High barrier polyhydroxyalcanoate food packaging film by means of nanostructured electrospun interlayers of zein

In this work, multilayer structures based on polyhydroxybutyrate-co-valerate with a valerate content of 12% (PHBV12) containing a high barrier interlayer of electrospun zein nanofibers were developed. It was observed that the method used for the preparation of the outer PHBV12 layers affected their functional properties, since mechanical resistance increased and water vapour permeability and transparency decreased in the multilayer containing outer layers prepared by compression-moulding to a higher extent than for their counterparts obtained by casting. The addition of zein interlayer produced minimum changes in mechanical and optical film properties while the incorporation of the zein nanostructured interlayers significantly improved oxygen barrier properties of the multilayer films prepared by both processing technologies. However, the effect of the interlayer on the water vapour and limonene permeability depended on zein content. Thus, this approach provides an innovative way to develop fully renewable microbial biopolyester-based multilayer structures with enhanced barrier performance of significant interest in food packaging applications.

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► The effect of the zein interlayer on PHBV12 multilayer films was analyzed.
► The multilayer processing method (casting and compression-moulding) was also studied.
► Films obtained by casting were more permeable to water vapour and limonene.
► Zein nanofibers improved oxygen permeability of the multilayer structures.
► Zein interlayer produced minimum changes in mechanical and optical film properties.