Anthocyanins are water-soluble, non-toxic flavonoid pigments, which produce the blue, red and purple color of many plants. Color change of anthocyanin extracts is a direct consequence of the transformation of their chemical structure when exposed to different pH conditions. Optical properties investigated in UV-Vis absorption and PL spectra show a clear difference between anthocyanins in acidic and in alkaline environments. Chitosan, a natural-based, non-toxic and biodegradable polysaccharide, is chosen as an ideal matrix for nanocomposites. It is proven to be a good carrier for anthocyanins, because of its ability to entrap the indicator dyes and at the same time the ability to release anthocyanins when in contact with an acidic environment. In this research, we have developed anthocyanin-enhanced biopolymer indicator systems, which provide fast colorimetric response to alterations in pH levels of the environment. Transmittance spectra of nanocomposites show excellent light-blocking properties of the films. This opens up possibilities for advancement in future technology of smart biodegradable food packaging biomaterials. The availability of innovative and healthy materials reduces the need for using synthetic plastic in the modern food industry.IX International School and Conference on Photonics : PHOTONICA2023 : book of abstracts; August 28 - September 1, 2023; Belgrad
