ReviewEdible and active films and coatings as carriers of natural antioxidants for lipid food

•Herbal essential oils and extracts were tested in active and edible packaging.•Mechanical and barrier properties were affected, sometimes positively.•Few essential oils provided antioxidant protection.•Water or ethanol extracts added to films retarded lipid food oxidation.•Green tea, oregano, and rosemary extracts were the most effective.

BackgroundLipid oxidation is one of the main causes of food spoilage. It can be delayed by the addition of antioxidants to food or by using vacuum or modified atmosphere packaging. A recent approach is the application of antioxidants in active packaging.Scope and approachThe scope of this review is to present and update all information about the incorporation of natural antioxidants in edible and active films and coatings. Natural antioxidants can replace chemical additives and are preferably accepted by the consumers. Their effect on the barrier, mechanical and antioxidant properties of the various films (chitosan, cellulose derivatives gelatin etc.) are discussed. The ability to delay food oxidation is examined in relation to the active components.Key findings and conclusionsWater or ethanol extracts from several herbs (rosemary, oregano, tea), berries, or plant by-products increased the total phenolic content and the antiradical activity of the films and proved efficient in delaying the oxidation of fish and meat products. Also, a protective activity was observed from the essential oils that were rich in carvacrol or thymol. The barrier properties of the films were positively affected, due to interactions between the active groups of the additive (e.g. polyphenols) and the film matrix. On the contrary, hydrophilic additives increased water vapor and oxygen permeability. The mechanical properties were in most cases adversely affected. Results are promising and further research on the release of antioxidant compound into food, the effect on sensorial properties, and application to other lipid foods may encourage practical application.