Characterization and preservation performance of active polyethylene films containing rosemary and cinnamon essential oils for Pacific white shrimp packaging

A new active packaging film of bilayer structure based on low-density polyethylene (LDPE) incorporated with rosemary essential oil (REO) and cinnamon essential oil (CEO) in the inner layer has been designed and developed for preserving shrimp. Six types of active packaging films [REO (1% w/w), REO (2% w/w), CEO (1% w/w), CEO (2% w/w), REO (1% w/w) + CEO (1% w/w) and control (film without EO)] were designed by blown film extrusion method. Tensile strength (TS), water vapor transmission rate (WVTR), oxygen transmission rate (OTR), thermogravimetric analysis (TGA), and microstructure of films were investigated to justify the effect of EOs on the film physical functionality. The outcomes of scanning electron microscopy (SEM) analysis revealed that the surface of active films became relatively rougher by the incorporation of REO or CEO into the LDPE matrix. Meanwhile, the films with different amount of EOs proved to have a slight decline in the TS, whereas improved the barrier properties. In addition, shrimp packaged in active films containing EOs revealed lower microbial counts, total volatile basic nitrogen (TVB-N) contents, and thiobarbituric acid reactive substances (TBARS) values compared to samples packed in control films during storage at 4 degrees C for 10 days. The results indicated that the blended film (REO + CEO) showed more effective in maintaining the freshness and extending the shelf life of packaged shrimps up to 4 days. This new active packaging film has potential to be used for enhancing the quality and storage stability of aquatic products. (C) 2018 Elsevier Ltd. All rights reserved.