INCAP studies of vegetable proteins for human consumption.

This article describes the efforts of the Institute of Nutrition of Central America and Panama (INCAP) to develop a relatively low-cost vegetable protein mixture suitable as a complementary food for infants and young children. As it turned out, the resulting product became popular with older children and adults, and its superior nutritional benefits were widely recognized by the population. This effort led to broader studies by INCAP of the nutritional quality of vegetable protein mixtures, including raw materials, processing to convert them into human-grade products, product formulation, and commercialization.

Effect of lime and wood ash on the nixtamalization of maize and tortilla chemical and nutritional characteristics.

The objective of the study was to obtain information on the chemical composition, functional properties, sensory quality and protein value of tortillas made from the nixtamalization of maize using either lime or wood ashes. The Ca, K, Mg, Fe, and Zn content of lime and wood ashes showed lime to be high in Ca content while wood ash contained more K and about 71% of the Ca content of lime. Both contained relatively high levels of Mg, Fe and Zn, but more so in the wood ashes. The level of reagent for nixtamalization was set at 0.8% of the maize weight. All other processing conditions were kept constant. The pH of the cooking solution was 12.0 for lime and 10.9 for wood ash. The moisture content of maize at 60 min of cooking was 45.8% for both treatments, however after 12 h of soaking, moisture level was 51.0% for the lime treatment and only 46.8% for the ash treatment. Solids (2.4%) in the lime cooking liquor were higher than in the wood ash liquor (1.0%). Chemical composition changes were similar between treatments in masa and tortilla; however, both masa and tortillas absorbed relatively high levels of all minerals including Fe and Zn from the wood ash treatment. The different treatment influenced functional properties particularly hardness and color. Tortilla characteristics were also similar. Protein quality of both alkali cooked products was lower than that of raw corn, more so the product from the wood ash treatment. Although some differences were observed in the sensory studies, human subjects did not dislike the wood ash made tortillas.

[The oil, fatty acid and squalene content of varieties of raw and processed amaranth grain]. / Contenido de aceite, ácidos grasos y escualeno en variedades crudas y procesadas de grano de amaranto.

The oil, fatty acid and squalene content of varieties of raw and processed grain amaranth. Six amaranth grain varieties were processed to yield a nixtamalized flour, one cooked in water, one expanded, a malted one and a laminate samples after a thermic treatment. The chemical values of the raw samples contained from 14.5% to 15.1% protein, 5.9 to 6.7% ether extract and from 2.3% to 3.2% ash on a dry weight basis. The flours from the different processes yield products with a fat content which varied from 6.4% to 7.0% for the 6 varieties. The flours coming from dry heat processing contained higher oil levels than those flours coming from wet processes. The oil from only 3 varieties and from 4 processes were analyzed from its fatty acid composition. The oil contained on the average 17.85% of C16:0, 68.1% of stearic, olic and linoleic acids, 3.86% of C18:3, 5.1% of C20:0 and small amounts of C20:1 and C22:0. The squalene content in the oil of the processed flours varied from 7.0 to 9.6 g/100 g for the raw flour, 8.1 -12.6 g/100 g for the flour from wet cooking in water, 9.0 -12.7g/ 100 g for the flour from the nixtamalization process, 10.1-12.8g/ 100 g for the expanded grain flour, 9.0 to 11.2 g/100 g for the malted flour and 6.0-9.5 g/100 g for the laminated grain flour. The squalene averages per process showed statistical significant differences.

Contenido de aceite, ácidos grasos y escualeno en variedades crudas y procesadas de grano de amaranto / The oil, fatty acid and squalene content of varieties of raw and processed grain amaranth

Seis variedades de Amaranto fueron procesadas para dar una harina cruda, una nixtamalizada, una cocida en agua, otra expandida, una malteada y una laminada después de un tratamiento térmico. Los valores analíticos en estas muestras se compararon con los valores en una muestra cruda. Los granos crudos contenían de 14.5 por ciento a 15.1 por ciento de proteína, 5.9 a 6.7 de grasa, y 2.3 por ciento a 3.2 por ciento de cenizas. Las harinas de las variedades de diferentes procesos dieron un contenido de grasa que varía entre 6.4 por ciento - 7.0 por ciento. Las harinas de procesos en seco contenían mas aceite que las de procesos en húmedo (cocida en agua). El aceite de tres variedades y de 4 procesos fue analizado por su contenido de ácidos grasos, dando en promedio 17.85 por ciento de C16:0, 68.1 por ciento de oleico + linoléico, 3.86 por ciento C18:3, 5.1 por ciento de C20:0 y cantidades menores de C20:1 y C22:0. El contenido de escualeno en el aceite de las harinas de los diferentes procesos fue de 7.0-9.6 g/100 g para la harina cruda, de 8.1-12.6 g/100 g para la de cocción húmeda, 9.0-12.7 g/100 g para la nixtamalizada, 10.1-12.8 g/100 g para la expandida, 9.0-11.2 g/100 g para la malteada y 6.0-9.5 g/100 g para la harina laminada.

