Preparation of α-tocopherol-chitosan nanoparticles/chitosan/montmorillonite film and the antioxidant efficiency on sliced dry-cured ham

The aim of this work was to prepare a novel antioxidant film by incorporating α-tocopherol-chitosan nanoparticles (TOC-CSNPs) with chitosan/montmorillonite film (namely, TOC-CSNPs/CS/MMT), and investigate the antioxidant activity of TOC-CSNPs/CS/MMT film on sliced dry-cured ham in a period of 120 days at 4 °C. Positively charged TOC-CSNPs with the average sizes of 214 nm were prepared using TPP-initiated ionic gelation mechanism. The amount of TOC-CSNPs was optimized based on the changes of water vapor permeability (WVP), water solubility and swelling ratio of the film. The TOC-CSNPs/CS/MMT film showed 46.5% radical scavenging activity after 16 days of storage, which was 23 times and 27 times higher than that of CS/MMT and CS film, respectively. The antioxidant activity of TOC-CSNPs/CS/MMT film was evaluated by measuring the peroxide value (POV) and thiobarbituric acid reactive substances (TBARS) values of sliced dry-cured ham coated with the TOC-CSNPs/CS/MMT film-forming solutions. The results indicated that compared with the CS (0.42 g/100 g for POV, 0.65 mg/kg for TBARs) and CS/MMT (0.38 mg/kg for POV, 0.59 mg/kg for TBARs) films, the biceps femoris muscle of the sliced ham coated with TOC-CSNPs/CS/MMT film showed much lower values of POV (0.15 g/100 g) and TBARs (0.15 mg/kg) during 120 days of storage. These results provide a theoretical basis for developing efficient and long-term antioxidant approach, which is crucial for improving and enhancing the quality of food products.