Oleic acid content is responsible for the reduction in blood pressure induced by olive oil.

Numerous studies have shown that high olive oil intake reduces blood pressure (BP). These positive effects of olive oil have frequently been ascribed to its minor components, such as alpha-tocopherol, polyphenols, and other phenolic compounds that are not present in other oils. However, in this study we demonstrate that the hypotensive effect of olive oil is caused by its high oleic acid (OA) content (approximately 70-80%). We propose that olive oil intake increases OA levels in membranes, which regulates membrane lipid structure (H(II) phase propensity) in such a way as to control G protein-mediated signaling, causing a reduction in BP. This effect is in part caused by its regulatory action on G protein-associated cascades that regulate adenylyl cyclase and phospholipase C. In turn, the OA analogues, elaidic and stearic acids, had no hypotensive activity, indicating that the molecular mechanisms that link membrane lipid structure and BP regulation are very specific. Similarly, soybean oil (with low OA content) did not reduce BP. This study demonstrates that olive oil induces its hypotensive effects through the action of OA.

[Physical and chemical characterization of industrial nixtamalized corn flour for human consumption in Central America]. / Caracterización física y química de harinas industriales nixtamalizadas de maíz de consumo humano en América Central.

The objective of this study was the characterization of industrial nixtamalized maize flour for human consumption and which are marketed in Central America for some selected physical and chemical properties which may contribute to food composition information and help nutrition and micronutrient fortification programs. A total of 12 brands purchased in triplicate were obtained from supermarkets in Guatemala, El Salvador and Honduras. These samples were kept under refrigeration until analyzed. The physical parameters measured and results were the following: particle size with most samples having a high percentage of particles greater than 60 mesh, pH (5.4-7.5), water absorption index (WAI) (3.4-4.0 g gel/g sample), water soluble index (WSI) (4.8-7.8 g/100 g) and flour density (0.410-0.547 g/ml). The differences were statistically significant for all parameters measured, except for WAI. The chemical characteristics included, moisture, protein, fat, ash and dietetic fiber. Differences between flour samples were statistically significant except for fat content. Protein content was low, ranging between 6.7-8.1 g/100 g and total dietary fiber varied between 7.7-12.0 g/100 g. The samples were analyzed for phytic acid with a variation from 632 to 903 mg/100 g, with statistical significant differences. The samples were also analyzed for total and soluble (pH 7.5) iron, phosphorus, calcium, potassium, zinc, copper, manganese, and magnesium. The difference in the iron and calcium content between flour samples were statistically significant. The physical and chemical variability found between flour samples of nixtamalized maize was relatively high and it is recommended to establish quality standards through raw material and process standardization for greater effectiveness of nutrition programs and activities on micronutrient fortification which may be pursued in the future.

[Vegetable food resources with agroindustrial potential from Guatemala. Manufacture of vegetable milk from the seed of morro fruit (Crescentia alata)]. / Recursos alimenticios vegetales con potencial de explotación agroindustrial de Guatemala. Elaboración de leche vegetal a partir de la semilla del fruto de morro (Crescentia alata).

The objective of the present study was to establish the conditions for the preparation of vegetable milk from the morro or jicara seed, and to characterize the products, the milk and the residue for their partial chemical composition and acceptability. From the ripe fruit, the seeds were obtained by maceration in water for 3.5 hrs, obtaining seed yields of 80%. This seed contained 38% fat and 26% protein on a dry weight basis. The harvested seed was then dehydrated to 9-12% moisture by exposure to solar energy. A similar lot was lightly roasted by heating on a hot surface for 10 min at 90-110 degrees C. The seed was used for the extraction of solubles or the vegetable milk. Water extraction with up to 10 minutes of mechanical blending gave low yields of soluble solids (4.66 +/- 0.10 to 4.98 +/- 0.07%) and low contents of fat, protein and ash in the extract with sun dried seed and significantly lower with the lightly roasted seed (3.0 +/- 0.05 to 3.4 +/- 0.03%). Due to the low yields of total soluble solids and to the low nutrient content by aqueous extraction, new extractants were used consisting of buffer solutions at pH 7.8, or 8.5 with and without saline solution at 0.5% concentration. With these solutions greater amounts of solids were extracted with a higher content of nutrients. The milk prepared from the sun dried seed and extracted with buffer at pH 8.5 and saline solution (0.5%) gave an extract with 9.85% of total solids, 3.37% protein, 4.44% fat. The extraction with roasted seed gave significantly lower yields. The residue of the extraction contained 21.47% fat and 14.72% protein. With the use of buffers and saline solution the extracts had better acceptability, with the milk produced from sun dried seed having better organoleptic characteristics in comparison with soy milk (5.84 vrs 3.76), however it was of lower acceptability when tested against cows milk (5.7 vrs 7.7). The isoelectric point of the extracted protein was between 4 4.45.

