Influence of Teucrium montanum Hydrolate Integration on the Functional Performance of Chitosan-Based Films

Natural biodegradable polymers such as chitosan are gaining increasing importance due to their favorable mechanical properties. Conversely, their limited antimicrobial and antioxidant activity requires enhancement with bioactive components. This study investigated the effect of Teucrium montanum L. hydrolate on the functional properties of chitosan films. The hydrolate was obtained as a by-product of hydrodistillation, and films were prepared with 0.6% (CH-TMh1), 0.8% (CH-TMh2), and 1.2% (CH-TMh3) hydrolate, along with a control film without hydrolate (CH). Hydrolate-enriched films exhibited greater thickness and elongation at break, with the highest values observed in CH-TMh3. The addition of hydrolate reduced moisture content (from 30.09% in CH to 12.25% in CH-TMh3), solubility, and swelling degree. Antioxidant activity increased significantly, with CH-TMh2 showing the highest free radical scavenging activity (92.9%) and total polyphenol content (38.78 mg GAE/g). Films containing hydrolate also displayed pronounced antimicrobial activity, with the largest inhibition zones against S. aureus ATCC 25923 (16.33 mm). Moderate activity was observed against B. subtilis, while there was no activity against C. albicans ATCC 2091. These results confirm that chitosan films enriched with T. montanum L. hydrolate possess improved mechanical, antioxidant, and antimicrobial properties, making them promising for potential application in the packaging of specific food products.