Effect of maize (Zea mays L.) grain hardness on yield and quality of tortilla
Efecto de la dureza del grano de maíz (Zea mays L.) sobre el rendimiento y calidad de la tortilla
Available online: 2010-12-15 / pages 5-11
Maize is the most important cereal in the diet of Mexican people. Maize is consumed mainly as tortilla, which can be produced from fresh masa or nixtamalized maize flour. The objectives of the present work were to establish the effect of maize grain hardness on masa and tortilla yields as well as its relationship with tortilla texture and the stability of this tortilla characteristic during the storage. There were used 27 maize samples obtained in the states of Puebla and Tlaxcala that were grouped according to their grain hardness. Physical, chemical and nixtamalization variables were evaluated in the samples. The tortilla quality during the storage was determined in function of texture and moisture. The maize samples with hard endosperm presented higher test weight and lower floatation index and thousand weight values than the maize samples with medium and soft endosperm. Grain hardness affected moisture content of tortilla and in this way tortilla yield, but not the tortilla texture. The favorable tortilla texture characteristics were lost after being storage for 24 h. To obtain an index yield of tortilla/maize ≥1.5, the tortilla moisture has to range from 45 to 46 %. Maize with soft to medium hardness grain let to have tortillas with these moisture requirements.
Integrated water resources management to reduce the vulnerability to land sliding and flooding in the sierra madre of Chiapas watersheds
Gestión integral de recursos hídricos para reducir la vulnerabilidad a deslizamientos e inundaciones en las cuencas de la sierra madre de Chiapas
José Luis L. Arellano-Monterrosas
Available online: 2010-12-15 / pages 23-37
In this research is analyzed the pertinence of applying the Integrated Water Resources Management (IWRM) methodology in order to reduce the vulnerability to land sliding and flooding in the Sierra Madre of Chiapas watersheds in Mexico. The costeral Chiapas watersheds are characterized by their pronounced topography, presence of extreme rainfall and poverty which make them very vulnerable to extreme hydrometeorological events. In the last years, these events have occurred with more frequency and intensity in the region. In this way, the hydrology-forestry recovery practices, as the conservation and management of soil and water that are performed in each crop system and watershed parcel, allow not just the control in situ of water erosion but the storage of water in the soil and a better infiltration that improve significantly the rainfall-runoff relationship to produced land sliding and flooding to start a territorial watershed development to decrease the watershed vulnerability to these disasters.
Vermicomposting of solids removed from a screening pre-treatment of swine waste water
Vermicomposteo de sólidos removidos de un pre-tratamiento de cribado de excretas porcinas
Available online: 2010-12-15 / pages 39-43
The waste water and manure are residues produced in swine industry. The daily production of wastes in hog farming represents a considerable volume. The contamination of water swine and manure varies due to different concentrations of contaminants. With decomposition of organic matter there are present fly grubs, which spray diseases. Solid wastes provide organic matter and nutrients to the soils. Treatments of waste water swine are: solids removal by sedimentation or screen separator, dewatering by sand filters, physicochemical and anaerobic treatment. All of these procedures generate solid wastes, which have to be treated in order to stabilize them and to reduce their contaminant effects. The purpose of this study was to evaluate the vermicompost efficiency in the stabilization and reduction of contaminants in the waste solids, removed during treatment of swine waste water and to evaluate agronomic characteristics. It was selected a hog farming that raising 5,000 hogs. The effluent was conducted by gravity; the bulk solids were removed by passing water through a mesh and they were used to feed a population of worms (Eisenia, sp.). Once vermicomposting process finished, it was obtained a stabilized biosolid Class A, Excellent Type for using without restrictions.
Effect of bulking agents adition to horticultural wastes in aerobic treatments
Efecto de la adición de agentes estructurantes a residuos hortícolas en tratamientos aerobios
Irwing M. Ramírez-Sánchez;
Ana Belem Piña-Guzmán;
Francisco J. Colomer-Mendoza
Available online: 2010-12-15 / pages 45-51
The effect of the addition of bulking agents (BA) to horticultural waste during aerobic degradation was studied. The mixture was composed of six organic wastes generated in great quantities in the Central Market of Mexico City; they were tomato, pineapple, banana, lettuce, orange and papaya fruit. These organic materials have a high content of moisture; therefore, it is necessary to add BA in order to improve their properties during aerobic composting or biodrying processes. The BA used were: a) wood shavings, b) yard waste and c) a mixture of compost with wood shavings. During the degradation process, the generation and pH of leachate, as well as temperature, moisture content and mass reduction of solid waste was measured. The results showed that the moisture content in horticultural waste can be regulated with dry bulking agents that absorb some of the leachate during the first weeks of the process, while improving pile structure thus avoiding anaerobic degradation. The best results were obtained from the treatment consisting of a mixture of compost and wood shavings as BA, which had a reduction in leachate generation of 64.6 % compared with the control sample. The reduction in dry mass basis, related to the initial total mass, averaged 89 % in all trials.