Archivos Latinoamericanos de Nutrición

Absorption of unlabeled reduced iron of small particle size from a commercial source: A method to predict absorption of unlabeled iron compounds in humans

The absorption of a commercial brand of small-particle reduced iron was evaluated in 10 normal subjects. For each subject, the hemoglobin incorporation method was used to measure the true absorption of 60 mg of iron from either ferrous sulfate or ferric ammonium citrate. The iron tolerance test (ITT) was also studied for these two compounds and for reduced iron. This procedure consisted of measuring the area under the curve of plasma iron elevations at specified times for 6 hours, or the peak plasma iron, corrected by the plasma iron disappearance rate obtained from measuring plasma iron at specified times for 4 hours after the slow intravenous injection of 0.4 mg of iron as ferric citrate. Only the ITT was used to measure the absorption of 60 mg of reduced iron. Reference dose iron ascorbate absorption was measured in each subject. The absorption of ferric ammonium citrate and reduced iron was expressed as percent of dose and also as absorption percent of that of ferrous sulfate. Mean % geometric "true absorptions" were 39.0 for reference dose, 10.4 for FeSO4 and 2.4 for ferric ammonium citrate. The later was 23% that of FeSO4. By ITT the mean geometric % absorptions were 7.9, 3.7 and 3.2 for FeSO4, ferric ammonium citrate and reduced iron respectively, or 47 and 41% of that of FeSO4. We propose that the true absorption of the commercial brand of reduced iron tested was 20% that of FeSO4 based on the relation between the ITT results of reduced iron and the ITT and true absorption values of ferric ammonium citrate in relation to FeSO4. The use of this method for measuring absorption of unlabeled iron compounds is discussed.

Absorción de hierro reducido comercial no-marcado y de partícula pequeña. Un método para predecir la absorción de compuestos no-marcados de hierro en humanos. La absorción de una forma comercial de hierro reducido de partícula pequeña se evaluó en 10 sujetos normales. La incorporación de hierro radioactivo en la hemoglobina se utilizó en cada sujeto para medir la "absorción verdadera" de 60 mg de hierro proveniente de sulfato ferroso o de citrato férrico amoniacal. La prueba de tolerancia de hierro (ITT) se usó también en cada sujeto para evaluar la absorción de hierro de estos dos compuestos y del hierro reducido no-marcado. Esta prueba consiste en medir el área bajo la curva de hierro plasmático obtenida por mediciones periódicas por 6 horas subsiguientes a la administración oral de los compuestos de hierro o por el valor pico de hierro plasmático corregidos por la constante de desaparición plasmática del hierro obtenida por mediciones seriadas de hierro plasmático por 4 horas después de la administración endovenosa lenta de 0.4 mg de hierro como citrato férrico. Para medir la absorción de 60 mg de hierro reducido se utilizó unicamente la prueba ITT. Se midió también la absorción de una dosis oral de referencia ( 3 mg de ascorbato de hierro) en cada sujeto, por incorporación en la hemoglobina. La absorción del citrato férrico amoniacal y la del hierro reducido se expresaron como porcentaje de la dosis administrada y como porcentaje de la absorción de la misma dosis de sulfato ferroso. El promedio geométrico de la "absorción verdadera" de la dosis de referencia fue de 39.0%, la del sulfato ferroso fue de 10.4% y la del citrato férrico amoniacal fue de 2.4%. Esta última fue 23% la absorción del sulfato ferroso. Por la prueba ITT los promedios geométricos de las absorciones fueron 7.9, 3.7 y 3.2% respectivamente para sulfato ferroso, citrato férrico amoniacal y hierro reducido, o sea 47 y 41% de la absorción del hierro de sulfato ferroso por esta prueba. Proponemos que la "absorción verdadera" de la fuente comercial de hierro reducido estudiada fue de 20 % la absorción del hierro del sulfato ferroso, basados en la relación entre los resultados de la prueba ITT para el hierro reducido y las del ITT y la "absorción verdadera" para el citrato férrico amoniacal, en relación a ambos resultados para el sulfato ferroso. Se discute el uso de este método para medir la absorción de compuestos de hierro no-marcados.

Utilização de diferentes concentrações de ferro por adolescentes grávidas também suplementadas com zinco e ácido fólico

A adolescente grávida é considerada nutricionalmente de risco, tendo em vista que a maioria delas ainda se encontra em processo de crescimento e de desenvolvimento, além de haver demanda extra sobre o seu organismo, para o crescimento e desenvolvimento do feto (1). Ferro, zinco e ácido fólico são nutrientes essenciais que com frequência apresentam-se deficientes em dietas de adolescentes. Além disso, no que diz respeito às quantidades recomendadas desses nutrientes durante a gravidez, e ainda sobre as possíveis interações entre os mesmos, os dados disponíveis são limitados e merecedores de maiores investigações. Este estudo foi conduzido numa maternidade pública em Teresina -Piauí, Nordeste do Brasil, com o objetivo de se investigar o efeito do uso de diferentes concentrações de ferro (sulfato ferroso) 80mg e 120mg , e constantes em ácido fólico (250µg) e zinco (5mg) na resposta hemoglobínica (concentração de hemoglobina) e reserva de ferro (ferritina plasmática) de adolescentes grávidas suplementadas com os citados nutrientes, iniciando o uso dos suplementos a partir do período de 16 a 20 semanas de gravidez até o parto. Os resultados mostraram que a utilização de 80mg e 120 mg de ferro por adolescentes grávidas provocou similar melhora na resposta hemoglobínica, porém, sem significado estatístico (p<0,05), não refletindo nas reservas orgânicas do mineral.

