Active alginate-based films and coatings loaded with polyphenol extracts from plant waste: Enhanced functional...

Polyphenol extracts derived from agro-industrial residues, such as purple onion peels and catuaba bark, provide bioactive compounds that can be effectively incorporated into edible materials and coatings, enhancing their functional performance and preservation capacity. This study investigated alginate-based edible coatings incorporating polyphenol-rich extracts from purple onion peel (OPE) and catuaba bark (CBE) as sustainable postharvest strategies for pear preservation. Compared to the alginate film (AF), functionalization with OPE and CBE extract improved film performance by increasing tensile strength by 52.4% and 12.8%, respectively, increasing the water contact angle by 52% and 44%, and opacity by 7.5- and 1.8-fold, respectively, resulting in enhanced UV-blocking properties. When applied to pears, alginate-based coatings functionalized with OPE and CBE reduced weight loss by 51.0% and 55.0% and firmness loss by 46.3% and 61.1%, respectively. They also reduced bacterial counts by 2.33 and 2.91 log CFU g^-1 and yeasts and molds by 2.19 and 2.35 log CFU g^-1, respectively, compared with uncoated fruits. These effects are attributed to the synergistic action of the semi-permeable alginate matrix, and bioactives effects present in the extracts. Overall, this work demonstrates that waste-derived active alginate coatings offer a sustainable and efficient approach to extend pear shelf life while valorizing agro-industrial by-products, highlighting their potential for circular bioeconomy-driven postharvest applications.