Guar gum-sodium alginate nanocomposite film as a smart fluorescence-based humidity sensor: A smart packaging material

Perishable packed foods are easily damaged by the change in relative humidity. In this work, we demonstrate that guar gum-sodium alginate blending with glucose-glycerol carbon dots nanocomposite film can be used to detect relative humidity. The fabricated nanocomposite film was an excellent smart sensor based on the fluorescence 'on-off' mechanisms against humidity. The study demonstrates that at different relative humidity conditions, such as 11 %, 33 %, 75.30 %, 84 %, and 97 %, there is a change in the fluorescence of biocomposite films under UV light. The practical feasibility of the biocomposite developed film was tested in real conditions by placing a piece of bread with high humidity conditions wrapped with the developed nanocomposite film. It was observed that under such conditions, marked quenching of fluorescence was observed and hence detection of humidity was possible. Hence, the fabricated nanocomposite film can monitor the packed food freshness using just a UV light source. Such biopolymer nanocomposite is potential materials and may find application as smart packaging materials, especially as food packaging materials.

Automated summary

This work demonstrates the use of guar gum-sodium alginate blending with glucose-glycerol carbon dots nanocomposite film to detect relative humidity. The fabricated nanocomposite film acts as an excellent smart sensor based on the fluorescence 'on-off' mechanism against humidity. By observing the fluorescence change under different humidity conditions, the study successfully detects the freshness of packed food in high humidity conditions using the developed nanocomposite film.