Whey protein films added with galactooligosaccharide and xylooligosaccharide

This study aimed to evaluate the effect of addition of xylooligosaccharide (XOS) and galactooligosaccharide (GOS) to whey protein (WP) films produced by casting technique and using glycerol as a plasticizer. The films were evaluated for thickness, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), mechanical properties, water vapor permeability (WVP) and contact angle. No effect of the addition of prebiotic components on thickness of the films was observed (0.13-0.14 mm, p > 0.05). XOS and GOS addition resulted in similar cross-sectional SEM images, presenting smaller and retracted laminated structures, with lower tensile strength and higher elongation at break (3.8-1.7 MPa and 144-208%, respectively, p < 0.05); In addition, the XOS and GOS addition reduced the WVP (1.09-0.63 g.mm.h(-1).m(-2).kPa(-1), p < 0.05), despite the higher hydrophobicity evidenced by contact angle reduction (56.61-46.69 degrees, p < 0.05). Finally, thermal analysis indicated that the increased XOS and GOS concentration resulted in films with lower melting points (169.6-135.65 degrees C, p < 0.05). The possibility of using XOS and GOS to manufacture WP-films formulation provided interesting changes, creating new forms to combine and add value to biopolymers, considering technological and functional aspects.