Innovative encapsulation strategy to improve sustainability of biodegradable bioactive food packaging: case of PHBV (Poly-3-hydroxybutyrate-co-3-hydroxyvalerate) containing carvacrol

International audience

إنجليزي. Increasing sustainability of the food chain means tackling, among others, the negative impacts of packagingmaterial, especially those linked to persistent plastic packaging, while reinforcing the positive impact of packaging,which is food quality preservation and food loss and waste mitigating prevention. To reach this goal, one solutionis to use biobased (but nonfood or nonfeed sourced), bioprocessed, biodegradable and bioactive packaging.Bioactive means that a natural compound is added to the polymer to enhance its ability to preserve food andextend shelf-life while the intrinsic biodegradability of the polymer is maintained. In this context, (Poly-3-hydroxybutyrate-co-3-hydroxyvalerate) is a good candidate as polymer as a biosourced, bioprocessed andbiodegradable molecule, and carvacrol is a good active molecule candidate, as it has a strong antimicrobial effect.However, carvacrol is also volatile and heat-sensitive, and encapsulation is necessary to avoid a loss of themolecule during the thermal formulation process of the packaging and during packaging storage. On the otherhand, encapsulation must not hamper the release of the active compound when needed, i.e., in contact with food.Finally, adding an active compound must not modify biodegradation kinetic; therefore, a strategy is to applyencapsulated carvacrol on the packaging surface in a thin coating layer.In this context, this work aimed to encapsulate carvacrol in PHBV (Poly-3-hydroxybutyrate-co-3-hydroxyvalerate)nanoparticle - intended to be deposited on the packaging surface - and to study the carvacrol release kineticduring storage. To do that, a nanoprecipitation method was adapted to shape PHBV nanoparticles. For instance,the molar mass of PHBV must be necessary below (150 kDa) to successfully obtain nanoparticles (SEMobservations). Then encapsulation was characterized, and the release of carvacrol from the nanoparticlespowder/material coated with PHBV nanoparticles was studied. A model describing the molecular diffusion usingthe second Fick’s law was developed and adjusted to experimental release data, with a good fitting. Such a modelwould permit us to anticipate the dimensioning of such active packaging as a function of food requirements (e.g.,antimicrobial compound concentration in the headspace, for instance).