Monodisperse W/O/W emulsions encapsulating L-ascorbic acid: Insights on their formulation using microchannel emulsification and stability studies

Stabilizing l-ascorbic acid is a challenge for food industries. The present study aimed to formulate monodisperse food-grade water-in-oil-in-water (W/O/W) emulsions containing a high concentration of l-ascorbic acid in an inner aqueous phase using homogenization and subsequent microchannel emulsification (MCE). The microchannel (MC) array plate used here was a silicon asymmetric straight-through MC array that consists of numerous 10. μm. ×. 100. μm microslots with a 30. μm depth, each connected to a 10. μm-diameter circular MC with a 70. μm depth. Water-in-oil (W/O) emulsions contained a soybean oil solution with 4-8% (w/w) tetraglycerin condensed ricinoleic acid ester as a continuous phase and an aqueous solution with 10-30% (w/v) l-ascorbic acid, 1% (w/w) magnesium sulfate, and 1% (w/v) gelatin as an inner aqueous phase. The W/O emulsion droplets formulated using a rotor-starter homogenizer had average droplet diameters of 2.6-2.9. μm and coefficients of variation (CVs) of 13-17%. MCE was performed using a dispersed W/O emulsion phase and a 5. mM phosphate buffer containing 1% (w/w) decaglycerol monolaurate and 10-30% (w/v) D(+)-glucose as an outer aqueous phase. Monodisperse W/O/W emulsions containing W/O droplets with average diameters of 26.0-31.5. μm and CVs below 10% were successfully formulated via an asymmetric straight-through MC array at a low hydrophobic emulsifier concentration, regardless of l-ascorbic acid concentration. The W/O droplets dispersed in these monodisperse W/O/W emulsions were physically stable in variation of average diameter and CV for more than 10d of storage at 4. °C. The monodisperse W/O/W emulsions also exhibited l-ascorbic acid retention exceeding 80% during storage.

Preparation and characterization of water-in-oil-in-water emulsions containing a high concentration of L-ascorbic acid

This study sought to encapsulate a high concentration of L-ascorbic acid, up to 30% (w/v), in the inner aqueous phase of water-in-oil-water (W/O/W) emulsions with soybean oil as the oil phase. Two-step homogenization was conducted to prepare W/O/W emulsions stabilized by a hydrophobic emulsifier and 30% (v/v) of W/O droplets stabilized by a hydrophilic emulsifier. First-step homogenization prepared W/O emulsions with an average aqueous droplet diameter of 2.0 to 3.0 μm. Second-step homogenization prepared W/O/W emulsions with an average W/O droplet diameter of 14 to 18 μm and coefficients of variation (CVs) of 18% to 25%. The results indicated that stable W/O/W emulsions containing a high concentration of L-ascorbic acid were obtained by adding gelatin and magnesium sulfate in the inner aqueous phase and glucose in both aqueous phases. L-Ascorbic acid retention in the W/O/W emulsions was 40% on day 30 and followed first-order kinetics.

Ultra high-pressure homogenized emulsions stabilized by sodium caseinate: effects of protein concentration and pressure on emulsions structure and stability

Microstructure, physical properties and oxidative stability of emulsions treated by colloid mill (CM), conventional homogenization (CH, 15 MPa) and ultra-high-pressure homogenization (UHPH, 100–300 MPa) by using different concentrations of 1, 3 and 5 g/100 g of sodium caseinate (SC), were evaluated. The application of UHPH treatment at 200 and 300 MPa resulted in emulsions that were highly stable to creaming and oxidation, especially when the protein content increased from 1 to 3 and 5 g/100 g. Further, increasing the protein content to 3 and 5 g/100 g in UHPH emulsions tended to change the rheological behavior from Newtonian to shear thinning. CH emulsions containing 1 g/100 g of protein exhibited Newtonian flow behavior with lower tendencies to creaming compared to those formulated with 3 or 5 g/100 g. This study has proved that UHPH processing at pressures (200–300 MPa) and in the presence of sufficient amount of sodium caseinate (5 g/100 g), produces emulsions with oil droplets in nano-/submicron scale with a narrow size distribution and high physical and oxidative stabilities, compared to CM and CH treatments.

La movilidad de personas como manifestación de la proyección política internacional de los Estados. Estudio de caso: Brasil y África lusófona durante el gobierno de Lula da Silva

La migración internacional está relacionada, en principio, con el movimiento de un grupo de personas a través de las fronteras nacionales y que implica la intención de desplazarse y permanecer en el lugar de destino , creando así vínculos de tipo comercial, económico, social y político. Sin embargo una subcategoría de análisis es la movilidad. De este flujo migratorio hacen parte aquellos movimientos de personas en las que la permanencia a largo plazo no es el objetivo fundamental, sino el desarrollo de una actividad concreta durante un periodo de tiempo determinado en el destino. Dentro de estos flujos se pueden mencionar la movilidad estudiantil, la movilidad de trabajadores calificados y empresarios, inversionistas y otros que son calificados por algunos como expatriados . La idea más fuerte para lograr materializar la movilidad internacional como parte del diseño de la política exterior de los Estados se basa en el hecho que la población que emigra a un nuevo destino encuentra un espacio laboral y profesional diferente en el cual desempeñarse, y es a partir de esto que existe la posibilidad de generar una homogenización de los patrones culturales ya que el intercambio de ideas, imágenes y conocimientos crea de inmediato un enlace y un impacto mucho más concreto entre los individuos originarios y las personas del Estado receptor.

Subjetividades políticas desde la representación : fotografía documental del campesinado en Colombia (1965-1975)

Esta investigación explora arqueológicamente el saber constituido sobre el campesinado en Colombia, en el período de 1965-1975, tomando como material empírico principal un archivo fotográfico documental que relacionaremos con hemerografía y las reconstrucciones socio-históricas de la década. Nuestro propósito es relacionar el archivo, sus condiciones, su porvenir, medios y definiciones con la constitución de subjetividades políticas. Las subjetividades son entendidas aquí en tanto procesos que al referir universos simbólicos socialmente compartidos, dotan al sujeto de un lenguaje cultural que a continuación internaliza, y adquiere así una singularidad que lo caracteriza y finalmente lo representa como “ser colectivo”. Descifraremos, a través de lo visible y lo oculto de las representaciones fotográficas, los enunciados posibles y las aproximaciones desde la sociología. Veremos como los discursos, por demás contradictorios, fungen a manera de proyectos de homogeneización de la cultura campesina efectuándose en la esfera de la heterogeneidad: campesinos marcados por diferencias entre sí, multiplicidad de subjetividades implicadas políticamente en los procesos inscritos dentro de la reforma agraria.

Artistic Expression: Another Challenge for Rural Education

This paper identifies the parameters required to create opportunities that would strengthen the social fabric and would promote a comprehensive development through the artistic expression as a method for expressing feelings and constructing –cultural and social– identities as individuals, which, in our global context have been eroded by the homogenization of experiences.