Encapsulation, aroma

In this chapter, different aspects of aroma encapsulation will be considered the choice of support material depending on the searched properties of microcapsules and the production of microcapsules, and examples of aroma encapsulation to produce complex structured products. 

The choice of the aroma encapsulating supports (matrix) is the base for the success of encapsulation, along the different steps from the formulation through the encapsulation process followed by storage and finally use/release. For example, a good support for encapsulation process may show bad properties during storage ... 

FIGURE 39.2 Schematic aroma encapsulation in powder particle. 

The research of the best aroma encapsulation process very often needs studies at different scales, from laboratory via pilot scale to industry scale, with the usual but not easy engineering problem of scaling-up. The choice of the process depends on the needed aroma protection and the possible supports for the wanted flnal use and release. 

Emulsions represent a liquid encapsulation form, a macroscopic dispersion of two nonmiscible liquids. For aroma encapsulation, the continuous phase is usually the solution of supports and the dispersed phase is the core aroma material (or aroma solubilized/dispersed in an oil base). They are... 

The emulsion represents a liqnid aroma encapsulation form, inexpensive, suitable for stable concentrated liquid with low volume (drinks, sances, cosmetics) (Figure 39.3). But it may be also the preliminary step before other transformation to give a dried emulsion. 

Many research works are pnblished concerning aroma encapsulation by spray-drying. Some of the works worthy of mention are the following Kerkhof and Thijssen, 1974 King et al., 1984 ... 

In that process, aroma encapsulated (uniform dispersion) in molten wax or fat with snrfactant is sprayed in drops at an airflow rate at ambient temperature or cold. Objective is to rapidly solidify the fat, avoiding crystallization. 

Examples of Studies on Aroma Encapsulation by Spray-Drying, with Some Important Parameters... 

FIGURE 39.13 Complementary processes for aroma encapsulated powders spray-drying, fluid bed coating/ agglomeration. 

For the aroma encapsulation, a wide variety of possible supports and techniques exist to prepare a stable product with controlled aroma composition, taking into account the different steps of production, storage, and final use. 

The choice for an aroma encapsulation project will be decided according to the initial objectives, with a multidisciplinary cooperation between the aroma and supports suppliers, the process... 

Summary of Techniques for Aroma Encapsulation in Food Products with Some Examples of Use... 

Tmchiuli C. and Dumoulin E., 2013a. Chapter 14 Aroma encapsulation in powder by spray drying, and fluid bed agglomeration and coating. In Advances in Food Process Engineering Research and Applications. Eds. S. Yanniotis, P. Taoukis, N.G. Stoforos, and T. Karathanos, Springer, New York, pp. 255-265. 

Sterilized and frozen canned food, infant food Sterilized and frozen canned food, aroma encapsulation Thickenig agent, emulsion stabilizer, ulcer treatment (pepsin inhibitor)... 

Mongenot N, Charrier S, ChaUer P. 2000. Effect of ultrasound emulsdfication on cheese aroma encapsulation. J Agric Food Chem 48 861-867. 

Encapsulation of Fragrances and Flavours a Way to Control Odour and Aroma in Consumer Products... 

Spray-drying is an economical effective method widely used for flavour encapsulation [22-27]. The technology has been used in the food industry since the late 1950s to provide protection of aroma chemicals against oxidation or degradation and to convert liquids into free-flowing solids. The main limitations... 

Co crystallisation is mainly done from supersaturated sugar solutions [15]. Aggregated particles (of 3-30 pm) of sugar crystals are formed which entrap guest molecules. The sugars form an oxygen barrier, thereby extending the shelf life of aroma chemicals. The procedure is simple and inexpensive, because relatively cheap encapsulation matrices can be used, such as sucrose. 

A recent study has been performed on various spray dried orange flavors(20% oil fixed in the powder) encapsulated on various Acacia gums and on mixtures of Acacia gums and malto-dextrins. The aromas in powder were tested by chromatography and then examined by electronic microscopy. This clearly shows the regular and uniform film covering each particle 10 to 40 microns in diameter. Prints of broken particles reveal numerous oil droplets (1 micron in diameter) spread in a gum nucleus. Protection of the oil phase then becomes fully effective. 

J. J. G. van Soest, Encapsulation of Fragrances and Flavours A Way to Control Odour and Aroma in Consumer Products. In Flavours and Fragrances Chemistry, Bioprocessing and Sustainability, R. G. Berger, Ed. Springer-Verlag Berlin, 2007 ... 

Protection of various food products (nuts, aroma and flavours encapsulation, fresh meat, battered meat, etc.) (Gennadios and Weller 1991)... 

Microencapsulation technology has been traditionally used in the food industry for flavour encapsulation where flavours are stabilized and their release controlled (Madene et al. 2006). Microencapsulation has also been used to enable the incorporation of sensitive bioactive component in fortified foods, while ensuring that the taste, aroma, or texture of food is not adversely affected (Pszczola 1998 Brazel 1999 Augustin et al. 2001). Microencapsulation can reduce off-flavours contributed by certain vitamins and minerals, permit time-release of the nutrients, enhance stability to extremes in temperature and moisture, and reduce undesirable chemical interactions with other ingredients. 

These additives can also be placed into microcapsules with a thin polymer skin. For example, they are filled with natural aromas and applied to the textile from a water dispersion in combination with a polyurethane or silicone binder. The ratio of micro bubbles to binder determines the efficiency and permanence of the finish. Good results after 4-12 washing cycles are reported. The encapsulated materials are released during wearing as the micro bubbles burst from rubbing caused by body movement or by diffusion through the thin layer of the capsules. A market available encapsulation in micro bubbles, built from chitosan, is described by Hampe. The incorporation and controlled release of fragrance compounds is also provided by the sol-gel nano-technique described in Section 18.4. 

Kopelman, I. J. Meydav, S. Wilmersdorf, R Freeze drying encapsulation of water soluble citrus aroma. Journal of Food Technology 12 (1), 65-72 (1977)... 

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