Formation of flavor components

TRESSL Formation of Flavor Components in Roasted Coffee... 

Pripis-Nicolau, L., de Revel, G., Bertrand, A., Maujean, A. (2000). Formation of flavor components by the reaction of amino acid and carbonyl compounds in mild conditions J. Agric. Food Chem., 48, 3761-3766. 

Tressl, R., Bahri, D., Holzer, M., and Kossa, T. 1977. Formation of flavor components in asparagus. 2. Eormation of flavor components in cooked asparagus. J. Agric. Food Chem. 25 459-63. 

Tressl R. (1989) Formation of flavor components in roasted coffee. Am. Chem, Soc. Symp. Ser. 409, 285-301. 

Tressl R., Holzer M., Apetz M. Formation of flavor components in asparagus. 1. Biosynthesis of sulfur-containing acids in asparagus. Journal of Agricultural and Food Chemistry, 25 455-459 (1977). 

The roasting process subjects peanuts to internal temperatures of 130 -150 C during which the typical roast peanut flavor is produced. The most important constituents of peanuts responsible for flavor formation are the amino acids, sugars, protein and lipids. There are close to 300 flavor compounds identified in roasted peanuts. Pyrazines contribute roasted nutty aroma and aldehydes are responsible for harsh green aroma. Recent development in the research include application of an absorption polymer Tenax GC to collect volatiles, quantitation of flavor components and computer aided correlation of instrmental and sensory data. 

Dismick, P. S. "The Formation and Characteristics of Flavor Components Derived from Food Lipids", 29th P.M.C.A. 

The intent of this chapter is to summarize naturally occurring flavor compounds in aromatic foods, and the formation of flavor during processing of foods including the Maillard, lipid oxidation, microbial, and enzymatic reactions. A brief discussion on the impact of interactions between these components on food flavor and off-flavor formation is also included. At the end of chapter, the manufacturing of flavor compounds by the utilization of biotechnology and pyrolysis techniques is further explained. 

Traditionally fermented dairy products have been used as beverages, meal components, and ingredients for many new products [60], The formation of flavor in fermented dairy products is a result of reactions of milk components lactose, fat, and casein. Particularly, the enzymatic degradation of proteins leads to the formation of key-flavor components that contribute to the sensory perception of the products [55], Methyl ketones are responsible for the fruity, musty, and blue cheese flavors of cheese and other dairy products. Aromatic amino acids, branched-chain amino acids, and methionine are the most relevant substrates for cheese flavor development [55]. Volatile sulfur compounds derived from methionine, such as methanethiol, dimethylsulflde, and dimethyltrisul-fide, are regarded as essential components in many cheese varieties [61], Conversion of tryptophan or phenylalanine can also lead to benzaldehyde formation. This compound, which is found in various hard- and soft-type cheeses, contributes positively to the overall flavor [57,62]. The conversion of caseins is undoubtedly the most important biochemical pathway for flavor formation in several cheese types [62,63]. A good balance between proteolysis and peptidolysis prevents the formation of bitterness in cheese [64,65],... 

R. J. McGorrin and L. Gimelfarb, Comparison of flavor components in fresh and cooked tomatiUo with red plum tomato, in Food Flavors Formation, Analysis, and Packaging Influences (E. T. Contis, C.-T. Ho, C. J. Mussinan, T. H. Parfiment, F. Shahidi, and A. M. Spanier, eds.), Elsevier, New York, NY, Developments in Food Science Vol. 40, 1998, p. 295. 

Volatiles or Aroma. The essential oil, or aroma, of tea provides much of the pleasing flavor and scent of green and black tea beverages. Despite this, volatile components comprise only - 1% of the total mass of the tea leaves and tea infusions. Black tea aroma contains over 300 characterizing compounds, the most important of which are terpenes, terpene alcohols, lactones, ketones, esters, and spiro compounds (30). The mechanisms for the formation of these important tea compounds are not fully understood. The respective chemistries of the aroma constituents of tea have been reviewed... 

In the case of diketopiperazine 13 and related compounds, dehydrogenation of the preceding diketopiperazine occurs in the side chain. A shift of the double bond into the central ring and dehydration may result in the formation of substituted pyrazines. Simple pyrazines are known as signaling compounds from animals. The pyrazines 16 and 17 have also been isolated from marine Streptomycetes [106]. GC/MS investigations of bacterial flavor components [951 indicate that these and others are very wide-spread. 

The flavor quality of food is a primary factor involved in a consumer s decision to purchase a food item. Therefore, food technologists require a thorough understanding of how flavor deteriorates if they are to prepare products that consumers will purchase repeatedly. This knowledge is particularly important in meat and meat products, since the deterioration of meat flavor is a serious and continual process (1-4) that involves both the loss of desirable flavor components 4,5) and the formation of off-flavor compounds (6-9) many of which are associated with lipid oxidation (10). 

WOF is a problem associated with the use of precooked meat products such as roasts and steaks. The term WOF was first used by Tims and Watts (2) to describe the rapid development of oxidized flavors in refiigerated cooked meats. Published evidence indicates that the predominant oxidation catalyst is iron from ntyoglobin and hemoglobin, which becomes available following heat denaturation of the protein moiety of these complexes. The oxidation of the lipids results in the formation of low molecular weight components such as aldehydes, adds, ketones and hydrocarbons which may contribute to undesirable flavor. 

Cheese is a complex matrix of several components. Isolation of compounds of interest and the analysis of target compounds without interference from the matrix has been a challenge with analytical techniques. With the development of extraction procedures and new sampling techniques for analysis, not only has this challenge been overcome to a certain extent but also the speed, quality, accuracy, and reliability of analysis have improved tremendously. With the mechanisms behind the formation of several flavor compounds in cheese still not clearly understood, these techniques have an increasing role in the efforts to understanding cheese ripening. Often times most of the techniques provide... 

The sugars, which contribute much to the acceptability of citrus juices, under adverse conditions can play a major role in the formation of off flavors that reduce the acceptability of the citrus juices and their products. The sugars, primarily the hexoses, can participate in "browning" reactions that cause darkening of the juice and these reactions give rise to components that are described generally as apricot-like or pineapple-like in flavor. In general,the more processed flavor that a citrus product exhibits, the less acceptable it becomes to the consumer. 

Wilson, el al. (41) also confirmed the presence of polysulfur heterocyclics in meat including thialdine (5,6-dihydro-2,4,6-tri-methyl-l,3,5-dithiazine) and trithioacetone (2,2,4,4,6,6-hexame-thyl-1,3,5-trithiane). Wilson (42) later discussed the possible routes of formation of some of these compounds from cysteine. Thialdine was found by Brinkman, et el. (43) in the headspace volatiles of beef broth. These workers also identified 3,5-di-methyl-1,2,4 - trithiolane from the same source. Both cis and trans isomers of this compound had previously been identified as flavor components of boiled beef by Chang, jit aL. (44) and Herz (45). 

The majority of heterocyclic compounds are formed through thermal interactions of reducing sugars and amino acids, known as Maillard reactions. Other thermal reactions such as hydrolytic and pyrolytic degradation of food components (e.g. sugars, amino acids and vitamins) and the oxidation of lipids also contribute to the formation of heterocyclic compounds responsible for the complex flavor of many foodstuffs. 

Alkylpyrazines have been recognized as important trace flavor components of a large number of cooked, roasted, toasted and deep-fat fried foods (3). As a rule, alkylpyrazines have a roasted nut-like odor and flavor. Formation pathways for alkylpyrazines have been proposed by numerous researchers (4, 5, 6). Model studies suggest that they are minor products of the Maillard reaction. 

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