Release kinetics of carvacrol and eugenol from poly (hydroxybutyrate-co-hydroxyvalerate) (PHBV) films for food packaging applications

Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) films, plasticized with PEG, incorporating 13 wt.% of active compounds (carvacrol-CA, eugenol-EU) were obtained by spraying the active between PHBV layers and their subsequent adhesion. Release kinetics of CA and EU in food simulants of different polarity was analysed and the films' antimicrobial activity was predicted, taking the minimal inhibitory concentration against some foodborne pathogens into account. Overall migration values were also determined. At equilibrium, an almost total release of both CA and EU occurred in 50% ethanol, about 20 and 50% of CA and EU, respectively, was delivered in the more aqueous simulants and 65-70% in fatty systems. The release rate increased when the polarity of aqueous simulants decreased, but it fell markedly in fatty systems. EU was released faster than CA in the less polar simulants, but more slowly in the more aqueous systems.