Active Packaging Development for Sliced Bread, Based on Polyvinyl Acetate Incorporated With Clove Essential Oil and Its Post-Consumer Bioconversion Into Enzymes
Authors: Silva Marina Gomes , Nascimento Maria Clara Barbosa , Santana Ingrid Larissa da Silva , Lucena Alex Leandro Andrade de , Napoleão Daniella Carla , Vinhas Glória Maria 
Published: December 2024

Objective: The objective of this study was to monitor the life cycle of a new active packaging (AP) based on polyvinyl alcohol (PVA) and clove essential oil (CO), in a proportion of 15% w/w, to be applied in the storage of sliced bread. In this cycle, the produced materials will be characterized, applied, and biodegraded by the fungus Penicillium expansum, whose enzymes will be quantified as a value-added bioproduct for the industry. 
 
Theoretical Framework: Active packaging (AP) are systems that promote the extension of the shelf life of products through their interactions with food. Among the functions of AP, antimicrobial characteristics are fundamental for food preservation and can be achieved through active constituents, such as essential oils, which are natural and non-toxic compounds. However, beyond merely developing new AP, it is necessary to evaluate environmentally friendly ways to dispose of these post-consumer materials. Among the possibilities is the biodegradation of polymeric residues by microorganisms in a liquid medium.
 
Method: Pure PVA films with 15% CO were produced using the casting method, employing water as a solvent. Subsequently, the materials were characterized through various analyses and applied as antimicrobial AP for sliced bread during 7 and 14 days of storage. After these periods, the microbial growth of the packaged food was quantified using colony-forming units (CFU). To quantify CFU, the food was dissolved in 0.1% peptone water at 0, 7, and 14 days, and 0.1 mL was distributed onto Petri dishes containing solidified Sabouraud medium. After the application of the produced materials, the packaging residues were biodegraded by the fungus Penicillium expansum as an environmentally friendly disposal method in liquid Sabouraud and modified Sabouraud media (without glucose). Finally, the lipase enzymatic activity in the biodegradation systems was evaluated as a value-added bioproduct for industrial use.
 
Results and Discussion: The characterization of the developed materials demonstrated that the CO does not significantly alter the properties of the polymer. In addition, it was observed that the systems using PVA+15%CO presented better control of microbial growth after 7 and 14 days of packaging the sliced bread compared to systems using pure PVA. After 7 days of storage, the bread contained in the PVA without CO showed microbial growth of 13,100 CFU·mL⁻¹, while the PVA+15%CO presented no colonies. Additionally, after 14 days of storage, the food contained in PVA without CO and PVA+15%CO packaging showed microbial growth of 25,400 and 300 CFU·mL⁻¹, respectively. This demonstrates the efficiency of the CO additive incorporated into the PVA matrix. In this sense, it was assessed that the extracts obtained after biodegradation contained lipase enzymatic activity, which has the potential to be used as a value-added bioproduct in industrial processes.
 
Originality/Value: Thus, this work highlights the environmental importance of monitoring the useful life of polymeric materials from production to disposal, addressing not only their functional performance but also their biodegradation and potential for generating value-added bioproducts. By proposing an integrated approach that combines sustainability, innovation, and environmental responsibility, this study contributes to advancing the development of active and eco-friendly packaging solutions that align with the principles of a circular economy.