Influence of a protein concentrate from Amaranthus cruentus seeds on lipid metabolism.

It is widely known that elevated cholesterol and triglycerides levels favor the development of heart disease. In this paper we studied the effect of a protein concentrate from Amaranthus cruentus (Ac) on the lipid content in serum and liver tissue of male Wistar rats. The animals were separated into two groups, each group with 16 rats. The control diet had casein as protein source (CD), and the experimental one had Ac protein concentrate (PCAcD). The diets contained 1% cholesterol. Parameters of oxidative stress in liver with CD and PCAcD were also evaluated. No significant differences were observed in serum total cholesterol, whereas LDL decreased and HDL increased (P < 0.001), and the amount of triglycerides decreased in PCAcD as compared to CD. In liver, a decrease of total cholesterol and triglycerides (P < 0.001) was observed in the experimental group in relation to control. Fatty acid synthase (FAS) activity decreased significantly in the experimental group. The mRNA of HMG-CoA reductase did not change, and mRNA of FAS decreased in rat liver fed with PCAcD compared with CD. The excretion of total lipids in feces increased with PCAcD compared to CD (P < 0.001). The activity of reactive substances to thiobarbituric acid in liver showed no significant differences between the control and experimental diets. However, total glutathione and reduced glutathione increased in PCAcD compared to CD (P < 0.001). It can be concluded that PCAcD has a hypotriglyceridemic effect, affects the metabolism of liver lipids, and increases parameters of antioxidant protection in male Wistar rats.

Comparison of the chemical composition and nutritional value of Amaranthus cruentus flour and its protein concentrate.

Plants constitute an alternative source of proteins in the human diet, with advantages over animal proteins because of their low content of saturated fats and absence of cholesterol. Within the framework of a wider research project on the role of Amaranthus cruentus (Ac) in lipid metabolism, in this work the chemical composition and biological value of the Ac flour and its protein concentrate were compared. Proximate chemical composition, amino acid and fatty acid profiles, some antinutrient factors, and biological values were determined for Ac seed flour and its protein concentrate obtained by extraction at pH 11 and precipitation at pH 4.5. The flour protein content was 16.6 g% while that of the concentrate was 52.56 g%. The content of the soluble dietary fiber with a hypolipemic function was notably higher in the protein concentrate (12.90 g%) than in the seed flour (4.29 g%). The protein concentrate also exhibited a higher content of insoluble dietary fiber. The Ac flour and the concentrate contain 75.44 and 56.95% unsaturated fatty acids, respectively. Squalene, which affects the biosynthesis of cholesterol, was detected both in the flour and the concentrate oils, with a higher content in the concentrate (9.53%) as compared to the flour (6.23%). Comparison of the amino acid composition with the FAO pattern protein indicated that the concentrate does not have limiting amino acids, while the flour has leucine, threonine, and valine. The content of lysine was high in both the flour and the concentrate, making these products particularly useful as a complement for cereal flour, which is deficient in this amino acid. The biological quality analysis demonstrated an improvement in the quality of the concentrate. The presence of saponins, phytic acid, and trypsin inhibitors in the concentrate, which favor the metabolism of lipids, suggests that consumption of the concentrate might reduce the risk of heart disease.

[Chemical composition of 2 wild vegetable species compared with chard]. / Estudio de la composición química, de dos especies vegetales silvestres en comparación con acelga.

The nutritional quality of two wild vegetable species, Kochia scoparia (Ks) and Chenopodium album (Cha) was evaluated and compared with Beta vulgaris var. cicla(chard) (Bv), in order to propose their domestication as alternative protein sources. Chemical percentual analysis (AOAC), gaseous chromatography fatty acid determination, and antinutrient searching (by chemical, enzymatic and immunological method) were performed. Protein quality was determined by the following indexes: net protein utilization (NPU), true digestibility (tD) and biological value (BV). The three species exhibited similar protein concentration values, 25.8, 25.0 and 22.1 g/100 g for Ks, Cha and Bv, respectively. Kochia scoparia showed the highest value for fatty acid analysis (82%), with predominance of linolenic acid. Since the samples were subjected to boiling, the amounts of antinutrients found can be considered to be within levels not affecting health. As regards the biological quality, the obtained values for Ks, Cha and Bv, respectively, were: NPU: 68.0 +/- 0.4, 55.0 +/- 6.1 and 56.0 +/- 4.2; tD 70.0 +/- 0.7, 71.0 +/- 4.0 and 76.0 +/- 8.2; BV: 97, 77 and 74. The analysis of the biological quality indexes gave highest nitrogen profit for Ks. These results indicate that Kochia scoparia is suitable for the objective proposed.

Estudio de la composición química, de dos especies vegetales silvestres en comparación com acelga / The study of the chemical composition of 2 wild vegetable species in comparison with chard

El propósito de este estudio fue evaluar la calidad nutricional de dos especies vegetales silvestres Kochia scoparia (Ks) y Chenoposium album (Cha) y comparalas con Beta vulgaris var. cicla (acelga) (Bv), con la finalidad de proponer la domesticación de las mismas, para introducirlas como fuente proteica alternativa. Se realizó la evaluación químico porcentual (AOAC), determinación de ácidos grasos por cromatografía gaseosa, la investigacón de antinutrientes (Métodos químicos, enzimáticos e inmunológicos) y mediante 'los índices de utilización proteica (NPU), digestibilidad verdadera (tD) y valor biológico (BV) (Miller y Bender), se determinó la calidad proteica. Se trabajó con muestras sometidas a cocción. El estudio de la concentración proteica, reveló valores similares para los tres vegetales Ks 25.8, Cha 25.0, Bv 22.1 g/100 g. Del análisis de ácidos grasos se observó un alto porcentaje de ácidos grasos insaturados correspondiendo el mayor 82 por ciento a Kochia scoparia, con predominio de ácido linolénico. Al trabajarse con material cocido los tenores de antinutrientes pueden considerarse en niveles que no comprometen la salud. Con respecto a la calidad biológica se obtuvieron los siguientes datos para Ks, Cha, Bv: NPU 68.0 + 0.4, 55.0 + 6.1, 56.0 + 4.2; tD 70.0 + 0.7, 71.0 + 4.0, 76.0 + 8.2; BV 97, 77 y 74 respectivamente. Del análisis de los indicadores por los cuales se evaluó la calidad biológica se encontró un mayor aprovechamiento nitrogenado en Ks. Por lo que Kochia scoparia cumpliría el objetivo previamente propuesto.

Nutrient and antinutrient composition of Amaranthus muricatus.

The chemical and nutritional composition of the aerial parts of Amaranthus muricatus was assessed. This is a wild plant growing well in arid and poor soil, which are not suitable for cereals. The material under study was boiled, dried and ground and then evaluated for chemical, nutritional and antinutritional properties. Protein concentration of the amaranth flour was 15.74 g/100 g and total dietary fiber content was high (53.81 g/100 g), with 79% coming from insoluble dietary fiber. The calcium content was 1533 mg/100 g and the Ca/P ratio (5.94) was markedly higher than the value suggested in the 1989 Recommended Dietary Allowances. Fifty-nine percent of the fatty acids present were unsaturated with linoleic acid accounting for 40% of the total fatty acid content. Nitrate, hemagglutinin, trypsin inhibitor and saponin contents were within the non-critical values. Net protein utilization (NPU), true digestibility (tD) and biological value (BV) measurements indicated a nitrogen gain of 74% that of casein. The results of this study indicate a nutritive potential for the A. muricatus leaves, therefore, domestication of this plant is suggested along with assessment of its chemical and nutritional properties.