Comparative study of beans from vine and bush type of vegetative growth. Effect of storage on cell wall components as factors in increasing cooking time.

Four samples each of black beans representing two types of vegetative growth were collected from farmers' fields in four locations in Guatemala. Soon after collection, samples were stored at 4 degrees and 38 degrees C at ambient relative humidity and subsamples were withdrawn at 0, 45, 90 and 135 days of storage for determination of water absorption, cooking time and analysis of neutral- and acid detergent fiber, cellulose, hemicellulose and lignin. The fiber fraction analysis were done on samples of 0, 45 and 90 days of storage. Water absorption for all 4 samples of the bush type was similar at both storage T, however the samples stored at 38 degrees C and at 135 days absorbed more water than when stored at 4 degrees C. The 4 vine types of beans showed different water absorption rates, with two showing patterns similar to those beans of the bush type and two which did absorbed water at a very slow rate. For both types of beans stored at 4 degrees C, cooking time decreased from 0 to 135 days of storage. On the other hand for all bean samples of the two types cooking time increased when stored at 38 degrees C. Analysis of variance showed highly significant effects due to plant type, days of storage, temperature and locality, and for some interactions. Analysis of variance of the fiber fractions showed high significant differences for days of storage for NDF, ADF, cellulose, hemicellulose, and lignin. Plant type gave significant differences for cellulose and hemicellulose. Highly significant differences for hemicellulose were found for the interactions of type x days, type x temperature, locality x type, and type x days x temperature. The rate of synthesis of the 5 fractions were calculated by simple regression analysis. For the bush type of beans some synthesis occurred at 4 degrees C, but it was enhanced when stored at 38 degrees C. For vine type of beans at 4 degrees C relative high rates of synthesis were observed, which were higher at 38 degrees C for NDF, hemicellulose and lignin. Cooking time and fiber fraction contents were subjected to regression analysis. The correlations at 38 degrees C were higher than at 4 degrees C for all fractions for both types of beans, but statistical significance was obtained only for NDF, ADF and cellulose for vine type of beans. These data show therefore that synthesis of cell wall structure fractions, and not only lignin formation, are responsible for the increase in cooking time observed upon storage at high temperature.

Effects of altitude above sea level on the cooking time and nutritional value of common beans.

The present study was conducted with the objective to determine the effects of altitude above sea level, on the cooking time and nutritional value of common black beans (Phaseolus vulgaris). Three 100 g samples of the Ostua variety were cooked at 8 individual locations, ranging in altitude from 0 to 2256 meters, in Guatemala, to establish water uptake and cooking time. The cooked samples were separated into cooked beans and cooking broth for chemical analysis. This included moisture, protein, lysine, tannins, total and enzyme susceptible starch, and fiber fractionation. The cooking liquor was analyzed for total solids, moisture, protein, ash and K. A 1200 g sample was cooked for the cooking time established previously, for biological testing of nutritional value, which included Net Protein Ratio (NPR), Protein Efficiency Ratio (PER), and protein digestibility. Altitude influenced cooking time which increased from 78 min at 0 m, to 264 min at 2256 m. Final moisture content in the cooked bean was similar at all altitudes and there was a tendency to yield smaller amounts of solids in the cooking broth at higher altitudes. The increase in cooking time was significant. Bean water uptake at all times was significantly slower and smaller at ambient as compared to water uptake at boiling T, at all altitudes. Protein and lysine content were not affected by altitude, however, tannin and catechin were lower in cooked samples, as compared to the raw material. Altitude did not affect the content of these substances. Total starch and total sugars were higher in the raw sample, as compared to the cooked samples, but there was no effect of altitude. Enzyme susceptible starch (ESS) was lower in the raw sample as compared to the cooked samples, which contained similar amounts with respect to altitude. No change was observed in fiber fractions of the cooked beans. Likewise, the composition of the cooking broth was very similar between cooking locations. There was a small tendency to a lower protein quality, with respect to altitude, the effect of which was more obvious in the apparent protein digestibility values. Undercooking or overcooking at one location influenced protein quality values. The extended cooking time of beans at high altitudes, has important economic and environmental implications, since significant amounts of wood have to be used.

