RESUMO

A mixed-mode solar drying was developed to evaluate the physicochemical and colorimetric properties of Zompantle (Erythrina americana). A 22-factorial design was used; the operation mode (mesh shade and direct) and airflow (natural convection and forced convection) were established as factors in this design. The initial moisture content in the Zompantle flower was reduced from 89.03% (w.b) to values that ranged from 3.84% to 5.84%; depending on the operation mode of the dryer, the final water activity ranged from 0.25 to 0.33. The Zompantle's components as proteins (4.28%), antioxidant activity (18.8%), carbohydrates (4.83%), fat (0.92%), fiber (3.71%), ash (0.94%), and total soluble solids (3°Brix) increased as the water was evaporated during the drying. The increment in the Zompantle's components depends on the operation mode; in direct mode and natural convection, the proteins, antioxidant activity, carbohydrates, fat, fiber, ash, and total soluble solids were 6.99%, 61.69%, 79.05%, 1.20%, 3.84%, 8.70%, and 45 °Brix, respectively. The total drying efficiency was 14.84% with the direct mode and natural convection (DM-NC) and 17.10% with the mesh shade and natural convection (MS-NC). The Hue angle measures the property of the color; the indirect mode and natural convection keep the hue angle close to the initial value (29.2 °). The initial chroma value of the Zompantle flower was 55.07; the indirect mode and natural convection kept high saturation (37.58); these dry conditions ensured a red color in the dehydrated Zompantle. Dehydrated Zompantle's flowers could have several practical applications, such as an additive in traditional Mexican cuisine.

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Resumen La industria alimentaria utiliza hasta el 15 % del total de la energía eléctrica que demanda el sector industrial, principalmente en procesos de secado. Esto suscita la búsqueda de nuevas alternativas de secado que reduzcan el uso de energía eléctrica. Una opción es el secado solar, principalmente, el de tipo indirecto, a través de captadores solares de placa plana (CSPP). El objetivo de este trabajo fue analizar los recientes desarrollos de los CSPP, características, ventajas, desventajas, eficiencia y diversas tecnologías utilizadas en conjunto, para aumentar la eficiencia térmica en el secado solar. Los CSPP han desarrollado, a través de la hibridación con la utilización de otras fuentes de energía (eléctrica, biomasa, solar), un incremento en su eficiencia que los vuelve cada vez más viables para ser utilizados en procesos comerciales de secado de alimentos.

Abstract The food industry uses up to 15 % of the total electrical energy demanded by the industrial sector, mainly in drying processes. This motivates the search for new drying alternatives that reduce the use of electrical energy. One option is solar drying; mainly indirect type solar drying, that uses flat plate solar collectors (FPSC). The objective of this work was to analyze the recent developments of the FPSC, their characteristics, advantages, disadvantages, efficiency, and the range of technologies used in conjunction with the FPSC to increase their thermal efficiency for solar drying. The FPSC have developed through hybridization with the use of other energy sources (electricity, biomass, solar), an increase in their efficiency, that increasingly turns them into viable options for food drying processes.

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Fish production worldwide has increased over the years due to increased populations and interest from consumers. This has led to an increase in the waste produced by this industry, with viscera being particularly notable as one of the main sources of negative environmental impact. This study will determine the environmental impact created when obtaining dry chemical silage from the viscera of red tilapia (Oreochromis spp.), using ecological footprint methodology as an indicator of sustainability. This process allows approximately 30% of CO2 emissions to be mitigated compared to those generated when fresh viscera are dumped into shallow landfills, while implementing actions that improve the process such as biogas production from waste and solar drying of the final product can mitigate approximately 86% of its environmental impact, when compared to the disposal of fresh viscera. It was concluded that the production of dry chemical silage using alternative drying energy is environmentally sustainable.

RESUMO

The quality of Theobroma cacao L. is influenced by different variables both in the crop and in the processes of postharvest, the latter it includes the fermentation and the drying, fundamental for the formation of aroma and flavor precursors, determinants in the characteristics of quality and differentiation of cocoa in the chocolate industry. The objective of the present research was to evaluate the effect of the solar drying process using a plastic roof solar dryer on the sensory and chemical quality of a mixture of cocoa cultivated in a region of Antioquia, Colombia. The content of total polyphenols, anthocyanins, sugars, mannitol, pH, total acidity, humidity, ethereal extract, ash, crude fiber and odor and flavor descriptors were analyzed. For analyzing the data, we used the methodology of longitudinal data analysis and repeated measurements, a Principal Component Analysis (PCA), and a principal factor analysis. The analyzed sensory characteristics are statistically different over time (p < 0.05). There was a decrease in the content of anthocyanins, total polyphenols and sucrose, and an increase in glucose and fructose during fermentation and drying. The analysis of factors allowed to define a series of groupings as indexes of quality according to the chemical and sensory properties analyzed in the drying process. Overall, the mixture of cocoa clones evaluated in the solar drying process presented indicators of sensory and chemical quality associated with descriptions of odor (spicy, dairy, nut, fruity, sweet cane), flavor (floral and spicy), ethereal extract, and pH that indicate a good benefit of cocoa and show the potential that Colombia has as a producer of fine aroma cocoa in high demand in premium markets.

