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

Abstract

In this research, different contents of eugenol in the 2.5-25 wt.% range were first incorporated into ultrathin fibers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by electrospinning and then subjected to annealing to obtain antimicrobial monolayers. The most optimal concentration of eugenol in the PHBV monolayer was 15 wt.% since it showed high electrospinnability and thermal stability and also yielded the highest bacterial reduction against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). This eugenol-containing monolayer was then selected to be applied as an interlayer between a structural layer made of a cast-extruded poly(3-hydroxybutyrate) (PHB) sheet and a commercial PHBV film as the food contact layer. The whole system was, thereafter, annealed at 160 • C for 10 s to develop a novel multilayer active packaging material. The resultant multilayer showed high hydrophobicity, strong adhesion and mechanical resistance, and improved barrier properties against water vapor and limonene vapors. The antimicrobial activity of the multilayer structure was also evaluated in both open and closed systems for up to 15 days, showing significant reductions (R ≥ 1 and < 3) for the two strains of food-borne bacteria. Higher inhibition values were particularly attained against S. aureus due to the higher activity of eugenol against the cell membrane of Gram positive (G+) bacteria. The multilayer also provided the highest antimicrobial activity for the closed system, which better resembles the actual packaging and it was related to the headspace accumulation of the volatile compounds. Hence, the here-developed multilayer fully based on polyhydroxyalkanoates (PHAs) shows a great deal of potential for antimicrobial packaging applications using biodegradable materials to increase both quality and safety of food products.

In vivo and Post-synthesis Strategies to Enhance the Properties of PHB-Based Materials: A Review

“…The use of PHBHV electrospun fibers to develop active multilayer materials for food packaging application was also investigated (Castro-Mayorga et al, 2017a ; Figueroa-Lopez et al, 2020 ). An active PHBHV-based multilayer, loaded with silver nanoparticles, was found effective against Salmonella enterica .…”

“…Electrospun mats of PHBHV fibers containing eugenol were used as an active interlayer between a food contact layer of PHBHV and a cast-extruded PHB sheet. After the annealing at mild temperature, the novel multilayer active packaging material exhibited, besides antimicrobial activity, high hydrophobicity, strong mechanical resistance, and improved barrier properties against water vapor and limonene vapors (Figueroa-Lopez et al, 2020 ).…”

Synthesis of D-Limonene Loaded Polymeric Nanoparticles with Enhanced Antimicrobial Properties for Potential Application in Food Packaging

“…The EOs can be used in these systems as additives in films or coatings, either directly or in the form of micro- and nano-encapsulated systems [ 16 , 17 ]. The direct blending of citrus EOs with polymeric materials, either natural or synthetic, is often considered the most effective approximation for the development of an active antimicrobial food packaging [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. Nevertheless, the encapsulation of an EO in nano-capsules is considered advantageous compared to the direct blending of an EO, in terms of protection from evaporation and possible thermal or photodegradation [ 15 ].…”

New Trends in the Use of Volatile Compounds in Food Packaging

“…However, the incorporation of eugenol to food packaging applications is usually limited by its high volatility and sensitivity to oxygen, light, and heat [ 31 ]. Nevertheless, eugenol has been used as active compound in food active packaging due to its antifungal [ 9 ], antimicrobial [ 10 , 32 ], and antioxidant properties [ 33 ].…”