Utilization of iron at different concentrations on pregnant teenagers also supplemented with zinc and folate. The pregnant teenager is considered at nutritional risk specially due to the fact that most of them still growing and developing. Therefore the demands of pregnancy compete with those of growth causing an extra need for her and the fetus (1). Iron, zinc and folate are essential nutrients that are frequently low on the teenagers diet. Besides that there is not much specific information available about these nutrient recommendations and their interaction among each other. The data available is limited and demands more investigation. This study was conducted at a Public Maternity Hospital located at Teresina, Piauí, Brazil. The main objective of this study was to investigate the effect of different concentrations of iron supplementation (80 and 120 mg of ferrous sulfate) together with folate (250 mu g) and zinc (5 mg) on the hemoglobin concentration and iron stores (plasma ferritin) of pregnant adolescents. The supplementation was done from the 16th to 20th weeks of gestation until delivery. The data founded proved that either 80 mg or 120 mg of iron supplements had similar effect on the improvement of hemoglobin concentration although results showed no statistical significance.

Growth and hematological studies on brazilian children of low socioeconomic level

Anemia and undernutrition are common all over the world, especially in less developed countries. The relationship between low weight, short stature and iron deficiency should be better understood so that appropriate measures might be taken to prevent these problems. A total of 115 institutionalized children aged 12 to 72 months were studied in day-care insitutions in the town of Pontal, Southeastern Brazil, during the second semester of 1999. Personal data, weight, height and hematological profile were obtained from all subjects. Food intake was evaluated in 20 children by a direct food-weighing method. The prevalence of low weight for age (2.6%), low weight for height (1.7%) and low height for age (4.3%) was considered low. Anemia was observed in 68.7% of the children. Diet was found to be adequate in terms of the major nutrients evaluated, but food iron supply was of low bioavailability. In conclusion, the population studied revealed a peculiar behavior i.e., the coexistence of fairly good anthropometric nutritional status along with iron-deficiency anemia. The prevention of this kind of malnutrition cannot be limited to an adequate calorie/protein supply but should also be based on the correction of the severe iron deficiency present in this low socioeconomic level preschool children in Brazil.

Crescimento e estado nutricional de ferro em crianças brasileiras de baixo nível sócio-econômico. Anemia e Subnutrição são problemas comuns em todo o mundo, especialmente nos países menos desenvolvidos. A relação entre baixo peso e baixa estatura e a deficiência de ferro precisam ser melhor compreendidas para que se possam instituir medidas de combate adequadas. Foram avaliadas 115 crianças institucionalizadas, com idades entre 12 e 72 meses, no segundo semestre de 1999, na cidade de Pontal, Sudeste do Brasil. Obtiveram-se Dados Pessoais, Peso, Estatura e dados Hematológicos. A partir de uma amostra de 20 crianças, foi realizada avaliação da alimentação através do método de Pesagem Direta dos Alimentos. As Prevalências de Baixo Peso para Idade (2,6%), Baixo Peso para Estatura (1,7%) e Baixa Estatura para Idade (4,3%) foram consideradas baixas. Observou-se Anemia em 68,7% das crianças. A alimentação revelou-se em geral adequada para os nutrientes avaliados mas observou-se que o ferro oferecido era de baixa biodisponibilidade. Em conclusão, a população estudada revelou um aspecto bastante peculiar isto é, a coexistência de bom estado nutricional antropométrico e anemia ferropriva. A prevenção desse tipo de subnutrição não pode se limitar ao adequado fornecimento de calorias e proteínas mas deve levar em conta, também, a presença marcante da deficiência de ferro nessa população carente do Brasil.

Serum lipids and lipoprotein levels in Costa Rican 13-18 year-old teenagers

Adverse levels of serum lipids tend to persist over time into adolescence and young adulthood, underlying the progression of Coronary Artery Disease (CAD). Therefore, the lipid profile of Costa Rican adolescents and its relationship with dietary intake, physical activity and Body Mass Index (BMI) was evaluated in a total of 322 adolescents ages 13-18 years from urban and rural areas of San José, Costa Rica. Levels of Total Cholesterol (TC) and HDL-C (High-Density Lipoprotein Cholesterol) were significantly higher in urban adolescents than in rural youngsters. No differences were found between LDL-C (Low-Density Lipoprotein Cholesterol) and triglyceride levels among urban and rural adolescents. TC, HDL-C and LDL-C levels were higher in females than in males. The mean LDL/HDL ratio was 2.3 with no differences between gender and area. Over 20% of adolescents showed borderline TC levels (4.42-5.17 mmol/L) and 10% borderline LDL-C levels (2.86-3.35 mmol/L). The proportion of females with borderline TC and LDL-C was higher than the proportion of males. No differences were found between areas. Around 50% of adolescents showed borderline HDL-C levels (0.91-1.17 mmol/L) and over 55% presented borderline triglyceride level (1.02-1.46 mmol/L). The prevalence of borderline and high triglyceride levels (³1.47 mmol/L) between urban and rural adolescents was similar. However the prevalence of high triglyceride levels was higher in females (22%) than in males (14%). An independent positive relationship was found between LDL-C, triglyceride, the cardiovascular fitness score and BMI. Likewise a negative relationship was found between cardiovascular fitness, BMI, gender and HDL-C. This study suggests that primary prevention programs are required to decrease the prevalence of cardiovascular risk factors among Costa Rican adolescents.

