Hydrocarbons flavoring from

Since 1980, there has been rapid development of SFE, for the extraction of fossil fuel and environmental samples such as pesticides, hydrocarbons, phenolics [12,13], food products including hops, fats and lipids from butter, perfumes and flavors from natural products [14], and oligomeric materials or additives from polymers [IS]. 

Natural food flavors such as terpenes, hydrocarbons, alcohols, aldehydes, ketones, esters, acids, lactones, amines, sulfur compounds are enzymatically produced in fruits and vegetables. On the contrary, processed food develops its characteristic acceptable flavors from chemical reactions within its components at temperatures far below those at which its major components, i.e., lipids, proteins and carbohydrates pyrolyze. 

We can recognize many organic functional groups in compounds we use every day. Pesticides and Freons often contain chlorinated hydrocarbons. Many fruits get their aromas and flavors from aldehydes, ketones, and esters. The sour taste in foods is because of carboxylic acids, and the many rotting smells are due to amines (6.4-6.13). 

Mono- and sesquiterpenes are most commonly associated with the flavor of citrus products, spices, and herbs. They are hydrocarbons based upon the five carbon isoprene unit (2-methyl-1,3-butadiene) with structures that may be open chain, closed chain, saturated, or unsaturated, and may contain O, N, or S. While a host of terpenes have been found to be produced by microorganisms, there are no fermented food products commercially available that derive their characteristic flavor from terpenes. 

Supercritical fluid extraction — During the past two decades, important progress was registered in the extraction of bioactive phytochemicals from plant or food matrices. Most of the work in this area focused on non-polar compounds (terpenoid flavors, hydrocarbons, carotenes) where a supercritical (SFE) method with CO2 offered high extraction efficiencies. Co-solvent systems combining CO2 with one or more modifiers extended the utility of the SFE-CO2 system to polar and even ionic compounds, e.g., supercritical water to extract polar compounds. This last technique claims the additional advantage of combining extraction and destruction of contaminants via the supercritical water oxidation process."... 

The major source of lycopene is tomato products but it also occurs in water melons, guavas, pink grapefruit, and in small quantities in at least 40 plants.14 The structure of lycopene is shown in Fig. 8.2. It is a long chain conjugated hydrocarbon and its structure suggests that it would be easily oxidized in the presence of oxygen and isomerized to cis compounds by heat. Both of these reactions occur in purified solutions of lycopene but in the presence of other compounds normally present in tomatoes, lycopene is more stable. Actually the absorption of lycopene in the human gut is increased by heat treatment probably because the breakdown of the plant cells makes the pigment more accessible. Preparations from tomatoes are widely used in pizza, pasta, soups, drinks and any product compatible with the flavor and color of tomatoes. 

Terpenes Terpenes [a-pinene (1), /f-pinene (2), and limonene (3)] are employed in the synthesis of flavors and fragrances (F F), although these compounds are often obtained by catalytic routes from hydrocarbons. 

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. 

Merritt (42) has carefully studied the yields of hydrocarbons on irradiation of meat and meat components and proposed mechanisms for their formation during irradiation. Despite this recent progress, the chemical characterization of irradiation flavor in meats is far from complete. Little is known about the radiation-induced chemical processes giving rise to the compounds proposed as important to irradiation flavor or the identity of the chemical precursors of these compounds. However, irradiation flavor in beef appears to be associated largely with the protein constituents in meat (21). 

Some materials are of natural origin, others are purely synthetic and some are available from both sources, natural and synthetic. Almost all kinds of organic functionalities are represented in the broad palette of the flavorist and perfumer - alcohols, aldehydes, ketones, esters, hydrocarbons, olefins, amines, phenols, heterocy-clics, etc. Alcohols are particularly important because they are prominent among the relatively inexpensive and readily available materials which make up the bulk of flavors and especially fragrances. 

The volatiles from cooked meat contain large numbers of aliphatic compounds including aldehydes, alcohols, ketones, hydrocarbons and acids. These are derived from lipids by thermal degradation and oxidation (J7) and many may contribute to desirable flavor. In addition, the aldehydes, unsaturated alcohols and ketones produced in these reactions, as well as the parent unsaturated fatty acids, are reactive species and under cooking conditions could be expected to interact with intermediates of the Maillard reaction to produce other flavor compounds. 

Nearly 1000 compounds have so far been identified in the volatile constituents of meat from beef, chicken, mutton and pork (6). The largest number of volatiles has been determined in beef and these were representative of most classes of organic compounds. Hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids, esters, lactones, ethers, sulfur and halogenated compounds as well as different classes of heterocyclic substances (Figure 1) namely furans, pyrldlnes, pyrazines, pyrroles, oxazol(in)es, thiazol(in)es, thiophenes were present in cooked meat flavor volatiles as shown in Table I. Many of these compounds are unimportant to the flavor of meat and some may have been artifacts (16). 

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