Evaluation of the nutritional quality of the grain protein of new amaranths varieties.

The efforts for promoting the consumption of food of plant origin are increasingly growing. The amaranth grain is an important vegetable protein source, superior in content and quality to traditional cereals. In the central-west region of Argentina, new amaranth varieties have been obtained to optimize its agronomic traits and promote its use. In this work, the analysis of the wholemeal flour protein from seeds of two new varieties of Amaranthus cruentus var. Candil (CC) and Amaranthus hypochondriacus var. Dorado (HD), as well as from advanced lines of Amaranthus hypochondriacus x Amaranthus cruentus H17a (H17) and Amaranthus cruentus G6/17a (CG6), was carried out in order to elucidate their nutritional contribution to human diet. The amino acids profile and the chemical score (CS) were determined, and the protein quality was evaluated in-vivo through the following indexes: net protein utilization (NPU), true digestibility (tD), biological value (BV) and protein digestibility corrected amino acid score (PDCAAS). In general, the amino acids values of the different varieties exceeded the requirements established by the WHO/FAO/UNU; however, valine was the limiting amino acid in all cases. The values obtained (%) were within the following ranges: NPU, 33.56-46.04%; tD, 68.80-75.40%; BV, 44.53-64.28%; and PDCAAS, 23.69-36.19%. These results suggest that the new amaranth flours varieties can be adequate for human consumption and as complementary protein source.

Soybean flour induces a greater increase of the antioxidant defenses in rats fed with a normocaloric diet compared with a hypercaloric diet.

BACKGROUND: Soybeans, due to their antioxidant properties, present beneficial health effects. The objective was to evaluate if replacing casein with soy flour, modifies antioxidant defenses in rat liver, compared to animals that continued being fed with casein based diets (normocaloric and hypercaloric). RESULTS: Four groups of rats were used: CC (control casein), CS (control soy), HC (hypercaloric casein) and HS (hypercaloric soy). Malondialdehyde, in serum and liver, did not present differences. In liver, when comparing CS vs. CC: increased superoxide dismutase 1 (P < 0.001), catalase (P < 0.01) and glutathione reductase (P < 0.05) activities, the total glutathione (P < 0.001) and reduced glutathione (P < 0.05) content and decreased oxidized glutathione content (P < 0.05). In HS vs. HC: increased carbonyl groups (P < 0.01) and superoxide dismutase 1 activity (P < 0.05), and decreased glutathione peroxidase activity (P < 0.01), total glutathione (P < 0.05) and oxidized glutathione content (P < 0.001). In HS vs. CS: decreased glutathione reductase activity (P < 0.01), total glutathione (P < 0.001) and reduced glutathione (P < 0.01) content, and increased oxidized glutathione content (P < 0.05). CONCLUSION: Replacing casein by soybean flour improves antioxidant defenses, mainly in normocaloric diets.

Biochemical and molecular study of the influence of Amaranthus hypochondriacus flour on serum and liver lipids in rats treated with ethanol.

Hyperlipidemia and hepatic steatosis are frequent alterations due to alcohol abuse. Amaranth is a pseudocereal with hypolipidemic potential among other nutraceutical actions. Here we study the effect of Amaranthus hypochondriacus (Ah) seeds on serum and liver lipids, and the expression of genes associated to lipid metabolism and liver histology in male Wistar rats intoxicated with ethanol. The animals were divided into four groups; two groups were fed the American Institute of Nutrition 1993 for maintenance diet (AIN-93M), and the other two with AIN-93M containing Ah as protein source. One of each protein group received 20% ethanol in the drinking water, thus obtaining: CC (control casein), EC (ethanol casein), CAh (control Ah) and EAh (ethanol Ah). When comparing EAh vs . EC, we found a positive effect of Ah on lipids, preventing the increment of serum cholesterol (p <0.001), through the higher expression of the LDL receptor (p <0.001); and it also decreased free (p < 0.05) and esterified cholesterol (p <0.01) in liver, probably via the reduction of the 3-hydroxy-3-methylglutaryl coenzyme A reductase expression (p <0.001). We also observed that amaranth contributed to the decrease of fat deposits in liver, probably through the decrease in acetyl-CoA carboxylase alpha (p <0.01), glycerol-3-phosphate acyltransferase 1 (p <0.01) and diacylglycerol O-acyltransferase 2 (p <0.05) expression. The histological study showed a decrease in the fat deposits in the amaranth group when compared to casein; this is consistent with the biochemical and molecular parameters studied in this work. In conclusion, amaranth could be recommended to avoid the alterations in the lipid metabolism induced by alcohol and other harmful agents.