Niveles séricos de lípidos y lipoproteínas en adolescentes costarricenses de 13 -18 años. Los niveles adversos de lípidos séricos tienden a persistir a lo largo del tiempo desde la adolescencia y la juventud favoreciendo el progreso de la Enfermedad de las Arterias Coronarias (EAC). Por tal razón se evaluó el perfil lipídico y su relación con el consumo dietético, actividad física e Indice de Masa Corporal (IMC) en 322 adolescentes de 13-18 años residentes de áreas urbanas y rurales de San José, Costa Rica. Los niveles de colesterol total (CT)) y HDL-C (lipoproteínas de alta densidad) fueron mayores en los adolescentes urbanos que en los rurales. No obstante, no se observaron diferencias en los niveles de LDL-C (lipoproteínas de baja densidad) y triglicéridos (TG). Los niveles promedio de CT, HDL-C y LDL-C fueron mayores en mujeres que en hombres. El valor promedio del radio LDL/HDL fue 2.3, sin evidenciarse diferencias por sexo y área. Cerca del 50% de los adolescentes mostraron un nivel limítrofe de C-HDL (0.91-1.17 mmol/L) y más del 55% presentaron niveles limítrofes de TG (1.02-1.46 mmol/L). La prevalencia de niveles limítrofes y elevados de TG entre los adolescentes urbanos y rurales fue similar. Sin embargo, la prevalencia de niveles elevados de TG fue mayor en mujeres (22%) que en hombres (14%). El análisis de regresión lineal determinó una relación positiva e independiente entre los niveles de C-LDL, TG, puntaje de resistencia cardiovascular e IMC. Así mismo se encontró una relación negativa entre el puntaje de resistencia cardiovascular, IMC, sexo y niveles de C-HDL. En conclusión, este estudio sugiere la necesidad de implementar programas de prevención primaria para disminuir la prevalencia de los factores de riesgo cardiovascular entre los adolescentes costarricenses.

Absorción de grasa proveniente de tres fuentes dietarias en ratas con diarrea inducida con lactosa

El déficit energético es uno de los principales contribuyentes al deterioro nutricional durante la diarrea y la grasa es el macronutriente con mayor valor energético, por ello buscamos identificar fuentes dietarias de grasa que presenten una mayor biodisponibilidad durante la diarrea. Con aceite de maíz, mantequilla o grasa de cerdo se prepararon tres dietas controles (con almidón) y tres dietas con 42.8% de lactosa para inducir la diarrea. El ensayo incluyó 48 ratas Sprague-Dawley de 28d de edad y peso inicial de 65.5± 5.2 g, distribuidas en 6 grupos que recibieron, durante 15d, las dietas mencionadas. En las ratas sin diarrea (controles), el tipo de grasa no afectó el consumo de dieta, el crecimiento ponderal, ni las pérdidas fecales. El menor crecimiento se observó en las ratas con diarrea, independientemente del tipo de grasa consumida y guardó relación con el bajo consumo de dieta. La absorción de grasas durante la diarrea fue: mantequilla 84%, grasa de cerdo 87% y aceite de maíz 91% y la dieta con este último se asoció a la menor excreción fecal y la mayor absorción de grasa durante los 15d. Considerando que las tres fuentes de grasa son de fácil adquisición y de amplia aceptación y dado que se recomienda el suministro de dietas con mayor densidad energética para el tratamiento nutricional de sujetos con diarrea, el aceite de maíz podría ser usado con mayores beneficios.

Fat absorption from three different dietary sources in rats with lactose induced diarrhea. Low energy intake is one the most important factors related to nutritional wasting during diarrheal episodes and fat is the macronutrient with the highest energy value. So we intended to seek dietary fat sources, with the highest bioavailability during diarrheal episodes. Three basal (control) and three 42.8% lactose containing diets, used to induce diarrhea, were prepared with corn oil, butterfat or lard. The assay included 48 Sprague-Dawley rats, 28d of age, initial weights of 65.5± 5.2 g, distributed in 6 groups that received the diets during 15d. The different types of fat did not affect diet intake, weight gain or fecal losses in rats without diarrhea (control). Low weight gain was found in rats with diarrhea regardless of the type of fat consumed and was related to low diet consumption. Mean fat absorption during diarrhea was as follows: butterfat 84%, lard 87% and corn oil 91%. The latter was related to lower fecal losses and higher fat absorption during the 15d study. Considering that the three fat sources evaluated are easily purchased and widely accepted, and that nutritional management of subjects with diarrhea includes the intake of energy dense diets, it seems that the use of corn oil in these formulations could offer greater advantages.

