Gas Permeability and Permselectivity of Poly(L‐Lactic Acid)/SiO <i> _x </i> Film and Its Application in Equilibrium‐Modified Atmosphere Packaging for Chilled Meat

Abstract

A layer of SiO_x was deposited on the surface of poly(L-lactic acid) (PLLA) film to fabricate a PLLA/SiO_x layered film, by plasma-enhanced chemical vapor deposition (PECVD) process. PLLA/SiO_x film showed Young's modulus and tensile strength increased by 119.2% and 91.6%, respectively, over those of neat PLLA film. At 5 °C, the oxygen (O₂ ) and carbon dioxide (CO₂ ) permeability of PLLA/SiO_x film decreased by 78.7% and 71.7%, respectively, and the CO₂ /O₂ permselectivity increased by 32.5%, compared to that of the neat PLLA film. When the PLLA/SiO_x film was applied to the equilibrium-modified atmosphere packaging of chilled meat, the gas composition in packaging reached a dynamic equilibrium with 6% to 11% CO₂ and 8% to 13% O₂ . Combined with tea polyphenol pads, which effectively inhibited the microbial growth, the desirable color of meat was maintained and an extended shelf life of 52 d was achieved for the chilled meat.