Publication: DESARROLLO DE PELÍCULAS COMESTIBLES CON INCORPORACIÓN DE ACEITE ESENCIAL DE ANÍS MEDIANTE MÉTODO DE EMULSIFICACIÓN
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Date
2017
Authors
PARRA AEDO, MARÍA ISABEL
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Abstract
La demanda de fruta fresca exige que llegue a su destino en condiciones de calidad, lo que se dificulta por la alta perecebilidad de ésta durante su transporte. Una posible solución es usar tecnologías de preservación con recubrimientos comestibles. El biopolímero quitosano ha destacado por formar películas con propiedades mecánicas, adhesivas y de permeabilidad de calidad. Por otro lado, el aceite esencial de anís contiene anisol como principio activo, el cual presenta elevada actividad antimicrobiana y antifúngica. Además, al ser un compuesto volátil, no es necesario que el aceite esencial de anís esté en contacto con el alimento para protegerlo.Este estudio se centra en el desarrollo de películas comestibles a base de quitosano, con incorporación de aceite esencial de anís mediante el método de emulsificación.Para esto se diseñaron películas a base de soluciones de quitosano al 2% p/v en ácido láctico al 1% v/v, las cuales se mantuvieron en agitación magnética constante durante 48 horas. Luego se tomaron 80 mL de solución de quitosano al 2% p/v, se le agregó aceite vegetal (0 mL, 0,25 mL y 0,5 mL, según correspondiera) y se agitó a 600 rpm durante 5 minutos, luego se añadió aceite esencial de anís (0 mL, 0,5 mL y 1 mL, según fuera el caso), y se continuó con la agitación constante a 2000 rpm durante otros 20 minutos. Luego se agregó 0,5 mL de glicerol como plastificante y 0,25 mL de Tween 80 como emulsificante, agitándose durante 20 minutos más. Para terminar, la solución resultante se mantuvo durante 1 hora dentro de un desecador conectado a una bomba de vacío a 60 psi, para eliminar las burbujas formadas durante la agitación. Para la formación de las películas, se tomaron 20 mL de solución y se depositaron en placas acrílicas de 9 cm x 16,5 cm, se llevaron a horno de secado y se mantuvieron a 30°C y 30% HR durante 48 horas. Se midió permeabilidad al vapor de agua (WVP), resistencia a las fuerzas de tracción y punción, opacidad y ángulo de contacto.Los resultados obtenidos para WVP estuvieron comprendidos entre 5,18*1011 y 6,02*1011 [g*m/s*m2*Pa], para las pruebas de tracción se obtuvieron esfuerzos entre 0,97 y 2,69 [MPa], deformaciones entre 2,67 y 15,79 [%], Módulo de Young entre 13,08 y 31,83 [MPa]; mientras que los ensayos de punción tuvieron por respuesta cargas entre 3,51 y 15,57 [N] y distancias entre 9,56 y 13,40 [mm]. Por su parte, la opacidad entregó resultados entre 31,64 y 289,70 [UA/nm] y el ángulo de contacto se movió entre 38,22° y 62,20°.Una vez realizadas las pruebas de laboratorio, se estableció que las películas con mayor contenido de aceite vegetal presentaban menor permeabilidad al vapor de agua, menor resistencia a las fuerzas de tracción y punción, mayor ángulo de contacto entre el agua y la superficie de la película y mayor opacidad frente al paso de la luz. Todas las películas lucían visualmente similares, no aceitosas, y presentaban sutil aroma a anís, como residuo del aceite esencial. Por otro lado, el contenido de aceite esencial de anís no mostró ser un factor determinante en la formación de las películas comestibles, según las características evaluadas en esta investigación.