Evaluation of bush and vine black beans for physical, chemical and nutritional characteristics.

The present study was undertaken to learn if there are physical, chemical and nutritional differences between vine and bush type of beans. Four samples of black color beans (Phaseolus vulgaris) of the vine type, and four of the bush type were collected from farmers in the same growing area. The samples were analyzed for some physical properties including, 100 seed weight, size distribution percent seed coat, water absorption, cooking time, and of solids on cooking waters. Vine type beans had larger 100-seed weights, larger sized beans, thicker seed coats, and lower of solids in the cooking water than bush type beans. Rate of water absorption was different. The chemical characterization included proximate analysis and fiber fractionation. Vine type beans had, on the average, less ether extract and protein than bush type. No differences were found in fiber fractions, although there was a higher variability in the vine types. Protein quality and protein digestibility when fed as the single protein source, were similar on the average, with more variability in the vine types. Both types, efficiently supplemented maize proteins and the protein digestibility was higher than when fed alone. In general there were no large differences, except in some physical measurements, between vine and bush type beans, with the former showing greater nutritional variability which could be useful in selection programs, if such variability is confirmed.

Changes in dietary fiber content and its composition as affected by processing of black beans (Phaseolus vulgaris, Tamazulapa variety).

This paper presents the effect that the traditional cooking process of black beans (Phaseolus vulgaris, Tamazulapa variety) has on the quantity and composition of soluble (SDF) and insoluble (IDF) dietary fiber of beans, as well as on its protein digestibility and protein quality. There was an increase of IDF from 18.1% in cooked beans to 22.4% in fried beans, and a decrease in SDF from 8.4% to 6.6%, respectively. Starch content decreased from 34.5% to 31.3%. No change was found in lignin. The xylose content was higher in IDF than in SDF and decreased to some extent from cooked to fried beans. Arabinose content was similar in IDF and SDF with no change caused by processing. The fraction containing glucose, mannose and galactose in IDF was higher than in SDF, the content increasing in IDF and decreasing in SDF, with processing. Protein content in IDF was higher than in SDF, with no major change when processing. About 29.5% of the total protein of beans was bound in DF. Protein digestibility and protein quality decreased from cooked to fried beans and was positively related to IDF.

[Preparation of flour processed with pigeon pea seed]. / Elaboración de harinas procesadas de semilla de gandul.

Pigeon pea is a legume grain of good production capacity and of a relatively high nutritive value, which has not been used in Latin America on the basis of the potential it offers. In this study experiments were conducted to learn about the possibility of processing pigeon pea to yield an intermediate flour with good functional characteristics for food product development. The intermediate pigeon pea flour was produced through a selection of a process to efficiently dehull the grain followed by a thermic process to improve its functional properties and nutritive value. The best dehulling process was subjecting the grain to a vapor treatment for five minutes, followed by a 2-hour dehydration of surface moisture with air at 60 degrees and dehulling with an 8-disc dehuller for 10 minutes. Yield was 84% with 70.7% dehulling efficiency. Pigeon pea flours were prepared by three thermic processes: pressure cooking at 15 lb (121 degrees C) for 5 and 10 minutes as a reference product; cooking and drying with a drum dryer at 120 degrees C and 4 rpm and by extrusion-cooking with the material with 18 and 21% moisture at 270 and 300 degrees F, respectively. Process selection was based on the functional properties such as water absorption index, water solubility index, soluble nitrogen and viscosity, through chemical analysis of protein, available lysine and methionine and residual trypsin inhibitors, and through a biological evaluation of protein digestibility and quality. Both pressure cooking products had similar functional and chemical characteristics, however, the 5-minute cooked product has higher protein quality than the 10-minute product.(ABSTRACT TRUNCATED AT 250 WORDS)

[Possibility of using flour of pigeon pea in products prepared with rice or wheat flour]. / Estudios sobre la posibilidad de aplicación de la harina de gandul en productos elaborados a base de arroz o harina de trigo.

