Enhanced mechanical and antioxidant properties of biodegradable poly (lactic) acid-poly(3-hydroxybutyrate-co-4-hydroxybutyrate) film utilizing α-tocopherol for peach storage

Abstract

Poly (lactic) acid-poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (PLA-PHB) blends were prepared through melting method and incorporated with α-tocopherol. The structural, thermal, mechanical and antioxidant properties of resulting active films were characterized, and its preservation effect on peaches (Prunus persica L.) was investigated. Results revealed that the glass transition temperature (Tg) of PLA film was reduced from 53.2°C to 39.7°C after addition of plasticizer but increased again to 43.3°C after supplementation with α-tocopherol. PLA-PHB are polyesters with carboxylic groups that interacted with the hydroxide groups of α-tocopherol. Furthermore water vapour permeability, gas permeability and elongation at break were significantly improved, and 72.1% 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity was observed. PLA-PHB-α-tocopherol group revealed higher combined water and less oxidative spoilage through low-field nuclear magnetic resonance (LF-NMR) and effectively extended the shelf life of peach. Thus, the plasticized PLA-PHB-α-tocopherol film can be used as an active biodegradable packaging for fruits and vegetables.