The protection and stability of flavours has attracted attentions in the food industry for high-quality products. The microencapsulation of flavours as a process of great importance encapsulates flavours in liquid form to obtain a dry flavoured powder. The capsules can be made of sugars, gums, proteins, polysaccharides, lipids and synthetic polymers. The advantages of this technology lies in the protection against degradative reactions, the loss of flavor and controlled release of flavours during food processing, storage and consumption. The first step is transformation of the feed liquid into a powder using a homogenizer. Some of the most useful encapsulating agents are maltodextrins, arabic gum, modified starches, xanthan and cyclodextrins.
Spray drying refers to the removal of moisture from fluid material by breaking it into small droplets in the presence of hot air to obtain a dry powder. Freeze drying is one of the most useful processes for drying thermosensitive substances that are unstable in aqueous solutions. The obtained powders are generally characterized by their low bulk density, high porosity as well as good aroma and taste retention. Fluid bed is widely applied in industry for coating solid particles such as pellets, granules or powders. An experiment was done to evaluate the effect of different drying methods on stability of microencapsulated strawberry flavour. Strawberry flavour is used in the confectionery industry in the production of chewing gum at a rate of 10 g/kg. The stability of this microencapsulated flavour is important to prolong the taste in the final product. According to the obtained results, the most appropriate agent for microencapsulating of the strawberry flavour was the blend maltodextrins /Hi-Cap (9/1) at a fixed concentration of cyclodextrins (1.7%). The best drying yield was observed in the case of freeze drying. Spray drying samples presented the lowest values of water content followed by freeze drying and fluid bed. The most stability at different temperatures and times was related to cyclodextrins with higher presence of volatile compounds in the powder. Spray drying resulted in smooth spherical particles, whereas in freeze drying the structure of the powder was amorphous and like glass and in the case of fluid bed, it was irregular.