Intermittent solar drying effect on the chemical composition of coffee

La calidad del café evaluada a partir de su composición química, características físicas y organolépticas se ha convertido en un tema de investigación de importancia nacional e internacional para lograr una mejor comercialización del grano de café pergamino. Se realizó un estudio del efecto del secado solar intermitente (intermitencia provocada por el día y la noche) sobre algunos compuestos químicos de interés en la calidad del café. El efecto del secado se correlacionó con atributos sensoriales para la especie C. arabica variedades Caturra y Castillo®. En la primera etapa experimental se realizó un diseño factorial por bloques con variables independientes: 6 niveles para el proceso de secado (secado mecánico: 40 ° C y 50 ºC con caudal de aire de 60 y 100 m3∙min-1∙t-1cps; secado con exposición al sol directo y secado solar en marquesina) y 2 niveles para la variedad de café (Caturra y Castillo®). Los experimentos de secado con dos repeticiones se realizaron en 3 fincas del departamento de Antioquia. En la segunda etapa experimental se construyó una marquesina para realizar el secado solar de café variedad Castillo® con recomendaciones técnicas del Comité de Cafeteros de Antioquia. Las variables como temperatura, humedad relativa y radiación solar dentro de la Marquesina se registraron con un Datalogger. Las curvas de pérdida de peso del café durante el secado solar y mecánico se construyeron bajo el método Gravimet (Cenicafé). La concentración de varios ácidos grasos y sacarosa se midió con técnicas de HPLC y GC-MS, y se concluyó que el tiempo de secado al sol afecta la evolución de estos compuestos. En este sentido, los procesos de secado al sol durante un período de tiempo más prolongado, como los de los sistemas artesanales (marquesina) condicionados por las condiciones climáticas y sometidos a la energía solar, hacen que los ácidos grasos y la sacarosa en los granos de café disminuyan de manera más significativa. En este estudio, se desarrolló un modelo matemático 1D para predecir la evolución temporal de la pérdida de humedad durante el secado solar, y se validó con éxito con datos experimentales.The quality of coffee evaluated from its chemical composition, physical and organoleptic characteristics has become a research topic of national and international importance to achieve a better commercialization of parchment coffee bean. A study was carried out of the effect of intermittent solar drying (intermittence caused by day and night) on some chemical compounds of interest in the quality of coffee. The effect of drying was correlated with sensory attributes for the species C. arabica varieties Caturra and Castillo®. In the first experimental stage, a factorial design by blocks was carried out with independent variables: 6 levels for the drying process (mechanical drying: 40 °C and 50 ºC with air flow of 60 and 100 m3/min∙tonCPS; drying with exposure to direct sun and solar drying in marquesina) and 2 levels for a variety of coffee (Caturra and Castillo®). The drying experiments with two repetitions were carried out in 3 farms in the department of Antioquia. In the second experimental stage, a canopy was built to carry out the solar drying of Castillo® variety coffee with technical recommendations from the Comite de Cafeteros de Antioquia. Variables as temperature, relative humidity and solar radiation inside the Marquesina were recorded with a Datalogger. The coffee weight loss curves during solar and mechanical drying were constructed under the Gravimet method (Cenicafé). The concentration of several fatty acids and sucrose was measured with HPLC and GC-MS techniques, and it was concluded that the sun-drying time affects the evolution of these compounds. In this sense, sun-drying processes over a longer period of time, such as those in handcrafted systems (marquesina) conditioned by climate conditions and subjected to sunlight energy, cause the fatty acids and sucrose in the coffee grains to decrease more significantly. In this study, a 1D mathematical model was developed for predicting the time evolution of the moisture loss during solar drying and was successfully validated with experimental data.DoctoradoSistemas de energí

Tendencias de investigación emergentes en cafés especiales: un análisis bibliométrico

