Use of colorimetric hydrogel as an indicator for food packaging applications

Abstract

A novel hydrogel was synthesized from N,N-dimethyl acrylamide (DMAAm), gelatin, citric acid (CA) and Basilicum extract (BE). This study was aimed at creating an advanced food packaging material that allows the detection of food spoilage, which can be monitored colorimetrically. The poly(gelatin-co-DMAAm)/CA–BE was synthesized in the form of a film on Petri dishes using a redox polymerization technique. Mechanical and water resistance properties of the hydrogel were further improved by the addition of CA and N,N-methylene-bis-acrylamide as crosslinkers; BE was added to the reaction mixture and entrapped in the polymer chains with the aim to introduce antimicrobial, antioxidant and anthocyanin properties for the desired utilization. The characterization of the synthesized hydrogel was carried out using a dynamic and mechanical analyser, thermo gravimetric analyser, Fourier transform infrared spectroscopy and scanning electron microscopy. The antimicrobial activity of the hydrogel was observed as it was tested against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. Furthermore, total antioxidant and anthocyanin activities of the hydrogels were also studied at different pH values to monitor the colour change capabilities. It was concluded that the hydrogel was a strong candidate for use in food packaging.