Luiz G. Elias

Reduction of Digestibility of Legume Proteins by Tannins

AbstractThe protein of certain legumes is known to be poorly digested. In this paper the effect of polyphenolic compounds present in the scedcoat of coloured varieties of common bean (Phaseolus vul...

Processed Vegetable Protein Mixtures for Human Consumption in Developing Countries

Publisher Summary Perhaps half of the worlds population is suffering from malnutrition. The most serious aspect of the problem, by far is protein deficiency. Thus, protein malnutrition remains a basic world-wide problem. There is no doubt that important advances have been made during the last 15 years in utilizing vegetable-protein sources in the fight against protein shortage. Probably the most important advance made is that vegetable proteins, properly processed and efficiently combined with one another, can replace animal-protein foods in the nutrition of man and expand the availability of dietary protein, now so scarce. Valuable advances have been made, but there are still complex problems to be solved. These range from a need for more specific and detailed information on the major proteins of seeds, their chemistry, and properties, to problems related to the actual use by people of the products being developed and tested. In between these extremes, of the basic and the applied, lies a whole range of problems dealing with the development of technologies to concentrate protein, and with new and more efficient methods of preserving nutritive value. This involves better control of heat damage; the elimination of interfering substances, toxic compounds, and fiber; the improvement of amino acid patterns; and the creation of physical textures and forms, which can be incorporated economically into accepted foods. Solution of the many remaining problems can come only from increased participation in this important and urgently needed area of endeavor, by scientists specialized in protein chemistry, biochemistry, nutrition, food science and technology, and by physicians, educators, industrialists, and economists. It is only through the efforts of all that the fight against protein-calorie malnutrition will be won, and the future masses of people living on earth will receive the protein, as well as other essential nutrients needed for a healthier, peaceful, and happy world.

Effect of salt solutions on the cooking time, nutritional and sensory characteristics of common beans (Phaseolus vulgaris)

Abstract The effect of using salt solutions to soak fresh and hard-to-cook beans on cooking time and protein quality (protein efficiency ratio and digestibility) was evaluated. A sensory analysis was also carried out after soaking and cooking. It was found that by increasing the ratio of monovalent (Na+ and K+) to divalent ions (Ca2+ and Mg2+) in the salt solutions, cooking time of both fresh and hard-to-cook beans decreased significantly (p ≤ 0·05). Protein quality was lowered significantly at lower (0·30) and higher (9·80) monovalent to divalent ion ratios. Although cooked bean flavour was slightly affected by the salt treatment, taste was improved by discarding the salt solutions after soaking and cooking with water. Cost analyses showed an energy saving of more than US

Effect of fertilizer application on the yield, protein and fat content, and protein quality of raw and cooked grain of three amaranth species

0·19 per kg of beans during cooking with a ratio of 8·30 of monovalent to divalent ions of salt solution. Data obtained indicated the feasibility of implementing this process at industrial or population levels in order to decrease cooking time of both fresh and hardened beans. The most effective soaking solution evaluated had a salt composition of 0·5% NaHCO3 and 2·5% K2CO3 (w/v) (a ratio of 8·30 of monovalent to divalent ions). Therefore, the recommended cooking method is to soak beans with this salt solution, discard the soaking solution and cook with fresh water.

Limiting amino acids in raw and processed amaranth grain protein from biological tests

Four selections of three amaranth species were used in the study:A. cruentus (US Rodale 82S-1034),A. hypochondriacus (US Rodale 81S-1024).A. caudatus (Cusco, Peru CAC-2002) andA. cruentus (GUA-17). These were fertilized with levels of 0, 30, 60 and 90 kg/ha of a 12-24-12 fertilizer formulation applied to experimental plots 3×4m2 in four replications. The harvested grain was used for protein and fat analysis, and for protein quality evaluations on raw and on heat processed samples.A. cruentus (US) andA. hypochondriacus flowered at 43–44 days at 60 and 43cm, respectively,A. caudatus (Peru) at 51 days and 65cm, andA. cruentus (Gua) at 50 days and 80cm height. Days at harvest varied from 100 to 129 days at heights of 125 to 180cm. Yield of grain fromA. hypochondriacus (US) andA. cruentus (Gua) was higher than forA. cruentus (US) andA. caudatus, but did not differ for each pair. although not influencing yield, the application of fertilizer increased protein content forA. caudatus (Peru) from 12.35 to 14.50%; but not the protein content of the other selections. The fat content was affected differently in all four selections. The application of fertilizer did not affect protein quality either in raw or processed grain. On the other hand, processing increased protein quality, food intake, and animal performance significantly most clearly seen withA. cruentus (US) andA. caudatus (Peru) and to a lesser extent forA. hypochondriacus (US) andA. cruentus (Gua)). The data obtained showed inconsistent effects on yield and chemical composition, and no effect on protein quality with fertilizer application.

Improvement of the protein quality of corn with soybean protein.

