180: Impact of Various Modification Techniques on Functional, Structural, and Rheological Characteristics of Elephant Foot Yam Starch for Application in pH-Based Intelligent Packaging

Introduction

The environmental issues associated with non-biodegradable, petroleum-derived polymers in food packaging have increased the need for biodegradable alternatives. Elephant foot yam (EFY, Amorphophallus paeoniifolius), a starch-rich tuber, shows potential as a raw material. Nevertheless, native EFY starch has limitations in strength, flexibility, and compatibility with active compounds, constraining its use in packaging films. The modified EFY starch overcomes these concerns by augmenting preferred characteristics. Moreover, anthocyanin-based intelligent packaging systems can assess food quality, safety, freshness, pH, and gas or water vapor transport, therefore predicting shelf life while providing fundamental packaging functions.

Methods

Starch was isolated from the tubers of elephant foot yam (Amorphophallus paeoniifolius) and Modified using three distinct treatments, namely Heat-moisture treatment (HMT), Crosslinking (CL) and Debranching (DB). HMT was performed at varying temperatures (90-110°C) and moisture levels (15-35%). CL-modified starch was obtained using epichlorohydrin at concentrations of 0.2–0.8%, while DB used pullulanase enzyme at 5, 10, and 15 U/g of starch. Furthermore, anthocyanin derived from black carrots was added to prepare a pH-responsive modified starch film.

Results

The highest amylose content was obtained at 25% moisture content and 110°C in HMT. The amylose content decreased as the concentration of epichlorohydrin increased, but it improved with a rise in pullulanase concentration. Among all the modifications, DB resulted in the highest WAC and solubility. The shift of H-O-H bond in FTIR results confirms the significant change in water-holding capacity and solubility of DB modified starch. All modifications resulted in XRD showing orthorhombic peaks, but with a minor shift indicating a change in the crystallinity due to modification. DSC thermogram of both HAO and CL-modified starch exhibited higher gelatinization temperature. The optical properties of the anthocyanin-loaded modified starch film indicated better sensitivity than the native starch film when exposed to volatile ammonia vapor.

Significance

The application of this modified starch for intelligent food packaging with the incorporation of anthocyanin for pH-based sensing will increase the functionality of biopolymer-based films.

Authors: Sachchidanand Pandey, Jayeeta Mitra