Cinnamaldehyde- and nonanal-incorporated polyvinyl alcohol/colloidal silicon dioxide films with synergistic antifungal activities

Biodegradable materials may help solve the problem of environmental pollution caused by conventional synthetic food packaging. Here, various amounts of colloidal silicon dioxide [CSD, 5, 10, and 15 wt% based on polyvinyl alcohol (PVA)] and 1 % S_CAN, a 1:1 (v:v) combination of cinnamaldehyde and nonanal, were added to fabricate PVA-based films. Microstructure analyses using atomic force and scanning electron microscopes revealed that the films had uniform CSD dispersion, and the surface roughness rose along with the CSD concentration. The addition of S_CAN prevented UV light transmission. In addition, the introduction of CSD enhanced the water-resistance abilities and tensile strengths of the composite films. The PVA/S_CAN films exerted remarkable antifungal activities against Aspergillus flavus owing to a synergistic effect between cinnamaldehyde and nonanal. Furthermore, the PVA/S_CAN/CSD film, contrasted with the PVA film containing S_CAN alone, attenuated the S_CAN loss during storage and also continually released S_CAN from the film. In peanut preservation, the PVA/S_CAN/CSD composite film was superior to the single-element films in antifungal activity, showing decreases of 76.66 % and 85.33 % in the production of conidia and aflatoxin B1, respectively. In conclusion, the PVA/S_CAN/CSD composite film with high UV barrier, water-resistance ability, excellent mechanical properties and antifungal activity possesses a promising application potential in food packaging.