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Biomedical subjects

R Bressani

Publications and source records attributed to R Bressani.

At least 91 records · Page 5Linked to original sources
PubMed1983

[Biological behavior of protein fractions isolated from the common bean (Phaseolus vulgaris)].

The purpose of this study was to determine the factors responsible for the low digestibility of bean proteins. To this effect, protein fractions were isolated from black beans through sequential extraction with distilled water, 70% ethanol and 0.01 M sodium hydroxide. Since the amount of protein extracted with the solvents was very low, it was practically impossible to carry out its biological evaluation in rats. Therefore, the protein fractions were added to casein diets in order to determine the decrease in casein digestibility due to the particular protein fraction added. The extracts and residues were heated and dehydrated prior to their incorporation in the rations. Nine rations were prepared. The first one was the control with casein only; 20% of whole bean flour was added to the 2nd; rations 3, 4 and 5 contained the water extraction residue, the water extract, and both, respectively; rations 6, 7 and 8 contained the ethanolic residue, the ethanol extract, and both, respectively. Finally, ration 9 was prepared with the NaOH residue. All the materials used as well as the rations were analyzed for their proximate composition and amino acid pattern. The results of the biological evaluation were as follows: casein and dry matter digestibility decreased significantly with the 2nd ration which contained 20% whole bean flour, effect which was significant also in rations containing either the water or the ethanol extract. This effect is attributed to the antiphysiological factors present in the beans which are resistant to heat treatment. The protein efficiency ratio was lower for the rations prepared with the residues from water and ethanol extractions (3 and 6) than for casein; these results are attributed to the lysine and methionine deficiency in the protein fractions, complicated by a lower protein intake. The lowest nutritive value was found in group 7, which was fed the ration containing the ethanol extract, but when the latter was added together with its residue (ration 8), the PER was superior than for ration 7, possibly due to a higher content of methionine and lysine in ration 8. Finally, it is suggested that better results could be obtained by using higher amounts of beans and their protein fractions in the ration.

Amino Acids↗
PubMed1983

[Evaluation of nutritional potential of fish in diets based on beans (Phaseolus vulgaris) and a cereal/corn (Zea mays) and/or rice (Oryza sativa)].

p6e complementation between corn and fish, and rice and fish was evaluated for the purpose of establishing the required levels of each constituent in the mixture to obtain the optimum value in the biological evaluations for each diet. The optimum fish levels were around 10 and 6% for the corn and rice diets, respectively. Complementary levels of fish in the bean: corn and bean:rice diets were evaluated in the same manner. The best values in the biological evaluation were obtained with only 2% of fish. The economical analysis of these mixtures revealed that the nutritional value of the Central American rural diets can be increased with the introduction of fish in small quantities in the habitual diets, without increasing the family food expenses.

Animals↗
PubMed1983

[Evaluation of chemical and nutritional characteristics of the seed of the rubber tree (Hevea brasiliensis)].

Some chemical and nutritional characteristics of the rubber seed Hevea brasiliensis were studied. The protein content, its amino acid composition as well as the iron, calcium, phosphorus and cyanide (free and bound) concentrations, were determined in the dehulled seed. The effect of soaking, cooking, soaking-cooking and cooking-fat extraction procedure of the seed on the cyanide content and its in vivo protein utilization, was also evaluated. The protein quality was biologically assessed using the protein efficiency ratio (PER). The protein content of the seed was 18%, and the most limiting amino acid was threonine, with a chemical score of 71.6. The iron, calcium and phosphorus contents were 6.2, 109 and 429 mg/100 g, respectively. Its fat content was 48% with a total energy value of 702 kcal/100 g (2,948 Kj/100 g). The total cyanide content in the fresh seed was 130-230 mg/100 g; 6% was in the free form and 94% as bound cyanide. The most effective treatment for reducing the cyanide content was found to be 20 hours of soaking in water, combined with one hour of cooking. The raw seed had a low nutritive value and produced weight loss and death when fed to rats. The protein value, however, improved upon the seed treatment, reaching PER values close to those found in traditional cereals such as corn. It is therefore concluded that the seed of Hevea brasiliensis is a good source of energy, calcium, valine, isoleucine, phenylalanine and tyrosine. In contrast, it is a poor source of threonine, leucine and lysine. Its cyanide content is high, but when removed by treatment, such as soaking in water, cooking or fat extraction, the protein utilization can be improved.

Amino Acids↗
PubMed1982

[Nutritive value of raw and processed cowpeas].