The demand for fresh fruit requires that it reaches its destination in conditions of quality, which is made difficult by the high perishability of this during transport. To solve this, investments have been made in technologies for the preservation of foods with edible coatings. The chitosan biopolymer has been outstanding for forming films with quality mechanical, adhesives and permeability properties. On the other hand, the anise essential oil contains anisole as active principle, which has high antimicrobial and antifungal activity. In addition, being a volatile compound, it is not necessary for the anise essential oil to be in contact with the food to protect it.This study focuses on the development of chitosan-based edible films, incorporating essential oil of anise by the emulsification method.Por this purpose, films based on 2% p/v chitosan were designed, prepared by dispersion of 6 [g] of chitosan in 300 mL of 1% v/v lactic acid, which were maintained in constant magnetic stirring for 48 hours. Then 80 mL of 2% p/v chitosan solution was added, vegetable oil (0 mL, 0,25 mL and 0,5 mL, as appropriate) was added and this was stirred at 600 rpm for 5 minutes, then anise essential oil (0 mL, 0,5 mL and 1 mL, as the case may be) was added, and continue stirring at 2000 rpm for another 20 minutes, until the correct emulsification of the mixture is achieved. Then, 0,5 mL of glycerol as plasticizer and 0,25 mL of Tween 80 were then added as the emulsifying surfactant, to be allowed to stir for an additional 20 minutes. To conclude, the resulting solution was maintained for a period of 1 hour in a desiccator connected to a vacuum pump at 60 psi, to eliminate any bubbles that might have formed during stirring. For the formation of the films, 20 mL of solution were taken and deposited on acrylic plates of 9 cm x 16,5 cm, then desposited in a drying oven and kept under conditions of 30 ° C and 30% RH for 48 hours.The results obtained for WVP were between5,18*1011 y 6,02*1011 [g*m/s*m2*Pa], for the tensile tests, tensions were obtained between 0,97 y 2,69 [MPa], deformations between 2,67 y 15,79 [%], Young's modulus between 13,08 y 31,83 [MPa]; while puncture tests had loads between 3.51 and 15.57[N] and distances between 9.56 and 13.40[mm]. On the other hand, the opacity gave results between 31.64 and 289.70 [UA/ nm] and the contact angle moved between 38.22° and 62.20°.After the laboratory tests, it was established that films with higher vegetable oil content had lower permeability to water vapor, lower resistance to tensile and puncture forces, higher contact angle between water and the surface of the film and higher opacity in front of the passage of the light. All films looked visually similar, non-oily, and presented little to no aroma of anise, as residue of the essential oil. On the other hand, the essential oil content of anise was not a determining factor in the formation of edible films, according to the evaluated characteristics in this research.
The demand for fresh fruit requires that it reaches its destination in conditions of quality, which is made difficult by the high perishability of this during transport. To solve this, investments have been made in technologies for the preservation of foods with edible coatings. The chitosan biopolymer has been outstanding for forming films with quality mechanical, adhesives and permeability properties. On the other hand, the anise essential oil contains anisole as active principle, which has high antimicrobial and antifungal activity. In addition, being a volatile compound, it is not necessary for the anise essential oil to be in contact with the food to protect it.This study focuses on the development of chitosan-based edible films, incorporating essential oil of anise by the emulsification method.Por this purpose, films based on 2% p/v chitosan were designed, prepared by dispersion of 6 [g] of chitosan in 300 mL of 1% v/v lactic acid, which were maintained in constant magnetic stirring for 48 hours. Then 80 mL of 2% p/v chitosan solution was added, vegetable oil (0 mL, 0,25 mL and 0,5 mL, as appropriate) was added and this was stirred at 600 rpm for 5 minutes, then anise essential oil (0 mL, 0,5 mL and 1 mL, as the case may be) was added, and continue stirring at 2000 rpm for another 20 minutes, until the correct emulsification of the mixture is achieved. Then, 0,5 mL of glycerol as plasticizer and 0,25 mL of Tween 80 were then added as the emulsifying surfactant, to be allowed to stir for an additional 20 minutes. To conclude, the resulting solution was maintained for a period of 1 hour in a desiccator connected to a vacuum pump at 60 psi, to eliminate any bubbles that might have formed during stirring. For the formation of the films, 20 mL of solution were taken and deposited on acrylic plates of 9 cm x 16,5 cm, then desposited in a drying oven and kept under conditions of 30 ° C and 30% RH for 48 hours.The results obtained for WVP were between5,18*1011 y 6,02*1011 [g*m/s*m2*Pa], for the tensile tests, tensions were obtained between 0,97 y 2,69 [MPa], deformations between 2,67 y 15,79 [%], Young's modulus between 13,08 y 31,83 [MPa]; while puncture tests had loads between 3.51 and 15.57[N] and distances between 9.56 and 13.40[mm]. On the other hand, the opacity gave results between 31.64 and 289.70 [UA/ nm] and the contact angle moved between 38.22° and 62.20°.After the laboratory tests, it was established that films with higher vegetable oil content had lower permeability to water vapor, lower resistance to tensile and puncture forces, higher contact angle between water and the surface of the film and higher opacity in front of the passage of the light. All films looked visually similar, non-oily, and presented little to no aroma of anise, as residue of the essential oil. On the other hand, the essential oil content of anise was not a determining factor in the formation of edible films, according to the evaluated characteristics in this research.
Description
Catalogado desde la version PDF de la tesis.
Keywords
PELICULAS COMESTIBLES A BASE DE QUITOSANO , PRESERVACION , PRUEBAS DE LABORATORIO , TRANSPORTE DE FRUTA