Production of chitosan-based biodegradable active films using bio-waste enriched with polyphenol propolis extract envisaging food packaging applications
Developing biodegradable active films has been a promising green approach to overcoming global concerns over
the environmental pollution and human health caused by plastic utilization. This study aimed to develop active
films based on chitosan (CS), produced from waste crayfish (Procambarus clarkii) shells enriched with bioactive
extract (5–20%) of propolis (PS) and to characterize its properties, envisaging food packaging applications. The
chromatographic profile of PS extract confirmed its richness, with 41 phenolic compounds. With increasing
extract addition to the chitosan, the thickness of the films increased from 61.7 to 71.7 μm, causing a reduction in
the light transmission rate, along with a greenish colour shift. The interactions between PS extract and CS was
confirmed by infrared spectroscopy, at the same time that the microstructural integrity of the films was checked
on the scanning electron microscopy micrographs. The findings also showed that addition of PS enhanced the
films thermal stability and mechanical properties e.g., tensile modulus, yield strength, and stress at break. Besides,
it improved the antioxidant and antimicrobial activities. Overall, CS-based composite films seem a
promising green alternative to petroleum-based synthetic plastics allowing to extend the shelf life of food
products due to their eco-friendly nature.
The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020) and contracts through the individual and institutional scientific employment program-contract with Soraia I. Falcão and Arantzazu Santamaria Echart. Thanks to the Programa
Apícola Nacional 2020-2022 (National Beekeeping Program) for
funding the project “Standardization of production procedures and
quality parameters of bee products” and to Project PDR2020-1.0.1-
FEADER-031734: “DivInA-Diversification and Innovation on
Beekeeping Production”. Finally, this work is funded by the European
Regional Development Fund (ERDF) through the Regional Operational
Program North 2020, within the scope of Project GreenHealth - Digital
strategies in biological assets to improve well-being and promote green
health, Norte-01-0145-FEDER-000042.