Contextualization: The specialty coffee market has increased in popularity due to its characteristics related to improvement and exclusivity in its sensory quality factors through different processes and determined actors. Through diverse processes and specific actors, it is aimed to guarantee excellence in each stage of the production chain of specialty coffees. It involves aspects such as the best temperature, altitude, and soil conditions selection, as well as the importance of harvesting, roasting, preparation, and enjoyment, which directly influences the quality experience. Knowledge gap: In relation to the field of knowledge on coffee, the application of literature reviews is deficient, mainly through bibliometric analysis techniques. Additionally, there is no document addressing the topic of specialty coffees or exhaustively describing the different lines of research and indicators. Purpose: This research aims to synthesize the academic literature related to the specialty coffee area through a bibliometric analysis. Hence, a historical search related to the field of knowledge is necessary to determine different indicators describing the current state of scientific production. Methodology: 417 documents were collected from the Scopus database for review. Different indicators are built to describe the main topics concerning production, authors, journals, countries, and most cited articles. Additionally, bibliometric networks are built to identify trends. Finally, the future lines of research are described through a qualitative analysis. Results and conclusions: Results reveal how the production and marketing context decisively influence research, especially considering that Brazil is the leading academic producer in this field. Through indicators and bibliometric networks, the lines of research that analyze the physicochemical components, the sensory quality of coffee, the market, and the consumption and governance of specialty coffees are recognized.Contextualización: el mercado de cafés especiales ha aumentado su popularidad debido a sus características relacionadas con una mejora y una exclusividad en sus factores sensoriales de calidad, a través de diferentes procesos y actores determinados, con los que se busca garantizar la excelencia en cada etapa de la cadena productiva de los cafés especiales. Esto implica aspectos como la selección de las mejores condiciones de temperatura, altitud y suelo, así como la importancia de la recolección, el tueste, la preparación y el disfrute, los cuales influyen directamente en la experiencia de calidad. Vacío de conocimiento: con relación al campo de conocimiento de los cafés, es deficiente la aplicación de revisiones de literatura, especialmente mediante técnicas de análisis bibliométrico. Adicionalmente, no se encuentra ningún documento que aborde la temática de cafés especiales y describa de forma exhaustiva las diferentes líneas de investigación e indicadores. Propósito: esta investigación pretende sintetizar la literatura académica relacionada con el campo de los cafés especiales por medio de un análisis bibliométrico, por lo que se hace necesaria una búsqueda histórica en relación con el campo de conocimiento para determinar diferentes indicadores que describan el estado actual de la producción científica.  Metodología: para la revisión se recolectaron 417 documentos de la base de datos Scopus. Se construyeron diferentes indicadores que describen los principales tópicos en relación con la producción, autores, revistas, países y artículos más citados, además, se construyen redes bibliométricas para identificar tendencias. Finalmente, mediante un análisis cualitativo se describen futuras líneas de investigación.  Resultados y conclusiones: los resultados revelan cómo el contexto de producción y comercialización influye de manera determinante en la investigación, especialmente considerando que Brasil ostenta el liderazgo como principal productor académico en este campo. A través de indicadores y redes bibliométricas, se reconocen líneas de investigación que analizan los componentes fisicoquímicos, la calidad sensorial del café, el mercado, consumo y gobernanza de los cafés especiales

Effect of Refractance Window™ and oven drying on physicochemical and sensory properties of peach (Prunus persica L.) surplus

Currently, approximately 34% of fruit is lost and wasted in emerging economies due to inefficient post-harvest processes, technological shortcomings, lesser valorization of surpluses, and byproducts. Peach (Prunus persica L.) is a fruit with a good yearly growth rate but higher postharvest losses in Colombia. One way to take advantage of this type of product is through the application of drying processes that increase its shelf life and its inclusion in the food chain. Refractance Window Drying (RWD) is a fourth generation drying technique implemented by the food industry in the last few decades and has been applied to several dehydrated food products. This study compared the effects of different drying methods on the physical and sensory properties of peaches surplus. Treatments consisted of (i) peaches were sliced (1, 2, and 3 mm thickness) and dried using RWD at 86°C, (ii) peach pulp mixed with maltodextrin (MD) (0.12–0.33 kg of MD/kg of sample) and RWD (RWD-MD), and (iii) conventional oven drying (OD) at 60°C (3 mm thick) dried for 24 h. The study found that the drying method significantly (p < 0.05) affected the texture, color, and general taste of peaches. The results showed that processing treatments combined with different drying conditions affected the physical properties of the peach. RWD in slices reduced water content to 0.05 kg H2O/kg in 40 min, showing fewer effects on color attributes. A surface response analysis on RWD showed good correlations for water activity (R2 = 0.8652–0.9894) and moisture content (R2 = 0.7048–0.9826). A higher diffusion coefficient (1.63 × 10−6 m2 s−1) was observed for RWD in slices with 3 × 10−3 m of thickness; however, for RWD-MD, differences in diffusion coefficients were present for the lowest MD addition (0.12 kg/kg), vitamin C was not detected on the dried slices, and higher concentration of β-carotene (175.88 μg/100 g) was found on the thinner slices. Principal component analysis showed that RWD in the slices was the most suitable drying process, followed by OD. Sensory analysis showed good acceptability for RWD slices after 30 days of storage

