Mechanical properties and solubility in water of corn starch-collagen composite films: Effect of starch type and concentrations

• The addition of starch granules increased thickness and roughness of collagen film.
• 10 wt% amount of starch was more beneficial than 50 wt% to enhancing film strength.
• Mechanical properties of films varied depending upon starch type and film state.
• All starches improved insolubility and thermal stability of collagen films.

This study investigated the possibility of enhancing the properties of collagen with three different maize starches: waxy maize starch, normal starch, and high amylose starch. Scanning electron microscopy images revealed that starch-collagen films had a rougher surface compared to pure collagen films which became smoother upon heating. Amylose starch and normal starch increased the tensile strength of unheated collagen films in both dry and wet states, while all starches increased tensile strength of collagen film by heating. Depending upon the amylose content and starch concentrations, film solubility in water decreased with the addition of starch. DSC thermograms demonstrated that addition of all starches improved the thermal stability of the collagen film. Moreover, X-ray diffraction results indicated that except for high amylose starch, the crystallinity of both starch and collagen was significantly decreased when subject to heating. FTIR spectra indicated that intermolecular interactions between starch and collagen were enhanced upon heating.