Microencapsulation of peppermint oil during spray-drying

Essential oils are natural liquid products obtained from plants by hydroor steam distillation. Oils contain from dozens to hundreds of components – secondary plant metabolites. The essential oils are used as natural aromas in food and toiletry, and due to medicinal properties, many of them are used in conventional medicine and aromatherapy. Components of the essential oils are first of all monoand sesquiterpene hydrocarbons and their oxygenated derivatives, and also phenylpropanoids. These are volatile substances sensitive to oxygen, light, moisture and heat. Stability of essential oils can be much increased by using microencapsulation. This process not only protects against losses and chemical changes during food production and storage, but also enables production of aromas in the form of powders – products with new properties. Main advantages resulting from their application include a much facilitated incorporation into solid products and a possibility of controllable release of the aroma during consumption. Dry microencapsulation product in the form of powder is most often obtained in spray drying of a multicomponent suspension, although other methods, e.g. extrusion, freeze drying, or cocrystallization are used as well [1]. As carriers for aroma microencapsulation carbohydrates are mainly used, i.e. starch and its derivatives, e.g. maltodextrin [2,3], β-cyclodextrin [4,5] and gum [6,7]. Recently, also proteins, e.g. milk or soya proteins, have become popular [6,8]. Frequently, mixtures of the mentioned materials are used in different proportions [8,9].