Flavor produced

One frozen dessert is made with Simplesse, a protein-based fat mimetic that contains no fat (37). Other dairy product developments include a fat flavor, produced by encapsulating milk fatty acids in maltodextrins (38) fat-free cottage cheeses and 2% fat milk, prepared by steam stripping cream with partial fat addback, with a cholesterol level about 60% lower than the starting material (39). 

The aroma of fmit, the taste of candy, and the texture of bread are examples of flavor perception. In each case, physical and chemical stmctures ia these foods stimulate receptors ia the nose and mouth. Impulses from these receptors are then processed iato perceptions of flavor by the brain. Attention, emotion, memory, cognition, and other brain functions combine with these perceptions to cause behavior, eg, a sense of pleasure, a memory, an idea, a fantasy, a purchase. These are psychological processes and as such have all the complexities of the human mind. Flavor characterization attempts to define what causes flavor and to determine if human response to flavor can be predicted. The ways ia which simple flavor active substances, flavorants, produce perceptions are described both ia terms of the physiology, ie, transduction, and psychophysics, ie, dose-response relationships, of flavor (1,2). Progress has been made ia understanding how perceptions of simple flavorants are processed iato hedonic behavior, ie, degree of liking, or concept formation, eg, crispy or umami (savory) (3,4). However, it is unclear how complex mixtures of flavorants are perceived or what behavior they cause. Flavor characterization involves the chemical measurement of iadividual flavorants and the use of sensory tests to determine their impact on behavior. 

Flavors. Flavor is the most important attribute of a carbonated beverage. Most carbonated beverages contain complex mixtures of different flavors produced ia several commercial forms as alcohoHc solutions, emulsions, and concentrates. The majority of flavors used ia carbonated beverages are derived from natural sources. 

Even if fish populations could be maintained by aeration, biocides may not be effective in controlling off-flavors. Most of the geosmin present (ca. 90-99%) is associated with cells rather than the media (16,43, 60,12), Biocide induced cell lysis may release off-flavor metabolites from cells (67) and render them available for adsorption by fish (8,9,13), Off-flavor metabolites require long periods of time to clear from fish (57). Off-flavor-producing populations may become reestablished before off-flavor metabolite clearance is complete. In addition, the biocides used may be carried off-site or taken up by fish. 

The industrial flavor producers offer a very broad selection of natural and synthetic flavors,mainly in the form of liquid concentrates.The majority of flavor constituents in such concentrates exhibit considerable sensitivity to air,light irradiation and elevated temperature. These flavor concentrates are moreover oily,greasy rather lipophilic materials,which are difficult to work with. The natural plant extracts also have microbiological contaminations that need to be removed. 

Finley, J. W. and Shipe, W. F. 1971. Isolation of a flavor producing fraction from light exposed milk. J. Dairy Sci. 54, 15-20. 

Vacuum distillation is preferred by many flavoring producers because it is more rapid than steam distillation. In this method, Ihe drying and resinification of flavoring constituents is avoided because of the absence of air. The separation of closer-boiling-point materials is more effective under vacuum. Undesirable side reactions between constituents are avoided because of the relatively low temperatures required. Thus, many delicate substances can be handled without thermal degradation. 

Knowledge of the volatile components of irradiated and nonir-radiated beef is reviewed. Concurrent and nonconcurrent irradiation procedures produce the same compounds but in different relative quantities. Storage of irradiated beef decreases irradiation flavor and the quantity of volatile constituents. Methional, 1-nonanal, and phenylacetaldehyde are of primary importance in beef irradiation off-flavor produced under the conditions described. 

Carbohydrates ranging from cellulose to simple sugars are subject to thermal alteration. Factors such as temperature, pH, compound concentration, and other reactants present can alter both the rate and complexity of decomposition reactions. Carbohydrate types are reviewed relative to degradation/carameli-zation pathways and endproducts. Some of the resulting typical food flavors produced are also discussed. 

Most of the original patents referring to meat flavors utilizing Maillard technology vere claimed by Unilever (48-52 56,57). More recent patents are involved with the production of meat-like flavors. While a majority of patents are concerned vith cysteine, cystine, or methionine as the sulfur source, others claim alternatives such as mercaptoacetaldehyde, mercaptoalkamines, etc. Several patents (53,54), declare the contribution to meat-like flavors produced from thiamine in the Maillard reaction. Alternately, a technical report describes the volatile flavor compounds produced by the thermal degradation of thiamine alone (55). 

Flavors Produced by Cysteine-glucose And Cysteine-pyruvaldehyde at Different Temperatures... 

Cheese/hutter flavor. Pregastric lipases, have, been used for years to intensify flavor in Menzyme-modified cheese , and for an intensified butter flavor in lipolyzed butter. Generally the fatty acid residues that need to be split off (to generate the right flavor) are the short chain fatty acids, especially the C to C-jq acids typical of Italian cheeses. The butyric acids are produced from butterfat more specifically by newly developed lipases (really esterases) from Mucor meihei and a very new one, from Aspergillus oryzae, especially for cheddar cheese flavor development. The latter enzyme is marketed under the name Flavor Age (4). Flavors produced in this manner are used widely in cheese-flavored snack foods the value of the intensified cheese flavors is on the order of 50 million, but the. value of the enzymes employed is only about 2-3 million. 

The flavors produced by the Maillard reaction also vary widely. In some cases, the flavor is reminiscent of caramelization. The Strecker degradation of a-amino acids is a reaction that also significantly contributes to the formation of flavor compounds. The... 

The hydrolysis of triglycerides in cheese is an example of a desirable flavor-producing process. The extent of free fatty acid formation is much higher in blue cheese than in Cheddar cheese, as is shown in Table 10-3. This is most likely the result of lipases elabo-... 

There are also other alterations of the same origin that produce other flavor defects - a very strong phenol flavor produced by the resin monomers or impurities (cresols, phenol, 2-ethylphenol, 3-ethylphenol, m-terbutylphenol (Fig. 10.2), 2,4-dichlorophenol, etc.). 

Figure 1. Carbonyls associated with characterizing fish flavors produced from the autoxldatlon of eicosapentaenoic acid.

Despite the possible practical significance of such procedures, they bring flavor enzymology to about the level to which the Buchner brothers brought fermentation in 1897. The reactions involved are not necessarily understood and the enzymes are defined only in terms of the flavors produced. Development of a cell-free preparation which carries out an organoleptically desirable change may be necessary to understand the reactions involved, but it is only a first step. Better control of flavor development requires definition of the products and substrates of the enzymes involved as well as purification of the enzymes. Without this knowledge it is diflBcult to define the enzymes let alone discuss them at a sophisticated level. 

Armstrong, D.W., Gillies, B. and Yamazaki, H. Natural Flavors Produced by Biotechnological Processing. In Flavor Chemistry Trends and Developments (Buttery, R.G., Shahidi, F. and Teran-ishi, R., eds.). American Chemical Society, Washington DC, pp. 105-120 (1989)... 

Flavors produced by bioconversion of waste material or solid-state fermentation (SSF)... 

Lactose sparingly water-soluble (20% at room temperature) sugar present in mammalian milk (4.8-5.1%). It is utilized as a carrier of other sweeteners. It improves flavor, produces a good image of food processed in microwave ovens, and improves the taste of dairy products. 

---