Effect of squalene rich fraction from shark liver on mechanical, barrier and thermal properties of fish (Probarbus Jullieni) skin gelatin film

Golden carp skin gelatin films incorporated with squalene rich fraction from shark liver (SRF) at various levels (5, 10, 15, 20 and 25%, w/w) were characterized in comparison with palm oil (PO) incorporated film and control film (CON) (without oil addition). PO films exhibited lower tensile strength (TS) but higher elongation at break (EAB) as compared to that of CON film. SRF films added with 25% SRF showed higher EAB as well as TS, compared to both CON and PO films (p < 0.05). SRF films showed significantly lower water vapor permeability (WVP) and lower lightness (L*) value than CON and PO films (p < 0.05). Moreover, SRF films with negligible fishy odor had lower transparency and yellowness than CON and PO films. SEM images showed that CON and SRF films exhibited relatively smoother surface, compared to PO film. Additionally, SRF films had lower oil at the surface of the films than PO film. Moreover, DSC and FTIR spectra results revealed that incorporation of PO and SRF lowered interaction between gelatin molecules with coincidentally disordered structure. Besides, both SRF and PO films demonstrated lower degradation (T-d), glass transition (T-g) and melting transition (T-m) temperatures than CON film. Thus, incorporation of SRF could render stronger films with higher TS and enhanced flexibility and also moisture barrier porperty of gelatin films.