Comparative Optical Response of DNA-Natural and Synthetic Food Colorant Systems

Biopolymers functionalized with chromophores exhibit interesting optical properties with a high potential for applications in photonics. Quinoline yellow (QY), sunset yellow (SY) and riboflavin (RB) are commonly used as colorants in the food industry, which makes them suitable candidates for the development and manufacture of environmentally friendly devices for integrated photonics. The incorporation of these dyes into a deoxyribonucleic acid (DNA) matrix could significantly contribute to enhance the optical response and sensitivity of the obtained composites. This enhancement is mainly due to the interaction between the conjugated π-electrons from the aromatic groups of the chromophores and the DNA matrix. Also, it may influence the appearance of interesting molecular structural arrangements and modify the local electronic environment. The linear optical analysis was performed by UV-Vis, fluorescence and Fourier transform infrared (FTIR) spectroscopies. At the same time, the pump–probe interferometric method was used to study the light-induced refractive index modification.