Extraction and Composite Film Formation of Arabinoxylans from Brewer’s Byproducts: Mechanical and Physicochemical Properties

In this study, barley biomass from the brewing industry was used to obtain fraction-rich arabinoxylans, polysaccharides that, due to their chemical and structural properties, can form films. The effect of adding three plasticizers at a concentration of 20% w/w on the mechanical, optical, and barrier properties of the thermoplasticized films was evaluated. Tensile strength (TS) and percent elongation (%E) tests were performed to determine the mechanical properties, water vapor transmission rate (WVTR) and water vapor permeability (WVP) were evaluated by gravimetric methods, the ΔE and color index (CI) were calculated with the chromatic coordinates of the CIE-L*a*b system, and structural morphology was determined by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR-ATR). The results show that plasticizers decrease the TS values and increase the %E, obtaining more flexible films compared to films made without plasticizers. The structural characteristics of plasticizers directly influence the CI of films. The values corresponding to %E and PVA were higher in the arabinoxylan films thermoplasticized with glycerol. Films’ stability was evaluated using electrochemical impedance spectroscopy. The results show that there are significant differences when the films are coated with polylactic acid.