The present study reports on the development of foods containing processed pigeon pea (Cajanus cajan) flour. The pigeon pea flours described in a previous publication were prepared from dehulled pigeon peas by cooking in autoclave, by extrusion-cooking and by cooking/dehydration by drum-drying. Mixtures of cooked pigeon peas and rice were first evaluated biological through a protein complementation design using NPR. The results of this study showed that the two products had high protein quality and were similar when mixed in ratios of 80:20 to 40:60. For the evaluation of the processed pigeon pea flour, mixtures with rice (80:20) were used. All pigeon pea flours gave similar protein quality values. On the basis of these results three products were developed and tested. One was a gruel ("atole"), a second a fruit-flavored thick drink with and without 15% milk. Cookies were also prepared with a series of blends of pigeon pea flour (extrusion-cooked) and wheat. The gruel and the fruit flavored products had high acceptability based on a sensory evaluation test. Cookies with 100% pigeon pea flour were unacceptable, however, mixtures of 75% wheat flour and 25% pigeon pea flour gave cookies of attractive appearance and good taste. The study showed the possibility of preparing and utilizing tropical grain legume flours for food products of relatively high acceptability and nutritive value.

[Comparative study of the chemical composition and nutritive value of runner bean (Phaseolus coccineus) and of common bean (Phaseolus vulgaris)]. / Estudio comparativo de la composición química y valor nutritivo del piloy (Phaseolus coccineus) y del frijol común (Phaseolus vulgaris).

Scarlet beans (Phaseolus coccineus) is an important food grain legume in the diet of rural populations living in the highlands of México, Guatemala and other countries of Latin America. The present study was conducted to obtain more chemical and nutritive data on this grain legume, because of its importance in agricultural production systems and due to the role it plays in rural diets. Ten samples were purchased in the highland markets of Guatemala, to compare their physical, chemical and nutritive characteristics with three samples of common beans (Phaseolus vulgaris). A sample of 10 kg was used for nutritional studies, fed alone and in mixtures with maize. The results indicated that P. coccineus has greater weight as compared to P. vulgaris (0.74 vs. 0.18 g) and are larger in size (0.60 vs. 0.14 cc/grain). Seed coat percentage was 10.2% for P. coccineus as compared to 9.0% for P. vulgaris. The cooking time was 231 minutes for P. coccineus and 180 minutes for common beans. Seed coat thickness and permeability are different when comparing P. coccineus with P. vulgaris, since at 24 hr soaking time, P. coccineus absorbed 80% of its water weight as compared to 100% for common beans. In chemical composition) small differences were found between P. coccineus and P. vulgaris. The first had slightly more ether extract, crude fiber and ash content than the second. Amino acid content among the six samples of P. coccineus was quite variable, but its pattern was rich in lysine and limiting in sulfur amino acids. Cooking time at 3 hr gave a higher NPR than when cooked at atmospheric pressure for 5 hr, with protein values relative to casein of 69.2 and 60.0%, respectively. P. coccineus protein quality was improved by methionine supplementation, and it appeared to be better digested than that of P. vulgaris. Mixtures of high protein quality were obtained with 15% P. coccineus and 85% maize while common beans and maize mixed in a 30 to 20 ratio showed maximum protein efficiency. The digestibility of the P. coccineus/maize mixtures was higher than that of common beans and maize.

[Evaluation of two methods to determine the polyphenol content in raw and cooked beans and its effect on protein digestibility]. / Evaluación de dos métodos para establecer el contenido de polifenoles en frijol crudo y cocido, y efecto que éstos provocan en la digestibilidad de la proteína.

