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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.

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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.

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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.

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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.

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A bibliometric study about the subject content of the articles published in the Mexican scientific journal Archives of Medical Research is reported. The journal, published by the Mexican Institute of Social Security (IMSS), is comprised of 100 regular issues and 12 special supplements giving a total amount of 1,424 reports on medical research performed in Mexico during the last 25 years. According to the type of studies published during this period, we found that there is a similar percent of biomedical and clinical reports in the journal (47 and 42%, respectively) and a low proportion of epidemiological and medical educational reports (8 and 3%, respectively). Six thematic areas of research have been permanently published in this journal: investigations on infectious and neurological diseases being the areas mainly represented (34% of the total, corresponding to 17% in each area), followed by studies in reproductive biology (10%) and endocrine (7%), oncological (5%) and cardiovascular (3%) diseases. The tendency of the subjects covered by the journal during this period shows an increment in reports on infectious and parasitic disorders together with an increase in publications related to medicinal plant pharmacology; reproductive biology and endocrine studies show also an increasing tendency. On the other hand, a moderate decrease in studies related to neurological, oncological and cardiovascular diseases is observed. The origin of contributions during the last five years has balanced the proportion of papers published from IMSS scientists, other Mexican biomedical researchers and foreign contributions, thus reflecting favorably the recent changes in the journal's policies. This journal represents a clear example of a scientific publication edited in a developing country, originating as a national publication that evolved progressively into an international biomedical journal.

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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.

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Characteristics and distribution of six plants are described. The chemical composition and in vitro digestibility of leaf and stem of Polymnia maculata, Trigonospermum annuum, Buddleia parviflora Kunt, Canna indica L, Gnaphalium oxyphyllum y Saurauia scabrida Hensl., selected for farmers information, were analysed as a potential resources in animal feeding. The results in dry matter: Crude protein (%): Go and Ss 10.9, Bp 16.7, Pm 11.7 and Ta 11.3. Cell wall (%): Go 54.1, Ss 52.3, Ci 54.4, Bp 68.3, Pm 27.8 and Ta 30.9. Lignin (%): Go and Ss 16.6, Ci 15.5, Bp 10.4, Pm 10.6 and Ta 13.3. IN vitro dry matter digestibility (%): Go 55.1, Ss 37.6, Ci 55.4, Bp 46.5, Pm 82.4 and Ta 81.4. Calcium and phosphorus (mg/100g) respectively: Go 1095 and 379, Ss 1132 and 387, Ci 600 and 421, Bp 800 and 855, Pm 1146 and 421 and Ta 905 and 480. Tannic acid (mg/100g): Go 1450, Ss 1480, Bp 575, Ci 518, Pm 3329 and Ta 2760. Trypsin inhibitor (UIT/g): Go 22264, Ss 29720, Bp 755, Ci 4228, Pm 931 and Ta 4412. Hemagglutinins were detected in Pm and Ta. Alkaloids were detected as scarce in Bp, Ci and Pm, moderate in Ta. Saponins and Cyanogenic glucosides were not detected. It is concluded that Pm and Ta could be considered as a forage for ruminants; Go, Bp and Ci as a complement; recommended the voluntary intake, in vivo digestibility and weight increase trials.

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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.

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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.

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