Six amaranth grain varieties were processed to yield a nixtamalized flour, one cooked in water, one expanded, a malted one and a laminate samples after a thermic treatment. The chemical values of the raw samples contained from 14.5 percent to 15.1 percent protein, 5.9 to 6.7 percent ether extract and from 2.3 percent to 3.2 percent ash on a dry weight basis. The flours from the different processes yield products with a fat content which varied from 6.4 percent to 7.0 percent for the 6 varieties. The flours coming from dry heat processing contained higher oil levels than those flours coming from wet processes. The oil from only 3 varieties and from 4 processes were analyzed from its fatty acid composition. The oil contained on the average 17.85 percent of C16:0, 68.1 percent of stearic, olic and linoleic acids, 3.86 percent of C18:3, 5.1 percent of C20:0 and small amounts of C20:1 and C22:0. The squalene content in the oil of the processed flours varied from 7.0 to 9.6 g/100 g for the raw flour, 8.1 - 12.6 g/100 g for the flour from wet cooking in water, 9.0 -12.7g/100 g for the flour from the nixtamalization process, 10.1-12.8g/100 g for the expanded grain flour, 9.0 to 11.2 g/100 g for the malted flour and 6.0 -9.5 g/100 g for the laminated grain flour. The squalene averages per process showed statistical significant differences.

[Use of cowpea (Vigna unguiculata) in mixtures with common beans (Phaseolus vulgaris) for the development of new food products]. / Uso del cowpea (Vigna unguiculata) en mezclas con fríjol común (Phaseolus vulgaris) en el desarrollo de nuevos productos alimenticios.

The objective of the study was to evaluate cowpeas (V. unguiculata) as a partial substitute of common beans (P. vulgaris) as a paste or as cooked dry flour. The degree of substitution would be that in which the flavor of cowpeas is not detected in the mixture with common beans. The study was developed utilizing the Black Peruchin variety of cowpea and the ICTA Ligero for common beans, the latter with 18.7% protein and cowpeas with of 24.4%. Other nutrients in the samples were similar. It was believed that the characteristic earth flavor of the cowpea was due to its content of polyphenolic compounds. To eliminate such compounds, the samples were soaked in water for various periods of time and cooked. Reduction was also achieved by dehulling. It was found that the polyphenolic levels obtained with 9 hrs. of soaking and 30 min. of cooking in water were equal to those measure with mechanical dehulling. Applying these process to cowpeas, two fried beans pastes were prepared with cowpeas (with and with out hulls) in a mixture of 70 common beans and 30 cowpeas. Likewise a precooked flour of the two legume grains in the same proportion was also tested. These samples were subjected to sensory trials using a triangular method, and by a descriptive profile. In these the following were evaluated: color, texture, salt level, and flavor, using a 10 point scale. The sensory evaluation of the two beans mixtures showed no significant differences with respect to common bean flavor. The protein content of the mixtures was high due to the high protein content of cowpeas. Even though the mixtures of common beans and cowpeas with and with out seed coat gave higher protein quality values as compared to common beans alone, the difference was not statistically significant.

