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.

Protein extraction from Atriplex lampa leaves: potential use as forage for animals used for human diets.

The purpose of this study was to evaluate the effect of pH on the extraction of protein nitrogen from Atriplex lampa leaves (Moquin) Dietrich. The chemical characterization of the dry matter indicated the following (g/100 g): protein, 26.93; ash, 21.80; ether extract, 4.65; dry matter, 37.30; sodium, 6.05; and calcium, 0.41. Non-critical values were obtained for saponins and nitrates. The high concentration of oxalic acid (8.52 g/100 g), together with elevated salt content account for the low palatability of the studied species. In order to determine the parameters needed to improve the extraction in protein nitrogen from leaves, fresh material was macerated with 2% sodium metasulfite, followed by pulping with a hand-driven grinder. Extractions were performed at different pH values (2-12) adjusting the value with 5N HCL or NaOH, with agitation followed by centrifugation and pressing. Supernatants were collected and kept. The last extraction was performed with Tween 20 in order to obtain maximum nitrogen recovery from the residue cake. Highest extraction (41.23%) was obtained at pH 10 with a 1:5 ratio (leaf: deionized water, w/v). It is proposed that this regional natural resource may be used to elaborate a protein concentrate, which can be made more palatable by decreasing potassium and sodium salt content with the use of membrane technology.

[Chemical-nutritional evaluation of Sorghum saccharatum var. sugar drip. A supplementation study with lactoserum proteins]. / Evaluación químico-nutricional de Sorghum saccharatum var. sugar drip. Estudio de complementación con proteína de lactosuero.

The chemical-nutritional composition and some indexes of biological quality of sorghum (Sorghum saccharum, var. sugar drip) unwashed whole flour were studied. The culture and selection of sorghum were assayed in the "San Roque" Experimental Station of the Agriculture Department, Undersecretary of Agricultural Affairs, San Luis, Argentina. The obtained protein content was 7.5% (Nx6.25). The values for net protein utilization (NPU); true digestibility (tD); net protein ratio (NPR) and and relative net protein ratio (RNPR) were 12.4 +/- 0.6, 22.0 +/- 0.2, 0.8 +/- 0.1 and 24%, respectively. Deficient nitrogen utilization constitutes a limitation for the use of sorghum. However, considering its abundance and low cost, sorghum could become a profitable feeding resource if conveniently supplemented without increasing costs. Sorghum flour was supplemented with protein recovered from ricotta serum (50:50), discarded as industrial waste, in order to compensate for lysine and threonine deficiency in this cereal. Studies performed on this mixture gave RNPR values of 85.7%. This might permit us to infer that despite its low biological value, sorghum can be used as food resource, potentially for poultry, with adequate supplementation.

[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.

Chemical and nutritional assessment of heifer's omasum flour.

The chemical and nutricional properties of flour from total calf omasum are assessed with the purpose of considering the utilization of a waste product from the meat industry as animal food. The results of the chemical percent analysis showed a high protein content of 78.6 g/100 g, a total lipid amount of 3.70 g/100 g and a cholesterol concentration of 0.14 g/100 g. From the study of the total saturated fatty acid composition it is deduced that palmitic acid prevails with a value of 28.4%. Unsaturated fatty acids show a value of 75% for oleic acid, this being the highest concentration. The values found for lipid composition are similar a fat bovine. Biological techniques were used to evaluate nitrogen utilization: Net Protein Utilization (NPU), true Digestibility (tD) and Biological Value (BV); a proof with casein as reference was simultaneously performed. The NPU, tD and the BV values found were: 58 +/- 7.0; 87 +/- 8.5 and 67 respectively. These results demonstrate that the assayed meat by-product had the adecuate nutritive elements for its industrialization as porcine balanced food.

[Amaranthus cruentus protein concentrate. Extraction methods. Functional properties]. / Concentrado proteico de Amaranthus cruentus. Métodos de extracción. Propiedades funcionales.

The most favorable conditions of pH, temperature ratio for the yielding of a protein concentrate (PC) of seed flour from Amaranthus cruentus was determined. The optimal values were: extraction pH 11, stirring time 1 h 30 min, precipitation pH 4.5 and a flour/ solvent ratio of 1:15. Obtained the PC, its functional properties were assayed. The PC chemical composition expressed in g/100 g was: protein 50.9: humidity 3.3; ethereal extract 5.8; raw fiber 6.4; ashes 3.8; total carbohydrates 29.9. The following PC functional properties were found: a maximal solubility value of 94.3 at pH 1); emulsification activity (EA) 47.90 +/- 4.9, water absorption capacity (WAC) 2.0 +/- 0.3; and oil absorption capacity (OAC) of 0.7 +/- 0.8. The use of this product as supplement for cereals and for others foods with poor lysine content is considered possible. Despite of the functional properties which show the hydrophilic character of the protein from the Amaranthus cruentus PC, great expectancies are inferred for its future utilization in bread products.

[Mountain chinchilla (Lagostomus maximus maximus Blainv) meat. Biological value]. / Carne de vizcacha (Lagostomus maximus maximus Blainv). Valor biológico.

In order to establish the vizcacha meat quality as food, the percentual chemical composition, cholesterol content and values of some fatty acids were determined. Assays were performed using Wistar rats for estimation of Net Protein Utilization (UPN), True Digestibility (TD) and Biological Value (BV). The results obtained were: protein, 23.87 g/100 g; total lipids, 3.74g/100g and a low content of cholesterol of 50 mg/100g. From the analysis of the fatty acids composition it is noticed a remarkable high proportion of insatured C18 fatty acids. The nitrogen availability calculated from UPN studies gave a value of 60.50 +/- 9.7, a TD of 85.00 +/- 13.20 and a BV of 70.60. Considering on the whole the results here obtained and the optimal approval of this product by man, it is inferred that vizcacha meat constitutes a good base for the production of foods suitable to be manufactured as can products. An adequate promotion of this product will be needed for its introduction in new markets.

[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.

[Biological value of protein from leaves of Atriplex suberecta]. / Valor biológico de la proteína foliar de Atriplex suberecta.

The study of Atriplex suberecta leaf protein concentrate has been included within our work line entitled "Biological value of the leaf protein of Atriplex" amino acid profile and chemical score. In order to evaluate nitrogen retention, net protein utilization (NPU), true digestibility (TD) and biological value (BV) data were obtained. Weight gain was studied after determining net protein ratio (NPR) and relative net protein ratio (RNPR) with the following results: CS = 96, calculated for sulphur amino acids; NPU = 60 +/- 4.00; TD = 76 +/- 5.20; BV = 87; NPR = 3.34 +/- 2.50 and RNPR = 88%, which enable us to infer that its protein is of good quality. These data, therefore, should indicate that the product studied could be a good complement for cereals, considering its high lysine content (CS superior to 100).

[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.