An electron beam irradiation treated eco-friendly glucomannan-aloe vera bioplastic sheet with a two-year shelf-life observation

Abstract

Foam nets and plastic have become common wrappers for preserving fruit freshness. However, their poor degradability poses environmental hazards and disrupts the natural life cycle. The combination of a glucomannan-Aloe vera blend with electron irradiation offers a smart, biodegradable alternative, addressing these issues. A Glucomannan 99 % and Aloe vera Chinensis Baker blend at 1:30 (w/w) ratio showed the highest resistance to fungal contamination. Furthermore, electron beam irradiation at 135 kGy played an important role in the cross-linking, which improved the mechanical properties of bioplastics, while simultaneously serving as a sterilization method for preservation. The cross-linking process in bioplastics was observed through several key findings after irradiation. FTIR spectra showed the emergence of new peaks at 2350.9 cm^-1 and the disappearance of peaks at 1418.2 cm^-1, indicating CO₂ and H₂O peak shifts, which signify cross-linking at low temperatures. Microscopic observations at 600x magnification showed layers interconnected through walls, forming a structured network that indicates increased physical cross-linking, along with the formation of small bubbles and pore structures. The XRD diffractogram displayed new peaks at 2θ around 31.33°, 35.6°, 38.8°, 44.8°, and 65.2°, confirming an increase in crystallinity after irradiation. SEM analysis further revealed more regular morphological changes in bioplastic sheets, resulting in more uniform shapes. The bioplastic exhibited a tensile strength of approximately 1.84 MPa, meeting the Japanese Industrial Standard (JIS) Z 1707: 2019 for edible packaging. The swelling test showed a value of 533 %, indicating strong potential as an adsorbent. This edible bioplastic remained mold-free for up to two years and fully composted within three days. Its byproducts could also be repurposed as animal feed to ensure a zero-waste process. This research presents a sustainable alternative to conventional plastic packaging and offers an innovative solution to environmental concerns.