Antioxidative activity and emulsifying properties of cuttlefish skin gelatin modified by oxidised phenolic compounds

Antioxidative activity and emulsifying properties of cuttlefish skin gelatin modified by different oxidised phenolic compounds including caffeic acid, ferulic acid and tannic acid at different concentrations were investigated. Oxidised phenolic compounds were covalently attached to gelatin as indicated by the decrease in amino groups. Fourier transform infrared spectroscopic studies indicated the presence of an aromatic ring and a hydroxyl group in gelatin after modification. Modified gelatin had the increased antioxidative activity but the decreased surface hydrophobicity. Gelatin modified with 5% oxidised tannic acid had no change in emulsifying properties. Emulsion stability and oxidative stability of menhaden oil-in-water emulsion stabilised by 0.5% and 1.0% gelatin without and with modification by 5% oxidised tannic acid were studied. Both gelatins at a higher concentration (1.0%) yielded an emulsion with a smaller particle size. Modified gelatin inhibited the formation of TBARS in the emulsion more effectively than the control gelatin throughout the 12 days of storage.