Efecto de la temperatura en las isotermas de adsorción de tres variedades de quinua (Chenopodium quinoa Willd)
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Date
2024
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Universidad Nacional de Trujillo
Abstract
El estudio de la relación del contenido de humedad de equilibrio y la actividad del agua es fundamental para preservar la propiedades nutricionales y maximizar la vida útil de los alimentos controlando las condiciones de almacenamiento. Así, este estudio tiene como objetivo determinar el efecto de la temperatura en isotermas de adsorción, calor isostérico y vida útil de tres variedades de quinua (INIA Salcedo, Pasankalla Roja y Negra Collana) a 30, 35 y 45°C. Las isotermas fueron obtenidas mediante el método DDI en un rango de actividad de agua (aw) de 0.1 a 0.9. Los resultados reflejan que el incremento de temperatura, a actividad de agua constante, conduce a una disminución del contenido de humedad de equilibrio en la isoterma de adsorción de humedad. El mejor ajuste de datos experimentales se obtuvo con el modelo GAB con valores de R2 mayores a 0.99 y un %E menor a 1.95% a cada temperatura evaluada. El calor isostérico neto tiende a ser constante y cercano a cero con una predisposición decreciente al aumentar el contenido de humedad con valores que de 42.07 a 2.21 KJ/mol para INIA Salcedo, 124.78 a 5.23 KJ/mol para Pasankalla Roja y 66.53 a 4.37 KJ/mol para Negra Collana. La vida Util estimada para INIA Salcedo, Pasankalla Roja y Negra Collana estuvo comprendida en el rango de 19.02 a 9.67 meses; 16.63 a 11.8 meses y 15.94 a 9.59 meses, respectivamente, entre las temperaturas de 30 a 45 °C.
ABSTRACT The study of the relationship between equilibrium moisture content and water activity is fundamental to preserve the nutritional properties and maximize the shelf life of foods by controlling storage conditions. Thus, the objective of this study was to determine the effect of temperature on adsorption isotherms, isosteric heat and shelf life of three quinoa varieties (INIA Salcedo, Pasankalla Roja and Negra Collana) at 30, 35 and 45 °C. The isotherms were obtained by the DDI method in a range of water activity (aw) from 0.1 to 0.9. The results reflect that increasing temperature, at constant water activity, leads to a decrease in equilibrium moisture content in the moisture adsorption isotherm. The best experimental data fit was obtained with the GAB model with R2 values greater than 0.99 and a %E less than 1.95% at each temperature evaluated. The net isosteric heat tends to be constant and close to zero with a decreasing bias with increasing moisture content with values ranging from 42.07 to 2.21 KJ/mol for INIA Salcedo, 124.78 to 5.23 KJ/mol for Pasankalla Roja and 66.53 to 4.37 KJ/mol for Negra Collana. Estimated useful life for INIA Salcedo, Pasankalla Roja and Negra Collana ranged from 19.02 to 9.67 months; 16.63 to 11.8 months and 15.94 to 9.59 months, respectively, between temperatures of 30 and 45 °C.
ABSTRACT The study of the relationship between equilibrium moisture content and water activity is fundamental to preserve the nutritional properties and maximize the shelf life of foods by controlling storage conditions. Thus, the objective of this study was to determine the effect of temperature on adsorption isotherms, isosteric heat and shelf life of three quinoa varieties (INIA Salcedo, Pasankalla Roja and Negra Collana) at 30, 35 and 45 °C. The isotherms were obtained by the DDI method in a range of water activity (aw) from 0.1 to 0.9. The results reflect that increasing temperature, at constant water activity, leads to a decrease in equilibrium moisture content in the moisture adsorption isotherm. The best experimental data fit was obtained with the GAB model with R2 values greater than 0.99 and a %E less than 1.95% at each temperature evaluated. The net isosteric heat tends to be constant and close to zero with a decreasing bias with increasing moisture content with values ranging from 42.07 to 2.21 KJ/mol for INIA Salcedo, 124.78 to 5.23 KJ/mol for Pasankalla Roja and 66.53 to 4.37 KJ/mol for Negra Collana. Estimated useful life for INIA Salcedo, Pasankalla Roja and Negra Collana ranged from 19.02 to 9.67 months; 16.63 to 11.8 months and 15.94 to 9.59 months, respectively, between temperatures of 30 and 45 °C.
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Keywords
Quinua, Isoterma, Temperatura, Humedad en equilibrio, Monocapa, Calor isostérico