Three experiments were carried out to determine the effects of autoclave cooking, extrusion and DL-methionine supplementation on the protein and energy value of cowpea. The two processes decreased the available lysine of cowpea from 6.3 to 5.7%. The starch content decreased from 50.7% in raw cowpea to 44.9% and 42.1% in cooked extruded cowpea, respectively. Cooking eliminated the trypsin inhibitor content of cowpea. Damaged starch increased from 0.3% in the raw cowpea, to 22.5% in cooked cowpea and to 30.5% in extruded cowpea. In the first experiment it was determined that the protein efficiency ratio (PER) in rats was not affected by cowpea processing (means = 1.17) and that DL-methionine supplementation increased (P less than 0.01) PER to 2.08. In the second experiment, it was established that energy digestibility of the diets used in the first experiment averaged 88.0% with no differences due to processing or supplementation. Digestible energy content (DE) was lower (P less than 0.01) in diets supplemented with DL-methionine (3.58, 3.56, 3.93) than in those without supplement (3.67, 3.93, 3.75). On the other hand, diets with extruded cowpea produced higher (P less than 0.01) DE (3.84 kcal/g) than diets with cooked cowpea (3.75 kcal/g). Classical (EM) and nitrogen corrected (EMn) metabolizable energy determined in chicks showed that both were higher (P less than 0.01) in cooked (3.01; 2.56 kcal/g) and extruded (3.16; 2.76 kcal/g) than in raw cowpeas (1.86; 1.81 kcal/g).

Animals↗
PubMed1982

[Preliminary trial of the cultivation of winged beans (Psophocarpus tetragonolobus) in Guatemala and variations in their chemical composition].

There is no reliable information concerning the cultivation practices of winged bean cultivars in the area; therefore, it was considered of interest to participate in the First International Winged Bean Trial, which was peformed according to a standardized procedure. The planting site was located at 90 degrees longitude and 15 degrees latitude, and 250 meters above sea level, in a hot-humid environment. Sowing was performed in the middle of November, under continuous irrigation until April. During the growth period no diseases or major pests were observed. At the initiation of harvesting in February, there were differences among varieties regarding time to reach maturity. The most promising varieties were Thailand, TPT 1, UPS 121 and Indonesia 1 with respect to seed yield. The highest protein value, 36.5%, corresponded to TPT 1, and the lowest value, 31.7% to UPS 62. Oil content in seeds of all varieties ranged from 14.0% to 19.2%. The five higher protein content varieties were analyzed for their amino acid content, and all varieties for their trypsin inhibitor activity. Leaves, roots and threshed mature pods were also analyzed for their protein content.

Agriculture↗
PubMed1982

[Significance of various antiphysiological and nutritional factors on the biological evaluation of various cultures of the common bean (Phaseolus sp.)].

Raw and cooked samples of beans supplemented with methionine were used to prepare 35 rat diets containing different amounts of methionine, tannins, and trypsin inhibitors. The effect of these diets on weight gain, mortality and protein utilization was measured. The weight gain/protein consumption ratio increased while mortality decreased as the proportion of raw beans decreased in the diet. The effects of diet, beans and their interaction were significant. Supplementation with methionine had no effect in diets with high proportions of raw beans, but it had a significant effect on the biological response to diets with high proportions of cooked beans. The high and early mortality that occurred with diets with a high content of raw beans did not permit the adequate determination of apparent digestibility. In diets with a high concentration of cooked beans, digestibility was higher for white than for black or red beans. Since methionine supplementation had no effect on digestibility, it is suggested that heat-induced changes in the protein could be of great importance in the improvement of bean protein. At the same time, heat destroys the antiphysiological factors, since no definite detrimental effect was observed in the cooked samples due to these factors. It is concluded that the low nutritive value of cooked beans is due to a deficiency of sulfur-containing amino acids, and that the structure of the protein is a factor of the utmost importance in determining its digestibility.

Animals↗
PubMed1981

Protein digestibility and protein quality of common beans (Phaseolus vulgaris) fed alone and with maize, in adult humans using a short-term nitrogen balance assay.

Various experiments using young human adults were carried out to measure the protein digestibility of common beans, fed alone and in different forms and fed together with maize as tortillas. In all, 36 young men were used. Common bean protein digestibility was significantly lower than that observed from meat, and similar to the digestibility of a textured vegetable protein soy protein product. It was also observed that forms of consumption may affect protein digestibility of beans. Using a short-term multiple intake protein quality assay method, it was found that feeding beans alone, N equilibrium was reached with an intake of 114 mg N/kg/day, while when fed with maize in a 87:13 ratio, N equilibrium was reached with 98 mg N/kg/day. This was attributed to both a complementary protein effect and an increase in protein digestibility.

Adult↗
PubMed1981

[Supplementary effect of 3 sources of soy protein on various corn products].

The purpose of the study was to demonstrate that the supplementary effect of soybean protein to corn depends on the protein quality of the soybean product and of the corn products used. Four types of corn flour of different protein quality were used, which included two whole corn flours produced from common corn, one from Opaque-2 corn, and one from degerminated corn. Likewise, three soybean products were tested, including a solvent-extracted soybean flour, a texturized soybean product and a soybean protein isolate. The study was carried out with weanling rats and the effects were measured by PER assays. The results corroborated the hypothesis that the protein quality of the ingredients controls the response observed. The supplementary effects were more evident for low-quality corn flours. Furthermore, large increments in quality were observed with additions of 5% soy protein, which became smaller as this level increased, independent of the corn flour used.

Amino Acids↗