Estudo do efeito da geometria de um secador solar típico para café com CFD

The objective of the present investigation was to computationally model a typical solar dryer for coffee, considering some alternative geometric configurations in the opening of windows to improve the thermal conditions within the drying structure which enable the water removal process of wet parchment coffee. The model was simulated in Ansys CFX® software. Simulation results showed that the geometry with an opening of 25 % in the air output window increased temperature in the coffee layer to 4.2 °C over room temperature, guaranteeing uniform drying, whereas the typical geometry with a 100 % opening increased temperature to 3.8 °C. When the maximum window opening for input and output of air was used, the relative humidity of air within the dryer decreased in comparison with the other geometries.El objetivo de la presente fue modelar el comportamiento térmico de un secador solar típico para café tomando en consideración algunas configuraciones geométricas en la apertura de ventanas, en pos de mejorar las condiciones de secado natural al interior de la estructura. El modelo se simuló con datos experimentales en un secador solar típico en Colombia con Ansys CFX®. Los resultados mostraron que la geometría con una apertura del 25 % en la ventana para la salida del aire aumentó la temperatura sobre la capa de café hasta 4,2 °C con respecto a la temperatura ambiente, lo cual garantiza uniformidad en el secado, mientras la geometría típica con una apertura del 100 % aumentó la temperatura hasta 3,6 °C, no obstante, con ambas aperturas se aumentó la humedad relativa sobre la capa de café hasta 0,7 % con respecto a la humedad relativa ambiental. Con la apertura máxima de las ventanas disminuyó la humedad relativa del aire.O objetivo do presente trabalho foi modelar o comportamento térmico de um secador solar típico para café ao levar em consideração algumas configurações geométricas na abertura de janelas, a fim de melhorar as condições de secagem natural no interior da estrutura. O modelo foi simulado com dados experimentais em um secador solar típico na Colômbia com Ansys CFX®. Os resultados mostraram que a geometria com uma abertura de 25 % na janela para saída do ar aumentou a temperatura sobre a camada de café até 4,2 °C com respeito à temperatura ambiente, o que garante uniformidade na secagem, ao passo que a geometria típica com uma abertura de 100 % aumentou a temperatura até 3,6 °C, não obstante, com ambas as aberturas houve um aumento da umidade relativa sobre a camada de café de até 0,7 % em comparação com a umidade relativa ambiental. Com a abertura máxima das janelas a umidade relativa do ar diminuiu

Efecto del secado mecánico en la calidad en taza del café especial producido en Caicedonia y Sevilla (Valle del Cauca).

El objetivo del presente trabajo fue evaluar el efecto de la aplicación del proceso de secado mecánico, sobre la calidad sensorial del café especial producido en tres fincas cafeteras de los municipios de Caicedonia (2 fincas) y Sevilla (1 finca). Asimismo, los resultados se compararon con muestras de secado al sol natural. Finalmente, este trabajo es una alternativa de procesamiento para los productores de café, con el objetivo de reducir el tiempo en el proceso de secado y producir granos de café que puedan ser comercializados en el mercado internacional como café de especialidad

Data_Sheet_1_Effect of Refractance Window™ and oven drying on physicochemical and sensory properties of peach (Prunus persica L.) surplus.pdf

Currently, approximately 34% of fruit is lost and wasted in emerging economies due to inefficient post-harvest processes, technological shortcomings, lesser valorization of surpluses, and byproducts. Peach (Prunus persica L.) is a fruit with a good yearly growth rate but higher postharvest losses in Colombia. One way to take advantage of this type of product is through the application of drying processes that increase its shelf life and its inclusion in the food chain. Refractance Window Drying (RWD) is a fourth generation drying technique implemented by the food industry in the last few decades and has been applied to several dehydrated food products. This study compared the effects of different drying methods on the physical and sensory properties of peaches surplus. Treatments consisted of (i) peaches were sliced (1, 2, and 3 mm thickness) and dried using RWD at 86°C, (ii) peach pulp mixed with maltodextrin (MD) (0.12–0.33 kg of MD/kg of sample) and RWD (RWD-MD), and (iii) conventional oven drying (OD) at 60°C (3 mm thick) dried for 24 h. The study found that the drying method significantly (p 2O/kg in 40 min, showing fewer effects on color attributes. A surface response analysis on RWD showed good correlations for water activity (R2 = 0.8652–0.9894) and moisture content (R2 = 0.7048–0.9826). A higher diffusion coefficient (1.63 × 10−6 m2 s−1) was observed for RWD in slices with 3 × 10−3 m of thickness; however, for RWD-MD, differences in diffusion coefficients were present for the lowest MD addition (0.12 kg/kg), vitamin C was not detected on the dried slices, and higher concentration of β-carotene (175.88 μg/100 g) was found on the thinner slices. Principal component analysis showed that RWD in the slices was the most suitable drying process, followed by OD. Sensory analysis showed good acceptability for RWD slices after 30 days of storage.</p