Electrospun Nanofibrous Mat-on-Film Bilayered Halochromic Freshness Marker-Enabled Intelligent Food Packaging Film Based on Red Cabbage Anthocyanins

Bi-layered smart films based on electrospun polyvinyl alcohol/red cabbage extract-anthocyanins (PVA/RCA) nanofibrous mats, bolstered by oxygen-plasma treated clay-filled polyethylene-based nanocomposites for monitoring the food freshness have been fabricated and evaluated. The nanofibrous mats (PVRC) of PVA/RCA were optimally fabricated by electrospinning, followed by their morphological and physio-mechanical characterization. The inclusion of RCA significantly enhanced the ductility ratio and surface hydrophobicity of electrospun PVRC mats. The pH-responsive sensing of the PVRC mats to hydrochloric acid (HCl) and ammonia (NH3) vapors as stimuli were analyzed using the absorption spectra corresponding to HCl and NH3 at ∼530 nm and ∼650 nm, respectively. An oxygen-plasma treated polyethylene/nanoclay (LLCP) based blown film was used as the outer substrate layer for freshness indicator for protecting inner PVRC-based electrospun mats. The contact angles of LLCP film with respect to water (∼72.31º) and diidomethane (∼54.18º) as a solvent were estimated along with X-ray photoelectron spectroscopy (XPS) and Energy dispersive X-ray (EDX) analysis for measuring the hydrophilicity for plasma treated and untreated blown films. The oxygen transmission rate (OTR) of 1083.7 cc/m3/day and water-vapor transmission rate (WVTR) of 8.07 g/m2/day for the novel bi-layered packaging construct showed enhanced barrier performance with respect to stand-alone LLDPE blown-film (LL) with OTR and WVTR of 1502.8 cc/m2/day 16.25 g/m2/day respectively. The bi-layered constructs were further evaluated as freshness indicators by real-time freshness monitoring of the flesh of chickens and prawns. The constructed bi-layered design incorporating RCA had the potential to serve as a freshness indicator for intelligent food packaging, in essence.