On food systems, lipid oxidation is one of the most important factors affecting food quality, nutrition, safety, color and consumer acceptance. The objective of this study was to determine the kinetic parameters of lipid oxidation and its influence in the shelf life of third generation (3G) snacks stored in three types of packaging (polyethylene, polypropylene + Kraft paper, and polyethylene + polypropylene) at 25 °C and 40 °C. The peroxide value was the quality parameter selected and monitored for a 60 day period using a spectrophotometric technique. Based on the Arrhenius equation and activated complex theory, reaction rate constants (k), activation energies (E a ), Q 10 factors, activation enthalpies (∆H ‡ ), and activation entropies (∆S ‡ ) for oxidative stability in 3G snacks were calculated. Results showed that oxidation phenomena can occur in the 3G snacks and affect its shelf-life. Packaging C (polyethylene + polypropylene) was the most appropriate for the storage of this kind of product. Finally, the shelf life of the analyzed pellets was longer than one year at 25 °C and it may be extended with the appropriate mix of packaging materials.

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The shelf life of third generation snacks (pellets) was estimated through the measurement of physicochemical parameters. Samples were provided by a snack manufacturing industry and were placed in three different types of packaging: high density polyethylene (HDPE); polypropylene/kraft paper; and polypropylene/ HDPE. The samples were tested under different conditions of temperature and relative humidity. Water activity (a w ) at 25 and 408C and moisture gain (89% relative humidity, 258C) were analyzed for 60 days. The polypropylene 1 HDPE packaging showed the best properties for sample preservation, allowing for a shelf life of 1 month under extreme conditions of humidity. Therefore, it is possible to extend the shelf life of the pellets studied by using proper packaging materials to limit phenomena of water sorption.

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Se evaluó la liberación de clorhidrato de metformina (HM) a través de una matriz de arabinoxilanos extraídos de bagazo de cebada (BSG-AX). Para ello, se prepararon dispersiones de BSG-AX y HM, con diferentes contenidos de Ca2+, las cuales se liofilizaron y se prensaron, con la finalidad de obtener sus correspondientes tabletas, que se sometieron a una cinética de liberación de HM. La concentración de HM liberada al medio acuoso se determinó a través de medidas de absorbancia, a una longitud de onda (l= 236 nm, máximo de de absorción de HM), cada 30 min. De acuerdo con los resultados obtenidos, el tiempo de liberación de HM aumentó en función del incremento de la concentración de Ca2+, teniendo una liberación de hasta el 90% (en 6.5 h) para la tableta sin Ca2+; mientras que, para la mayor concentración de Ca2+ (0.3 mol L-1) se obtuvo 75% de liberación en 11.5 h. Los resultados sugieren que los BSG-AX constituyen un material adecuado para la producción de vehículos de liberación de fármacos, como el HM.