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.

[Protein concentrate from Amaranthus mantegazzianus. Physical, chemical and biological characterization]. / Concentrado proteico de Amaranthus mantegazzianus. Caracterización físico-químico-biológica.

The aim of this study was the obtainment of a protein concentrate (PC) from A. mantegazzianus seed powder and the evaluation of its percentual chemical composition, functional properties and biological protein quality. For this purpose, the optimal PC conditions assessed were: pH values for maximal and minimal solubility 11.5 and 5 respectively; flour/solvent ratio 1:20, stirring time 1.30 h at room temperature. A product exhibiting a protein content value of 55.3 g/ 100 g was obtained. The functional properties were evaluated by means of the following indexes Nitrogen Solubility Index (NSI) 94.9% at pH 11.5; emulsification activity (EA) 47 +/- 4.8; water absorption capacity (WAC) 2.1 +/- 0.3 and oil absorption capacity (AOAC) 0.8 +/- 0.1. The water and oil absorption index (WOAI) expressed as WAI/OAI was 2.6. These results render the product useful for bread baking due its high solubility, water absorption capacity and the OAI value which shows hydrophilic characteristics. The PC biological quality were calculated determining the net protein utilization (NPU): 64 +/- 7.4, true digestibility (tD): 88 +/- 7.6, biological value (BV): 73, intake: (I) 74 +/- 8.9 and weight gain (delta P) 23 +/- 4.5. The results of this study show a good nitrogen utilization, which plus the functional characterization let us infer that the A. mantegazzianus PC constitutes a good resource for the enrichment of bread baking products, preparing of diets for special regimens and protein complement for deficient foods.

[Amaranthus mantegazzianus. Chemical composition and protein biological value]. / Amaranthus mantegazzianus. Composición química y valor biológico de la proteína.

The objective of this work was to obtain the raw seed powder from Amaranthus mantegazzianus, the evaluation of its chemical and protein amino acid composition using certain biological indexes such as: net protein utilization (NPU), true digestibility (TD), biological value (BV), net protein ratio (NPR) and relative net protein ratio (RNPR). A protein content (N x 5.85) of 12.54 g/100g, and a chemical score (CS) (FAO/OMS/UNU 1985) of 74, represented by leucine as the first limiting amino acid were found. The biological test results obtained were: NPU = 54 +/- 6.4; TD = 81 +/- 7.4; BV = 67; NPR = 2.7 +/- 0.3 and RNPR = 60. No significant concentrations of the anti-nutrients studied were found. The high value of available lysine found is remarkable (48 mg/g protein). Therefore, it is concluded that this species could constitute an interesting potential source to supplement proteins which are deficient in this amino acid.

[Chemical composition and nutritive value of the protein of Amaranthus quintensis]. / Composición química y valor nutritivo de la proteína de Amaranthus quintensis.

An account is given of some considerations concerning the chemical recognition and evaluation by biological methods of the quality of the flour obtained from Amaranthus quitensis seeds, submitted to grinding and sifting. The protein content of the flour (21.70g/100g) can be considered as very important, as well as that of the available lysine (5.20g/16gN). The calcium content was also remarkable (500mg/100g), and the starch ratio reached 45.00g/100g. The amount of nitrates found was 20.00mg/100g, which is an acceptable limit. The research for organic nitro compounds was negative. As for the biologic quality of the protein, the experiments revealed that it has quite an acceptable availability, as demonstrated by the following values: NPU = 42.50 +/- 6.10, D = 68.50 +/- 5.30, VB = 62, NPR = 2.10 +/- 1.80 and RNPR = 42.

[Biologic value of the protein concentrate of Atripex lampa and its value as a complement to wheat flour]. / Valor biológico y complementario a la harina de trigo, del concentrado proteínico de Atriplex lampa.

The Atriplex lampa, chenopodiáceae, is a very abundant bush in the arid and semiarid regions of our Province. This work was undertaken to characterize from the chemical point of view, both the fresh leaves and the protein concentrate (PC) obtained from them. A second purpose was to determine the biological value of the protein, and to evaluate its capacity as a complement to wheat flour (WF). Through this study, the leaf was shown to have a high content of ashes, sodium, potassium and silica, what accounts for its low palatability. The PC obtained has a protein concentration of 59.37 g/100 g and its biological value is limited by the sulfur amino acids, with a chemical score of 85.70. Since the protein is poorly utilized, this results in a relatively low value of its net protein utilization (NPU), a fact which may be attributed to its low true digestibility. The studies on the complementary effects of PC on WF were made at three levels, i.e., 30, 50 and 60%, respectively. The results revealed that the best complementation, measured by the nitrogen utilization, happened to be when 50% of the protein contribution was provided by the A. lampa protein concentrate.

[Effects of treatment with polyvinylpyrrolidone on nutritional quality of sorghum]. / Efectos del tratamiento con polivinilpirrolidona (PVP) sobre la calidad nutricional del sorgo.

