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Biomedical subjects

L G Elías

Publications and source records attributed to L G Elías.

At least 19 recordsLinked to original sources

[Effect of the seed coat on the hardening of common beans (Phaseolus vulgaris)].

Samples of cotyledons and whole black beans (Phaseolus vulgaris), Tamazulapa variety were stored during six weeks at 37 degrees C and 90% relative humidity to establish chemical and physical changes which occur during storage, and to determine the role played by the seed coat in the hard-to-cook phenomenon. After the storage period, samples of whole beans were divided in two subsamples, with and without the seed coat. These two samples and the cotyledons were analyzed for cooking time, water absorption, dietary fiber, tannic acid, soluble pectins and phytic acid. Cooking time of the whole beans increased from 99 to more than 480 minutes in the six-weeks period; for the cotyledons this value increased from 45 to 111 minutes. Cooking time of the dehulled bean, stored as whole bean, increased from 45 to 111 minutes. Cooking time of the dehulled bean, stored as whole bean, increased from 45 to 103 minutes. Water absorption in the whole beans and the cotyledons decreased, although in the cotyledons it was higher, due perhaps to the great absorption capacity to the seed coat. No changes were observed in the dietary fiber content of the cotyledons nor in the beans dehulled after storage. However, in the whole grains neutro-detergent fiber decreased, while acid detergent fiber, cellulose and lignin did not present significant changes. On the other hand, soluble pectates decreased in the whole bean and in the cotyledons; nevertheless the tannin content (as tannic acid) decreased only in the whole beans (from 3.28 to 1.64 mg/g). The data obtained suggest that the seed coat plays a significant role in the hard-to-cook process of hardening of the bean, before and during storage.

Dietary Fiber↗

Culinary practices and consumption characteristics of common beans at the rural home level.

A survey was carried out on housewives of rural bean-producing areas for the purpose of collecting information on bean selection procedures, culinary practices and bean consumption in rural homes from four departments of northeastern Guatemala. The study sample consisted of 10 families selected at random from each of 19 municipalities. The questionnaire used had been pretested in two rural communities not included in the study sample. As already shown by other INCAP surveys of this nature, it was found that all families consumed common black beans, and on rare occasions beans of different color or species. With respect to cooking practices, it was found that beans are not usually soaked prior to cooking, and that few housewives add salt at the beginning of cooking. Two fractions are usually obtained, the cooked beans and the cooking broth. Another finding was that beans are consumed in four preparations: cooked whole, strained and fried, ground and fried, and cooked and fried. Bean broth is consumed by both adults and children, and a thick broth is preferred since it is considered to be more nutritious and better tasting. Children begin to consume bean broth as early as two months of age, and beans at 14 months. The average amount of broth ingested was 62 g, and whole cooked beans, 70 g. Mothers surveyed indicated that broth was administered to children because: it was nutritious (56% of the mothers); in order to teach children how to eat (15%); or because of its taste (9%). Regarding the hard-to-cook phenomenon, 32% of the housewives indicated that storage time was responsible for it, while 17% attributed this condition to bad seeds, and 18% to sun-drying or inadequate postharvest practices and to their preparation for consumption. Although the survey confirmed the importance that common beans have in rural diets, the main finding was that the first bean food product fed to children is the bean-cooking liquor or broth, which on the average contains 8.52% of total solids and 1.48% protein.

Cooking↗

[Genetic variability and correlation of yield, grain size, chemical composition and protein quality of 25 varieties of amaranth (Amaranthus caudatus)].

The purpose of the present research was to establish the variability in agronomic, chemical and nutritional characteristics among 25 amaranth (A. caudatus) cultivars. A large variability was found among cultivars in all the parameters evaluated. Average seed weight was 0.75 mg, and had an average size of 1.23 x 1.14 mm. The average moisture, protein and fat content was 11.81, 12.66 and 8.44%, respectively. The average values for methionine, threonine, cystine, leucine and lysine were: 168, 276, 74, 381 and 370 mg/g N, in the same order as presented. It was possible to establish significant, positive correlations between yield-protein, methionine-cystine, methionine-lysine, and threonine-leucine, as well as significant negative correlations between protein-cystine, fat-methionine and cystine- leucine. Furthermore, it is not possible to select cultivars of higher yield on the basis of seed weight, since these two variables were negatively correlated, although not statistically significant. Among all 25 cultivars studied, some were deficient in sulfur-containing amino acids, while based on the FAO/WHO essential amino acid pattern, all of them were deficient in leucine. The average protein quality value expressed as NPR was 3.54 in thermally-processed samples, with no differences between cultivars. Nevertheless, protein digestibility values probably classified the samples in two groups with average values of 79 and 81%, respectively. The variability found can thus be used to select cultivars with higher yields and higher nutritional characteristics.