Multielemental analysis and classification of amaranth seeds according to their botanical origin.

The characterization of amaranth seeds (Amaranthus spp.) was developed for Amaranthus hypochondriacus, Amaranthus cruentus, and Amaranthus dubius. The elemental concentrations were determined by inductively coupled plasma optic atomic spectroscopy. Pattern recognition methods were used for the characterization of seed samples: nonsupervised methods included principal components analysis and cluster analysis; supervised methods were linear discriminant analysis and partial least squares discriminant analysis (PLS-DA). Informed are the concentrations of the following elements: Ag, Al, Ba, Ca, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, S, Sr, V, Zn, and Zr. The lowest mineral content was found in A. hypochondriacus, and the highest one was found in A. dubius. For the classification, selected variables for all multivariate methods were Ba, Cr, Li, Mn, Ni, S, and Sr. Nonsupervised methods allowed us to distinguish between the three species of amaranth; however, PLS-DA supervised methods showed the best prediction ability.

Antioxidant properties of Amaranthus hypochondriacus seeds and their effect on the liver of alcohol-treated rats.

Amaranth constitutes a valuable pseudocereal, due to its nutritional quality and its nutraceutical properties, which contribute to improve human health. This work evaluated the effect of a diet based on Amaranthus hypochondriacus (Ah) seed on oxidative stress and antioxidant status in the liver of rats sub-chronically exposed to ethanol. The seed extract was investigated for antioxidant capacity in vitro, showing an adequate content of total phenols and antioxidant activity elevated. For in vivo assays, four groups of six rats each were fed with an AIN-93 M diet for 28 days. In groups III and IV casein was replaced by Ah as the protein source; groups II and IV were received ethanol in the drinking water (20% v/v). When comparing groups IV and II, the following was observed: significant decrease in the activity of aspartate aminotransferase and content of malondialdehyde (p<0.001) in serum; decrease of malondialdehyde and increase in the activity and gene expression of Cu,Zn-superoxide dismutase, also, decrease in the NADPH oxidase transcript levels (p<0.05) in liver. Our data suggest that Ah is a good source of total phenols and exerts a protective effect in serum and in liver of rats intoxicated with ethanol.

Estudio comparativo del valor biológico de acelgas y hojas de amarantos / Comparative study of the biological value of chards and amaranthus leaves

El propósito de este trabajo fue realizar un estudio comparativo de Beta vulgaris var.cicla (acelga) (A) y dos especies de Amaranthus , A. cruentus cv. Don guiem (Ac) y A. mantegazzianus cv. Don Juan (Am), para evaluar la posibilidad de inclusión de hojas de amarantos como sustitutos de la acelga en la dieta, dado que se ha encarado la producción como hortalizas de hoja. Se determinó la composición química de las hojas secas, mediante el análisis químico proximal. Se evaluó la utilización proteica neta (NPU), digestibilidad verdadera (TD) y se calculó el valor biológico (BV). De los resultados obtenidos en el análisis químico proximal se puede inferir que el contenido proteico es similar para las tres especies. Es destacable el mayor contenido de calcio en los Amaranthus (0,95;2,75;2,27g por ciento para A, Ac y Am respectivamente). Igual conclusión nos merece el contenido de hierro (31,5;42,4 y 45,2mg por ciento para A, Ac y Am). En cuanto a nitratos la concentración es menor en A(0,30g por ciento ) que en Ac(0,78g por ciento ) y Am(0,63g por ciento ). No se detectaron diferencias entre los valores NPU (A=56 ñ 4,2; Ac=51 ñ 3,1 y Am=54 ñ 2,9). Igual comentario podemos hacer para los valores de TD(A=76 ñ 8,2; Ac=72 ñ 7,4 y Am=71 ñ 4,3) y para BV(A=74; Ac=71 y Am=76). En los aumentos de peso se observaron diferencias significativas para acelga con respecto a marantos (A=24; Ac=11; AM=14) para p<0,001. Se concluye que el valor nutritivo de los amarantos es bueno, destacando su contenido de Fe y Ca. Esta característica unida a su bajo costo y buena aceptación del material cocido por el hombre, permiten aconsejar su inclusión en la dieta como sustituto de la acelga