Phytate from an alternative dietary supplement has no effect on the calcium, iron and zinc status in undernourished rats

A mixture of cereal bran, eggshells and cassava leaf powder, known as multimixture (MM), has been widely used in developing countries as a dietary supplement to combat malnutrition in children. The introduction of phytate from cereal bran in infant diets has generated serious controversy about MM due to the mineral chelating effect of phytate. This paper reports on a study to investigate the bioavailability of calcium, iron and zinc in rats fed with a deficient diet supplemented with MM. Undernourished rats were treated with a deficient diet (DD) to which MM containing different phytate and mineral concentrations was added. Body weight gains, Ca, Fe, Zn and phytate balances, blood hemoglobin concentration and the mineral content of tissue were determined. DD supplemented with 5% and 25% of MM increased the rats hemoglobin blood concentration, fur regrowth, Ca concentration in the femur and promoted body weight gain 40 times higher than did the DD. Extra calcium, iron and zinc added to the diet with 25% of MM did not increase the rats growth rates. Both the addition of NaCl, KF and KI in MM and the use of dephytinized bran in the MM composition led to a significant increase in the rats growth (P < 0.0001); however, these changes failed to increase Ca, Fe and Zn bioavailability. Our findings suggest that the Ca, Fe and Zn bioavailability was not affected by the MM phytate content or by the concentrations of NaCl, KF and KI in the diet.

El fitato de una dieta suplementaria alternativa, no tiene efecto sobre el estatus del calcio, hierro y zinc en ratas subnutridas. Una mezcla de salvado de cereal, cáscara de huevo y hoja de mandioca en polvo, conocida como multi-mezcla (MM), ha sido ampliamente utilizada en países sub-desarrollados como suplemento de la dieta para combatir la desnutrición en niños. La introducción de fitato proveniente de salvado de cereal en dietas para bebés ha generado serias controversias acerca de la MM debido al efecto quelante de minerales por parte del fitato. Este artículo describe un estudio llevado a cabo para investigar la bio-disponibilidad de calcio, hierro, y zinc en ratas alimentadas con una dieta deficiente suplementada con MM. Ratas sub-alimentadas se trataron com una dieta deficiente (DD) a la cual se le agregó una MM conteniendo diversas concentraciones de fitato y minerales. Se determinó el aumento de peso corporal, Ca, Fe, Zn, balance de fitato, concentración de hemoglobina en la sangre y el contenido mineral de los tejidos. La DD suplementada con 5% y 25% de MM aumentó la concentración de hemoglobina en la sangre de las ratas,-crecimiento del pelo, concentración de Ca en el fémur y promovió un aumento de peso corporal 40 veces mayor que con DD. Extra calcio, hierro y zinc agregados a la dieta con 25% de MM, no aumentó la velocidad de crecimiento de las ratas. Tanto la adición de NaCl, KF y KI en la MM así como el uso de salvado sin fitato en la composición de la MM produjeron un aumento significativo en el crecimiento de los animales (P>0,0001); sin embargo, estos cambios fallaron en aumentar la bio-disponibilidad del Ca, Fe y Zn. Nuestros resultados sugieren que la bio-disponibilidad del Ca, Fe y Zn no fue afectada por el contenido de fitato en la MM o por las concentraciones de NaCl, KF y KI en la dieta.

Efeito hipolipidêmico dos flavonóides naringina e rutina

Flavonóides são pigmentos fenólicos de plantas que possuem várias atividades biológicas, sendo que muitas destas estão associados com prevenção de doenças crônicas como câncer e hiperlipidemia. Este trabalho teve como objetivo avaliar o efeito dos flavonóides naringina e rutina sobre o metabolismo lipídico de aves hipercolesterolêmicas. De acordo com os resultados pode-se observar que naringina e rutina reduziram significativamente as concentrações de colesterol total, colesterol-LDL, colesterol-VLDL e triacilgliceróis totais, não apresentando, entretanto, reduções nos níveis de colesterol-HDL.

Hypocholesterolemic effect of flavonoids naringin and rutin. Flavonoids are pigments fenolics of plants that possess several biological activities, and many of these are associated with prevention of chronic diseases as cancer and hyperlipidemy. This work had as objective evaluates the effect of the flavonoids naringin and rutin on the metabolism lipidic of chicks hypercholesterolemic. In agreement with the results it can be observed that naringin and rutin reduced the levels of total cholesterol significantly, cholesterol-LDL, cholesterol-VLDL and triglycerols, not presenting, however, reductions in the levels of cholesterol-HDL.