The polyphenolic compounds present in raw and cooked, and dried, with and without the cooking broth of common white, black and red beans (Phaseolus vulgaris) were measured by the Folin-Denis method for total polyphenols, and by the protein precipitation method of Hagerman-Butler, which measures their biological activity. The polyphenol content was measured during 20 consecutive days on the same sample, using three different extracts of volume from each sample. Statistical analysis of the results by the Folin-Denis method indicated that variability among the three aliquots was different for each bean color. A non-parametric analysis, however, indicated that the average in the three levels of concentration for beans of all colors, was the same. A similar analysis of the results by the Hagerman-Butler method demonstrated that variability and average values for the three aliquots were equal for black and red beans but not for white beans. The coefficient of variation was lower for the higher aliquot of the extract. A significant correlation (r = 0.72, P less than 0.05, n = 60) was found between the two methods for all beans using the larger aliquot of the extract. The correlation was highly significant (r = 0.84, P less than 0.05) when white bean values were eliminated. The polyphenolic content varied with seed color and the thermic process reduced their content, as measured by the two methods. The losses in polyphenolics as measured by the Folin-Denis in the cooked beans dried with broth, varied from 31.4 to 36.3%, and from 39.8 to 51.1% for the cooked bean flour dried without broth. The losses by the Hagerman-Butler method were from 25.0 to 93.5% in the cooked bean flours dried with cooking broth, and from 33.3 to 95.7% when dried without the broth. The higher losses were recorded for red beans. In vivo digestibility for cooked bean flours, dried and without broth, were 73.2, 69.6 and 64.5%, and 71.9, 71.9 and 68.8% for white, red and black beans, respectively. A negative correlation (r = -0.39) and significant (p less than 0.05) was found between polyphenolic content in the diet and in vivo protein digestibility.

[Effect of reheating on iron availability and the protein nutritive value of cooked black bean (Phaseolus vulgaris)]. / Efecto del recalentamiento sobre la disponibilidad de hierro y el valor nutritivo de la proteína del frijol negro (Phaseolus vulgaris) cocido.

In Guatemala, at the rural level, beans are prepared for family consumption every two days. Beans are cooked again every 12 hours for 15 minutes prior to their consumption. Due to the adverse effect that the process causes on nutritive value, the present study evaluated the method and preparation practice of beans on protein value; tannin and soluble and ionizable iron content. As to the effect of re-cooking on protein level, findings revealed that there were no significant statistical effects on net protein ratio (NPR) or in protein efficiency ratio (PER) and number of bean cooking. Nevertheless, a constant effect in quality in the first and second cooking procedure was detected. The second cooking gave a similar value as the first. Also, the first and second heating reduced protein digestibility, but the third gave a value similar to the initial one. No changes were observed in the digestibility of dry matter. Relatively high amounts of protein were found in the cooking broth, which was not affected by the number of heating. It was also found that the bean broth contained high levels of tannins in the initial heating, decreasing later significantly. The same was observed in the cooked beans alone and in beans with their broth. With respect to iron, findings showed a relatively high transference of beans to broth, in total iron as well as in soluble, ionizable and insoluble iron. No changes were observed in whole beans without broth caused by number of heatings, on total, soluble or ionizable iron. In beans with their broth, a similar effect was observed, although a slight increase in insoluble iron was detected at the end of heating. A decrease in soluble and insoluble iron was observed in broth with number of heatings. Correlations were calculated among the parameters studied, which suggested an effect of tannins on the bioavailability of iron caused by tannins.

[Bioavailability of amino acids in beans (Phaseolus vulgaris)]. / Biodisponibilidad de aminoácidos en el frijol (Phaseolus vulgaris).

Biological availability of amino acids of three common bean (Phaseolus vulgaris) varieties was evaluated in four, healthy adult subjects, consuming bean-based diets by the amino acid absorption technique and the short-term nitrogen balance method. The amino acid composition was determined according to the ionic interchange method, and tryptophan was estimated by a colorimetric procedure. The essential amino acid (EAA) and non-essential amino acid (NEAA) pattern suggests that no significant differences in content exists in the three bean varieties. When the EAA patterns were compared with those of FAO/WHO, the limiting AA in decreasing order were found to be: tryptophan, valine and threonine (sulfur AA are not considered because the hydrolysis used in this study destroys them); and the AA surpassing the reference pattern were the aromatic AA and isoleucine. Apparent (AD) and true (TD) digestibilities of the EAA fluctuated between 33 and 59% and 60 and 85%, respectively, for black beans. With red beans, these results diminished: 29 and 55% AD and 64 and 81% TD, while for white beans the limits extended: 18 and 57% AD and 36 and 86% TD. Valine proved to be the EAA of lower biological availability, and lysine and phenylalanine the most available. It is suggested that the low digestibility of valine could be due to the amino acid imbalance existing in the bean protein, since this contains an excess of isoleucine and leucine in relation to valine. The AD and TD of the AAE with respect to the NEAA were of 0.89 and 0.98 for black bean, 0.89 and 0.96 for the red and 0.77 and 0.90 for the white, which indicates that biological availability of the NEAA is higher than that of the EAA. Findings thus confirm that biological determination of the TD of protein permits prediction of the TD of the AA, since a positive correlation (r = 0.93) statistically significant was found (p less than 0.05) among them. Utilization of the TD parameter instead of that of AD to estimate the protein quality is therefore recommended.