Uso del cowpea (Vigna unguiculata) en mezclas con fríjol común (Phaseolus vulgaris) en el desarrollo de nuevos productos alimenticios / Use of cowpea (Vigna unguiculata) in mixtures with common beans (Phaseolus vulgaris) for the development of new food products

El objetivo del presente estudio fue el de evaluar el cowpea (Vigna unguiculata) como sustituto parcial del frijol común (Phaseolus vulgaris) como pasta o como harina. El grado de sustitución sería aquel en el cual no se detecte el sabor del frijol cowpea alterando el sabor del frijol común. Para la ejecución del estudio se utilizó la variedad Peruchin Negro del frijol cowpea y el ICTA Ligero del frijol común con un contenido de proteína de 24.4 por ciento y 18.7 por ciento respectivamente. No hubo diferencias significativas en otros nutrientes. Se postuló que el sabor característico a tierra del cowpea era debido al contenido de polifenoles, la cual se redujo con tratamientos de remojo, cocción y descascarado. Se estableció que los niveles de polifenoles logrados con 9 horas de remojo y 30 minutos de cocción eran iguales a los obtenidos con el descascarado. Con estos procedimientos previos en el cowpea se prepararon 2 pastas de frijol frito a base de una mezcla de frijol negro/cowpea (con y sin cáscara) en la relación 70/30 las cuales fueron enlatadas y una mezcla de harina precocida en las mismas proporciones. Estas pastas se sometieron a pruebas sensoriales de tipo triangular y de perfil descriptivo. En el perfil descriptivo se evaluó: color, textura, punto de sal y sabor, en una escala de 10 puntos. Las evaluaciones sensoriales de las 2 mezclas de frijol no mostraron diferencia significativa respecto al sabor del frijol común. El contenido de proteína en las mezclas fue más alto debido a la mayor concentración de este nutriente en el cowpea. Aunque las mezclas de frijol común con cowpea entero y sin cáscaras dieron mayor valor proteico (NPR) que el de frijol solo, la diferencia no fue estadísticamente significativa.

Preparation and characterization of protein isolate from fresh and hardened beans (Phaseolus vulgaris L.).

The purpose of the present work was to determine the effect of accelerated hardening of beans on yield and physicochemical, functional, and toxicological properties. Protein isolates were obtained from fresh and hardened common beans (Phaseolusvulgaris L.). Acid treatment was an effective method to produce hardened bean. Protein recovery in the isolation procedure for fresh bean isolate (FBI) was 45.5% and 36.15% for hardened bean isolate (HBI); however, the amount of protein was similar in both isolates. In general, the amino acid pattern was similar in both isolates. Electrophoresis analysis showed that the main protein (phaseolin) remained unchanged during the isolation procedure. HBI showed a decrease in the bands of 14 to 26 kDa corresponding to the phytohemagglutinin group, and this was associated with a 56.6% decrease in the concentration of the trypsin inhibitor (TI). Heat treatment of FBI reduced 89.4% of the TI and the hemagglutining activities, and it was reflected in an adequate weight gain of young animals. FBI showed better functional properties than HBI, and both isolates showed the same amount of flavonoids.

G protein-coupled receptor systems and their lipid environment in health disorders during aging.

Cells, tissues and organs undergo phenotypic changes and deteriorate as they age. Cell growth arrest and hyporesponsiveness to extrinsic stimuli are all hallmarks of senescent cells. Most such external stimuli received by a cell are processed by two different cell membrane systems: receptor tyrosine kinases (RTKs) and G protein-coupled receptors (GPCRs). GPCRs form the largest gene family in the human genome and they are involved in most relevant physiological functions. Given the changes observed in the expression and activity of GPCRs during aging, it is possible that these receptors are directly involved in aging and certain age-related pathologies. On the other hand, both GPCRs and G proteins are associated with the plasma membrane and since lipid-protein interactions regulate their activity, they can both be considered to be sensitive to the lipid environment. Changes in membrane lipid composition and structure have been described in aged cells and furthermore, these membrane changes have been associated with alterations in GPCR mediated signaling in some of the main health disorders in elderly subjects. Although senescence could be considered a physiologic process, not all aging humans develop the same health disorders. Here, we review the involvement of GPCRs and their lipid environment in the development of the major human pathologies associated with aging such as cancer, neurodegenerative disorders and cardiovascular pathologies.

[Effect of different cooking treatments of Mucuna beans on its L-Dopa content]. / Efecto de diversos tratamientos en la cocción del frijol Mucuna sobre el contenido de L-Dopa.

