关键词: 聚乳酸, 牛至精油, 抗氧化活性, 包装

Abstract: The polylactic acid/oregano essential oil antioxidant activity packaging films were prepared by a casting method using polylactic acid as the substrate, oregano essential oil as the antioxidant active component and Siban 80 as the plasticizer, and their properties were tested. The influence of oregano essential oils on the mechanical properties of polylactic acid packaging films was evaluated by measuring tensile strength, elongation at break and elastic modulus, the influence of oregano essential oils on the barrier propertiesof polylactic acid packaging films was evaluated by measuring water vapor transmission rate and oxygen transmission rate, the influence of oregano essential oils on the antioxidant properties of polylactic acid packaging films was measuredby radical scavenging rate. The results showed that the polylactic acid/oregano essential oil films possessed good antioxidant properties and the antioxidant effects increased with the increase of oregano essential oilconcentration. The addition of different amount of oregano essential oils had different effects on the packaging performance of polylactic acid packaging films. When oregano essential oil content reached 1.5%, the free radical scavenging rate of the polylactic acid/oregano essential oil film reached 82.6%. At this time, the thickness of the film material increased significantly to （136.2±6.0） μm, the tensile strength and elastic modulus were respectively significantly decreased to （10.0±0.9） MPa and （22.7±3.0） MPa, the elongation at break decreased slightly to （343.4±18.2）%, the water vapor transmission rate was significantly decreased to （34.7±1.2） g/m²·24 h, and the oxygen transmission rate was slightly increased to （988.3±39.6） mL/m²·24 h·atm.

Key words: polylactic acid, oregano essential oil, antioxidant activity, packaging