IMMOBILIZATION OF ANTHOCYANINS BY BACTERIAL NANOCELLULOSE IN PRODUCTION OF INDICATORS FOR PH-CONTROLLED SMART PACKAGING

The main objective of this research was the production and characterization of bio-based indicators for pH-controlled smart packaging. Since pH-sensitive indicators can change color depending on the freshness or spoilage of the food, they can be used to monitor the freshness level and safety of food products. Potato and maize starch without and with the addition of bacterial nanocellulose (BNC) were used as a polymer matrix for the immobilization of pH-sensitive indicators. The natural pigment anthocyanin, extracted from the peels of red onions, was used as a pH-sensing element. In addition, an ultrasound treatment of the extracted anthocyanins was performed to determine the influence of the treatment on the color response of the produced films. The colorimetric and optical differences between the different starch films with ultrasound-treated and untreated anthocyanins were observed. To observe the color response of the prepared indicators when exposed to different pH environment, their optical and colorimetric changes were monitored before and after exposure to altered pH values. The results obtained show the potential for the production of pH-sensitive films immobilized by BNC. In addition, the results will provide the information about the influence of ultrasound treatment during anthocyanin extraction on the optical and colorimetric changes of the pH-sensitive starch-based films.