Physical, Mechanical and Barrier Properties of Carp and Mammalian Skin Gelatin Films

Abstract

Films of 0.11 to 0.13 mm thickness were prepared using gelatins from the skins of cultured freshwater carpspecies and mammalian gelatins viz., porcine and bovine skin gelatin. A comparative study was made on the physical,mechanical, and barrier properties of these films. The amino acid composition, gel strength, clarity, and gel settingpoint of the gelatins were also determined. Carp skin gelatins had a lower imino acid content (19.16% to 20.86%) thanmammalian skin gelatins (22.91% to 23.7%). Grass carp gelatin had gel strength of 230.2 B that is comparable to thereported value for bovine skin gelatin (227.2 B). The bloom values of rohu and common carp skin gelatins were 188.6B and 181.3 B, respectively, which were significantly lower than mammalian gelatins. Mammalian gels have significantlyhigher (P < 0.05) setting temperatures (23.7 to 24.2◦C) than carp skin gelatins. Tensile strength (TS) was lowest forfilms from common carp and rohu skin gelatin (490 and 497 kg/cm2, respectively) and highest for porcine skin gelatinfilm. The degree of transparency (L∗) was significantly higher for films from g rass carp, bovine hide, and pork skin gelatinfilms. Carp skin gelatin films had significantly lower water vapor permeability (WVP) and oxygen permeability (OP)than mammalian skin gelatin films, which indicated that carp skin gelatin based films have superior barrier propertiesthan mammalian skin gelatin films.