Physical Properties of Composite Films from Tilapia Skin Collagen with Pachyrhizus Starch and Rambutan Peel Phenolics

Different composite films composed of tilapia skin collagen (TSC) with Pachyrhizus starch (PS) or rambutan peel phenolics (RPP) were prepared, and the physical properties of these films were determined. The effects of PS and RPP on TSC films were investigated, and our results indicated that PS and RPP could improve the physical properties of TSC films. Opacity and film thickness showed an enhanced trend with increasing PS and RPP contents in TSC films, whereas solubility in water, elongation-at-break (EAB), and water vapor permeability (WVP) showed declining trends. TSC film with 10% PS and 0.5% RPP had the highest tensile strength, and the tensile strength dropped drastically when the content of PS and RPP increased. The light transmittances of the films could decrease with the incorporation of PS and RPP. Differential scanning calorimetry (DSC) demonstrated that the addition of PS and RPP improved the thermal stability of TSC films. In addition, X-ray diffraction indicated that the crystallinity of the films decreased and the amorphous structure of the films tended to become more complex with the addition of PS and RPP. As shown by fourier transform infrared spectroscopy (FTIR) analysis, PS and RPP can strongly interact with TSC, resulting in a modification of its structure. Scanning electron microscope (SEM) analysis showed that there was a good compatibility between TSC, PS, and RPP. The results indicated that TSC film incorporated with 10% PS and 0.5% RPP was an effective method for improve the physical properties of the film. TSC–PS–RPP composite films can be used not only in biomedical applications, but also as active food packaging materials.