The coatings and films prepared whey (WPI) and chitosan (CHI) are known to be antifungal and also a barrier to the transference of water vapor, having an effect on the preservation of fruits. The aim of this study was to determine the effect of a coating of WPI and CHI on respiration of banana during storage at ambient conditions (25 ± 3 °C and 75 ± 5% RH) and its relation to water vapor permeability (PVA) of the films. Different concentrations of WPI and CHI were evaluated. CHI was used at 75% of deacetylation (solution of 1,2%, 1,5% and 1,8% w / v) and WPI of 96% (solution 3% and 4% w/v). The respiration rate was determined using a digital respirometer by measuring each sample during 55 minutes. The best coating was 1,5% -WPI CHI 3%. In this treatment the maturity and respiration was controlled and the climacteric peak occurred on day 9 of storage with 109,84 mg CO2/kg-h (in the control sample occurred on day 7 with 172,71 mg CO2/kg-h). The water vapor permeability of the film made with this formulation had an intermediate value (7,43x10-4g-mm / m2-h-Pa) over other formulations. Films with the highest and the lowest permeability shown the highest respiration rates. | Los recubrimientos y películas elaborados lactosuero (WPI) y quitosano (CHI) son conocidos por ser antifúngicos y por ser barrera para la transferencia de vapor de agua, logrando un efecto en la conservación de frutas. El objetivo de este trabajo fue determinar el efecto de un recubrimiento de WPI y CHI sobre la respiración del banano durante el almacenamiento en condiciones ambientales (25±3 ºC y 75±5% HR) y su relación con la permeabilidad al vapor de agua (PVA) de las películas. Para la elaboración del recubrimiento se evaluaron distintas concentraciones de WPI y CHI. Se empleó CHI al 75% de desacetilación (solución de 1,2%, 1,5% y 1,8% p/v) y WPI al 96% (solución de 3% y 4% p/v). La tasa de respiración se determinó realizando mediciones durante 55 minutos para cada tratamiento empleando un respirómetro digital. El mejor recubrimiento fue CHI 1,5%-WPI 3% donde la maduración y respiración fue controlada y el pico climatérico ocurrió el día 9 de almacenamiento con 109,84 mg CO2/kg–h (en la muestra control fue eldía 7 con 172,71 mg CO2/kg–h). La permeabilidad al vapor de agua de la película elaborada con esta formulación tuvo un valor intermedio (7,43x10-4g-mm/Pa-h-m2) respecto a las demás formulaciones. Las películas con la mayor y la menor permeabilidad mostraron las tasas de respiración más altas.

Stainless steel AISI 316 was coated with aluminum-silicon by Chemical Vapor Deposition in Fluidized Bed Reactor (CVD-FBR) to 540°C and subsequently heat treated to improve its mechanical properties and its behavior against oxidation, by inter diffusion of the alloying elements. Later, oxidation was performed austenitic stainless steel aluminum-silicon coated at temperatures of 700 and 750°C, in an environment with 100% steam, to evaluate their performance. Mass gain graphs were made and oxide films were analyzed by SEM and X-ray diffraction to observe the morphology of the oxides. Thermodynamic simulation was carried out during oxidation in water vapor of the substrates for possible solid phases which could be formed. The form of attack at 750°C is similar to 700°C, although the rate of oxidation is increased, because the diffusion of the alloying elements and the oxidation reactions are faster. These coatings have good resistance to oxidation in water vapor and forming an alumina surface layer which protects the substrate from corrosion attack.