The main limiting factor in the consumption by humans of the velvet bean (Mucuna) is its relatively high content of L-Dihydroxyphenylalanine (L-Dopa), with levels as high as 9%. Conventional cooking methods used to transform raw velvet bean into an edible product are not sufficiently effective in reducing the levels of L-Dopa in adequate processing time. In this report, Mucuna beans were cooked by microwave, utilizing vapor and in water solutions at pH 3, 6, 7, 9 and 11. Cooking alkaline solutions were achieved using sodium hydroxide, potassium hydroxide, and calcium hydroxide. The acid pH was achieved through the use of HCl. The initial cooking time was fixed at 6 hrs. The processed bean samples were dried, ground and analyzed for L-Dopa and protein. The ground samples were further washed with boiling water for 0, 3 and 6 minutes, them dried and analyzed. None of the procedures evaluated was capable of eliminating L-Dopa from Mucuna beans. The Ca(OH)2 treatment at pH 9 which was washed with hot water produce a reduction of L-Dopa of 80.4%. There was not effect attributed to the alkaline ions. Reducing particle size appears to be most effective as it has been shown by other workers.

Efecto de diversos tratamientos en la cocción del frijol Mucuna sobre el contenido de L-Dopa / Effect of different cooking treatments of Mucuna beans on its L-Dopa content

El factor más limitante en el consumo del frijol Mucuna (Frijol Terciopelo) para el ser humano es su alto contenido de L-Dihidroxifenilalanina (L-Dopa) con niveles que pueden ser del 9 por ciento. Los métodos convencionales utilizados para transformar el frijol crudo en comestible no son suficientemente efectivos en reducir los niveles de L-Dopa en tiempo razonables para su preparación. Varios otros procesos se han utilizado con resultados poco prometedores. En este trabajo, el frijol Mucuna fue cocinado por microondas, con vapor y a cocciones en soluciones de pH 3, 6, 7, 9 y 11. Las cocciones alcalinas se lograron con hidróxido de sodio, hidróxido de potasio e hidróxido de calcio, mientras que las de pH ácido con ácido clorhídrico. El tiempo inicial de cocción fue constante por 6 hrs. Además las muestras secas y molidas de los tratamientos anteriores fueron cocidas en agua por 0, 3 y 6 minutos, y el proceso fue evaluado por el nivel de eliminación de L-Dopa. Ninguno de los métodos evaluados fue capaz de eliminar el L-Dopa del frijol Mucuna. El tratamiento de cocción con Ca(OH)2 a pH 9 y luego lavado con agua caliente produjo la reducción mas alta del 80.4 por ciento. No hubo efecto de los iones alcalinos. La reducción del tamaño de la partícula por molienda parece ser efectivo como ha sido demostrado por otros autores

Desarrollo de un producto de planificación apto para el adulto mayor a base de harina de trigo y harina de arroz / Development of bakery products for greater adult comsumption based on wheat and rice flour

Como es un aporte a la nutrición/alimentación de la creciente población de adultos mayores en Guatemala, se desarrolló el presente trabajo cuyo objetivo fue evaluar la calidad química, nutritiva y sensorial de pan preparado de la sustitución parcial de harina de trigo por harina de arroz. Se evaluaron de 15, 20, 30, 40, 50 y 60 por ciento de harina de trigo por harina de arroz. Se encontraron diferencias con el pan control (100 por ciento harina de trigo) en el proceso de preparación, en la textura, volumen, altura, peso y volumen específico. Se notaron efectos importantes en el manejo de las masas en particular con los 40, 50 y 60 por ciento de harina de arroz. Así mismo, a mayor nivel de arroz se encontró una textura harinosa. La calidad de la proteína del pan aumentó con el nivel de situación, sin embargo la diferencia en calidad proteínica entre el pan de trigo y el de 60 por ciento de arroz no alcanzó significancia estadística. En base a un análisis estadístico de las características físicas se seleccionó el pan con 30 y 40 por ciento de harina de arroz y a través de una prueba de preferencia se seleccionó el pan con 30 por ciento de harina de arroz como el más adecuado para los fines del estudio. Este pan no fue diferente al pan de trigo en varios parámetros nutricionales y en algunos fue superior. Cada porción de pan tiene un peso de 80 gramos (3 rebanadas) que aporta cantidades adecuadas de calorías, proteína y sodio aunque un poco menos en fibra dietética que el pan de 100 por ciento trigo

Effect of processing conditions on phytic acid, calcium, iron, and zinc contents of lime-cooked maize.

