Abstract:

The effect of glycerol concentration on the properties and structure of rabbit skin gelatin film was studied by
measuring its mechanical properties, water vapor permeability, subunit composition and structure. The results showed that
glycerol concentration had no significant effect on thickness, and the water vapor permeability of gelatin film increased with
glycerol concentration. Tensile strength (TS) and elongation at break (EAB) significantly increased (P < 0.05) when glycerol
content was increased to 22%. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated that gelatin
molecules did not degrade or aggregate and the band intensity and tensile strength of gelatin film increased when glycerol
concentration was 30%. FT-IR analysis showed that amide A band moved to low wave numbers (3 446.9–3 398.9 cm-1),
which indicated that glycerol molecules reacted with NH groups in peptides to form hydrogen bonds in film matrix. Curvefitting
of amide I band showed that random coil decreased while triple helix increased gradually with glycerol concentration,
suggesting that glycerol promoted gelatin film to form an ordered structure and in turn to improve its film-forming and
mechanical properties.

Key words: rabbit skin, gelatin film, glycerol, structure