No abstract

No abstract

Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo intemperizados en suelos y sedimentos (Biodegradation modeling of sludge bioreactors of total petroleum hydrocarbons weathering in soil and sediments)

The use of edible films for covering food matrices has been of great importance due to they protect and extend the shelf life of different foods. The aim of this paper was to determinate the rheological changes caused by microcapsules incorporation on edible films made from carrageenan. All rheological measurements were carried out in the viscoelastic zone, which was determined using the Kelvin-Voigt model. Both films (with and without microcapsules) presented predominantly elastic characteristics (G′ > G″). The microcapsules addition decreased the recovery values as a result of a film-degradation structure. The relaxation time ranged between 9.245 x 10-3 to 9.427 x 10-3 s and the instantaneous compliance (J0) values were 88.51 times higher than the retarded compliance (J1) values in the studied films indicating the loss of elasticity of the films due to microcapsules incorporation.

The development of functional foods is essential to meet food needs and prevent some health problems of the population. The objective of this work was to standardise the process of making a tree tomato jam (Solanum betaceum) with functional properties. The jam was added with Aloe vera (Aloe Barbadensis Miller), stevia (Stevia rebaudiana) as a sweetener and Lactobacillus bulgaricus as a probiotic. Experimental design of 15 treatments was generated, according to the Box-Behnken design for three factors. These treatments were subjected to sensory analysis establishing the general acceptability of a panel of trained tasters. The computer program "Minitab Statistical Software" version 15 for Windows was used, obtaining the treatment with maximum acceptability. The best treatment had 50% pulp, 0.21% stevia, 0.18% pectin, 0.05% benzoate, 1.06% citric acid and 21.6% sucrose with a pH of 4.27 and 41.43 °Brix. This treatment was characterised physicochemically and microbiologically.

This study aimed at determining the effect Lactobacillus. acidophilus inclusion on mechanical and barrier properties of films based on low acyl gellan (LAG) gum and whey protein concentrate (WPC) storage for 30 days. The counting of probiotic bacteria indicated that WPC facilitates the microbial growth. This behavior may lead to a breaking structure of the films resulting in changes to the barrier and mechanical properties of films. Considering those as mentioned above it seems no convenient used WPC as a probiotic carrier. Thus, the microbial addition on film made from LAG could be viewed as an alternative in the production of active films.

Objective: In this study, a Box-Behnken design was employed in order to optimize the concentration of sodium alginate (SA), low acyl gellan (LAG) and glycerol (GLY) as a function of tensile strength (TS) and elongation at break (EB) of the biofilms. Methods: A texturometer Shimadzu model EZ-Test EZ-S was employed to evaluate TS and EB by using constant displacement control with a crosshead speed of 30 mm/min. Rafael E. González-Cuello et al. Results: The regression model developed herein indicates that the selected variables were statistically determinants (p < 0.05) for the studied mechanical properties. The optimal concentration to obtain high TS values (134.38 MPa) were 1.00% (w/v) of SA, 1.00% (w/v) of LAG and 8.00% (v/v) of GLY. However, low values of EB (15.95%) were also obtained using the same concentrations of AS, GBA and GLY. Conclusions: By increasing the concentration of SA and LAG result in highly resistant biofilms with low flexibility while increasing the glycerol concentration and reducing the concentration of biopolymers yielded the opposite effect. The Box-Behnken design is a useful statistical method for improving the mechanical properties studied depending on the final application of the biofilms.

* Autor a quien debe ser dirigida la correspondencia.Recibido Ago. 24, 2016; Aceptado Oct. 18, 2016; Versión final Nov. 21, 2016, Publicado Feb. 2017 Resumen El objetivo del presente estudio fue caracterizar las propiedades físico mecánicas y de barrera al vapor de agua de biopelículas (BP) a base de carboximetilcelulosa (CMC) y goma xantana (GX) formuladas con varias concentraciones de goma gelana de bajo acilo (GBA). Las BP fueron elaboradas por el método de casting y posteriormente fueron determinadas la permeabilidad al vapor de agua (PVA), elongación al quiebre (EQ), resistencia a la tensión (RT), humedad y transparencia. Los resultados obtenidos indicaron que las BP con menores concentraciones de GBA mostraron propiedades más deseables con respecto a las demás formulaciones, ya que se producen BP con baja humedad y PVA. Además presentan elevados valores de EQ y son más transparentes. Estos resultados son realmente prometedores y sugieren la posibilidad de utilizar combinaciones terciarias de CMC, GX y GBA como una fuente de empaque biodegradable para aplicaciones alimentarias. Effect of Gellan Gum Addition on the Barrier and Physico mechanical Properties of Binary Biofilms AbstractThe aim of this study was to characterize physico mechanical and water vapor barrier of biofilms based on carboxymethylcellulose (CMC) and xanthan gum (XG), formulated with various concentrations of low acyl gellan (LAG). The biofilms, were prepared by the casting method and then the water vapor permeability (WVP), elongation at break (EAB), tensile strength (TS), moisture and transparency were determined. The findings indicated that biofilms with low concentrations of LAG showed more desirable properties when is compared with the others formulations, because they yields biofilms with low moisture and WVP. In addition, these biofilms had high values of EAB and were more transparent. These results are promising and suggest the possibility of using tertiary mixtures of CMC, GX and LAG as a source of biodegradable packaging for food applications. et al., 2010). En este sentido, las BP basadas en polisacáridos son vistas como potenciales sustitutos de los empaques sintéticos tradicionales y han sido caracterizadas por múltiples investigadores (Ahmadi et al., 2012;Ghasemlou et al., 2011), ya que son considerados barreras efectivas contra los gases y solutos por su densa matriz polimérica. KeywordsLa carboximetilcelulosa (CMC) es un polisacárido derivado de la celulosa con un residuo lineal aniónico de glucopiranosa β (1-4) (Su et al., 2010). La CMC es originada por sustitución parcial de grupos hidroxilos por grupos carboxilos (Tong et al., 2008). Varios autores han reportado la importancia de producir BP a base de CMC debido a la posibilidad de obtener una matriz continua (Ghanbarzadeh y Almasi, 2011). La goma xantana (GX) es un heteropolisacárido que consiste de D-glucosa, D-manosa y ácido D-glucurónico. La GX es producida por Xantomonas campestris a través de fermentación aeróbica en cultivo sumergido (Guo et al., 2014) y sus dis...