Loading oregano essential oil into microporous starch to develop starch/polyvinyl alcohol slow-release film towards sustainable active packaging for sea bass (Lateolabrax japonicus)

Microporous starch (MS) was used as an adsorption carrier to load with oregano essential oil (OEO). The starch/ polyvinyl alcohol (STA/PVA) films containing OEO or MS loaded with OEO (OEO-MS) were prepared. The films' properties and their application in sea bass packaging were investigated. The FTIR spectra indicated that OEO and OEO-MS were successfully incorporated into STA/PVA film and their interaction occurred through hydrogen bonds. The SEM results demonstrated that loading OEO into MS promoted the dispersion of OEO in the film. The incorporation of OEO-MS improved tensile strength of film and reduced its flexibility. The water vapor and oxygen permeability of film decreased for OEO-MS incorporation, while the addition of OEO showed opposite results. The films containing OEO or OEO-MS both exhibited antioxidant and antibacterial activities. It showed that the release rate of OEO released from films into food simulant (10% ethanol) slowed down for loading OEO into MS. The preservation results of sea bass showed that the films containing OEO or OEO-MS could efficiently inhibit the growth of microorganisms, lipid oxidation and the decomposition of protein of sea bass. The STA/PVA film added with OEO-MS was the best to maintain the freshness of sea bass and prolonged its shelf life. Therefore, this sustained release active films showed a good potential for aquatic products packaging.