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α‐Tocopherol, usually used as an antioxidant in the packaging industry, was loaded into inner pore channels of Mobil composition of matter NO.41(MCM‐41) mesoporous silica material to control its release from packaging materials into fatty food simulant. Different amount of α‐tocopherol/MCM‐41 assembly were coextruded with low‐density polyethylene (LDPE) granulates to prepare antioxidant active films by flat extrusion. The influence of the assembly addition amounts on the properties of LDPE films including physical properties and antioxidant release profiles were thoroughly investigated. The results showed that the addition amounts obviously influenced the physical properties of LDPE films as well as migration profiles of the antioxidant. As compared to pure LDPE, tensile strength of LDPE films loaded with 4% (w/w) of the assembly decreased by ∼20% on machine direction. As to release profiles of the antioxidant, LDPE films loaded with 0.2% of the assembly showed the fastest release rate, and the highest amount of the assembly gave rise to the longest release period, which was ∼23% longer than that of 0.2% additives. These results may offer theoretical instructions for further industrial applications of LDPE antioxidant active films loaded with α‐tocopherol/MCM‐41 assembly. POLYM. ENG. SCI., 58:1710–1716, 2018. © 2017 Society of Plastics Engineers

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Antioxidant active packaging films were prepared with low-density polyethylene (LDPE) being incorporated with α-tocopherol-loaded MCM-41 mesoporous silica. In order to study the influence of pore size and morphology of the mesoporous material on physical and release properties of films, the mesoporous materials were synthesized with various pore sizes and morphologies. MCM-41 mesoporous silica materials before and after being loaded with α-tocopherol were characterized, as well as the active films. The results show that physical properties and release profiles of active films can be changed when being incorporated with mesoporous materials with different structures: crystallinity of films prepared ranged from 11.30% to 18.13%, and the tendency of change was in good accordance with that of specific surface area of mesoporous silica materials. Variation of release rates of the antioxidant in packaging films can be achieved by changing MCM-41 pore size, and the release period can be prolonged by 64% in the scope of this study. These demonstrate that LDPE/α-tocopherol/MCM-41 films with adjustable release profile and physical properties have the potential to be used as antioxidant active packaging films.

In order to match the solid food oxidation during logistics and storage process under severe high temperature, a double-switch temperature-sensitive controlled release antioxidant film embedded with lyophilized nanoliposomes encapsulating rosemary essential oils (REOs) was prepared. The double switch temperature at 35.26 and 56.98 °C was achieved by development of a temperature sensitive polyurethane (TSPU) film. With biaxially oriented polyethylene terephthalate (BOPET) as a barrier layer, the intelligent complex film was prepared via coating the TSPU embedded with lyophilized nanoliposomes encapsulating REOs on BOPET. The results indicate that the REO is well encapsulated in nanoliposomes with encapsulation efficiency (EE) of 67.3%, high stability and lasting antioxidant effect during 60 days. The incorporation of lyophilized nanoliposomes containing REOs into TSPU remains the double-switch temperature-sensitive characteristic of the prepared TSPU. In agreement with porosity and WVTR results, the diffusion coefficient (D) of the antioxidant complex film sharply increases respectively at two switching temperatures, indicating that the intelligent double-switch temperature-sensitive controlled release property is functioning. Furthermore, compared with films directly added with REO, the lower Ds of films added with lyophilized nanoliposomes encapsulating REOs provides a longer-lasting antioxidant activity. Thus, the acquired controlled release antioxidant film sensitive to temperature at 39.56 and 56.00 °C can be potentially applied for protection of solid food during distribution and storage process under severe high temperatures.