Vida útil de harina de quinua (Chenopodium quinoa) obtenida por secado convectivo y envasada en polietileno de baja densidad
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Date
2024
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Universidad Nacional de Trujillo
Abstract
La finalidad llevada a cabo en esta investigación fue la estimación del tiempo de vida útil de harina de quinua (Chenopodium quinoa), variedad Blanca Junín. Las características del envase fueron determinadas de acuerdo a la permeabilidad del polietileno de baja densidad (9.15 ×10−7 kg H2O. m-2.Pa-1.dia-1) y del espesor (100μm). Muestras de 5 g de esta harina, (humedad inicial de 13.7% en base húmeda), fueron colocadas en 8 recipientes de vidrio que contenían sales saturadas. Las lecturas programadas para la Aw fueron desde 0.1 a 0.9, a temperaturas de 20, 25 y 30°C. El tiempo en el que se consiguió el balance termodinámico (humedad en equilibrio) fue de 15 días. El modelo empleado (GAB) mostró un adecuado ajuste frente a los datos obtenidos en la experimentación, en vista de que los coeficientes de correlación eran superiores al 0.95 y el error medio relativo (%E) inferior al 4.7%, informando 0.0867, 0.0850 y 0 .0818 g de H2O/g ms como valores para monocapa para las tres temperaturas analizadas respectivamente. La vida útil se evaluó en bolsas de polietileno (baja densidad) y la humedad crítica del 15% (0.1765 g H2O/ g bs), valor tomado como referente de la empresa Qali Warma (ficha técnica), se utilizó el modelo de Heiss y Eichner, bajo las condiciones de la ciudad de Huamachuco, HR (humedad relativa) del 80%, y a una temperatura promedio de 15°C siendo 303 días (10 meses). A su vez se evaluaron propiedades termodinámicas como entropía (𝚫𝚫S), entalpia (𝚫𝚫H) y energía libre de Gibbs (𝚫𝚫G). Los valores de entropía (𝚫𝚫S)>0, señalaron que la adsorción del sistema es no estructurada o de alto desorden a nivel molecular. La energía libre de Gibbs (𝚫𝚫G) al tener valores negativos, muestran una adsorción espontánea con un proceso entrópico controlado.
ABSTRACT The purpose carried out in this research was the estimation of the useful life of quinoa flour (Chenopodium quinoa), Blanca Junín variety. The characteristics of the container were determined according to the permeability of low-density polyethylene (9.15×10-7 kg H2O.m-2.Pa-1.day-1) and the thickness (100μm). Samples of 5 g of this flour, (initial humidity of 13.7% on a wet basis), were placed in 8 glass jars containing saturated salts. The programmed readings for water activity were from 0.1 to 0.9, at temperatures of 20, 25 and 30 °C. The time in which thermodynamic balance (equilibrium humidity) was achieved was 15 days. The model used (GAB) showed an adequate fit to the experimental data, given that the correlation coefficients were greater than 0.95 and the relative mean error (%E) less than 4.7%, reporting 0.0867, 0.0850 and 0.0818 g. of water/g d.b. as values for monolayer for the three temperatures analyzed respectively. The useful life was evaluated in polyethylene bags (low density) and the critical humidity of 15% (0.1765 g H2O/g d.b.), a value taken as a reference from the company Qali Warma (technical sheet), the Heiss model was used and Eichner, under the conditions of the city of Huamachuco, relative humidity of 80%, and at an average temperature of 15°C for 303 days (10 months). In turn, thermodynamic properties such as entropy (𝚫𝚫S), enthalpy (𝚫𝚫H) and Gibbs free energy (𝚫𝚫G) were evaluated. The entropy values (𝚫𝚫S) >0 indicated that the adsorption of the system is unstructured or highly disordered at the molecular level. The Gibbs free energy (𝚫𝚫G), having negative values, shows spontaneous adsorption with a controlled entropic process.
ABSTRACT The purpose carried out in this research was the estimation of the useful life of quinoa flour (Chenopodium quinoa), Blanca Junín variety. The characteristics of the container were determined according to the permeability of low-density polyethylene (9.15×10-7 kg H2O.m-2.Pa-1.day-1) and the thickness (100μm). Samples of 5 g of this flour, (initial humidity of 13.7% on a wet basis), were placed in 8 glass jars containing saturated salts. The programmed readings for water activity were from 0.1 to 0.9, at temperatures of 20, 25 and 30 °C. The time in which thermodynamic balance (equilibrium humidity) was achieved was 15 days. The model used (GAB) showed an adequate fit to the experimental data, given that the correlation coefficients were greater than 0.95 and the relative mean error (%E) less than 4.7%, reporting 0.0867, 0.0850 and 0.0818 g. of water/g d.b. as values for monolayer for the three temperatures analyzed respectively. The useful life was evaluated in polyethylene bags (low density) and the critical humidity of 15% (0.1765 g H2O/g d.b.), a value taken as a reference from the company Qali Warma (technical sheet), the Heiss model was used and Eichner, under the conditions of the city of Huamachuco, relative humidity of 80%, and at an average temperature of 15°C for 303 days (10 months). In turn, thermodynamic properties such as entropy (𝚫𝚫S), enthalpy (𝚫𝚫H) and Gibbs free energy (𝚫𝚫G) were evaluated. The entropy values (𝚫𝚫S) >0 indicated that the adsorption of the system is unstructured or highly disordered at the molecular level. The Gibbs free energy (𝚫𝚫G), having negative values, shows spontaneous adsorption with a controlled entropic process.
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Keywords
Quinua, Humedad en equilibro, Modelo de GAB, Vida útil