Preparation of an eco-friendly antibacterial agent for food packaging containing Houttuynia cordata Thunb. extract

This study aims to develop an antibacterial agent that can be used for food packaging. Essential oils of Thunb., a well-known medical herb, were extracted by two methods: multi-solvent consecutive extraction method and single ethanol extraction with a pre-heating method. Consequently, the extract obtained by the single ethanol extraction with a pre-heating method was more satisfactory from the operational and economic aspects. Afterwards, one of the encapsulation techniques: co-precipitation method using β-cyclodextrins as wall materials, was applied to form capsules for the protection of the obtained extract. After the capsule synthesis, the results of scanning electron micrographs and X-ray diffraction showed β-cyclodextrin crystallites in the form of thinner plates became oriented upon co-precipitation. Combining the results of Fourier transform-infrared spectra and an antibacterial assay using as an object microorganism, the extract was confirmed to be successfully encapsulated within hollow cavities of β-cyclodextrins. A significant inhibitory activity on the growth and breeding of was observed after the addition of fabricated capsules, which suggests the capsules containing the Thunb. extract can be used as eco-friendly antibacterial agents for food packaging.