Ricardo Bressani

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

A comparison of in vivo and in vitro estimates of protein digestibility of native and thermally processed vegetable proteins

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.

Protein quality evaluation of amaranth in adult humans.

Research was performed to determine the suitability of the rapid multienzymatic assay for in vitro protein digestibility estimation by using a group of native and thermally processed vegetable proteins which constitute the staple foods in developing countries. The in vitro digestibility was assessed by measuring the extent to which the pH of the protein suspension dropped when treated with a multienzyme system consisting of trypsin, chymotrypsin, and peptidase for 10 min, andStreptomyces griseus protease for 10 min more. The best correlation occurred between in vivo rat protein digestibility and the pH of the protein suspension after 15 min enzymatic treatment. The response of different types of proteins to the multienzyme assay was different, and thus distinct equations were derived for the in vitro digestibility estimation of the samples assayed. The first group included nonprocessed cereal grains and oilseeds, and cereal grain-leguminous seed mixtures. The second group was formed by leguminous seeds, and the third by thermally processed cereal and oilseed products. Although highly significant correlations between in vivo and in vitro estimates for the three groups were found, important differences occurred in the group of processed samples; therefore, more research is required with these types of samples.

Effects of dietary fiber and tannins on protein utilization in dry beans (Phaseolus vulgaris)

This study was carried out to determine the nutritional quality of the protein of amaranth grain submitted to extrusion and popping processes, using cheese protein as reference. For the biological evaluation, the short-term nitrogen balance index method was followed with 12 experimental adult male human subjects. A Latin square series 3×3 was used (three periods, three subjects) as an experimental design balanced to minimize residual effects by randomly ordering treatments, columns and rows. The study consisted of three periods of nine days each.The first period started by feeding all subjects a low nitrogen diet, followed by increases of the protein level every two days. The levels were 0.2, 0.4, 0.6/g protein/kg/day, keeping other nutritional elements constant and adequated, including calories, minerals and vitamins. All subjects received all their meals using as a sole source of protein extruded amaranth, popped amaranth or processed cheese. Water intake was kept at a rate of 0.8–1.0 ml per calories consumed. During the study, the subjects maintained regular physical activity.Amaranthus cruentus was utilized. The extruded amaranth was prepared with the Brady Crop Cooker under conditions previously established in other studies. The popped amaranth was prepared at a 250°C temperature during 15–20 sec.The extruded and popped amaranths were provided as a sweet puree and, as all the other foods conforming the diets of each subject, they were weighed with 0.1 g of accuracy. Diet samples, as well as faeces and urine, were collected daily, which were ordered according to period and level of protein, conforming pools to determine their nitrogen content by the Kjeldahl method. True digestibility results of the protein were 101.4, 89.8 and 85.5% for cheese, extruded amaranth and popped amaranth, respectively. The statistical analysis according to the Tukey test showed that the true digestibility of the protein was the same for the two products of amaranth and different than the digestibility of cheese. Nitrogen balance index values from the equation between nitrogen intake and nitrogen retained, were 0.97, 0.86 and 0.79 for cheese, extruded amaranth and popped amaranth, respectively. The respective values between nitrogen absorbed and nitrogen retained were 0.97, 0.98 and 0.96. The Tukey test indicated that for NI to NR cheese was statistically different for the two amaranth products, which were similar between them. For the relationship NA to NR all values were statistically the same. The calculation of nitrogen intake for nitrogen equilibrium indicated that the amaranth protein is among the highest in nutritive quality of vegetable origin and close to those of animal origin products.

Relationship between content and intake of bean polyphenolics and protein digestibility in humans

Abstract The nutritional value of dry bean ( Phaseolus vulgaris ) protein is typically lower than that of cereal and animal proteins, but the factors responsible for the low nutritional value of bean protein have not been clearly identified. In this study, the ability of dietary fiber and tannins to lower protein utilization in dry beans was investigated using weanling rats. The rats were fed eight experimental diets containing varying amounts of bean dietary fiber and tannins. Both protein digestibility and net protein ratio (NPR) were determined as measures of protein nutritional value. Soluble dietary fiber significantly increased fecal nitrogen losses ( P ≤ 0.001) and reduced protein digestibility ( P ≤ 0.001), while insoluble dietary fiber and tannins had no effect on either fecal nitrogen loss or protein digestibility. However, neither soluble nor insoluble dietary fiber had a significant effect on NPR, but tannins significantly reduced NPR values ( P ≤ 0.01). Both dietary fiber and tannins appear to contribute to the low nutritional value that is typical of bean protein, with soluble dietary fiber being primarily responsible for the reduction in protein digestibility that is commonly associated with dietary fiber in foods.

Effect of processing on the nutritive value of Canavalia Jackbeans (Canavalia ensiformis (L))

The purpose of this study was to determine the effect of bean polyphenolics on bean protein digestibility in humans. Steam pressure cooking decreased tannic acid in beans by: 38.2 (white), 23.9 (red), 38.5 (white:black mixture, 50:50), 20.5 (Ipala black) and 44.4% (Jalpatagua black). The reduction in catechin was: 57.5, 97.6, 83.0, 78.7 and 88.4%, respectively. The content of tannic acid in dried cooked beans was: 284.9 in white, 834.5 in red, 620.2 in the white:black mixture, 1,021 in Ipala black and 1,009 mg/100 g in the Jalpatagua black bean. These percentages correlate significantly with fecal nitrogen (r=0.29, p<0.05). Catechin of the dried cooked beans was 7.5 in white, 27.4 in red, 25.4 in the white:black mixture (50:50), and 60.1 and 55.5 mg/100 g in each of the black cultivars, and correlated significantly with fecal nitrogen (r=0.34, p<0.01), absorbed nitrogen (r=−0.37, p<0.01) and protein digestibility (r=−0.35, p<0.01). It was concluded that one of the factors that reduces bean protein digestibility is the polyphenlic compound.

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

A comparative study of roasting, cooking with and without calcium hydroxide and extrusion cooking on the protein quality of Canavalia was conducted. The results suggested both extrusion and pressure cooking with lime to be equally effective in improving the protein quality of Canavalia and superior to pressure cooking alone and roasting, the latter effective possibly in destroying the antiphysiological factors in Canavalia but possibly also damaging its protein quality.The individual effects of roasting, cooking with different levels of calcium hydroxide, and with water under pressure at different times on the protein quality of Canavalia were also studied. These indicated a beneficial effect of calcium hydroxide added at a level of 0.45% by weight of seed, for 30 minutes under pressure. Cooking in water under pressure for 30 minutes with and without lime added was slightly better than cooking for longer periods of time. Roasting was also effective in improving the quality of Canavalia particularly when the T was adjusted at 170°C, and roasting conducted for 15 minutes. A significant improvement in the protein quality of processed Canavalia was obtained by methionine supplementation.

Research needs to up-grade the nutritional quality of common beans (Phaseolus vulgaris)

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.