Tortillas are made by cooking maize in a lime solution during variable times and temperatures, steeping the grain for up to 12 h, washing and grinding it to a fine dough, and cooking portions as flat cakes for up to 6 min. The effects of the main processing steps on the chemical composition, nutritive value, and functional and physicochemical characteristics have been areas of research. The present work evaluates the effect of lime concentration (0, 1.2, 2.4, and 3.6%) and cooking times (45, 60, and 75 min) on phytic acid retention of whole maize, its endosperm, and germ, as well as on the content of calcium, iron, and zinc on the same samples. The effects of steeping time and temperature and steeping medium on the phytic acid of lime-cooked maize were also studied. Finally, phytic acid changes from raw maize to tortilla were also measured. The results indicated that lime concentration and cooking time reduce phytic acid content in whole grain (17.4%), in endosperm (45.8%), and in germ (17.0%). Statistical analyses suggested higher phytic acid loss with 1.2% lime and 75 min of cooking. Cooking with the lime solution is more effective in reducing phytic acid than cooking with water. Steeping maize in lime solution at 50 degrees C during 8 h reduced phytic acid an additional 8%. The total loss of phytic acid from maize to tortilla was 22%. Calcium content increased in whole maize, endosperm, and germ with lime concentration and cooking and steeping times. The increase was higher in the germ than in the endosperm. The level, however, can be controlled if steeping of the cooked grain is conducted in water. Iron and zinc contents were not affected by nixtamalization processing variables but were affected in steeping.

[Development of bakery products for greater adult consumption based on wheat and rice flour]. / Desarrollo de un producto de panificación apto para el adulto mayor a base de harina de trigo y harina de arroz.

The present investigation was developed as a contribution to Guatemalan's elderly food and nutrition. Its main objective was to evaluate the chemical, nutritional and sensory quality of bread prepared from the partial substitution of wheat flour with rice flour. Wheat flour substitutions with rice flour in the order of 15, 20, 30, 40, 50 and 60% were evaluated. Differences with the control (100% wheat bread) were found during the process of preparation, as well as texture, volume, height, weight and specific volume. Important effects in dough handling were noted specifically in the 40, 50 and 60% rice bread. Thus, a sandy texture was found in breads of higher rice levels. The bread protein quality increased with the level of substitution; however the protein quality difference between the wheat bread and the bread with 60% rice flour did not achieve statistical significance. Based on a statistical analysis of the physical properties the bread with 30 and 40% rice flour was selected, and through a preference test between these last two, the 30% rice flour bread was selected as the sample best suited to the present study's purposes. This bread was not different to wheat bread in many nutritional parameters, although in others it showed to be superior. Each serving size of bread has a weight of 80 grams (2 slices) that contributes adequate quantity of calories, protein and sodium, although a little less dietary fiber than 100% wheat bread.

[Protein fraction distribution in milling and screened physical fractions of grain amaranth]. / Distribución de la proteína en fracciones físicas de la molienda y tamizado del grano de amaranto.

The purpose of the study was to establish the protein distribution based on solubility in physical fractions of amaranth flour, in particular between the flour from the germ and that from the perisperm. The protein distribution was obtained applying a series of solvents sequentially utilized in the classical methodology of Osborne & Mendel. The sample of A. cruentus weighing 2000 g was divided into 4 subsamples of 500 g each. One was left as the control while the other 3 were ground individually with a mill. Each flour was screened through 18, 20, 30 and 40 mesh screens, so that 5 fractions were obtained from each of the whole grain flours. Samples of each screened fractions were observed by stereoscopy and analyzed for moisture, fat and protein. This characterization suggested that the fraction above the 30 mesh screen and the flour which passed the 40 mesh screen probably were the perisperm and germ respectively. The 30 mesh sample contained 2.34 fat and 9.05% protein while the 40 mesh contained 16.18% fat and 26.46% protein. The extraction and partitioning of the proteins indicated that the most important fractions in germ and perisperm were the water soluble and glutelins measured by Kjeldahl. The relationship of the water soluble + globulin to glutelins ratio was 2.1 to 1 in the whole grain, 1.9 to 1 in the perisperm and 1.7 to 1 in the germ. The distribution of proteins was very much alike between germ and perisperm. The levels of prolamines were quite low. The protein extraction of the perisperm proteins retained on the 30 mesh screen was low (71.1%) measured by Kjeldahl and 47.4% with the Bradford method to measure protein.

