Barrier and mechanical properties of methylcellulose–whey protein films
Abstract:Water vapour permeability (WVP) and mechanical properties were assessed in edible films prepared from methylcellulose (MC) and MC–whey protein isolate (WPI) or MC–whey protein concentrate (WPC). Glycerol (Gly) was used as the plasticizer. Two MC–WP films were formulated. For Group I films, the mass ratio of WP : Gly was constant, whereas for Group II films the mass ratio of polymer (MC + WP) : Gly was constant. The WVP of MC–Gly film decreased with increasing MC concentration, while the tensile strength (TS) and percent elongation (E) increased. The WVP of Group I and Group II films decreased erratically and TS increased when the MC concentration was increased. Group I films had higher TS values than Group II films at the same MC : WP ratios. E of both groups increased with increasing MC concentration (p < 0.05), excluding the films with the highest MC : WP ratio tested (0.8) in Group I films. Group I films had lower E values than Group II films at the same MC : WP ratios. MC effectively governed WVP, TS and E of the WP films. Generally, MC–WP films of this work showed lower WVP than that of MC‐ and WP‐based edible films in the literature. This can potentially make MC–WP films a suitable film material for moisture‐sensitive food products. Copyright © 2005 John Wiley & Sons, Ltd.
Document Type: Research Article
Publication date: November 1, 2005
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