Maillard´s reaction in parenteral solutions supplemented with arginine

Arginine, as a basic amino acid, can alter the pH of a parenteral solution and consequently to interfere in the stabilility of other amino acids. The objective of this study was to analyze the chemical stability of amino acids in solutions for parenteral nutrition with arginine supplementation. Amino acids concentrations were determined using an amino acid analyzer in intervals of 12, 36, 72 hours, 7 and 28 days. Storage temperatures were -20° C, 5° C and 25° C. A decrease was observed (p<0.05) in the concentrations of threonine, methionine, isoleucine, leucine, proline and lysine on the 28th day of study, in the solutions kept at 25ºC. The side chains of threonine, methionine, isoleucine, leucine, proline and lysine have hydrophobic groups, which renders them less soluble in water when compared to amino acids that have polar side chains. The degradation of lysine was significant in the sample of parenteral nutrition supplemented with arginine, possibly due to the fact that the solution's pH was between 7.5 and 7.6, therefore facilitating the Maillard reaction between lysine and glucose.

Reação de Maillard em soluções parenteral suplementadas com arginina. A arginina sendo um aminoácido básico, pode alterar o pH da solução de nutrição parenteral e consequentemente pode influenciar na estabilidade de outros aminoácidos. O objetivo deste estudo foi verificar a estabilidade química dos aminoácidos em soluções de nutrição parenteral com suplementação de arginina. As concentrações dos aminoácidos foram determinadas no analizador de aminoácidos em intervalos de 12, 36, 72 horas, 7 e 28 dias. As temperaturas de estocagem foram -20° C, 5 ° C e 25° C. Foi observado um decréscimo (p<0.05) nas concentrações de treonina, metionina, isoleucina, leucina, prolina e lisina no 28 dia de estudo, nas soluções estocadas a 25ºC. As cadeias laterais de treonina, metionina, isoleucina, leucina, prolina e lisina tem grupos hidrofóbicos o que torna estes aminoácidos menos solúveis em água quando comparados aos aminoácidos que tem cadeias laterais polares, diminuindo o Ph e a concentração dos aminoácidos na solução, estando mais disponíveis para ragir com a cetona do aldeído da glicose. A degradação de lisina foi significativa nas amostras de nutrição parenteral suplementadas com arginina, possivelmente devido ao pH da solução estar entre 7.5 e 7.6, facilitando a reação de Maillard entre a lisina e a glicose.

Changes in protein fractions, trypsin inhibitor and proteolytic activity in the cotyledons of germinating Chickpea

The chickpea seed germination was carried out in 6 days. During the period it was observed a little variation on total nitrogen contents, however the non protein nitrogen was double. A decrease of 19.1 and 20.6% in relation to total nitrogen was observed to the total globulin and albumin fractions, respectively. The gel filtration chromatography on Sepharose CL-6B and SDS-PAGE demonstrated alterations on the distribution patterns of the albumin and total globulin fractions between the initial and the sixth day of germination suggesting the occurrence of protein degradation in the germination process.The assay for acid protease only appeared in the albumin fraction with casein and chickpea total globulin as substrates, whereas the former was more degradated than the latter, however the transformations detected in the protein fractions apppear indicated that others enzymes could be acting during the process. The trypsin inhibitor activity had a little drop after six day of germination indicating a possible increase on the digestibility of the proteins.

Variación de las fracciones proteínicas, inhibidor de tripsina y actividad proteolítica durante la germinación de las semillas de garbanzo. La germinación de las semillas de garbanzo fue realizada durante 6 días. En ese período fue observada una pequeña variación en el contenido de nitrógeno total, sin embargo el contenido de nitrógeno no proteico duplicó. Una disminución de 19,1 y 20,6% en relación al nitrógeno total fue observada para las fracciones de globulina total y albúmina, respectivamente. La cromatografia de filtración en gel de Sepharose CL-6B y PAGE-SDS demostraron alteraciones en el perfíl de distribución de las fracciones albúmina y globulina total entre el inicio y final de la germinación, sugiriendo que ocurrió degradación de proteina durante el proceso de germinación. La actividad de la enzima proteasa ácida solamente fue detectada en la fracción albúmina utilizándose caseína y globulina total como substrato de la reacción, siendo la primera mas degradada que la última, entretanto las transformaciones detectadas en las fracciones proteicas parecen indicar que otras enzimas podrían estar actuando durante ese proceso. La actividad del inhibidor de tripsina presentó pequeña alteración despues de 6 días de germinación indicando posiblemente un aumento en la digestibilidad de las proteínas.

O processamento doméstico do feijão-comum ocasionou uma redução nos fatores antinutricionais fitatos e taninos, no teor de amido e em fatores de flatulência rafinose, estaquiose e verbascose