Amino Acids↗

[Amaranth: a technological alternative in child nutrition].

The relative high protein and oil content of amaranth grain and its relative high-protein quality are desirable characteristics to use it as a weaning food. Such a product was prepared with A. caudatus grain. Batches were processed without previous treatment of the grain, washed with water or with a bicarbonate solution. Processing consisted of cooking at atmospheric pressure for 10 min before passing the partially cooked grain through a double drum-drier heated with steam at 70 psi, and at a velocity of 3 rpm. Batches were also processed with the addition of strawberry flavor. All samples were analyzed for damaged starch and fluid characteristics using a 10% concentration, viscosity (by the Brabender amylograph), water absorption and retention, particle size, stability of the suspension, and soluble sugars. The different samples were organoleptically evaluated for acceptability, consistency, astringency, sweetness flavor and aroma, with a 20-member panel. A product with water or with milk and sugar was also evaluated. The results indicated that washing the grain prior to cooking increased the consistency of the product and eliminated the astringency of the grain. Washing also increased water absorption and retention, soluble sugars and the coefficient of consistency. all samples exhibited 100% damaged starch and had a pseudoplastic behavior. The raw grain flour gave a viscosity of 500 UB, while for the processed samples this value increased to 1,420 UB. In general, its acceptability on the part of the panelists was high. It was good for the product with strawberry flavor, but it was even better for the sample without flavor which had been previously washed. These results, as well as others reported on nutritive value, confirm the hypothesis regarding the use of processed whole grain amaranth as a weaning food.

Amaranthus↗

[Effect of processing and amino acids supplementation on the protein quality of amaranth (Amaranthus caudatus)].

The present study was undertaken to evaluate the effect of thermic processing on the protein quality of amaranth (A. caudatus). It was also intended to establish the order of essential amino acid deficiencies suggested by the chemical score as limiting protein quality. The A. caudatus grain was cooked in water in the autoclave at 15 lb pressure during 0, 10, 20, 30, 40, 50 and 60 min. Once cooked, the samples were dehydrated with hot air at 60 degrees C and ground into flours. These were analyzed for: tannins, trypsin inhibitors, hemagglutinins (with cow, sheep, and human erythrocytes), damaged starch, available lysine, protein quality (by the NPR method), and true digestibility. Results indicated that the flours (0 to 60 min cooked) did not contain trypsin inhibitors and that their small tannin content, expressed as catechin, disappeared after 30 min of cooking. The quantities of these antiphysiological substances in the raw material are so small that they do not constitute a factor that may cause a decrease of the product's quality. A positive response was obtained for hemagglutinins, stronger with human erythrocytes, which disappeared with cow's and sheep's erythrocytes after 10 min of cooking and with human erythrocytes, after 20 min. As expected, cooking time increased the damaged starch and a slight increase was observed in available lysine, a finding which was impossible to explain satisfactorily. There were no important changes in true protein digestibility with respect to cooking time. Once again, results demonstrated the positive effect thermic treatment had on protein quality, suggesting the presence of antiphysiological active substances or a low nutrient bioavailability in raw samples. Longer cooking times did not alter substantially the protein quality (NPR and digestibility) and it was concluded that 10 min of cooking is an adequate time for the type of processing used. A sample of processed A. caudatus was utilized for the supplementation studies carried out with threonine, methionine, leucine, individually, or with the three amino acids together at 8.0, 9.5 and 1.0% protein in the diet. According to the results obtained, higher NPR values were observed with 9.0 and 9.5% protein content in the diet. No clear effects were detected when the amino acids were added, but there was an interaction between protein in the diet and amino acids. No effect occurred when leucine was added, suggesting that it is not a limiting amino acid. Possibly, threonine is a more limiting amino acid, but the effects were not as high, probably due to the level added to the diets.(ABSTRACT TRUNCATED AT 400 WORDS)

Amaranthus↗

The chemical composition and protein quality of amaranth grain germ plasm in Guatemala.

