Carbohydrate matrix, encapsulation

A formulation given for the carbohydrate matrix used in the encapsulation of orange oil is as follows ... 

A patent has been recently issued on extrusion encapsulation to Miller and Mutka ( ). This patent contains no new formulation or process innovations but rather a refinement of the existing art (1, 3), A flow chart of the overall process is presented in Figure 1 with a view of the extrusion process presented in Figure 2. The carbohydrate matrix consists of a high DE maltodextrin and sugar, e.g., 6025 g of 20 DE maltodextrin solution (70% solids) plus 4125 g sugar (Example 1 in patent). This carbohydrate matrix is heated to promote solubility and then cooked to 120 to 124 C to reduce moisture content. They found a... 

Gunning, Y.M., Gunning, P.A., Kemsley, E.K., Parker, R., Ring, S.G., Wilson, R.H., and Blake, A. Factors affecting the release of flavor encapsulated in carbohydrate matrixes, /. Agric. Food Chem., 47, 5198,1999. 

Ono, F. New encapsulation technique with protein-carbohydrate matrix. Journal of Japanese Food Science Technology 27, 529-535, 1980. 

The fat in coffee whiteners is encapsulated within a water-soluble carbohydrate matrix, making it unavailable to extracting solvents. Dry powder extraction will typically achieve only 1—5% of the fat. To obtain the total fat ... 

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... 

The effects of water on the destruction of the protective food structure in some specific dehydrated foods is probably involved in prevention of lipid oxidation in heated meat systems (Karel, 1986). In systems in which there are both surface lipids and lipids encapsulated within a carbohydrate, polysaccharide, or protein matrix, the surface lipids oxidize readily when exposed to air. The encapsulated lipids, however, do not oxidize until the structure of the encapsulated matrix is modified and/or destroyed by adsorption of water as shown by Simatos and Karel (1988). In some IM meats, muscle may be considered as being encased in or surrounded by a humectant matrix. However, free lipid may be left on the surfaces. The unwarranted overuse of lipids, which often happens in the indirect drying process to improve heat transfer and to prevent burning, is detrimental to the products. Prevention of this structural change is of considerable... 

The release mechanism of carbohydrate-based matrix capsules prepared by spray drying is solvent activated, which means that the powder readily dissolves upon contact with water. This release mechanism has limited the range of appUcations to dry products in the past. However, through selection of the matrix constiments and buildup of more sophisticated physical structures, a controlled release of encapsulated ingredients can be achieved. This is of particular importance with respect to the release of pharmaceutical or food ingredients, which need to be delivered to specific parts of the gastrointestinal systan. " " ... 

Carbohydrates are used extensively in spray-dried encapsulations of food ingredients as the encapsulating support—that is, the wall material or carrier. The ability of carbohydrates to form a protective matrix, complemented by their diversity and low cost, makes them the first choice for encapsulation. The main limit for their application is their high water sensitivity and fast hydration when in contact with water. 

Highly oxidizable oils such as fish oils can be protected by a process known as microencapsulation, which coats the oil with a matrix of protein (gelatin, casein), carbohydrates (starch, cellulose, carboxymethylcellulose or cellulose derivatives) and lecithin. Microencapsulation provides protection against oxidation and imparts oxidative stability. The use of carboxymethylcellulose and cyclodextrins as coatings is claimed to provide better protection of oils by improved oxygen barrier properties. For special applications as nutritional supplements, fish oils enriched in n-3 PUFA are microencapsulated, in the presence of antioxidants, into a powder that is relatively stable at ambient temperatures. However, encapsulated fish oils can impart undesirable fishy taste when incorporated into food emulsions. More research and development is needed to evaluate potential applications and benefits of active packaging to increase the shelf life of fish oils and other highly oxidizable oils in foods. 

According to the glass transition theory, lipids are dispersed in the free volume of the food matrix composed of carbohydrates and protein polymers. In the rubbery state, the lipids react readily with oxygen and become oxidized. In the glassy state, however, the lipids are stable to oxidation because they are encapsulated and there is no free volume. The glass transition temperature, which determines when the food matrix changes from one state to the other, increases with a decrease in moisture and water activity. In many foods the... 

The advent of continuous extrusion has also provided the opportunity to use a wider variety of matrix materials. In the past, viscosity has been a limiting factor, but this is no longer as critical when twin screw extruders are used. The wider range of matrix materials has provided the opportunity to use materials that can offer some controlled release properties, e.g., proteins or less soluble carbohydrates. This offers further advantage to this encapsulation process. 

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