Amino acid supplementation studies with young rats were carried out using raw and processed amaranth grain (A. cruentus) of dark- and cream- or light-colored seeds. The results of various studies repeatedly indicated that threonine is the most limiting amino acid in raw and processed, dark and cream-colored grain. Protein quality as measured either as NPR or PER was improved by threonine addition alone or with other amino acids and decreased liver fat to values similar to those measured with casein. This finding contradicts the reports that state that leucine, determined by chemical score, is the most limiting amino acid. Leucine addition alone or with other amino acids did not improve protein quality. The study confirmed cream-colored grain to be nutritionally superior to dark grain and that properly processed grain, light- or dark-colored, has higher protein quality than raw grain.

Long-term rat feeding studies with vegetable protein mixtures containing cottonseed flour produced by different methods.

In most Central American countries, lime-treated corn provides 31% of the total protein and 45% of the energy intake, and beans 24% of the protein and 12% of the calories. Such diet is low in protein quality and quantity, as well as in energy. To overcome these deficiencies, corn can be supplemented either with its limiting amino acids, lysine and tryptophan, or better still, with whole soybeans which improve not only the amount and quality of the protein consumed but, because of their high oil content, the energy intake as well. In addition, animal experiments have shown that for maximum utilization of these nutrients, adequate vitamin and mineral intake is indispensable. At a level of 15 parts of whole soybean or 8 parts soybean-derived products, to 85--92 parts of corn there were no significant changes in the rheological or organoleptic characteristics of the tortilla prepared there of. Higher levels of soybean products, however, may affect the consistency of the lime-treated corn dough and, therefore, the tortilla acceptability. Since corn is usually cooked, but not ground, at home, the soybean supplement can be successfully added at the wet--milling stage of dough preparation or whole soybeans and corn may be cooked together, when a nutritional intervention is desired at the village level. At an industrial scale, if whole soybeans are used, they may be cooked together with corn, and if soy flour is used, this can be mixed at the end of the process when the cooked corn is ground to a flour. A flow diagram for supplementing corn with 15% whole soybeans is presented. If interventions of this nature are to be successful, there is need for increasing the prestige of corn-based food, as well as of nutrition education programs in these populations.

The nutritive value of the Brazil nut oil

well-known limitation to the use of cottonseed flour in nutrition is the presence of small amounts of the A pigment gossypol (Altschul et ul., 1958; Braham et d., 1965; Bressani et al., 1964; Danke et ul., 1965), which is toxic in varying degrees to all monogastric animals. The swine is probably the animal least resistant to dietary gossypol, while higher levels also affect rats. chicks, dogs, and other animals (Altschul er ul.. 1958). As with many other toxic substances that are ingested daily in small amounts, gossypol accumulation may reach a level in important tissues sufficient to initiate the appearance of signs of toxicity culminating in a relatively prompt death (Clawson and Smith, 1966; Sharma et a/.. 1966). Most studies with gossypol-containing cottonseed flours have been carried out for relatively short periods. It was, therefore, of practical interest to conduct long-term feeding experiments with rats for the purpose of determining if any deleterious effects were due to the constant intake of gossypol in cottonseed flour. The results of such a study are also important in human nutrition, in view of the fact that, recently, cottonseed Hour is being used in human food supplements (Bressani et a/ . , 1966).

The nutritional value of diets based on starchy foods and common beans

The chemical composition of the decorticated Brazil nut in the natural and fat-free state was determined, and the results confirm that this seed contains significant amounts of oil and protein. In three growth experiments carried out in rats, the Brazil nut oil had a nutritive value comparable to that of butterfat and the common table oils, olive oil, cottonseed oil, and corn oil. The use of levels of the Brazil nut oil up to 20% of the diet did not reduce growth or food consumption of rats. Heat treatment of the oil up to 120 min. at 140°C. did not reduce its nutritive value. The coefficient of digestibility of the Brazil nut oil was similar to that of the other oils, fresh and heated. The digestibility of the Brazil nut oil averaged 98% and was not affected by the heat treatment. The data indicate that Brazil nut oil is comparable to other animal and vegetable fats and oils in common use for human consumption.

Chemical composition, amino acid content and protein quality of Canavalia spp. seeds

Feeding trials were carried out to determine the minimum amount of common beans, with and without methionine supplementation, needed to obtain positive weight gains of rats fed cassava, sweet potato, plantain and potato flours. The protein content of these materials was 1.4, 3.8, 3.1 and 9.5% on a dry weight basis as compared to 22.8% in common beans. The amount of beans added varied from 0 to 40.0% without and with 0.3% methionine. Without methionine addition, the amount of beans required to maintain body weight was 24.8% for plantain, 19.3% for cornstarch, 20.0% for cassava and 40.1% for sweet potatoes. With just potato flour in the diet, the animals gained weight. With methionine addition, the amount of beans required for body weight maintenance was: 20.1% for plantain, 10.1% for cornstarch, 14.5% for cassava, 14.6% for potato and 29.3% for sweet potatoes. Mixtures of potatoes with as little as 10% beans with methionine gave excellent protein quality values. The results confirm previous findings on sulfur amino acid contents of beans. It is of interest to point out that factors other than a low level of protein in the starchy food tested are influencing the level of beans needed in the presence or absence of methionine supplementation.