The present research was carried out for the purpose of collecting part of the germ plasm of grain amaranth in Guatemala, as well as to evaluate it in terms of yield, chemical composition and nutritive value. A total of 27 Guatemalan selections, one from Mexico and seven from Peru were planted in June 1982 in 7.5 m2 experimental plots replicated four times. The harvest seed was utilized for analysis of protein, ether extract, crude fiber, tannin content and trypsin inhibitors, as well as for NPR assays. A group of five pooled samples was made based on protein content for amino acid analyses; 10 samples were selected for a second NPR and protein digestibility assay. A preliminary assay on amino acid supplementation of raw grain flour is also reported. The selections were significantly different in grain yield. In general, selections which flowered at a short height and were harvested also at short height, tended to yield more seed. Findings revealed a negative relationship between plant height and grain yield, but a positive relationship between plant height and dry vegetable residue. Protein content of the grain averaged 15.0% with values ranging from 12.8 to 17.4%. Fat content varied from 5.6 to 10.6% with an average of 8.4%. Amaranth grain with a higher protein content contained greater amounts of amino acids on a weight basis, but when these were expressed on a nitrogen basis, differences disappeared. Based on the FAO/WHO amino acid reference pattern, grain amaranth protein was deficient in sulfur amino acids. Although the biological trial corroborated this deficiency, more studies should be undertaken. The NPR values of the samples from Peru averaged 2.30, the one from Mexico 2.04 and those from Guatemala, 2.36. Protein digestibility was 80, 82 and 74%, respectively. The data suggest that there is sufficient variability to select materials of a higher chemical composition, nutritive value, and yield.

Guatemala↗

Nutritional evaluation of roasted, flaked and popped A. caudatus.

A study was carried out with a selection of A. caudatus CAC-064, which was processed in three different forms: popped, flaked and roasted. The popped sample was prepared by subjecting the grains to a temperature between 175 and 195 degrees C for 15-25 seconds. The flaked sample was obtained by adjusting moisture content to 26% and using heated (200 degrees C) rotating drums for a contact time of 1-3 seconds, and roasting was achieved by heating the grain at 150 degrees C for a lapse of 60-90 seconds. All samples, including a raw sample, were analyzed for proximate chemical composition, minerals, available lysine and tryptophan content, as well as damaged starch, calories, soluble and insoluble fiber, and protein quality. Differences in chemical composition due to the processing applied were small and insignificant, except for lower available lysine values, and insoluble fiber with higher values in the roasted sample than in the flaked and popped samples. Likewise, the roasted sample had higher levels of damaged starch. Protein quality was highest in the popped sample (NPR 3.19), followed by the flaked (NPR 2.78), the roasted (NPR 2.24) and the raw (NPR 1.73) samples. These values were related to available lysine. Protein digestibility was lowest in the roasted material followed by the flaked and the popped products. It is concluded that establishment of optimum processing conditions is necessary in order to achieve maximum utilization of amaranth grain.

Amaranthus↗

[Nutritional quality of pigeon pea protein, immature and ripe, and its supplementary value for cereals].

The purpose of the present research was to determine the differences which could exist between immature and mature pigeon pea in gross chemical composition and protein quality, raw and cooked, as well as their respective supplementary value to rice, and to mature and immature corn and sorghum. The chemical composition data showed only small differences in proximate composition between the mature and immature grain. The cooking process did not affect chemical composition. Based on the FAO/WHO amino acid reference pattern, immature pigeon pea was more deficient in threonine than mature pigeon pea, which was limiting in valine. Both grains were limiting in sulfur amino acids. The protein quality of the immature grain was higher than that of the mature grain, and both responded positively to cooking, suggesting the presence of antiphysiological substances in both. Amino acid supplementation studies demonstrated that both the immature and mature grain responded to methionine addition, the first limiting amino acid, and to tryptophan, the second limiting amino acid. The effects were more marked when samples were cooked. Both types of grains were good supplements to rice, when added in amounts of 10-20%. Mature pigeon peas supplemented relatively well the proteins of sorghum, immature and mature corn, at the 20, 30 and 20% levels, respectively. The differences found could be explained on the basis of the amino acids limiting cereal grains and pigeon peas protein.

