Fabrication of anthocyanidin-encapsulated polyvinyl alcohol nanofibrous membrane for smart packaging

Smart colorimetric packaging has been an important method to protect human health from external hazardous agents. However, the currently available colorimetric detectors use synthetic dye probes, which are costly, toxic, difficult to prepare, and non-biodegradable. Herein, an environmentally friendly cellulose nanocrystal (CNC)-supported polyvinyl alcohol (PVA) nanofibrous membrane was developed for the colorimetric monitoring of food spoilage. Anthocyanidin (ACY) is a naturally occurring spectroscopic probe that was isolated from pomegranate (Punica granatum L.). By encapsulating the anthocyanin probe in electrospun polyvinyl alcohol fibers in the presence of a mordant (M), M/ACY nanoparticles were generated. After exposure to rotten shrimp, an investigation on the colorimetric changes from purple to green for the smart nanofibrous fabric was conducted using the coloration parameters and absorbance spectra. In response to increasing the length of exposure to rotten shrimp, the absorption spectra of the anthocyanin-encapsulated nanofibrous membrane showed a wavelength blueshift from 580 nm to 412 nm. CNC displayed a diameter of 12–17 nm. The nanoparticle diameter of M/ACY was monitored in the range of 8–13 nm, and the nanofiber diameter was shown in the range of 70–135 nm. Slight changes in comfort properties were monitored after encapsulating M/ACY in the nanofibrous fabric.