A novel colorimetric indicator film based on chitosan, polyvinyl alcohol and anthocyanins from jambolan (Syzygium cumini) fruit for monitoring shrimp freshness

This study aims to develop and characterize colorimetric indicator films based on chitosan, polyvinyl alcohol and anthocyanins from jambolan fruit (Syzygium cumini) prepared by casting method. The effect of anthocyanin extract on thickness, microstructure, moisture content, solubility in water, hydrophobicity, chemical structure, color and opacity of films was analyzed. In addition, anthocyanins photodegradation in films as well its application to monitoring shrimp freshness was studied. Significant effect (p < 0.05) of anthocyanin extract from jambolan fruit on the thickness and optical properties of the films was observed. Anthocyanin extract from jambolan fruit was efficiently incorporated and dispersed into film. The films containing anthocyanins showed visible changes from red color to blue color when used to monitor shrimp freshness at several temperatures (between −20 °C and 20 °C). This research reports for the first time information regarding the valorization and application of anthocyanins from jambolan fruit as an alternative for food packaging sector.