Aroma compound encapsulation

The surrounding medium of encapsulated aroma such as polysaccharides, proteins, lipids, and salts could play an important role in release in liquid media and then on aroma compound retention by the film matrix. Different behaviors have been observed in the presence of salt or sucrose molecules of aroma compound volatility in food products, observing that some of them presented a salting out effect (favored release by volatilization), others an opposite salting in effect, and for some others no modification (Lubbers et al., 1998 Van Ruth et al., 2002). Similar effects could be observed in the release of the aroma compounds encapsulated in films. While the salting out effect should accelerate the release, the salting in could decrease the rate of the release. 

Fabra, M.J., Chambin, O., Assifaoui, A., Debeaufort, F. 2011. Influence of temperature and salt concentration on the release in liquid media of aroma compounds encapsulated in edible films. Journal of Controlled Release. 

Release of Encapsulated Aroma Compounds from Amorphous Maltodextrin Matrices... 

Encapsulation of aroma compoimds in amorphous carbohydrate matrices can be carried out, for example, by freeze- or spray-drying (Levine et al., 1991 Roos, 1995). Aroma compounds often remain encapsulated in glassy carbohydrate matrices stored at temperatures below their glass transition. Release of encapsulated aroma compounds may occur when amorphous carbohydrate matrices are stored at temperatures above their glass transition, allowing sufficient molecular mobility and diffusion. 

The aim of the present study was to investigate the effect of the physical state of the matrix on the release of encapsulated aroma compounds from amorphous maltodextrin matrices. 

The physical state of the matrix was found to affect the rate of release of aroma compounds from amorphous maltodextrin matrices the rate increased with increasing storage temperature and T — Tg. The results obtained can be used for evaluation of proper storage conditions for amorphous maltodextrin matrices containing encapsulated aroma compounds, as well as for evaluation of the usefulness of various analyzing techniques for aroma release in such studies. 

Many studies have been performed to use CDs for protecting flavors against heat, oxygen and evaporation [28,29]. For example, /3-CD as a stabilizing or thickening agent can retain some aroma compounds in food products [36]. As a molecular encapsulant, it also can improve the flavor quality and provide a longer period preservation compared to other encapsulants [28]. 

FIGU RE 38.3 Retention and controlled release of aroma compounds added at the food surface or entrapped in edible coatings/films. (a) Deposition of volatile-active compound on food surface and (b) food coated with an edible film encapsulating the volatile-active compounds. 

Hambleton, A., Debeaufort, F, Beney, L., Karbowiak, T., Voilley, A. 2008. Protection of active aroma compound against moisture and oxygen by encapsulation in biopolymeric emulsion-based edible films. Biomacromolecules, 9(3) 1058-1063. 

Marcuzzo, E., Debeaufort, F., Hambleton, A., Sensidoni, A., Tat, L., Beney, L., VoUley, A. 2011. Encapsulation of aroma compounds in biopolymeric emulsion emulsion-based edible films to prevent oxidation. Food Research International. 

The objective was to encapsulate a vegetable oil (representing a model for aroma compound) into a powder. The oil (ISI04) (VO) will be at a concentration of 5% TS into a matrix made of maltodex-trin MD (DE 12) and acacia gum (AG) (3/2 MD/AG). The composition of matrix was defined in a previous research work on encapsulation of aroma by spray-drying (Bhandari et al., 1992 Turchiuli et al, 2005 Fuchs et al, 2006). 

The retention or loss of aroma compounds is also influenced by the structure (amorphous or crystallized) of the dried product Structural changes can be used for spray drying encapsulation processes (Bhandari et al., 1992 Re, 1998). Crystallization tends to increase the loss of aroma, because it rejects impurities, including volatiles. Senoussi et al. (1995) measured the loss of diacetyl as a function of the rate of crystallization of lactose during storage. They found that when the lactose was stored at 20 °C above the glass transition temperature Tg, the amorphous product immediately crystallized and practically all diacetyl was lost after 6 days. Levi and Karel (1995) also found increased rates of loss of volatile (1-n-propanol) as a result of crystallization in an initially amorphous sucrose system. 

Dr. Reineccius teaches courses in Chemical and Instrumental Analysis of Foods, Food Processing, and Flavor Chemistry and Technology. He has written a college textbook on food flavors with Henry Heath. This was the first textbook in the flavor area that combined both flavor chemistry and technology. Dr. Sara Risch and he edited and were major contributors to two books on flavor encapsulation. He is the editor of the Source Book of Flavors and an ACS symposium proceeding titled Heteroatomic Aroma Compounds. ... 

Solid materials containing aroma compounds present additional challenges to the analyst. Matrix effects need to be addressed, the aroma components are often present in encapsulated form, homogeneity issues become important, and equilibrium parameters between the solid and gas phases are not as well defined as the case with liquids. Most of these concerns can be alleviated by converting the solid material into a solution or suspension before analysis. 

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. 

Methanethiol is a very volatile (b.p. 6.2°C) compound possessing a intensely putrid, fecal-like aroma even at low concentrations. The detection threshold value for methanethiol has been reported as 0.02 ppb in air (49, 50), and it readily undergoes oxidative condensation with itself in the presence of oxygen to yield dimethyl disulfide (51) which also exhibits pronounced aroma properties (12 ppb detection threshold in air 49, 50). Besides the difficulties in handling and encapsulating methanethiol for flavor applications, its propensity to adsorb to surfaces and react with other organics makes the use of this compound in flavor concentrates very troublesome indeed. 

Lyophilization or freeze-drying is a simple technique that is suitable for the encapsulation of aromas, water-soluble essences, drugs, and importantly used for the dehydration of almost all heat-sensitive materials. It is a process that requires a long dehydration period. The retention of volatile compounds during lyophilization is dependent upon the chemical nature of the system. ... 

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