En este trabajo se estudió el efecto de la incorporación de harina de soja y de concentrado proteico de suero de queso sobre las propiedades físicas de la masa y sobre la calidad del pan de molde. Se realizaron estudios farinográficos y alveográficos sobre las masas. Los panes fueron evaluados por sus atributos sensoriales a través de un panel entrenado y con relación a sus características nutricionales a través de puntaje químico, lisina disponible y disponibilidad potencial del hierro de fortificación y del zinc y calcio intrínsecos. La incorporación de harina de soja (HS) y de concentrado proteico de suero de queso (WPC) produjeron una importante modificación en las propiedades físicas de la masa. El agregado de WPC a un nivel de 6% de reemplazo, incrementó el puntaje químico del pan de 40.2 a 41.4, mientras que con 6% de harina de soja se elevó a 52.2. La mezcla de ambas fuentes proteicas (HS 6% + WPC 6%) permitió aumentar ese puntaje químico a 60.0 sin deterioro evidente de las características organolépticas de los panes. Además, la pérdida de lisina disponible que ocurrió con el WPC fue atenuada con la incorporación simultánea de harina de soja. El agregado de WPC si bien incrementó el aporte de Ca, disminuyó la disponibilidad de Fe y Zn. Este efecto negativo sobre el Fe fue superado por el agregado de promotores de la absorción de minerales, siendo el agregado del EDTA el más beneficioso. Por otra parte el agregado de harina de soja al 6% mejoró el aporte de proteínas sin perjudicar el de minerales.

The effects of the addition of soy flour and whey protein concentrate (WPC) on dough properties and mold bread quality were studied. Farinograph and alveograph were used to evaluate dough properties. Mold bread quality was evaluated by assessing sensory attributes using a trained panel and analyzing some nutritional characteristics, such as: protein chemical score, available lysine, and potential availability of fortified iron and also of the intrinsic calcium and zinc. Addition of soy flour and WPC caused significant changes on dough properties. Chemical score of bread was increased from 40.2 to 41.4 when 6% WPC was used, from 40.2 to 52.2 when 6% soy flour was added and up to 60.0 when substitution was made with 6% WPC plus 6% soy flour. This last improvement was obtained without impairing sensory attributes. The highest value of available lysine loss during baking, corresponded to the blend containing WPC, but it was reduced when WPC was used together with soy flour. WPC addition increased calcium content but reduced potential availability of iron and zinc. This negative effect on iron availability was overcome by adding mineral absorption promoters, being EDTA the most effective. On the other hand addition of 6% soy flour improved protein value without affecting mineral availability.

In the present work the effects of extrusion on mineral availability of extruded mixtures based on maize and cowpea (with and without previous inactivation treatment) were analyzed. In the formulation of foods aimed to food programs the amount and the quality of protein and bioavailability of the nutrients must be considered. One alternative, explored in this work, is to use bean flours, assuring the organoleptic quality, by lipoxigenase inactivation treatments. Mineral availability was estimated as the percentage of dialyzed mineral after in vitro digestion. Results showed that maize/cowpea mixture had a significant improvement in the amount of protein and its quality in comparison with maize. The inactivation treatment did not affect iron dialyzability of the cowpea flour while extrusion increased it. Although both process moderately impaired zinc dialyzability, the values were still high

En el presente trabajo, se analizaron los efectos de la extrusión sobre la disponibilidad de minerales, utilizando mezclas de maíz y frijol (con y sin tratamiento previo de inactivación). Al formular alimentos destinados a programas alimentarios se debe considerar el contenido y la calidad proteica y la biodisponibilidad de nutrientes. Una alternativa explorada en este trabajo es utilizar harinas de frijol, asegurando la calidad organoléptica del producto mediante tratamientos de inactivación de lipooxigenasa. La disponibilidad de los minerales se estimó a través del porcentaje dializado tras la digestión in vitro. Los resultados mostraron que las mezclas maíz/frijol presentaron una mejora significativa de la cantidad y calidad proteica, con respecto al maíz. La inactivación no afectó la dializabilidad de hierro en la harina de frijol, mientras que la extrusión la mejoró. Si bien ambos procesos tuvieron un ligero efecto desfavorable en la dializabilidad del zinc, el valor de ésta fue bastante alto

The objective of the present study was the evaluation of experimental milling at a pilot plant for the production of flours having characteristics similar to those obtained in an industrial process. The physical, chemical, and technological aspects of flours from different wheats, produced by two experimental and one industrial mill were evaluated. The evaluations of the flours were carried out in triplicate and statistically analyzed using a Duncan multiple range test. Differences were found among amylographic and farinographic values, as well as in the chemical compositions of the flours. The alveographic and technological behavior showed not significant differences (a = 0.05). It is concluded that the diagrams proposed for experimental milling could be used to predict the behavior of flour in industrial mivdroppelmann@unab.cllling .

