Carolina Valenzuela

The effect of proteins from animal source foods on heme iron bioavailability in humans

Forty-five women (35-45 year) were randomly assigned to three iron (Fe) absorption sub-studies, which measured the effects of dietary animal proteins on the absorption of heme Fe. Study 1 was focused on heme, red blood cell concentrate (RBCC), hemoglobin (Hb), RBCC+beef meat; study 2 on heme, heme+fish, chicken, and beef; and study 3 on heme and heme+purified animal protein (casein, collagen, albumin). Study 1: the bioavailability of heme Fe from Hb was similar to heme only (∼13.0%). RBCC (25.0%) and RBCC+beef (21.3%) were found to be increased 2- and 1.6-fold, respectively, when compared with heme alone (p<0.05). Study 2: the bioavailability from heme alone (10.3%) was reduced (p<0.05) when it was blended with fish (7.1%) and chicken (4.9%), however it was unaffected by beef. Study 3: casein, collagen, and albumin did not affect the bioavailability of Fe. Proteins from animal source foods and their digestion products did not enhance heme Fe absorption.

Actualización en el uso de antioxidantes naturales derivados de frutas y verduras para prolongar la vida útil de la carne y productos cárneos

En la actualidad existe gran preocupacion por parte de la poblacion por consumir alimentos que ademas de su funcion de nutrir aporten otras caracteristicas a la salud, como los alimentos funcionales. Tambien los consumidores estan cada dia mas exigentes requiriendo alimentos inocuos y naturales; lo que ha determinado que la industria haya ido reemplazando los antioxidantes artificiales por naturales; lo que tambien ha generado una tendencia en la industria de la carne. Los antioxidantes tienen por funcion prevenir el deterioro oxidativo que presentan en forma fundamental los lipidos y proteinas que constituyen los componentes musculares de la carne. Entre los antioxidantes naturales empleados por esta industria se encuentran los derivados de frutas, hierbas y vegetales, que han sido caracterizados, sin embargo su aplicacion en carnes y productos carnicos, y la evaluacion de su efectividad es limitada a nivel industrial, y aumentan el ultimo tiempo la investigacion en esta area. El objetivo de la presente revision fue realizar una actualizacion del uso y aplicacion de antioxidantes de origen natural en carnes y derivados carnicos.

The Effect of Plant Proteins Derived from Cereals and Legumes on Heme Iron Absorption

The aim of this study is to determine the effect of proteins from cereals and legumes on heme iron (Fe) absorption. The absorption of heme Fe without its native globin was measured. Thirty adult females participated in two experimental studies (15 per study). Study I focused on the effects of cereal proteins (zein, gliadin and glutelin) and study II on the effects of legume proteins (soy, pea and lentil) on heme Fe absorption. When heme was given alone (as a control), study I and II yielded 6.2% and 11.0% heme absorption (p > 0.05). In study I, heme Fe absorption was 7.2%, 7.5% and 5.9% when zein, gliadin and glutelin were added, respectively. From this, it was concluded that cereal proteins did not affect heme Fe absorption. In study II, heme Fe absorption was 7.3%, 8.1% and 9.1% with the addition of soy, pea and lentil proteins, respectively. Only soy proteins decreased heme Fe absorption (p < 0.05). These results suggest that with the exception of soy proteins, which decreased absorption, proteins derived from cereals and legumes do not affect heme Fe absorption.

Nutritional properties of dried salmon silage for broiler feeding

The aim of this study was to evaluate the chemical composition, energy and amino acid profile of dried salmon silage (DSS) for broilers. The DSS was obtained by acid digestion of salmon mortalities and subsequently co-dried with wheat bran in a 70:30 ratio (70 parts silage and 30 parts wheat bran). Samples of DSS were evaluated for chemical composition, gross energy, nitrogen-corrected true metabolizable energy (TMEn ), mineral content, total and digestible amino acids for broilers, and amino acid score. The chemical composition of DSS was (mean ± SD): moisture (12.3 ± 0.8%), crude protein (44.0 ± 1.1%), ether extract (5.0 ± 2.4%), crude fiber (3.3 ± 0.4%) and ash (9.4 ± 0.6%). The gross energy and TMEn for broilers were 4 069 kcal/kg and 2 613 kcal/kg, respectively. The DSS mineral composition showed a high content of calcium (1.01%) and phosphorus (1.08%). The DSS had high levels of digestible methionine (0.74%), lysine (2.27%), and threonine (1.16%), and did not present limiting amino acids for broilers. Nutritional composition of DSS showed high protein content with an amino acid profile considered to be suitable as a protein source for broiler feeding.

El cerdo como modelo experimental para la nutrición de hierro

ABSTRACTDisorders due to iron (Fe) defi ciency are quite common in the world population, especially in developing countries. This has generated a considerable increase of research related to the Fe homeostasis on rats and mice animal models in the last years. For several decades the pig model has been used for Fe nutritio-nal studies due to its physiological similarities with the human gastrointestinal tract, and several types of Fe supplementation have been tested on them. However, differences on the effects of some dietary compounds, which could enhance or inhibit the non-heme Fe absorption have been reported between pigs and humans. The newborn pig usually develops Fe defi ciency anemia in the perinatal period, being an ideal model for Fe nutrition studies. Therefore, the aim of this review was to update concepts about the absorption of heme and non-heme Fe, its homeostasis in pigs, and to establish similarities and differences with Fe human metabolism. Recent investigations that use the pig as a model for studies in Fe nutrition are also reviewed.Key words: pig, humans, anemia, iron defi ciency.

DETERMINACIÓN DE HIERRO, ZINC Y COBRE EN CARNE DE BOVINO

Iron, zinc and copper content of 33 bovine meat cuts (in accordance with Chilean standards) were measured from two cow specimens. We obtained triplicate samples of each basic cut of meat as well from the principal organs. The samples underwent acid digestion and were read using AAS. The average quantities of Fe and Zn in the corresponding cuts from each canal of the two specimens did not exhibit significant differences and were significantly correlated (r=0.91, p<0.001 and r=0.68; p<0.001, respectively). The values obtained for copper from the two samples were not significantly correlated. The Fe, Zn and Cu content (mg/100 g) of the 33 cuts analyzed ranged from 1.02-3.42 mg Fe; 2.14-5.32 mg Zn; 0.06-0.19. Fe, Zn, and Cu concentrations in organs were respectively (mg/100 g): heart 3,23; 1,46 and 0,25; lung 5,70; 1,64 and 0,13; brain 0,94; 0,98 and 1,02; liver 6,04; 3,89 and 5,85; spleen 31,15; 2,61 and 0,09; and kidney 3,02; 1,53 and 0,28. We conclude that cow meat does not exhibit large fluctuations in iron content in contrast with zinc, which differs in content depending on the cut. Copper content in bovine meat is minimal. As for the organs, there are evident differences in mineral content which are related to their functions.