Exploring the properties of modified fish gelatin films incorporated with different fatty acid sucrose esters

Incorporation of hydrophobic materials with surfactant properties such as fatty acid sucrose esters (FASEs) into edible protein films may reduce their drawbacks of having poor water barrier for wider application. In this study, two types of FASEs, PASE and SASE were studied as glycerol substitute in gelatin films at different concentrations (25, 50, 75 and 100%). Interesting to note that high amounts of the FASEs reduced the films’ water vapor permeability and solubility but increased opacity. Moisture sorption isotherm revealed that at water activity above 0.75, FASEs improved the water barrier. Meanwhile, tensile strength and Young's modulus were enhanced whereas percentage elongation was decreased. SEM displayed a rougher surface morphology of Gel-PASE and Gel-SASE which was a consequence of disrupted polymeric structure in the film matrix. ATR-FTIR proved the conformational changes in those films as portrayed by the band shifts at 3286–3297 cm⁻¹, 2919–2927 cm⁻¹ and 1036–1079 cm⁻¹.