Avaliou-se o efeito da maceração e do processamento doméstico do feijão-comum na composição química, nos teores de fitatos, de taninos, de amido e de fatores de flatulência, utilizando os seguintes tratamentos: feijão-comum cru (FC), cozido sem maceração liofilizado (FCSM), cozido sem água de maceração não absorvida liofilizado (FCSAM), cozido com água de maceração não absorvida liofilizado (FCCAM) e na água de maceração (AM). Os feijões foram macerados por um período de 16 horas, na proporção 3:1 (água:feijão), em temperatura ambiente. Através de ensaio biológico com ratos machos Wistar, estudou-se o efeito de fitatos e taninos no quociente de eficiência protéica líquida (NPR) e digestibilidade protéica. Observou-se redução nos teores de fitatos (85%) pela utilização da maceração. No caso do conteúdo de taninos, somente o processo de cozimento do feijão promoveu alta decomposição dos mesmos (84%). No tratamento (FCSAM) observou-se redução nos teores de rafinose (25,0%), estaquiose (24,8%) e verbascose (41,7%) e no teor de amido (26,8%). No ensaio biológico observou-se que o NPR da dieta controle (caseína) e da dieta caseína mais sólidos solúveis da água de maceração, não apresentaram diferença significativa (p> 0,05); entre os tratamentos de feijão também não houve diferença significativa, sendo os valores dos NPR menores do que aqueles da caseína. A digestibilidade do tratamento (FCSM) foi a maior dentre os tratamentos de feijão (74,3± 5,8%); a caseína apresentou valor de 94,6± 0,9%. A remoção dos fatores antinutricionais fitatos e taninos, teor de amido e dos fatores de flatulência do feijão-comum foi mais efetiva no tratamento onde a água de maceração não absorvida era descartada (FCSAM).

The domestic processing of the common bean resulted in reduction in the antinutritional factors phytates and tannins, in the starch content and in the flatulence factors raffinose, stachiose and verbascose. The objetive of this study was to evaluate the effect of the soaking step and the domestic processing of the common bean, on the chemical composition, the levels of phytate, tannin, starch and flatulence factors by utilizing the follows treatments: raw bean (FC), freeze-dried cooked unsoaked bean (FCSM), freeze-dried cooked bean without the non-absorved soaking water (FCSAM), freeze-dried cooked bean with the non-absorved soaking water (FCCAM) and the soaking water (AM). The beans were soaking for a period for 16 hours in the proportion 3:1 (water:beans) at room temperature. The effect of the phytates and tannins on the net protein efficiency ratio (NPR) and protein digestibility using male Wistar rats were studied. A decrease in the phytate content of the beans (85%) with use of soaking was observed. In the case of the tannin content, only the cooking of the beans promoved high decomposition (84%). In the (FCSAM) treatment a decrease in the raffinose (25.0%), stachiose (24.8%), verbascose (41.7%) and starch (26.8%) contents was observed. Diets containing casein (control), casein plus the soluble solids obtain from the soaking water showed no significant difference (p>0.05) for the NPR, as well as for the different bean treatments, although these showing lower values. The treatment (FCSM) showed the higher digestibility (74.3± 5.8%) of the bean treatments, the casein diets showing 94.6± 0.9%. The reduction of the phytates, tannin, starch contents and flatulence factors in the common bean was most effective when the soaking water not absorved was descarted (FCSAM).

Actividad ureásica en productos de soja: Propuesta de un nuevo método

La evaluación de la actividad ureásica residual en productos de soja es habitualmente empleada como indicador de la eficacia del tratamiento de inhibición practicado. El propósito de este trabajo consistió en realizar una comparación entre el método propuesto por la AACC (22-90), basado en medir diferencias de pH y una técnica en la que se mide la actividad ureásica por su acción hidrolítica de la urea y posterior dosaje del amonio producido mediante la reacción de Berthelot. Se utilizaron los dos métodos para procesar 20 muestras de harina de porotos de soja sin tratar y con diferentes tratamientos térmicos de inactivación. El nuevo método correlaciona satisfactoriamente con el de la AACC, r = 0,9416, (p < 0.0001), asimismo, presenta mayor especificidad ya que mide la concentración del producto de la reacción y ofrece una respuesta más amplificada que el incremento de pH.

Ureasic activity in soy products. Proposal of a new method. The evaluation of residual ureasic activity in soy products is usually employed as an indicator of the efficiency of the inhibition treatments. The purpose of this study is to compare the AACC method (22-90), based on differences of pH, with an assay where ureasic activity is measured by its hidrolitic action on urea and quantification of the ammonium produced with Bethelot reaction. Twenty different samples of soy bean flour with and without thermal inactivation treatments were assessed with the two methods. The new method has a good correlation with that of the AACC - r = 0,9416 (p < 0.0001). It also presents a better specificity because it measures the concentration of the reaction product and shows a more amplified answer than the increase of pH.

Inefficacy of cooking methods on mercury reduction from shark

Shark and other carnivorous fishes present high potential risk of excessive contamination by mercury. The distribution of mercury throughout the body of blue shark - Prionace glauca - was analysed, and the effects on mercury levels by frying and baking in a laboratory oven, and in a microwave oven, were measured. There was no significant statistical difference in mercury levels in the samples taken from regions near the head, or from central and tail parts, indicating homogeneous distribution of the metal in muscles throughout the body. Frying and baking did not affect original mercury levels present in blue shark. This study indicates that specific studies are needed to define the efficacy or inefficacy of the cooking methods on mercury reduction from fish, in order to clearly resolve divergent opinions in the literature.

