Loss of Sensory Cup Quality: Physiological and Chemical Changes during Green Coffee Storage.

Coffee is one of the most valued consumer products. Surprisingly, there is limited scientific knowledge about the biochemical processes during the storage of green coffee that affects its sensory quality. This review analyzes the impact of the different variables involved in the green coffee storage on quality from a chemical point of view. Further, it highlights the relationship between the physiological processes of the grain, its viability, and shelf-life. Notably, the storage conditions and postharvest treatment affect both the longevity and the sensory quality of the coffee, probably due to the biological behavior of green coffee. Various studies found modifications in their chemical profiles involving carbohydrates, lipids, proteins/amino acids, and phenolic compounds. To make future studies more comparable, we recommend standardized protocols for evaluating and linking the sensory coffee quality with instrumental analysis methods and pre-defined settings for experimental storage conditions.

Extracción y caracterización reológica del mucílago de Malvaviscus penduliflorus (San Joaquín) / Extraction and rheological characterization of Malvaviscus penduliflorus (sleeping hibiscus) mucilage

Introducción: los mucílagos presentan amplias e importantes aplicaciones en la industria farmacéutica, alimenticia y cosmética, entre otras. Los atributos primordiales de estos compuestos poliméricos es que son biocompatibles, económicos y fácilmente disponibles. Objetivos: desarrollar un método para la extracción del mucílago de hojas de San Joaquín y describir el comportamiento reológico de este. Métodos: se emplearon 5 procedimientos para la obtención del mucílago, que corresponden a extracción por ebullición, por baño de María, por microondas, por ultrasonido y por reflujo. posteriormente, se realizó la caracterización reológica de los mucílagos a temperatura de 25 ºC, el rendimiento de estos se valoró mediante la determinación de la viscosidad de las soluciones; también se verificó la concordancia con los resultados por el método reológico, aplicando un ensayo gravimétrico, en el cual se precipitó el mucílago utilizando etanol para después secarlo y pesarlo. Resultados: se obtuvieron 5 soluciones que contenían mucílago, las cuales presentaban color café claro y aspecto viscoso; se determinó el reograma para cada solución, en los cuales se observó que la solución más viscosa era la obtenida por reflujo y que todas las curvas presentaban un comportamiento pseudoplástico. Con la técnica gravimétrica se obtuvieron 5 precipitados secos de color similar al de las soluciones. Conclusiones: la técnica apropiada para la extracción del mucílago de San Joaquín es el reflujo, este resultado se demostró mediante reometría y gravimetría; el comportamiento reológico del hidrocoloide es no newtoniano con propiedades de flujo pseudoplástico, lo cual lo cataloga como un material potencial para la estabilización de dispersiones coloidales.

Introduction: mucilages have a variety of important applications in the food, pharmaceutical and cosmetic industries, among others. The main advantage of these polymeric compounds is that they are biocompatible, economical and easily available.Objectives: develop a method to extract mucilage from sleeping hibiscus leaves and describe its rheological behavior. Methods: five procedures were applied to obtain the mucilage: boiling, bain-marie, microwave, ultrasound and reflux. Rheological characterization of the mucilages was then conducted at a temperature of 25ºC. Their yield was assessed through determination of the viscosity of solutions. Agreement with the results was verified with the rheological method, applying a gravimetric assay in which the mucilage was first precipitated with ethanol, and then dried and weighed. Results: five light-brown, viscous solutions were obtained that contained mucilage. Determination was conducted of the rheogram for each solution, which showed that the most viscous solution was the one obtained by reflux, and that all curves presented pseudoplastic behavior. Five dry precipitates were obtained with the gravimetric technique. Their color was similar to that of solutions. Conclusions: the appropriate technique to extract mucilage from sleeping hibiscus is refluxing. This result was demonstrated by rheometry and gravimetry. The rheological behavior of the hydrocolloid is non-Newtonian with pseudoplastic flux properties, which makes it a potential material for the stabilization of colloidal dispersions.