Mirta Eva Valencia

In vitro measurement of available iron in fortified foods

Abstract The objective of this study was to investigate the influence of base systems used to regulate pH values of digests on iron dialysability as an indicator of bioavailable iron. We studied the pertinence of measuring titratable acidity to pH 7.5 with KOH to calculate mEq of NaHCO 3 to be used for pancreatic digestion/dialysis. The pH achieved using the same mEq of each base was lower when using NaHCO 3 than when using KOH. The discrepancy between achieved and attempted pH was uneven for several iron sources. Differences in pH regulation procedure, including type and concentration of base or buffer added to the pepsin digest rendered different final digest/dialysate pH values, thus affecting dialysable iron. A modification of in vitro equilibrium dialysis method is proposed using PIPES buffer of sufficient molarity to obtain a uniform final pH of 6.5 in digest/dialysate systems. The main factors taken into account to calculate buffer concentration were buffer capacity of food matrix (HCl mEq required to reach pH 2), HCl mEq included in the aliquot of pepsin suspension, acid or base mEq generated through enzymatic hydrolysis during in vitro digestion and intrinsic food pH (HCl mEq to adjust food matrix pH to 6.5). With these data buffer molarity for each food matrix can be calculated. Modifications suggested for the equilibrium dialysis method allowed development of a uniform final pH of the digest/dialysate system in a variety of foods assayed.

Iron absorption of ferric glycinate is controlled by iron stores

Abstract Ferric glycinate bioavailability and its absorption control by iron stores was assessed by radioisotopic studies in 30 subjects (17 women and 13 men), in apparent good health, of normal iron status and of high socioeconomic level. Absorption studies used ferric glycinate labeled intrinsically during the synthesis process of this compound as a tracer. In two groups of 15 subjects, iron bioavailability of a milk fortified with 6 mg of elemental iron as ferric glycinate (study 1) and 15 mg elemental iron as ferric glycinate (study 2) was studied. On day 1, the subjects received 250 ml of milk fortified with ferric glycinate labeled with 74 kBq of 55 Fe, and on day two 50 ml of a reference dose of 60 mg elemental iron/L as ferrous ascorbate. The iron bioavailability of the reference dose of ferrous ascorbate was similar in both groups of subjects, 16.5% and 16.4% in study 1 and 2 respectively. Iron absorption of ferric glycinate given with milk in a concentration of 6 or 15 mg/l of elemental iron was not significantly different (5.4% and 4.0% respectively). When iron absorption was standardized to 40% absorption of reference dose, the corresponding percentages of iron absorption were 13.1% and 9.6% for milk fortified with 6 and 15 mg of iron/L respectively. There was a direct correlation between the absorption of ferrous ascorbate and ferric glycinate (r=0.75, p

Mineral dialyzability in milk and fermented dairy products fortified with FeNaEDTA.

Iron, zinc, and calcium dialyzability and ascorbic acid (AA) concentrations were evaluated in milk and yogurt fortified with FeNaEDTA (FE) or ferrous sulfate (FS) as a control, with or without AA addition. The values obtained for FE iron dialyzability in milk were much higher than those obtained for FS. The addition of AA to milk improved Fe dialyzability when using FS and slightly decreased Fe dialyzability in the FE-fortified nonfermented samples. Milk fermentation increased iron availability from both iron sources. Zinc and calcium dialyzability in products containing any of the two iron sources was increased in fermented milks. EDTA improved Zn dialyzability from intrinsic zinc in every manufactured dairy product. Whereas for milks fortified with FS and stored at 4 degrees C for 24 h, the AA content remained close to the original concentration, a higher AA degradation was observed when milks were fortified with FE.

DIALIZABILIDAD DE HIERRO Y ZINC EN CEREALES PARA DESAYUNOS COMERCIALES FORTIFICADOS CON HIERRO ELEMENTAL, SULFATO FERROSO O EDTA FERRICO SODICO

Se comparo la dializabilidad de Fe y Zn en 7 cereales para desayuno comercialmente fortificados o no, con Fe elemental y ZnO y se comparo la dializabilidad de Fe y Zn en tres tipos diferentes de cereales experimentalmente fortificados con ZnO y FeNa2EDTA o FeSO4 en el laboratorio. Se utilizo una metodologia in vitro que mide el porcentaje de dializabilidad (D%) del mineral en condiciones controladas de pH. Los cereales comercialmente fortificados presentaron valores de DFe% entre 0,4 y 15,0 y entre 1,0 y 5,6; sin y con leche. Para DZn% los valores fueron entre 3,3 y 16,1 y entre 3,3 y 30,8, sin y con leche. Casi todos los cereales fortificados en el laboratorio presentaron mayor DFe% (entre 19,5 y 28,6) y DZn% (entre 12,4 y 29,2) cuando fueron fortificados con FeNa2EDTA (con y sin leche). Los resultados obtenidos muestran al FeNa2EDTA como una alternativa viable para la fortificacion de cereales para desayuno.

DETERMINACIÓN DEL CONTENIDO DE GLIADINAS EN ALIMENTOS ELABORADOS CON AMARANTO, QUÍNOA Y/O CHÍA

Resumen es: Amaranto, quinoa y chia, por ser naturalmente libres de gluten, pueden ser incorporados en la dieta celiaca. Con el objeto de evaluar una posible contami...

Biodisponibilidad de hierro en la dieta infantil

La alimentacion del nino en el primer ano de vida reviste gran importancia por las consecuencias negativas que las deficiencias nutricionales pueden tener sobre el crecimiento y desarrollo infantil, a corto y a largo plazo. Por ello es fundamental promover la lactancia exclusiva en los primeros 6 meses de vida, asi como incorporar oportunamente alimentos complementarios de calidad adecuada.1 En este contexto, se debe recordar que la deficiencia de hierro constituye la carencia nutricional mas comun en America latina y tambien en nuestro pais.2,3 Mantener el balance de minerales de acuerdo a los requerimientos fisiologicos requiere considerar, no solo la ingesta total de estos nutrientes, sino tambien su biodisponibilidad. Esta ultima supone la presencia en el alimento/dieta de compuestos que la favorezcan y la ausencia de otros que la inhiban. La forma quimica del mineral y su interaccion con componentes del alimento/dieta determinara variaciones en la biodisponibilidad que es preciso evaluar para conocer, no solo la cantidad aportada por el alimento, sino tambien la cantidad disponible para su bioutilizacion. Los metodos para evaluar la biodisponibilidad incluyen ensayos in vivo e in vitro. En algunos casos se utilizan ensayos en ratas. Sin embargo, el uso de modelos animales para evaluar la biodisponibilidad en seres humanos esta limitado por las diferencias entre especies, tanto en la velocidad de crecimiento como en la