Fabrication and Characterization of a pH-Responsive Intelligent Packaging Film From Amorphophallus paeoniifolius...

This study aimed to develop a pH-sensitive intelligent packaging film using starch extracted from elephant foot yam (EFY) (Amorphophallus paeoniifolius). The starch was dual-modified and blended with polyvinyl alcohol (PVA) and anthocyanin-rich Clitoria ternatea extract (CTE) to produce composite films capable of real-time chicken meat freshness monitoring. LC-MS/MS profiling confirmed the presence of several phenolic and flavonoid compounds, including rutin, delphinidin, and quercetin. Structural analyses using field-emission scanning electron microscopy (FE-SEM), confocal laser scanning microscopy (CLSM), along with spectroscopic techniques such as Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), indicated  good dispersion of CTE within a semicrystalline polymer matrix. Incorporation of CTE modifies film properties: film thickness increased from 0.12 to 0.16 mm, while water vapor permeability decreased from 1.77 to 1.46 g mm/m²/day/kPa. Colorimetric sensitivity increased, with ΔE values rising from 1.80 to 17.5 across a broad pH range. Mechanical performance was peaked at 3% CTE, resulting in a tensile strength of 16.36 MPa and elongation at break of 24.20%. The films also exhibited notable antioxidant and antimicrobial activity against Escherichia coli and Staphylococcus aureus. Application to chicken packaging showed distinct color changes correlated with freshness indicators, including pH, microbial growth, TBARS (0.45-2.32 mg MDA/kg), and total volatile basic nitrogen (TVB-N) (10.2-38.7 mg/100 g). Overall, the results suggest that EFY starch-PVA-CTE films are promising sustainable and biodegradable materials suitable for intelligent food packaging and real-time freshness monitoring.