The purpose of this paper was to show that a high polyphenolic compound content in the sorghum grain (Sorghum saccharatum, var sugar drip) has an unfavorable influence on the nitrogen absorption. In order to arrive at this conclusion, the tannin content in sorghum flour was reduced by means of a treatment with polyvinylpyrrolidone (PVP) as a complexing agent. Several biological experiments were performed with non-treated flour (S) and with PVP-treated flour (S + PVP). Treatment improved true digestibility (D), having obtained the following values: for S = 31 +/- 2.67, and for S + PVP = 55.8 +/- 3.48 (significance P less than 0.001). The tannin evaluation yielded the following results: S = 1.90 g/100 g, and S + PVP = 0.85 g/100 g reported as tannic acid. The digestibility increase induced a better nitrogenous utilization, the net protein utilization (NPU) values being from 19 +/- 1.58 to 37 +/- 3.36 for S, and S + PVP, respectively.

[Biological quality of the protein isolated from the leaves of Atriplex numularia]. / Calidad biológica del aislado proteínico de hojas de Atriplex numularia.

Plant leaf proteins have acquired great relevance during the last two decades because of their well-balanced amino acid composition. A study was therefore undertaken to evaluate the biological quality of the leaf protein of Atriplex numularia. The protein content of the fresh leaves from this plant was found to be 4.70 g/100, with a dry matter content of 18.70 g/100 g. A protein concentrate (PC) from the same material was then obtained by macerating the leaf in a 2% sodium sulfite solution at a pH of 10 and subjecting it to filtration and pressing. The product thus obtained had a dark greenish color and contained 55.42 g/100 g of protein. The amino acid analysis revealed that its protein has a balance similar to that of animal origin proteins, with a lysine and methionine content of 8.5 g/16 g N and 3.0 g/16 g N, respectively. Biological assays were then carried out to evaluate nitrogen utilization, with the following resulting values: net protein utilization (NPU) = 48.3 +/- 2.7; digestibility (D) = 58.0 +/- 1.4, and biological value (BV) = 83. As inferred from the NPU value, nitrogen utilization was low. Therefore, to improve digestibility values, the action of papain on the PC was assayed. The material thus treated was again submitted to biological trials, obtaining, this time a D of 75.4 +/- 1.05, and thus, an improved new NPU value of 54.8 +/- 1.1 (p less than 0.01).

[Obtaining flour and protein concentrate from seeds of Melilotus albus. Study of the protein quality]. / Obtención de harina y concentrado proteínico de semillas de Melilotus albus. Estudio de la calidad de la proteína.

The present research was carried out to determine the nutritive quality of the flour and protein concentrate from Melilotus albus (white clover) seeds. The flour was studied first. The protein analysis showed methionine to be the first limiting amino acid with a chemical score of 25, with threonine as the second. The biological value obtained was 27. Supplementation studies were performed with different levels of methionine and it was found that the 0.3% level resulted in the best net performance. The biological value obtained under these conditions was 60. The protein efficiency ratio (PER) was also determined, with a value of 1.40 after being corrected with respect to casein. The protein was isolated after studying the pH optimum solubility and precipitation conditions until the flour coumarin compounds were eliminated. Further biological experiments were carried out with the supplemented isolated protein. Under these conditions, a PER value of 2.4 and a biological value of 69 were obtained. No toxicity was observed in rats of both sexes by administration of the protein concentrate during 60 days, at least in the parameters studied during this period.

[Cassia aphylla flour. Study of its chemical composition and the biological quality of its proteins]. / Harina de Cassia aphylla. Estudio de la composición química y calidad biológica de la proteina.

The chemical and biological value of the flour from Cassia aphylla was determined. The chemical study showed that this flour contains a good amount of protein, calcium, phosphorus, iron, ascorbic acid, niacin and thiamine. It is also a good source of lysine and sulfur amino acids. Tests concerning nutritive value carried out were: net protein utilization (NPU), 54.7 +/- 2.45; digestibility, 71.00 +/- 0.30; biological value, 77.00, and protein efficiency ratio (PER) 1.74, corrected with respect to casein. Toxicological tests were performed with rats during a period of 30 days. The criteria used in these tests were: hematological data, organ weights, liver composition and histopathology of the liver and kidney. These tests revealed no signs of pathological damage under the experimental conditions used by us. Based on these results, it can be concluded that this product has a potential value as a feedstuff.

Harina de Cassia aphylla. Estudio de la composicion quimica y calidad biologica de la proteina. / Cassia aphylla flour.Study of the chemical composition and biological quality of the protein

El presente estudio se realizo con el objeto de establecer las caracteristicas quimicas y biologicas de la harina de Cassia aphylla. El estudio quimico porcentual evidencio un buen contenido proteinico, asi como de calcio, fosforo, hierro, acido ascorbico, niacina y tiamina. La determinacion de aminoacidos demostro que la harina en estudio es una fuente muy buena de lisina y aminoacidos azufrados.La utilizacion proteinica neta (NPU) encontrada fue de 54.70 mas o menos 2.45, la digestibilidade, de 71.00 mas o menos 0.3 y el valor biologico, de 77.00. La razon de eficiencia proteinica (PER) fue de 1.74 corregida con respecto a la caseina. Para determinar su inocuidad se realizaron ensayos toxicologicos en ratas durante un periodo de 30 dias.Los analisis hematologicos, peso de organos, composicion del higado y rinon, no mostraron dano patologico en las condiciones en que se realizo el ensayo. A partir de estos resultados, es posible concluir que el producto estudiado es un buen recurso para la alimentacion animal