Solid flavors spray dried

Even more recent has been the introduction of cncapsiilaiion/exirusion. which also permits conversion of Havorants. such as essential oils, into solid form. Spray drying is nut required. In the encapsulation process, the flavor substance is "enrobed." A viscous carbohydrate, with less than ]O f water, is created by heating, after which an emulsifier and acid flavoring ingredients are added. The ingredients are reacted under pressure in a cool alcohol bath, and then the product is extruded to fornt filaments, Thus, the final easy-to-handle product contains the flavor within a small capsule. 

One of the primary variables which influences the recoveries of volatile flavor and aroma chemicals during spray drying is the wall material. Utilization of spray dried flavors in food systems presents further constraints on the wall material selection process. Of the food grade polymers available to the manufacturer of spray dried flavorings (i.e., gum acacia, lipophilic starches, maltodextrins, corn syrup solids), no single wall material exhibits the ideal traits deemed necessary for this economically important process. 

While the infeed solids content of the infeed material has an unquestionably greater influence on the retention of volatile flavors than does the type of carrier used, carrier type does influence flavor retention during spray drying (4, 16, 31, 3Z. ... 

Spray drying is the most widely used, least expensive and favored route among the methods available for encapsulation (2) Various theories of volatile retention in spray drying have been proposed and reviewed (3). In addition to the nature of flavor compounds, flavor retention is governed by type of carriers, infeed composition, solids concentration (4), dryer inlet/exit air temperature, air velocity and humidity, feeding rate and atomization characteristics. In addition to flavor retention,the stability of the encapsulated product, as mentioned earlier, is also of importance and is governed by nearly the same parameters. However,the effect and mechanics of each individual factor are much less understood. 

The primary benefit claimed in this patent was the maintainence of fresh flavor in encapsulated citrus oils which otherwise would readily oxidize during storage, yielding objectionable off-flavors. While spray dried flavorings have continued to dominate the dry flavor market, encapsulated products have been gaining market share. Initial studies that led to the work of Swisher (1 ) were done by Schultz et al (2), This work involved the addition of citrus oils to a molten solution of sucrose and dextrose, cooling the solution to form a hard slab similar to rock candy and then grinding the solid to the desired size. 

Flavoring agents may be classified as natural, artificial, or natural and artificial (N A) by combining the allnatural and synthetic fiavors. Pharmaceutical flavors are available as liquids (e.g., essential oils, fluid extracts, tinctures, and distillates), solids (e.g., spray-dried, crystalline vanillin, freeze-dried cinnamon powders, and dried lemon fluid extract), and pastes (e.g., soft extracts, resins, and so-called concretes, which are brittle on the outside and soft on the inside). Liquid flavors are by far the most widely used because they diffuse readily into the substrate. They are available both as oily (e.g., essential oils) or non-oily liquids. Their texture is generally dependent on the solvent within which they are prepared. Fluid extracts may contain a single ingredient or a variety of compounded ingredients. Tinctures are obtained by maceration or percolation of specific herbs and spices in alcohol. 

The selective diffusion theory has been well formulated mathematically and solved by numerical calculations. On the basis of such calculations, flavor retention during spray drying increases with the increase in solids content in the feed, inlet gas temperature and inlet gas flow rate, as well as with the decrease in inlet gas humidity, see Fig. 6.20. All of these conditions favor the early formation of a dry skin on the surface of the droplet (Furuta et ol., 1984). 

Flavor carrier choice has been shown to influence volatile retention during spray drying by numerous authors [19,62-66]. This influence can be indirect in the sense that some carrier materials become very viscous at relatively low solids contents. For example, Dronen [67] has shown that a soy protein concentrate infeed is limited to ca. 15% infeed solids or its viscosity prohibits effective atomization. Low solids means poor flavor retention. Dronen [67] found an average retention of a model volatile mixture to be only 13.1% when spray dried in a soy concentrate but 24.7% when dried in a whey protein isolate carrier (30% infeed solids). We assume that the two proteins would act reasonably similarly in terms of retaining volatiles and the difference in retention is primarily due to the low infeed solids of the soy protein infeed. 

Once a carrier (or blend of carriers) has been selected, it (or they) must be rehydrated in water. It is desirable to use a particular infeed solids level that is optimum for each carrier or combination of carriers. Research has shown that infeed solids level is the most important determinant of flavor retention during spray drying (Figure 13.9). While most research has suggested that one should use as high an infeed soUds level as possible, other work has shown that there is an optimum infeed solids level for each carrier system [68]. The existence of an optimum in solids content may be due to either the possibiUty that adding solids beyond their solubility... 

Liquid flavors are encapsulated in solid carriers to protect them from oxidation, volatilization, moisture, etc. There are numerous methods for encapsulation as well as types of solid carriers that are utilized. Spray drying and extrusion are the two most widely used techniques. Both methods typically encapsulate the flavor with some form of modified starch or sugar. It is necessary to monitor the performance of any encapsulation technique by determining the actual flavor loading versus the theoretical load. 

The dry product is primarily collected in cyclone collectors (a few bag houses still remain), sieved, and finally packaged in moisture barrier containers. The exit air from the dryer often has to be treated to meet local pollution control laws. While many of the older dryers use gas incineration, as energy costs have increased these incineration systems have become quite costly to operate. New dryer installations use scrubbing systems (e.g., aqueous/chemical sprays) to remove entrained solids and gaseous volatile flavors. 

Spray some drops of coffee into a vacuum chamber, and they, too, boil until they freeze. Even after they are frozen, the water molecules continue to evaporate into the vacuum until all that is left to be seen are little crystals of coffee solids. This is how freeze-dried coffee is made. The low temperature of this process tends to keep the chemical structure of the coffee solids from changing. When hot water is added, much of the original flavor of the coffee is retained. 

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