Formulación de un recubrimiento comestible para frutas cítricas, estudio de su impacto mediante aproximación metabolómica y evaluación de la calidad poscosecha

RESUMEN: El objetivo del presente trabajo fue el desarrollo un recubrimiento comestible compuesto por dos productos naturales obtenidos de residuos agroindustriales como ingredientes principales: Pectina cítrica como agente estructural y Aceite esencial de cítricos como agente antifúngico, ambos, integrados en una formulación hidrocoloidal compuesta, se determinaron sus propiedades funcionales mediante la aplicación in vivo del recubrimiento en una línea de tratamiento industrial, se evaluaron variables relacionadas con la calidad externa e interna de los frutos, se evaluó la actividad antifúngica y se estableció una plataforma analítica metabolómica para la identificación de marcadores de cambio mediante metodología metabolite profiling utilizando un sistema GC/qEIMS. Durante la etapa de desarrollo de la formulación se optimizó la retención de sustancias volátiles en la matriz de la película de recubrimiento, las sustancias retenidas mostraron una potente actividad fungistática frente Penicillium digitatum y Penicillium italicum, entre ellas se destacaron principalmente los componentes aromáticos: Carvacrol, Timol y p-Cimeno, los cuales aportaron una sinergia considerable a la bioactividad del componente mayor (Limoneno 74-93%). La plataforma analítica permitió establecer diferentes librerías automatizadas para más de 400 metabólitos, entre ellos, se destacaron alrededor de 180 moléculas target que aportaron información de los cambios en la química de la maduración, senescencia y del impacto de materiales de recubrimiento: metabólitos terpénicos (volátiles monoterpénicos y sesquiterpénicos), carbohidratos, aminoácidos, lipidos, ácidos orgánicos (cinámicos, fenólicos) y otros. Finalmente se obtuvo un prototipo de formulación, el cual se comparó con ceras comerciales en cuanto a su capacidad para preservar la vida útil y conservar la calidad de naranja valencia en condiciones simuladas de comercialización, frigoconservación y cuarentena de exportación.ABSTRACT: Technologies exist to extend the life of fresh fruit and vegetables in post harvest, to preserve the attack of pathogenic organisms and maintain overall quality. It emphasizes the use of edible coatings, which form a barrier on the surface of the fruit to modulate the exchange of gases and water vapor. The most important functional characteristic of an edible film is the resistance to moisture migration, therefore we must keep the critical levels of water activity to ensure the quality and integrity metabolic control ripening and senescence. However, it should ensure a certain permeability to oxygen and carbon dioxide to prevent anaerobic status. Currently edible coatings are made from varieties of polysaccharides, proteins, natural waxes and resins, among others, with GRAS designation. The technical challenges involved in the development of edible coatings with functional properties include selecting the type and concentration of the materials used in the formulation, preparation techniques, durability, and adhesion, among others. Therefore basic studies are needed to design the functional properties of edible films for applications in specific plant. The aim of this study was to develop an edible coating composed of two natural products derived from agro-industrial wastes as ingredients: Citrus Pectin as a structural agent and citrus essential oil as an antifungal agent, both integrated into a composite hydrocolloidal formulation. Their functional properties were identified in vivo by applying the coating on industrial processing line, we evaluated variables related to external and internal quality of fruit, antifungal activity was evaluated and established a metabolomics analytical platform for the identification of markers of change through metabolite profiling method using a GC/qEIMS. During the development stage of the formulation was optimized the retention of volatile substances in the coating film matrix, retained substances showed potent fungistatic activity against Penicillium digitatum and Penicillium italicum, including mainly highlighted the aromatic components: Carvacrol, Thymol and p-Cymene, which provided a considerable synergy to the bioactivity of the major component (74-93% limonene). The analytical platform allowed us to establish different automated libraries for more than 400 metabolites, including about 180 highlighted target molecules that provided information on changes in the chemistry of maturation, senescence and the impact of coating materials: terpene metabolites (volatile monoterpenes and sesquiterpenes), carbohydrates, lipids, amino acids, organic acids (cinnamic, phenolic) and others. Finally, we obtained a prototype design, which was compared with commercial waxes in their ability to preserve life and maintain the quality of Valencia oranges in simulated conditions of merchantability, cold storage and export quarantine. The prototype excelled in some quality parameters and showed a better performance in terms of direct marketing for 2 weeks (25 ° C), and was even useful for cold storage for 4 weeks (7°C). The proposed formulation proved to be useful in terms of direct marketing. No formulation has effectiveness in cold storage conditions