The use of copper phthalocyanine pigments as blue colorants in gelatin films for aquatic food packaging

In this study, Copper (Cu) phthalocyanine pigments, coded PD1 and PD2, were characterized, and the possibility of using them as blue colorants in gelatin-based materials for aquatic packaging was evaluated. Synthesized phthalocyanine pigments were compared with imported commercial PB15:1 (control) in terms of Fourier Transform Infrared Spectroscopy (FTIR), high-performance liquid chromatography (HPLC) results, Cu, and ash content. It was found that the synthesized PD1 and PD2 samples were the ones closest to the commercial powder in terms of FTIR peaks, Cu amount, and HPLC results. The selected sample coded PD1 at 0.5 wt% with respect to the solution was further added to gelatin-containing solutions containing 10% and 5% glycerol, and dried films of GL10 and GL5 were obtained, respectively. Although the 10% glycerol-added film showed better color properties, L, a, b, Hue angle, and Chroma parameters were insignificant (p>0.05). Tensile tests and creep/recovery curves showed that GL10 had 107% higher elongation at break, 29% lower Young’s modulus, and higher strain values compared to GL5, making it softer and more flexible. Deformation parameters such as hardness, chewiness, and gumminess were also compared at different deformation rates for the selected GL10 sample. Results indicated that blue pigment-added gelatin films can be used in aquatic food product packages.