A gas selective film for equilibrium-modified atmosphere packaging: Bio-based γ-PGA coating on plasma-modified LDPE for fresh-cut papaya preservation

This study aims to develop an equilibrium-modified atmosphere packaging (EMAP) system by incorporating poly-gamma-polyglutamic acid (γ-PGA) as a sustainable coating material to enhance gas selectivity in low-density polyethylene (LDPE) films. The objective is to achieve a controlled gas permeability that optimizes the packaging environment for extended food preservation. The γ-PGA coating treatment increases the tensile strength, gas barrier properties, and CO 2 /O 2 selectivity of the composite film, which accelerates the gas composition change to a low-oxygen and high-carbon dioxide concentration environment for fresh-cut papaya (FCP). The prepared EMAP film coated with 5 % γ-PGA maintained a balanced gas content of 7.27 %–10.50 % CO 2 and 13.03 %–7.80 % O 2 for FCP over 12 days of storage, which reduced the respiration rate by 29.37 % of FCP. Quality was well maintained, with a 31.65 % reduction in weight loss and a 42.98 % reduction in firmness loss compared to the LDPE packaging. γ-PGA coating provides suitable gas transmission rate properties for fresh-cut papaya, extending the quality deterioration period by 6 days compared to pure LDPE. This research explores the potential of utilizing γ-PGA in EMAP, demonstrating its effectiveness as a sustainable coating material. The findings indicate that gas transmission and selectivity properties can be modulated by adjusting the coating concentration, offering flexibility for food preservation technologies. • γ-PGA coating improved the tensile strength of LDPE by 44.8 %. • γ-PGA coating modified CO 2 /O 2 permeability and selectivity of the packaging. • γ-PGA EMAP obtain stable atmospheres with 10.50 % CO 2 and 7.80 % O 2 with papaya. • γ-PGA coating film decreases the respiration by 29.37 % of fresh-cut papaya. • γ-PGA coating extends the quality deterioration period by 6 days.