , Ovalbúmina/química , Espectrofotometría Atómica
17.
Sci Total Environ ; 128(1): 83-98, 1993 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-8424155

RESUMEN

Atomic absorption spectrometric determination of zinc, copper and selenium in milk from cow and goat from Burundi provide values, which agree quite well with literature data. Muscle from both animals is a rich source of zinc, but not for copper and selenium. Liver accumulates the highest amount of copper, while for selenium the kidney is the target organ.


Asunto(s)
Bovinos , Cobre/análisis , Cabras , Carne/análisis , Leche/química , Selenio/análisis , Zinc/análisis , Animales , Burundi , Femenino , Riñón/química , Hígado/química
19.
Z Lebensm Unters Forsch ; 195(1): 3-7, 1992 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-1502856

RESUMEN

This study reports on selenium distribution in goat milk. Skim milk was found to contain the major part (94%) of total milk selenium. The selenium distribution over casein and whey protein fractions depends on the separation method used, but irrespective of these methods, skim milk selenium is mainly associated with the casein fraction (greater than 69%). Approximately 9%, 7% and 24% of selenium is removed by dialysis (molecular cutoff 10-12 kDa) from skim milk, casein and whey respectively, indicating a major association of selenium with milk proteins. This observation is confirmed by selenium analysis of individual caseins and whey proteins isolated through ion-exchange chromatography and gel filtration. Selenium concentrations of the different isolated milk proteins show considerable variation (caseins: 294-550 ng Se/g; whey proteins: 217-457 ng Se/g).


Asunto(s)
Leche/análisis , Selenio/análisis , Animales , Caseínas/química , Cromatografía en Gel , Cromatografía por Intercambio Iónico , Electroforesis en Gel de Poliacrilamida , Cabras , Focalización Isoeléctrica , Lípidos/química , Proteínas de la Leche/química , Proteína de Suero de Leche
20.
Z Ernahrungswiss ; 31(2): 138-46, 1992 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-1496832

RESUMEN

Manganese has been proven to be an essential trace element in animals since 1931. Today, it is known that manganese deficiency results in a wide variety of structural and physiological defects in animals. For humans, the safe and adequate range of intakes for manganese by enteral nutrition is 2.0 to 5 mg per day; for parenteral nutrition a range of 0.15 to 0.8 mg per day is proposed. The manganese content of components of enteral nutrition (EN) and total parenteral nutrition (TPN) solutions is determined using electrothermal atomic absorption spectrometry. Comparison is made between calculated and measured values. The manganese present in supplementary nutrition and flavor stuffs is also measured. The intake of manganese by EN is calculated based on the daily administration, and is found to vary from 192 to 7373 micrograms per day. In prepared TPN-solutions, the manganese contribution of all components before adding the Oligo Complex is found to be less than 0.2% of the total manganese content. After addition of the Oligo Complex mixture, a mean daily intake of 5.02 +/- 0.16 mg per day is found.


Asunto(s)
Nutrición Enteral , Alimentos Formulados/análisis , Manganeso/análisis , Nutrición Parenteral , Humanos , Manganeso/administración & dosificación , Espectrofotometría Atómica
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