[Dietary fiber content and nitrogen digestibility in Central American foods: Guatemala]. / Contenido de fibra dietética y digestibilidad del nitrógeno en alimentos centroamericanos: Guatemala.

The study herein reported presents information on the dietary fiber content of four food groups consumed in Central America. These are: cereals, grains and products; raw and processed beans; raw and processed vegetables, and starchy foods such as potatoes, cassava and plantain. Besides data on soluble and insoluble fiber, data on in vitro protein digestibility are included. The total dietary fiber content of the wheat flour products varied from 1.62 to 2.83% on a fresh basis, with the exception of whole-wheat bread, which showed a 7.57% content. The maize tortilla presented values ranging from 3.96 to 5.21% in respect to beans, and the values for cooked and raw beans fluctuated between 6.36 and 7.00%, independent of the color; however, fried beans reported values from 15.28 to 17.58%. Vegetables contained total dietary fiber values of 1.51 to 4.34, and the tubers, from 1.31 to 2.86%.

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

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 degrees C, and roasting conducted for 15 minutes. A significant improvement in the protein quality of processed Canavalia was obtained by methionine supplementation.

[Bean grain quality]. / Revisión sobre la calidad del grano de frijol.

As the title states, the present document is a review of the factors which may influence the bean grain quality. This quality is determined by factors such as acceptability by the consumer, cooking characteristics and by its nutritive value. At the same time, these factors are affected by the genetic constitution of the grain as well as by the environmental conditions of production. Therefore, the improvement obtained on the bean-grain quality will be measured through the interaction established among the different disciplines, such as geneticists, agronomists and scientists in food science and nutrition. The above-mentioned factors are influenced by the events that occur in the different links of the food chain. This article analyzes the effect of processing on the nutritive quality of the grain and, likewise, a brief review of the hard-to-cook problem which affects the acceptability of the grain by the consumer is made. It also considers the low protein digestibility problem and the effects that have been associated to tannin content, as well as the carbohydrate utilization. Finally, some recommendations are suggested to improve the nutritional quality of beans, which is the most important protein source for large segments of the worldwide population.

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

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.

[Intake of dietary fiber in the Central American isthmus: nutritional implications]. / Ingestión de fibra dietética en los países del istmo Centroamericano: implicaciones nutricionales.

Mean intakes of dietary fiber (DF) were estimated in the population of Central America and Panama, using the results of dietary surveys conducted in 1969 and 1986 both in rural and urban areas, as well as data on the DF content of foods as consumed in the region. Data on preschool children were also estimated. The results indicated that DF intake in urban areas is lower than that of rural areas, particularly in Costa Rica and Panama. In 1969, intake varied from 32g in El Salvador to 15g in Panama in urban areas, while in rural areas intake was from 45g in El Salvador to 13g in Panama. The foods which contributed most to the total intake in Guatemala, El Salvador and Honduras were tortillas and beans, while in Costa Rica and Panama, beans provided the largest intake. In preeschool children, intake was 12.5g in El Salvador and 5.4g in Costa Rica in 1969, which is the same tendency as that found for adults. From more recent data on food intake, it was found that DF intake had decreased in the rural areas of El Salvador, Honduras and Costa Rica, being between 4 and 9% in the first two countries and 12% in Costa Rica. In the urban area of the latter, from 1969 to 1986 a decrease in DF intake of around 20% has taken place.

[Effect of the seed coat on the hardening of common beans (Phaseolus vulgaris)]. / Efecto de la cáscara sobre el mecanismo de endurecimiento del frijol común (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.

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.