Amino Acids, Essential↗

[Chemical composition and evaluation of the protein quality of beans in adult humans by the short-term nitrogen balance method].

Three varieties of common beans were chemically analyzed and their protein quality was evaluated in 12 human male adult subjects by the short-term nitrogen balance method. Chemical analyses were performed for both raw and cooked grains. Cooking reduced the trypsin inhibitors in 28 to 73%, hemagglutinins, 100%, tannins as acid tannic equivalents, 9 to 72%, and 55 to 75% as catequin equivalents, and alkali-soluble nitrogen in 65%. Red and black beans contained more residual trypsin inhibitors and tannins than white beans, while the latter contained more alkali-soluble nitrogen. Although cooked colored beans had more antinutritional factors that affect protein digestibility, their protein quality was similar to that of white beans. This could be explained by the fact that the amino acid composition and/or balance of red and black beans absorbed nitrogen is better than that of white beans, so that the final nutritional value will be determined by the sum of interactions between all factors. In this study, each of the three varieties presented at least one protein quality depressor in higher concentration than the other two varieties. Therefore, the overall differences found between treatments and residual effect, were small or non existent, while significant differences (p greater than 0.05) were found between subjects and nitrogen balance periods. A level of 0.65 g of bean protein/kg/day was not enough to maintain nitrogen balance in subjects fed a diet where beans were the only protein source. According to calculations, 0.9-1.0 g of bean protein/kg/day are necessary for nitrogen balance in male adults, and 1.2-1.3 g of protein bean would be the recommendation for a normal population.

Adult↗

Studies on the development of infant foods from plant protein sources. Part I. Effect of germination of chickpea (Cicer arietinum) on the nutritive value and digestibility of proteins.

For the purpose of developing an infant food of improved dispersibility characteristics and high nutritive quality, different treatments and technologies were applied to chickpea (Cicer arietinum). Samples were germinated for two and four days at room temperature (25 - 27 degrees C). One portion of each germinated chickpea sample was boiled for 40 min and the other portion was autoclaved at 15 psi for 15 min. These processed samples were then compared with the corresponding value of raw germinated and ungerminated samples as well as with the ungerminated processed ones for the following characteristics: chemical composition, contents of antiphysiological factors, solubility of proteins, lysine availability, net protein ratio (NPR), and digestibility of proteins. Germination caused an increase in the protein content of the seeds. No appreciable changes were observed in the trypsin inhibitor and tannin contents during germination. Availability of lysine was found slightly lower in the germinated seeds. The solubility of the nitrogenous constituents was markedly increased during germination. Along with processing, germination had no beneficial effect in improving protein quality, although digestibility of the proteins was increased. Boiling was more advantageous in the case of germinated seeds than autoclaving, whereas the reverse was true in the case of ungerminated seeds.

Animals↗

[A new alternative for estimating recommendations of protein intake in humans. Protein requirements of an adult population fed with a diet based on rice and beans].

This paper proposes a new approach to estimate the protein needs of a population; recommendations are also made on the protein intake of adults fed diets based on rice and beans. For this purpose, the nitrogen balance data previously reported for 40 adult human subjects who had participated in 160 nitrogen balance periods fed diets based on rice and beans, with and without animal protein and/or energy supplementation were used. The proposed method is based on the curvilinear response between nitrogen intake and its nitrogen balance. The second degree equation describing the relationship between nitrogen balance and intake is calculated. Using the mathematical concept of the first and second derivatives, the point of inflexion is obtained, and interpreted as that condition wherein the individual utilizes with maximum efficacy the ingested nitrogen; nitrogen ingestion, which corresponds to that point, is therefore taken as the dietary nitrogen recommendation for the individual. When the values obtained by means of the quadratic equation are compared to those obtained by the traditional linear equation, values were found to be statistically equal (p less than 0.05) for both calculation methods. The recommended protein intake of an adult population fed a diet based on rice and beans was 0.80 and 0.77 g/kg/day for the quadratic approach, and for the conventional method, respectively. When this diet was supplemented with 10% milk protein and with the same energy level, the calculated values were 0.64 and 0.71 g protein/kg/day for both methods, in this same order. The essential amino acid intake and absorption values were also calculated from the protein levels recommended by both methods to be in nitrogen balance, from a diet based on rice and beans. Findings revealed, in all cases, that the intakes of each and all essential amino acids met those levels indicated by FAO/WHO, with the exception of isoleucine and the sulphur-containing amino acids, which apparently limit the quality of the diet.

