Development of gas phase controlled-release antimicrobial and antioxidant packaging film containing carvacrol loaded with HNT-4M（halloysite nanotubes etched by 4 mol/L hydrochloric acid）

In order to inhibit the spoilage of the packaged food, a gas phase controlled-release low-density polyethylene (LDPE) film containing carvacrol loaded with halloysite nanotubes (HNTs) was prepared and studied in this work. HNTs were etched by 4 mol/L hydrochloric acid to obtain HNT-4M, which increased the carvacrol loading capacity. Then, it was characterized before and after loading with carvacrol by transmission electron microscopy, nitrogen adsorption isotherms, and thermogravimetric analysis. A new LDPE film containing carvacrol adsorbed on HNT-4M was prepared by extrusion, and the physical properties were studied. In addition, the release rate of carvacrol in the film was measured, and the antibacterial and antioxidant properties of the film were evaluated. The results showed that the carvacrol load of HNT increased from 6.7% to 24.2% after acid etching. The diffusion coefficient of carvacrol from the active film containing HNT-4 M/carvacrol was 9.546 × 10-12 cm2·s-1, which was decreased by 57.3% compared with the films directly adding carvacrol. Moreover, according to the DPPH radical scavenging assay and micro-atmosphere diffusion antibacterial test, it was verified that carvacrol retained its antioxidant activity and antibacterial activity in the new film.