Sustainable and eco-friendly poly (Lactic acid)/cellulose nanocrystal nanocomposite films for the preservation of oxygen-sensitive food
Dangkamol Wongthanaroj, Lindsay A. Jessmore, Yawei Lin, Teresa M. Bergholz, Nicole M. Stark, Ronald Sabo, Laurent M. Matuana
Abstract
The development of enzymatic browning constitutes one of the key issues in the preservation of highly perishable fresh-cut and oxygen-sensitive fruits such as avocados. This study explored the use of a packaging solution based on PLA/cellulose nanocrystal (CNC) films produced using a solvent-free cast extrusion process with strong oxygen and UV barrier properties to reduce browning in cut avocados and to prolong shelf life. Specifically, the effects of packaging material types (neat PLA vs PLA/CNC nanocomposite) and storage conditions (temperature and time) on discoloration (browning), microbial growth, and shelf life were assessed. Enzymatic browning was visually evaluated and total discoloration (ΔE*) quantified as a function of storage time and temperature to estimate the shelf life of the avocados. Compared with neat PLA, nanocomposite packaging reduced the enzymatic browning more and resulted in additional shelf life extension of 1.3 days at 23 °C and 5.4 days at 4 °C. Both PLA-based films reduced the microbial growth. The potential of sustainable and eco-friendly nanocomposite film to prolong the shelf life of food that is oxygen sensitive is clearly demonstrated.