El objetivo del presente trabajo fue evaluar el potencial de la molienda experimental de planta piloto para la producción de harinas con características similares a las obtenidas en el proceso industrial. Se analizaron los aspectos físicos, químicos y tecnológicos de harinas provenientes de distintos trigos, producidas por dos molinos experimentales y por uno industrial. Las evaluaciones de las harinas fueron realizadas por triplicado y analizadas estadísticamente por el test de rango múltiple de Duncan. Se encontraron diferencias en los valores amilográficos, farinográficos y en la composición química de las harinas. Las características alveográficas y el comportamiento tecnológico mostraron diferencias no significativas (α=0.05). Se concluye que los diagramas propuestos en la molienda experimental pueden ser utilizados para predecir el comportamiento del trigo en la molienda industrial.

Oito variedades e quatro amostras comerciais de arroz de boa qualidade foram analisadas com relação a algumas características físico-químicas e de cozimento. Algumas propriedades mecânicas foram avaliadas utilizando-se tanto o viscoamilógrafo como o equipamento Instron (Instron Universal Testing Machine), tais como, o tempo de gelatinização (Gt), a endoterma de gelatinização e o conteúdo de amilose. Os resultados mostraram que existe uma boa correlação entre a temperatura de gelatinização e Gt, contudo não foi observada correlação relevante entre outras características físico-químicas. Em relação às propriedades mecânicas, ambos os métodos permitiram mostrar significantes diferenças entre algumas amostras. Existe uma boa correlação linear entre dureza e conteúdo de amilose, por outro lado, nenhum dos parâmetros viscoelastográficos apresentaram boa correlação com a amilose. Um ponto interessante é que a inclinação da reta de correlação linear obtida entre firmeza e tempo de cozimento pode ser utilizada como uma medida da resistência ao cozimento de cada amostra e relacionada à taxa de absorção de água.

Some physicochemical and cooking characteristics corresponding to different varieties and commercial samples of rice were analysed. Some mechanical properties determined by both, the viscoelastograf and the Instrom Universal Food Testing Machine were also analysed. Gelatinization time (Gt), gelatinization endotherm and amylose content were determined. The results showed that there was a very good correlation between gelatinization temperature and Gt, while no noticeable correlation among others phsycochemical characteristics was observed. Regarding the mechanical properties, both methods permited to show significant differences among most of the samples. However, when the samples order obtained with hardness (Instrom) values was compared with that corresponding to firmness (Viscoelastograf) values, some discrepancies were observed. This could be attributable to the number of grains and the cooking time used in each method. There was good linear correlation between hardness and amylose content. On the contrary, none of the viscoelastograf parameters are correlated well with amylose. An interesting point was that the slope of the regression line obtained between firmness and cooking time could be utilised as a measure of cooking resistance of each sample and was related to the rate of water absorption.

Estudaram-se as propriedades de hidratação de isolados de soja com diferentes condições de procesamento (tratamentos térmicos, pH e concentração de proteínas). Para diferentes amostras determinaram-se e correlacionaram-se o gráu de desnaturalização, a solubilidade em água, em 0,2mol/L NaCl e em diferentes concentrações de dodecil sulfato de sódio, viscosidade e capacidade de absorção de água. Os tratamentos a temperaturas superiores aos 80ºC desnaturaram as fracções 11S e 7S, provocando a exposição de grupos hidrofóbicos os que produziram agregados insolúveis, em água como em solução com alta força iónica. Estes isolados posuiam alta capacidade de absorção de água e dispersões com alta viscosidade. Achou-se uma correlação significativa entre as propriedades de hidratação e o coeficiente "m", calculado através da função de potência que relaciona a viscosidade com a concentração proteica da dispersão. Este coeficiente "m" também correlacionou com a entalpia dos isolados. Sobre a base destes resultados poderia-se sugerir que o coeficiente "m" - dependente do comportamento hidrodinâmico das partículas - foi um bom estimador do grau de desnaturação proteica.

Hydration properties of soybean isolates with different processing conditions (heat treatments, pH and protein concentrations) were studied. Degree of denaturation,, solubility in water, in 0.2mol/L NaCl, and in media of different sodium dodecyl sulfate concentrations, viscosity and water imbibing capacity of the different samples were determinated and correlated. Treatments at temperatures higher than 80ºC denatured 11S and 7S proteins, leading to exposure of hydrophobic groups, which produced insoluble aggregates either in water or in high ionic strength media. These isolates possessed high water imbibing capacities and gave rise to viscous dispersions. Significant correlations were obtained between hydration properties and the "m" coefficient as calculated by a power law equation relating viscosity with the protein concentration of the dispersion. This "m" coefficient also correlated with the denaturation enthalpy of the protein isolates. On the basis of these results, it might be suggested that the "m" coefficient - dependent of the hydrodynamic behaviour of the particles - was a good estimator of the degree of protein denaturation.