Ineficiencia de la fritura y el asado en la reducción de mercurio en tiburón. Los tiburones y otros peces carnívoros presentan alto potencial de riesgo por la excesiva contaminación con mercurio. La distribución de mercurio a través del cuerpo del tiburón azul - Prionace glauca - fue analisada, y medido los niveles de reducción de mercurio por el efecto de la fritura y el asado en horno de laboratorio y en horno de microondas. No hubo diferencias estadísticamente significativas en los niveles de mercurio en las muestras tomadas de la región próxima a la cabeza, región central y región próxima a la cola, indicando una distribución homogénea del metal en el músculo a través del cuerpo. La fritura y el asado no afectaron los niveles de mercurio presentes en el tiburón azul. Estudios específicos son necesarios para definir la eficiencia o ineficiencia de los métodos de fritura y asado en la reducción de mercurio del pescado, con el propósito de resolver definitivamente las opiniones divergentes de la literatura.

Fortificacion y evaluacion de tortillas de nixtamal

Se evaluó el efecto de la adición de vitaminas y pasta de soya desgrasada sobre la calidad de la tortilla de nixtamal (TN), así como las pérdidas de algunos nutrientes durante el proceso de nixtamalización. La adición de vitaminas y pasta de soya desgrasada se fijaron en 0.15% y 4% respectivamente, puesto que valores superiores afectaron negativamente el color y sabor en el producto. Se observó que el maíz pierde aproximadamente 1.5% de proteínas durante su transformación a tortilla, mientras que la tortilla de nixtamal fortificada con 4% de soya desgrasada (TNS) presentó 3% mas proteína que la TN. Los contenidos de calcio en las tortillas fueron de 7.7, 114 y 212.5 mg/100 g para el maíz, TN y para TNS respectivamente. Respecto a la pérdida de vitaminas durante la transformación de maíz a tortilla se cuantificó 29.0% de pérdida para niacina, 46.3% para ácido fólico, 36.4% para tiamina y 80% para riboflavina. Durante el lavado del nixtamal se pierden gran cantidad de vitaminas, se cuantificó una pérdida de 18.2% de tiamina, 16.6% de riboflavina y 20.7% de ácido fólico. Por el contrario la harina nixtamalizada integral, en cuyo proceso de elaboración no se contempla el lavado, presentó un balance de niacina positivo del 7.9%. Las pérdidas durante el cocimiento de la tortilla fueron muy elevadas especialmente para la riboflavina, ya que del 80% de pérdidas de esta vitamina durante el proceso total, el 63.8 % se presentó durante su cocimiento y el 16.6% durante el lavado del nixtamal.

Fortification and evaluation of the nixtamal tortillas. The effect of the addition of vitamins and soy protein on the quality characteristics of nixtamal tortillas (TN) and the losses of nutrients during the nixtamalization process were evaluated. Vitamins (0.15% as is) and defatted soy (4% as is) were added to the tortillas without affecting their sensory characteristics. Higher values of those nutrients had a negative effect on the color and flavor of the product. During the production of the tortilla the corn lost approximately 1.5% of proteins. The nixtamal tortilla fortified with 4% of defatted soy (TNS) showed 3% higher protein content than the TN. The calcium content in the samples was 7.7,114 and 212.5 mg/100 g for the corn, the TN and the TNS respectively. In the process of produccing the nixtamal tortillas from corn 28.9% of the niacin, 46.3% of the folic acid, 36.3% of the thiamin and 80% of the riboflavin were lost. During the washing and rinsing of the nixtamal there were losses of 18.2% of the thiamin, 16.6% of the riboflavin and 20.7% of the folic acid. Although the niacin showed a 28.9% loss, the alkaline process caused an important release of that vitamin. The losses during the cooking of the tortillas were high especially for riboflavin which showed a total loss of 80% in comparison with the original corn. Of the total, 63% was lost during cooking and 16.6% was lost during washing of the nixtamal.

Mezclas legumbre/cereal por fritura profunda de maiz amarillo y de tres cultivares de frejol para consumo "snack"

Como una manera de aumentar el consumo de legumbres y mejorar la calidad de la proteína entregada en los productos tipo "snack", se formularon mezclas de frejol/maíz fritos en diferentes proporciones: 60:40 (A); 50:50 (B) y 40:60 (C). El maíz frito utilizado para realizar estas mezclas se sometió a una solución de remojo predeterminada (NaOH/EDTA) y posteriormente fue sacochada por 5 minutos. Cada cultivar de frejol (Pinto 114, Suave 85 y Tórtola Inia) se mezcló con maíz amarillo dentado frito en las proporciones ya descritas, formulándose nueve mezclas las que se caracterizaron química, física y sensorialmente. Estas mezclas resultaron ser muy homogéneas en todas sus características analizadas. Se destacó el contenido de proteína de la mezcla A, que resultó ser mayor que las otras dos proporciones, pero en el análisis sensorial resultó ser la mezcla menos aceptada. El contenido de humedad y la actividad de agua de estas mezclas fue bajo, lo cual asegura una buena estabilidad microbiológica en almacenamiento. La elección de la mejor mezcla legumbre-cereal se realizó por el aporte proteico de cada especie en las diferentes proporciones formuladas. De esta manera se buscó que este aporte proviniera en un 50% del frejol y el otro 50% del maíz, y sólo la mezcla C fue la que más se acercó a esta condición, en el caso de frejol Pinto 114. Para los otros frejoles, la mejor proporción fue la C, en cuanto a aceptabilidad, a pesar de presentar un menor aporte de proteínas.

