Flavour microencapsulation spray drying

Microencapsulation using extrusion is mainly described for glassy carbohydrate matrices [14-16, 28-29]. The glassy carbohydrates, such as starch and maltodextrins, are melted at elevated temperature and low water contents and are intensively mixed with the active in the extrusion barrel. Extrusion has been used for volatile and unstable flavours. The shelf life of flavour oils could be extended from several months to 5 years, compared with 1 year for spray-dried materials. The main drawbacks of the technology are the high investments costs and the formation of rather large particles (500-1,000 pm). 

Spray drying is the most commonly used method in the food industry. Bioactive ingredients microencapsulated by this method include fats and oils, flavours, essential oils and other oil-soluble bioactives. Water-soluble bioactives can also be encapsulated by spray drying, where the encapsulant forms a matrix structure rather than a film surrounding the core. This process typically involves the dispersion of the core material into a solution of the encapsulant (e.g., protein, carbohydrate) and atomization of the mixture into the drying chamber. This leads to evaporation of the solvent... 

Gharsallaoui, A. Roudaut, G. Beney, L. Chambin, O. Voilley, A. Saurel, R., Properties of spray-dried food flavours microencapsulated with two-layered membranes Roles of interfacial interactions and water. Food Chemistry (2012) 132, 1713-1720. 

Spray drying is the most commonly used microencapsulation technique in the food industry [37-39]. The process is relatively simple and easily converts liquids to powders and protects volatile compounds against degradation and oxidation [40]. Consequently, spray drying has been used to encapsulate a variety of substances, for example, flavours, vitamins, fish oils and flavours [41]. 

The next chapter describes the basic physical and biotechnological processes which are today available for the production of flavourings and flavour extracts. These range from more traditional methods such as extraction and distillation to more recent developments, e.g. supercritical fluid extraction, spray and freeze drying as well as microencapsulation, and include the rapidly increasing field of biotechnology. 

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