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As biosolids application to croplands becomes a common practice, potential harm from pathogenic microbes needs to be mitigated for its safe reuse. The objective of this study was to investigate the impacts of tilling treatment on biosolids drying and microbial inactivation during the solar drying process in a semi-arid and temperate region. Solar drying experiments were conducted in sand and gravel dying beds open-to-the-air and under covering structures with biosolids to 20 cm depth from 2004 to 2006. Anaerobically- and Aerobically-digested biosolids received different tilling treatments throughout the drying process, while a series of biosolids samples were collected to determine the impact on total solids and microbial concentrations (Salmonella spp and heminth ova). Tilling treatments appeared to enhance the biosolids drying and microbial inactivation. Tilling was more effective during the cold season compared with the summer season and tilling treatments were also helpful in elevating biosolids temperature by expediting biosolids drying. The combined effect of temperature increase and moisture decrease by tilling may have resulted in faster microbial inactivation, particularly for persistent helminth ova. It was concluded that incorporation of tilling into biosolids solar drying can expedite biosolids drying as well as microbial inactivation, and thus can be an effective measure for shortening the biosolids conversion to Class A biosolids in which pathogens are reduced to below detectable levels.

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The process of extraction of the pigment bixin results in a large amount of residual grain annatto. Most of this material is discarded, but you can enjoy it by incorporating it into animal feed and human food. This study aimed to dry grain residual annatto using solar energy. The beans were divided into two batches, one with oil, reproducing conditions of the grains after extraction of bixin oil, and other oil-free. The drying was performed during the day in the concrete base covered with black polythene bag with samples in trays and exposed to the sun; overnight half of the samples was placed in a dryer to dry heat accumulator and the other half was in bench laboratory for control. The grains showed levels of initial and final moisture of about 18% wb and 5% wb, respectively. Use the dryer heat accumulator at night allowed the collection of samples with the moisture ratio below 0.1 in the evening of the first day of drying, while the control samples absorbed water during the night. All models studied showed good fit to experimental data, with values of determination coefficients above 0.95 and average values of the squared deviations of less than 0.1. The diffusivity coefficients were of the order of 10-9 m2 s-1 for all treatments, with the grain samples without oil showing the greatest value.(AU)

O processo de extração do pigmento bixina resulta em uma grande quantidade de grãos residuais de urucum. A maior parte desse material é descartada, mas é possível aproveitá-lo incorporando-o em rações para animais e na alimentação humana. Neste trabalho, objetivou-se secar grãos residuais de urucum utilizando energia solar. Os grãos foram divididos em dois lotes, um com óleo, reproduzindo as condições dos grãos após a extração oleosa de bixina e outro lote sem óleo. As secagens foram realizadas durante o dia em base de concreto recoberta com lona de polietileno preta, com as amostras em bandejas e expostas ao sol; durante a noite metade das amostras foi posta a secar em secador acumulador de calor e a outra metade ficou em bancada de laboratório para controle. Os grãos apresentaram teores de umidade inicial e final de aproximadamente 18% b.u. e 5% b.u., respectivamente. A utilização do secador acumulador de calor no período noturno possibilitou a obtenção de amostras com razão de umidade abaixo de 0,1 na noite do primeiro dia de secagem, enquanto as amostras controle absorveram água no período noturno. Todos os modelos estudados apresentaram bom ajuste aos dados experimentais, com valores de coeficientes de determinação superiores a 0,95 e valores de desvios quadráticos médios inferiores a 0,1. Os coeficientes de difusividade foram da ordem de 10-9 m2 s-1, para todos os tratamentos estudados, com as amostras de grãos sem óleo apresentando o maior valor.(AU)

Assuntos

RESUMO

The process of extraction of the pigment bixin results in a large amount of residual grain annatto. Most of this material is discarded, but you can enjoy it by incorporating it into animal feed and human food. This study aimed to dry grain residual annatto using solar energy. The beans were divided into two batches, one with oil, reproducing conditions of the grains after extraction of bixin oil, and other oil-free. The drying was performed during the day in the concrete base covered with black polythene bag with samples in trays and exposed to the sun; overnight half of the samples was placed in a dryer to dry heat accumulator and the other half was in bench laboratory for control. The grains showed levels of initial and final moisture of about 18% wb and 5% wb, respectively. Use the dryer heat accumulator at night allowed the collection of samples with the moisture ratio below 0.1 in the evening of the first day of drying, while the control samples absorbed water during the night. All models studied showed good fit to experimental data, with values of determination coefficients above 0.95 and average values of the squared deviations of less than 0.1. The diffusivity coefficients were of the order of 10-9 m2 s-1 for all treatments, with the grain samples without oil showing the greatest value.

O processo de extração do pigmento bixina resulta em uma grande quantidade de grãos residuais de urucum. A maior parte desse material é descartada, mas é possível aproveitá-lo incorporando-o em rações para animais e na alimentação humana. Neste trabalho, objetivou-se secar grãos residuais de urucum utilizando energia solar. Os grãos foram divididos em dois lotes, um com óleo, reproduzindo as condições dos grãos após a extração oleosa de bixina e outro lote sem óleo. As secagens foram realizadas durante o dia em base de concreto recoberta com lona de polietileno preta, com as amostras em bandejas e expostas ao sol; durante a noite metade das amostras foi posta a secar em secador acumulador de calor e a outra metade ficou em bancada de laboratório para controle. Os grãos apresentaram teores de umidade inicial e final de aproximadamente 18% b.u. e 5% b.u., respectivamente. A utilização do secador acumulador de calor no período noturno possibilitou a obtenção de amostras com razão de umidade abaixo de 0,1 na noite do primeiro dia de secagem, enquanto as amostras controle absorveram água no período noturno. Todos os modelos estudados apresentaram bom ajuste aos dados experimentais, com valores de coeficientes de determinação superiores a 0,95 e valores de desvios quadráticos médios inferiores a 0,1. Os coeficientes de difusividade foram da ordem de 10-9 m2 s-1, para todos os tratamentos estudados, com as amostras de grãos sem óleo apresentando o maior valor.

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