Deep frying snack product of legume/cereal mixture based on corn and three varieties of beans. To increase legume consumption and give a better protein quality in the snack products, mixtures of fried beans-corn were formulate in different proportions: 60:40 (A); 50:50 (B) and 40:60 (C). Fried corn used in mixtures was previously soaked in a predetermined solution (NaOH/EDTA) and then blanched. Three beans varieties (Pinto 114, Suave 85 and Tórtola Inia) were mixed with fried yellow dent corn in the above described proportions, obtaining nine mixtures whose physical, chemical and sensorial characteristics were evaluated.The mixtures were very homogeneus in all the analyzed characteristics. The protein content for the A mix was the greatest, nevertheless the sensorial analysis showed the last acceptance. The moisture content and water activity of these mixtures was low assuring a good microbiological stability under storage conditions. The protein contribution of each specie in different prepared mixtures determined the selection of the best cereal/legume mix. From a nutritional stand point the best results were obtained when the 50% of protein was supplied by bans and the 50% by corn. From the mixtures tried in this study, mix C with bean Pinto 114 one closed to the recommended conditions. Nevertheless, for each cereal/legume mix, the best proportion was C, due to its better acceptability, even though it had less nutritional value.

Caracterización física y química de harinas industriales nixtamalizadas de maíz de consumo humano en América Central

El objetivo del presente estudio fue el de caracterizar las harinas industriales nixtamalizadas de maíz de consumo humano que se comercializan en Centro América por algunas propiedades físicas y químicas que puedan contribuir en conocer su composición química y ser de ayuda a programas de nutrición y de fortificación de alimentos con micronutrientes. Se adquirieron 12 marcas en triplicado de los supermercados en Guatemala, El Salvador y Honduras, muestras que se mantuvieron en refrigeración hasta el momento de su análisis. Los parámetros físicos y resultados fueron: granulometría, con muchas harinas con niveles que no pasan 60 mesh, pH (5.4-7.5), índice de absorción de agua, WAI (3.4-4.0 g gel/g muestra), índice de sólidos en agua, WSI (4.8-7.8 g/100g) y densidad (0.410-0.547 g/ml). Las diferencias entre harinas fueron estadísticamente significativas para todos los parámetros, menos para WAI. Las características químicas incluyeron humedad, proteína, grasa, cenizas y fibra dietética. Las diferencias fueron estadísticamente significativas entre harinas con la excepción de la grasa. El contenido de proteína fue bajo, variando entre 6.7 - 8.1 g/100g y el de fibra dietética total entre 7.7-12.0 g/100g en base seca. Las muestras fueron analizadas por ácido fítico con una variación de 632 a 903 mg/100g, siendo las diferencias estadísticamente significativas. Las harinas fueron analizadas por su contenido de hierro total y soluble (pH 7.5), calcio, zinc, fósforo, potasio, magnesio, cobre y manganeso. Las diferencias en el contenido de calcio y hierro entre harinas fueron estadísticamente significativas. La variabilidad física y química entre las harinas de maíz nixtamalizado fue relativamente alta por lo que se recomienda que se establezcan estándares de calidad a través de materia prima y procesamiento, para una mayor efectividad de acciones en fortificación con micronutrientes que se pretenda realizar en el futuro.

Physical and chemical characteristics of industrial nixtamalized maize flour for human consumption in Central America. The objective of this study was the characterization of industrial nixtamalized maize flour for human consumption and which are marketed in Central America for some selected physical and chemical properties which may contribute to food composition information and help nutrition and micronutrient fortification programs. A total of 12 brands purchased in triplicate were obtained from supermarkets in Guatemala, El Salvador and Honduras. These samples were kept under refrigeration until analyzed. The physical parameters measured and results were the following: particle size with most samples having a high percentage of particles greater than 60 mesh, pH (5.4-7.5), water absorption index (WAI) (3.4-4.0 g gel/g sample), water soluble index (WSI) (4.8-7.8 g/100g) and flour density (0.410-0.547 g/ml). The differences were statistically significant for all parameters measured, except for WAI. The chemical characteristics included, moisture, protein, fat, ash and dietetic fiber. Differences between flour samples were statistically significant except for fat content. Protein content was low, ranging between 6.7-8.1 g/100g and total dietary fiber varied between 7.7-12.0 g/100g. The samples were analyzed for phytic acid with a variation from 632 to 903 mg/100 g, with statistical significant differences. The samples were also analyzed for total and soluble (pH 7.5) iron, phosphorus, calcium, potassium, zinc, copper, manganese, and magnesium. The difference in the iron and calcium content between flour samples were statistically significant.The physical and chemical variability found between flour samples of nixtamalized maize was relatively high and it is recommended to establish quality standards through raw material and process standardization for greater effectiveness of nutrition programs and activities on micronutrient fortification which may be pursued in the future.