Carbohydrate polymer-based triboelectric devices for energy harvesting and intelligent packaging for food-quality monitoring

Abstract

Humidity can significantly impact the quality of food. In the case of low-moisture foods – a category characterized by its low water activity – humidity can cause undesirable physical and chemical changes. In this study, we developed intelligent packaging for such foods based around versatile triboelectric nanogenerators (TENGs) that incorporated triboelectric layers fabricated from a carbohydrate polymer, pectin, and glycerol. We found that such TENGs generated their highest electrical output, making them suitable for use as energy harvesters, when the glycerol content of such a layer was 70 % of its pectin content. We further demonstrated that such energy harvesters could successfully convert mechanical energy into sufficient electricity to power small electronic devices such as a hygrometer and a calculator. However, when the pectin-containing triboelectric layer’s glycerol content was reduced to 50 % of its pectin content, the resulting TENG-based sensors exhibited distinctive behaviors during sorption and desorption processes. Those behaviors were leveraged to create a triboelectric food-quality sensor (TFQS) that we integrated into food packaging for food-quality monitoring. Testing of the TFQS indicated that it could effectively measure a key quality attribute, hardness, of our target low-moisture food, crackers. These findings illustrated not only how altering their compositions can endow triboelectric devices with multifunctionality, but also such devices’ potential to help reduce food waste by providing consumers with accurate, dynamic quality information. As such, they could address a core limitation of the current pre-printed food-date label system, which does not account for storage conditions.