Distribución de la proteína en fracciones físicas de la molienda y tamizado del grano de amaranto / Protein fraction distribution in milling and screened physical fractions of grain amaranth

The purpose of the study was to establish the protein distribution based on solubility in physical fractions of amaranth flour, in particular between the flour from the germ and that from the perisperm. The protein distribution was obtained applying a series of solvents sequentially utilized in the classical methodology of Osborne & Mendel. The sample of A. cruentus weighing 2000 g was divided into 4 subsamples of 500 g each. One was left as the control while the other 3 were ground individually with a mill. Each flour was screened through 18, 20, 30 and 40 mesh screens, so that 5 fractions were obtained from each of the whole grain flours. Samples of each screened fractions were observed by stereoscopy and analyzed for moisture, fat and protein. This characterization suggested that the fraction above the 30 mesh screen and the flour which passed the 40 mesh screen probably were the perisperm and germ respectively. The 30 mesh sample contained 2.34 fat and 9.05 protein while the 40 mesh contained 16.18 fat and 26.46 protein. The extraction and partitioning of the proteins indicated that the most important fractions in germ and perisperm were the water soluble and glutelins measured by Kjeldahl. The relationship of the water soluble + globulin to glutelins ratio was 2.1 to 1 in the whole grain, 1.9 to 1 in the perisperm and 1.7 to 1 in the germ. The distribution of proteins was very much alike between germ and perisperm. The levels of prolamines were quite low. The protein extraction of the perisperm proteins retained on the 30 mesh screen was low (71.1) measured by Kjeldahl and 47.4 with the Bradford method to measure protein.

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

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.

Características de cocción por nixtamalización de once variedades de maíz / Nixtamalización cooking characteristics of 11 maize varieties

En el presente estudio se analizaron once variedades de maíz cultivadas en la misma localidad y en el mismo año, para evaluar su calidad de procesamiento para harinas nixtamalizadas de maíz. Las muestras fueron analizadas por sus características físicas como contenido de humedad (promedio 13,3 por ciento), peso de 1000 gramos (promedio 312,5 g), dureza a través de densidad (promedio 1,28 g/ml) y el índice de flotadores (promedio 9,5 por ciento). Estos datos indicaron que todas las variedades contienen un endospermo duro lo cual es preferido por la industria para la nixtamalización. Las once variedades estaban formadas en promedio de 5,7 por ciento de pericarpio, 11,5 por ciento de germen y 82,8 por ciento de endospermo,sugiriendo el porcentaje de pericarpio pérdidas bajas de sólidos por nixtamalización. La calidad de cocción de los maíces se evaluó utilizando un proceso de nixtamalización estandarizado. Se obtuvo una pérdida de materia seca promedio de 3,2 por ciento con un contenido de cáscara residual del 0,8 por ciento, la absorción de agua promedio 40,8 por ciento al finalizar la cocción y 46,9 por ciento al finalizar el remojo. La humedad del nixtamal fue de (41,5 por ciento al finalizar la cocción) y de 47,9 por ciento al finalizar el remojo por 12 horas). El tiempo de cocción y remojo para 50 por ciento de humedad en el grano varió entre 69 a 122 minutos en las once variedades, a una altura de 1500 m sobre el nivel del mar. El maíz nixtamalizado fue deshidratado y luego molido, no lográndose una harina con la granulometría igual a la de harinas industriales. Sin embargo los parámetros de calidad de la masa para tortilla fueron aceptables con un índice de penetración en harina hidratada de 178,67 mm, pH 7,97 índice de absorción de agua (WAI) 3,23 g.gel/g harina y el índice de solubilidad en agua (WSI) de 4.11 por ciento. Las harinas de todos los maíces dieron tortillas aceptables en cuanto a características físicas y sensoriales se refiere, sin embargo de las 11 variedades, 7 incluyendo el control, fueron superiores a las otras 4 variedades

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) / Vegetable food resources from Guatemala with agroindustrial potential: preparation of a vegetable milk from the seed of morro fruit (Crescentia alata)

