AN INVESTIGATION OF THE MECHANICAL, MICROSTRUCTURAL AND THERMO-MECHANICAL PROPERTIES OF COLLAGEN FILMS CROSS-LINKED WITH SMOKE CONDENSATE AND GLUTARALDEHYDE

Collagen films were produced from five commercial collagen dispersions used for in-line sausage co-extrusion production. Films were prepared by partially dehydrating in a salt solution (30%) and crossed linked with smoke condensate (15%) or glutaraldehyde (GA; 0-1%). Both treatments increased the tensile strength (0.32 to 0.91 MPa) and reduced % elongation while differences among the dispersions were observed. Overall, % elongation generally decreased with a higher degree of cross linking. Transmission electron micrographs revealed that collagen fibers were swollen to varying degrees, likely influencing the mechanical behaviours. Protein concentration affected the transparency of the films with a difference of 100% in light transmission between the clearest and most opaque film studied. Cross-linking with GA appeared to thermally stabilize films up to 80 degrees C. Aldehydes in the smoke condensate were identified by gas chromatography showing highest concentration of benzaldehyde, 4-hydroxy-3,5-dimethoxy.