Estabilidad de betanina en extracto acuoso y etanòlico en cáscaras de pitahaya roja (Hylocereus undatus Haw)
Fecha
2018
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Universidad de Guayaquil. Facultad de Ciencias Químicas
Resumen
Los colorantes sintéticos constituyen la segunda opción de los consumidores ya que prefieren productos naturales, generalmente obtenidos de vegetales y frutas. En la presente investigación se trabajó con las cáscaras de pitahaya roja (Hylocereus undatus Haw), provenientes del Cantón Cerecita de la Provincia del Guayas que pueden proporcionar pigmentos naturales como la Betanina. El objetivo de este trabajo fue evaluar la estabilidad de dicho pigmento en extractos acuoso y etanólico en condiciones variables de temperatura (4°C,
25°C, 60°C), pH (3, 5, 8) y tiempo de almacenamiento. Los extractos etanòlico y acuoso fueron analizados por 15 días empleando un espectrofotómetro UV/VIS, dentro de un rango visible de 200 y 600 nm, obteniendo la presencia de Betanina entre longitudes de ondas de 537 y 540 nm por técnica de HPLC. Aplicando el modelo cinético para el proceso de degradación, se calculó la constante de velocidad (k); y se obtuvo la energía de activación (Ea) para ambos extractos, según la ecuación de Arrhenius. Los valores obtenidos indican que la estabilidad en medio etanòlico se incrementa al aumentar los valores de pH y un comportamiento inverso en medio acuoso. Los resultados indican que la mayor degradación del pigmento Betanina ocurre a la temperatura de 60 °C a pH 8, tanto en medio acuoso como etanólico y que la mayor estabilidad se alcanza a la temperatura de 4°C a pH 3 ó 5
The synthetic colorants are the second choice of consumers because they prefer natural products, generally obtained from vegetables and fruits. In the present investigation we worked with the red pitahaya peels (Hylocereus undatus haw), from the Canton Cerecita of the Province of Guayas that can provide natural pigments such as Betanin. The objective of this work was to evaluate the stability of Betanin in aqueous and ethanolic extracts under variable temperature conditions (4 °C, 25 °C, 60 °C), pH (3, 5, 8) and storage time. The ethanolic and aqueous extracts were analyzed for 15 days using a UV / VIS spectrophotometer, within a visible range of 200 and 600 nm, obtaining the presence of Betanin between wavelengths of 537 and 540 nm by HPLC technique. Applying the kinetic model for the degradation process, the velocity constant (k) was calculated; and the activation energy (Ea) was obtained for both extracts, according to the Arrhenius equation. The obtained values indicate that the stability in ethanolic medium increases with increasing pH values and an inverse behavior in aqueous medium. The results indicate that the greatest degradation of the Betanin pigment occurs at a temperature of 60 ° C to pH 8, both in aqueous and ethanol medium and that the highest stability is reached at a temperature of 4 °C at pH 3 or 5
The synthetic colorants are the second choice of consumers because they prefer natural products, generally obtained from vegetables and fruits. In the present investigation we worked with the red pitahaya peels (Hylocereus undatus haw), from the Canton Cerecita of the Province of Guayas that can provide natural pigments such as Betanin. The objective of this work was to evaluate the stability of Betanin in aqueous and ethanolic extracts under variable temperature conditions (4 °C, 25 °C, 60 °C), pH (3, 5, 8) and storage time. The ethanolic and aqueous extracts were analyzed for 15 days using a UV / VIS spectrophotometer, within a visible range of 200 and 600 nm, obtaining the presence of Betanin between wavelengths of 537 and 540 nm by HPLC technique. Applying the kinetic model for the degradation process, the velocity constant (k) was calculated; and the activation energy (Ea) was obtained for both extracts, according to the Arrhenius equation. The obtained values indicate that the stability in ethanolic medium increases with increasing pH values and an inverse behavior in aqueous medium. The results indicate that the greatest degradation of the Betanin pigment occurs at a temperature of 60 ° C to pH 8, both in aqueous and ethanol medium and that the highest stability is reached at a temperature of 4 °C at pH 3 or 5
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PIGMENTO NATURAL, ESTABILIDAD, BETALAÍNAS, BETACIANINAS, BETAXANTINAS, BETANINA