Adult↗

[Biochemical and nutritional studies of germinated soybean seeds].

The purpose of this work was to determine the biochemical and nutritional changes of soybean seeds during germination. Soybean seeds were soaked for a period of eight hours and then germinated for 0, 1, 3 and 5 days. Part of them was subjected to an autoclave process. Then, both the raw and cooked seeds were dried, ground and analyzed. During the germination process an increase in the percentage content of protein and fiber in the seeds occurred; cooked seeds, in contrast, showed a slight decrease with respect to the former. Ether extract increased in percentage until the third day, and then decreased on the fifth. In the cooked seeds, higher values than in the raw seeds were obtained, due to the fact that when seeds were autoclaved, protein and carbohydrate losses occur. In regard to ash content, this diminished in percentage as germination advanced; the same happened to the free-protein extract. The raffinose and stachyose sugars, factors which cause flatulence, disappeared on the third germination day. As to nitrogen extraction, a greater percentage was obtained using distilled water as solvent, both for the raw and cooked seeds, than when using NaOH and NaCl. The trypsin inhibitors content increased on the first day of germination and then decreased. Ungerminated, autoclaved seeds, showed no trypsin inhibitors activity, whereas in the germinated cooked seeds, it increased slightly as germination days went by. Regarding protein efficiency ratio (PER), seeds with 0, 1 and 3 germination days presented no significant differences among them, the cooked seeds exhibiting higher values than the raw seeds. Apparent digestibility increased as the germination period advanced, having obtained better values when they were autoclaved. In the soybean milk acceptability test, no significant differences were observed between milk from ungerminated soybean seeds, and milk from the 3-day germinated seeds.

Animals↗

Studies on the development of infant foods from plant protein sources. Part II. Effect of processing conditions on the chemical and nutritive properties of chickpea (Cicer arietinum).

In order to improve the taste, flavor and nutritional quality of chickpea (Cicer arietinum), various processing conditions were studied. The decorticated samples were processed under various conditions, either by presoaking or non-soaking in water or sodium carbonate solution. The proteins were also isolated from water or carbonate-presoaked chickpea and subjected to various processing. Carbonate-presoaked samples gave slightly lower protein and ash values. No major changes in other constituents were observed. Subjective analysis of the intensity of characteristic chickpea flavor in processed samples was carried out, indicating some improvement in the carbonate-presoaked samples. Carbonate-treated samples exhibited a lighter color. The carbonate presoaking procedure had no adverse effect on the availability of lysine and nitrogen solubility index (NSI), as compared to the water-presoaking procedure. The time required to inactivate trypsin inhibitors in carbonate-presoaked chickpea at boiling temperature, was half that required in the case of water-presoaked ones. Under the conditions used in treating chickpea with sodium carbonate, no beneficial effect was observed in reducing the tannin content. No significant differences were observed in net protein ratio (NPR) among the various processed chickpea samples, even though in some cases isolated protein gave significantly lower NPR values. Digestibility values were higher for isolated protein than for whole chickpea samples.

Animals↗

Studies on the development of infant foods from plant protein sources. Part III. Preparation, processing and properties of various products developed.

Studies have been carried out on the development of a low-cost, high-quality infant food of low paste viscosity from rice, chickpea (Cicer arietinum) and cow's milk. In order to improve the overall quality of the product, chickpea was processed by different methods prior to its incorporation. A number of formulations was prepared by mixing 52% rice, 30% each, the processed chickpea sample, and 18% whole milk powder. These mixtures were processed by extrusion cooking or drum drying. In the case of the extrusion cooking method, from the nutritional and technological points of view, it was found advantageous to incorporate milk powder after cooking a mixture of rice and chickpea. The values of net protein ratio (NPR) of the products developed, whether processed by extrusion cooking or drum-drying methods, were statistically equal, and not significantly different from those of casein. Supplementing the product with methionine and threonine showed no effect in improving the NPR value, suggesting that these amino acids were not limiting. There were slight differences in the digestibilities of proteins in the products developed and all were lower than that of casein. Depending on the processing method, differences were observed in paste viscosities of the products. After partial hydrolysis of the products with pounds amylase, both the cold and hot paste viscosities were greatly reduced and were comparable with those of whole milk powder. From the results herein reported, it can be concluded that the drum-dried product prepared using rice:chickpea (carbonate presoaked):milk (52:30:18) is the best of all the products developed. Its amino acid composition compares favorably with that of the milk proteins.

