Development of electrospun active films of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by the incorporation of cyclodextrin inclusion complexes containing oregano essential oil

Abstract

Oregano essential oil (OEO) has good antioxidant and antimicrobial activity and its incorporation into food packaging is challenging because of its intense flavor, high volatility and instability, and insolubility in aqueous systems. Additionally, the sensory perception of EO can be changed as a consequence of oxidation, heating, volatilization or chemical interactions. Cyclodextrins (CDs) can be used to avoid these inconveniences because they are able, due to their peculiar chemical structure, to encapsulate hydrophobic molecules such as OEO improving its aqueous solubility and reducing its volatility. In this work, kneading (KM) and freeze-drying (FDM) methods were evaluated to encapsulate OEO in two cyclodextrins types (α-CD and γ-CD). After, the α-CD:OEO and γ-CD:OEO inclusion complexes (ICs) were included in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) electrospun fibers by electrospinning and annealed for film formation. Results showed that the encapsulation efficiency of oregano essential oil is influenced by both the encapsulation methods and the cyclodextrin type. The antimicrobial and antioxidant activity of the α-CD:OEO and γ-CD:OEO inclusion complexes were higher compared with pure OEO. The optimal concentration of α-CD:OEO inclusion complexes and γ-CD:OEO inclusion complexes for homogeneous and continues films formation was 15 and 25 wt%, respectively. At these concentrations, the films showed a strong antimicrobial and antioxidant activity, up to 15 days. In addition, the mechanical properties of the films were also improved (Young's modulus + 35%). In conclusion, this work shows that the encapsulation of CD:OEO inclusion complexes by electrospinning into PHBV polymeric matrix opens a new path in the development of bioactive packaging materials using EOs.

Development of Electrospun Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Monolayers Containing Eugenol and Their Application in Multilayer Antimicrobial Food Packaging

“…Similar results were obtained by da Silva et al ( 72 ), who observed that eugenol entrapped in cellulose nanostructures and then incorporated in the poly(butylene adipate- co -terephthalate) (PBAT) prepared by solvent casting improved the thermal stability of pure eugenol. Likewise, the previous reports of our research group agreed with the thermal properties attain in the present study, showing that the thermal stability of essential oils incorporated into PHAs by electrospinning was improved ( 59 , 67 , 73 ). Therefore, the development of thermally stable systems expands the potential use of electrospinning for the design of active food packaging as an alternative to melt processing technologies such as extrusion or compression molding.…”

Encapsulation of Flavours and Fragrances into Polymeric Capsules and Cyclodextrins Inclusion Complexes: An Update

“…A polymer-free electrospinning approach was applied on CD inclusion complexes to enhance the water solubility; improve the high temperature stability and control the release of carvacrol [ 90 ], tymol [ 91 ], camphor [ 92 ], menthol [ 93 ], limonene [ 94 ], citral [ 95 ], cineole and p-cymene [ 96 ] and eugenol [ 97 ]. In other studies, the volatiles/inclusion complexes with CDs were incorporated in a biopolymer matrix as zein [ 98 , 99 ], o pullulan [ 100 ], semisynthetic polymers such as cellulose acetate [ 101 ] or synthetic polymers such as poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) [ 102 ] via electrospinning. These polymers have been used for the formation of edible or biodegradable antimicrobial films, as well as porous membranes for packaging or biomedical applications.…”

Preparation and Applications of Electrospun Optically Transparent Fibrous Membrane

“…In order to meet the material safety requirements of food packaging, safe and non-toxic natural polymers are usually selected, such as oregano essential oil for its significant antibacterial effect [ 162 ]. Lopez produced packaging films of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with alpha- and gamma-cyclodextrins (α-CD and γ-CDs) containing oregano essential oil (OEO).…”