Barrier and tensile properties of transglutaminase cross-linked gelatin films as affected by relative humidity, temperature, and glycerol content

Gelatin films were prepared by enzymatic cross-linking with transglutaminas e, and their mechanical and barrier properties were evaluated as functions of relative humidity (RH, 30 to 75%), temperature (15 to 35 degrees C) and glycerol content (15 to 31%). Water and glycerol plasticized the films syne rgistically, resulting in greater elongation but lower tensile strength val ues. Films with higher glycerol contents exhibited higher moisture contents , indicating higher hydrophilicity of the films, Permeabilities of oxygen a nd allyl isothiocyanate (an antimicrobial vapor from Cruciferae plants) wer e low when the films were dry, but increased considerably when RH>50%. Ther efore, RH conditions during end-use applications must be considered to opti mize the performance of these films.