Amino Acids↗

Effects of cone opening, initial moisture content and multiple extrusion on the protein quality of extruded soybean using the Brady Crop Cooker.

In the present study, three cone openings (0.133; 0.106, and 0.080 cm) and three initial moisture content values (9%, 15% and 21%) were used as treatments to evaluate their effects on the protein quality of full-fat soybean flour, extruded in the Brady Crop Cooker. The specific volume, protein and oil contents as well as available lysine content characteristic of the final product, were not affected by the treatments used. Processing temperatures, however, decreased when the initial moisture content of the material was increased. The nitrogen solubility index was affected by the cone opening but not by the moisture content of the material. With respect to the trypsin inhibitors content, the increase in the initial moisture content in soybeans gave conflicting results. At the 21% moisture treatment, the amounts of trypsin inhibitors were higher than those present in the raw material; a similar effect was also observed with urease activity. At the other two moisture contents (9 and 15%) the amounts of trypsin inhibitors and urease activity were decreased by heat treatment, mainly at the 9% moisture level, which were related to the cone opening of the extruder. PER values in rats were influenced by the moisture content and were not affected by the cone opening. Results obtained in the biological assays with chicks, both for weight gain and conversion efficiency, were favored by a decrease in cone opening. Nevertheless, the increase in the moisture content induced a decrease in weight gain at the 5- and 8-week periods, without affecting the conversion efficiency. The effect of consecutive passes of the material through the extruder was also studied. The product obtained with two extrusions presented a good biological value, probably as a consequence of the low values in the trypsin inhibitors and urease activities. When the material was extruded three times, results proved to be poor, due to a reduction to significant low levels of available lysine content--which becomes limiting--, and nitrogen solubility index of the full-fat soybean flour.

Animals↗

[Protein digestibility and energy in diets based on rice and beans in human adults].

Four studies were carried out for the purpose of measuring the digestibility of diets based on rice and beans (Phaseolus vulgaris), and in order to quantify the effect of their supplementation with animal protein (milk) and energy (oil), on the energy and protein digestibility of such diets in human adults. Diets were offered so that they supplied 46, 72, and 103 mg N/kg/day. When the basal diet--where rice provided 60% of the protein and beans 40%--was administered at a level of 102.5 mg of nitrogen/kg/day and 49.5 Kcal/kg/day of gross energy, an apparent and true nitrogen, energy and metabolizable energy digestibility of 59.1, 70.8, 93.8 and 92.5%, respectively, were observed. When substituting 10% of the vegetable protein by milk protein in the same diet, the same indicators revealed a digestibility of 65.3, 76.8, 93.5 and 92.1%, respectively. The information indicates that supplementation with animal protein improves nitrogen absorption at any of the energy levels studied. In contrast, caloric supplementation does not have any positive effect on nitrogen or energy absorption. It was also found that nitrogen apparent digestibility increases significantly when the N level in the diet is raised, and stabilizes when intake exceeds 100 mg nitrogen/kg/day. It is therefore proposed that for digestibility studies in diets where animal protein is utilized at a nitrogen level of around 120 mg/kg/day, true digestibility remains constant, no matter what nitrogen level is used in the diet.

Adult↗

[Relation between the digestibility and protein value of the common bean (Phaseolus vulgaris)].

The main nutritional limitations of common beans are the low digestibility of their protein and the deficiency of the latter in sulfur amino acids. Analysis of the information presented indicates that with 57 samples of different color (23 red, 21 black, 10 white and 3 brown), no relationship was found between protein digestibility and its quality as measured by NPR. Nevertheless, white beans have a higher protein digestibility than black, red and brown. The greater digestibility of white beans, however, does not increase the protein quality when mixed with cereal grains above that observed with black and red, probably because the protein that gives the higher digestibility is highly deficient in its sulfur amino acids content. These aspects require further research for programs aimed at increasing the nutritive value of food grain legumes.

Amino Acids, Sulfur↗