Use of the electrohydrodynamic process to develop active/bioactive bilayer films for food packaging applications

In this work, the electro-hydrodynamic process was used to encapsulate an antioxidant, alpha-tocopherol, using different hydrocolloid matrices (whey protein isolate-WPI-, zein and soy protein isolate-SPI-) as shell materials. These hybrid structures were directly electrospun/electrosprayed as a coating layer onto one side of a thermoplastic wheat gluten film, thus giving rise to active/bioactive bilayer packaging structures. The water vapour barrier efficiency of thermoplastic wheat gluten films were improved by the presence of the active coating layer. Moreover, when submitting these structures to a typical industrial sterilization process, the alpha-tocopherol stability was preserved, especially when zein was used as shell material. The amount of the alpha-tocopherol released in the aqueous media was assessed by a spectrophometric method. The alpha-tocopherol release profiles showed a delayed release of the encapsulated antioxidant in zein matrices (fibres morphology). The release was faster for WPI and SPI-GG probably due to both the capsule morphology and the swelling and faster dissolution of these water-soluble protein matrices. This work provides a new method for developing active/bioactive packaging systems of interest in food applications. (C) 2015 Elsevier Ltd. All rights reserved.