Enhancing the quality of Havarti cheese: Chitosan films with nettle Urtica dioica L. extract as slice separators to retard lipid oxidation

The aim of this study was to develop an active slice separator based on a chitosan film with nettle extract (Ch_NE) for vacuum-packed Havarti cheese and to evaluate the changes during storage for 45 days at 5 degrees C. The active properties of the developed slice separator film were evaluated by measuring antioxidant and optical properties of the cheese and the film, as well as lipid oxidation of the cheese. The addition of nettle extract to chitosan films caused a decrease in mechanical properties such as tensile strength from 58.02 to 1.81 MPa and Young's Modulus from 1535.92 to 4.43 MPa, making them easy to apply and handle as slicing separators. Furthermore, the thermal properties of the films indicated their stability at temperatures commonly encountered during food heat pro-cessing. After 45 days of refrigerated storage, the Ch_NE slice separator demonstrated a significant reduction in thiobarbituric acid reactive substances in cheese samples, indicating a 56% decrease in lipid oxidation compared to the control group. In conclusion, an environmentally friendly alternative to synthetic and non-biodegradable slice separators have been successfully developed using chitosan, a by-product of the fish industry, enriched with an extract from nettle, a widely distributed wild plant.