El objetivo de este trabajo fue establecer las condiciones para la preparación de leche de semilla de morro o jícara, y caracterizar química y sensorialmente los productos obtenidos, la leche vegetal y el residuo. Del fruto maduro de obtuvo por maceración en agua por 3.5 horas la semilla en un rendimiento del 80 por ciento. Esta semilla contiene en base seca 38 por ciento de grasa y 26 por ciento de proteína. La semilla separada de la pulpa se deshidrató al sol a una humedad entre 9-12 por ciento, que fue utilizada para la extracción de los sólidos solubles o la leche vegetal. Un lote similar se tostó ligeramente por 10 minutos a 90-110ºC en una superficie a esas temperaturas. Las extracciones con agua hasta por 10 minutos de licuado, dio bajos rendimientos de sólidos solubles totales (4,66 ñ 0.10 a 4,98 ñ 0,97 por ciento) y contenidos bajos de grasa, proteínas y ceniza, con semilla secada al sol y mucho más baja con la semilla que había sido ligeramente tostada (3,0 ñ 0,005 a 3,4 ñ 0,03 por ciento). Debido a los bajos rendimientos de sólidos solubles totales y contenidos de nutrientes por extracciones acuosas, se optó por utilizar para la extracción soluciones buffer a pH 7,9 o soluciones salinas (0,5 por ciento) con y sin solución buffer a pH 8,5, con lo cual se logró una mucho mejor extracción de sólidos totales y nutrientes en el extracto. La leche de semilla secada al sol y extraída con buffer a pH 8,5 y solución salina al 0,5 por ciento produjo un extracto con 9,85 por ciento de sólidos solubles totales, 3,37 por ciento de proteína y 4,43 por ciento de grasa. Las extracciones en semilla ligeramente tostada fueron significativamente menores. El residuo de la extracción mostró en base seca 21,43 por ciento de grasa y 19,72 por ciento de proteína. Con la utilización de buffer y/solución salina se obtuvo extractos de mejor aceptabilidad, siendo la leche de semilla secada al sol la de mejores características organolépticas en comparación con la leche de soya (5,84 vrs 3,76) pero de menor calidad sensorial a la leche de vaca (5,7 vrs 7,7). El punto isoeléctrico de la proteína extraída se localizó a un pH de 4 a 4,5

Recursos vegetales con potencial de explotación agroindustrial de Guatemala. Caracterización química de la pulpa y la semilla de Theobroma bicolor / Vegetable resources with agroindustrial potential from Guatemala. Chemical characterization of the pulp and of the seeds of Theobroma bicolor

T. bicolor grows wild in certain regions of Guatemala. The fruit is utilized by the rural population for the preparation of drinks from the pulp and the seed, replacing cocoa (T. cocoa). The fruit of T. bicolor used in the present study, measured on the average, 15 cm long and had an average weight, of 752 g. The pulp, the shell, and the seed represented 23.8, 62.5, and 13.7, respectively, of the fruit weight. The pulp contained on the average, 38 seeds/fruit, which weighted on the average, 1.11 g and were 2.4 cm long. T. cacao seeds weighted 0.62 g and were 1.6 cm long. The protein content (24.42) and fiber content (30.86) of the T. bicolor seeds, was greater than those from T. cacao, although fat content was lower (25.48). The fat of the seeds of T. bicolor has different physicochemical characteristics than the fat of the seeds of T. cacao, such as melting point, iodine value, and saponification number. The seeds of both, T. cacao and T. bicolor, were used for the preparation of a local drink using toasted corn flour, sugar, and anatto flour in equal preparations, with and without toasted whole soybean flours (6.25). Through a sensory ranking trial, it is established that the drink from T. bicolor and soybeans, was preferred over other preparations with T. cacao. The pulp of T. bicolor with an interesting chemical composition, yielded an aromatic pleasant drink, and from T. bicolor, is an interesting resource for industrialization and for genetic characteristics for T. cacao improvement.

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 locationes in Guatemala. Soon after collection, samples were stored at 4 and 38 degrees Celsius at ambient relative humidity and subsamples were withdrawn at 0,45, 90 and 135 days of strage 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 Celsius and at 135 days absorbed more water than when stored at 4 degrees Celsius. 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 Celsius, 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 Celsius. 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 Celsius, but it was enhanced when stored at 38 degrees Celsius. For vine type of beans at 4 degrees Celsius relative high rates of synthesis were observed, which were higher at 38 degrees Celsius for NDF, hemicellulose and lignin. Cooking time and fiber fraction contents were subjected to regression analysis. The correlations at 38 degrees Celsius were higher than at 4 degrees Celsius for all fractions for both types of beans, but statistical significance was obtained only for NDF, ADF and cellulose for vince type of beans. These data show therefore that synthesis of cell wall structure fractions, and not only lignin formation, are responsible...