Properties of film from cuttlefish (Sepia pharaonis) skin gelatin incorporated with cinnamon, clove and star anise extracts

Abstract

Properties of film from cuttlefish (Sepia pharaonis) ventral skin gelatin without and with partial hydrolysis (1.2% degree of hydrolysis) incorporated with 1% ethanolic extract of cinnamon (CME), clove (CLE) and star anise (SAE) were determined. Films with different herb extracts (without and with oxidation) had higher tensile strength (TS) but lower elongation at break (EAB), compared with the control film (without addition of herb extracts) (p<0.05). Lower water vapor permeability (WVP) and L∗-value but higher b∗- and ΔE∗-values were observed when the extracts were incorporated (p<0.05). Electrophoretic study revealed that cross-linking was pronounced in films containing different herb extracts. Oxidized extracts yielded films with higher TS and WVP than those without oxidized herb extracts (p<0.05). Generally, similar properties were noticeable for films from gelatin with and without partial hydrolysis. Nevertheless, higher mechanical properties were obtained for the latter. FTIR spectra indicated that protein–polyphenol interactions were involved in the film. Thermo-gravimetric analysis revealed that films incorporated with SAE or SAE with oxidation (OSAE) exhibited lower heat susceptibility and weight loss in the temperature range of 50–600°C, compared with control film. Films with SAE and OSAE had smoother surface for gelatin without hydrolysis; however, coarser surface was observed in film from gelatin with partial hydrolysis. Thus, the incorporation of different herb extracts directly affected the properties of film from cuttlefish skin gelatin with and without hydrolysis.