Esters flavors

An oral dental riase geaeraHy coasists of water, alcohol, a humectant, an emulsifier, flavor, color, and an active agent. Water is the primary vehicle. The alcohol provides bite and is also a formulation aid. The humectant improves the feel ia the mouth and also prevents locking of the cap to the container between uses glycerin or noncrystaUiziag sorbitol may be satisfactory. The emulsifier is a nonionic type, for example, a polyoxyethylene—polyoxypropylene block copolymer or a polyoxyethylene sorbitan fatty acid ester. Flavors are generally a type of mint or cinnamon. Colors are FD C or D C. 

In addition to diacetyl, O. oeni produces esters, flavor compounds also important for wine flavor and aroma. Esters are primarily produced by Saccharomyces during alcoholic fermentation (Mason and Dufour, 2000 Nykanen, 1986 Nykanen and Nykanen, 1977 Soles et al., 1982), although evidence shows that esters such as ethyl acetate, ethyl lactate, ethyl hexano-ate, and ethyl octanoate can be synthesized by O. oeni (De Revel et al., 1999 Delaquis-Pascal et al., 2000 Edwards and Peterson, 1994 Maicas et al., 1999 Tracey and Britz, 1989). For example, Edwards and Peterson (1994) reported that strains of O. oeni synthesized relatively large amounts of ethyl lactate (183-1280 /ig/L) during growth in microbiological medium. In agreement, Maicas et al. (1999) reported that 50 mg/L of ethyl lactate was produced in wines fermented with O. oeni, as well as isoamyl acetate and ethyl caproate, compounds important for a pleasant fruity note in wine (Gil et al., 1996 Mason and Dufour, 2000 Nykanen, 1986). 

Use Intermediate for rubber antioxidants and accelerators, for neopentyl glycol synthesis of amino acids, cellulose esters, flavors, etc. 

Other interesting examples were reported on the use of SILM for the selective separation of the substrates and products of transesterification reactions. The biosynthesis of organic esters commonly used in the perfumery and flavor industries can be carried out by transesteriflcation from vinyl esters and alcohols catalyzed by enzymes in non-conventional media (i.e., n-hexane [88] and IL [90]) at low water content. When the biochemical reaction reaches the equilibrium, the reaction medium could consist of a mixture of alcohol, vinyl ester, organic acid, and alkyl ester (flavor ester). The possibility of using SILMs for the selective separation of these reaction mixtures has been extensively analyzed [30,88,91-93]. 

At present, over a thousand synthetic and natural flavors are available. The majority of these are concentrates or extracts from the material whose flavor is desired and are often complex mixtures of from tens to hundreds of compounds. A number of ester flavoring agents are synthesized industrially. Many have flavors very close to the target flavor, and adding only one or a... 

Essential oil components are often found in the glands or intercellular spaces in plant tissue. They may exist in all parts of the plant but are often concentrated in the seeds or flowers. Many components of essential oils are steam-volatile and can be isolated by steam distillation. Other methods of isolating essential oils include solvent extraction and pressing (expression) methods. Esters (see the essay "Esters-Flavors and Fragrances") are frequently responsible for the characteristic odors and flavors of fruits and flowers, but other types of substances may also be important components of odor or flavor principles. Besides the esters, the ingredients of essential oils may be complex mixtures of hydrocarbons, alcohols, and carbonyl compounds. These other components usually belong to one of the two groups of natural products called terpenes or phenylpropanoids. 

Technique 25 Preparation of Samples for Spectroscopy Essay Esters—Flavors and Fragrances... 

Levulinate esters Flavoring and fragrance industries, plasticizer for cellulose plastics, oxygenate additive in fuel... 

Chloroacetate esters are usually made by removing water from a mixture of chloroacetic acid and the corresponding alcohol. Reaction of alcohol with chloroacetyl chloride is an anhydrous process which Hberates HCl. Chloroacetic acid will react with olefins in the presence of a catalyst to yield chloroacetate esters. Dichloroacetic and trichloroacetic acid esters are also known. These esters are usehil in synthesis. They are more reactive than the parent acids. Ethyl chloroacetate can be converted to sodium fluoroacetate by reaction with potassium fluoride (see Fluorine compounds, organic). Both methyl and ethyl chloroacetate are used as agricultural and pharmaceutical intermediates, specialty solvents, flavors, and fragrances. Methyl chloroacetate and P ionone undergo a Dar2ens reaction to form an intermediate in the synthesis of Vitamin A. Reaction of methyl chloroacetate with ammonia produces chloroacetamide [79-07-2] C2H ClNO (53). 

Chemical bleaching is never used on oils intended for edible use because it oxidizes unsaturated fatty acids to cause off-flavors. However, it does find wide usage for specialty linseed oil, for the paint industry, and fatty chemicals such as sorbitan esters of fatty acids and sodium stearoyl lactylate. Residual peroxide is destroyed by heating above its decomposition temperature. 

It has been found that the flavor of fmit can be increased by a process called precursor atmosphere (PA) (77). When apples were stored in a controlled atmosphere containing butyl alcohol [71-36-3] the butyl alcohol levels increase by a factor of two, and the polar products, butyl ester, and some sesquiterpene products increase significantly. The process offers the possibiUty of compensating for loss of flavor in fmit handling and processing due to improper transportation conditions or excessive heat. 

Formic acid is used as an intermediate in the production of a number of dmgs, dyes, flavors, and perfume components. It is used, for example, in the synthesis of aspartame and in the manufacture of formate esters for flavor and fragrance appHcations. 

Ghlorpropham. (3-Chlorophenyl)carbamic acid 1-methyl ester [101-21-3] (Chlorpropham, CJPC) (21) was patended in the early 1950s and is a carbamate. Its only use in the United States is on stored Irish potatoes to inhibit bud development. The potatoes, which are generally stored at temperatures >10° C for maximum flavor, are treated by passing a stream of air laced with chloropropham over the potatoes for 48 hours after which the potatoes are purged with pure air. 

Another significant use of 3-methylphenol is in the production of herbicides and insecticides. 2-/ f2 -Butyl-5-methylphenol is converted to the dinitro acetate derivative, 2-/ f2 -butyl-5-methyl-4,6-dinitrophenyl acetate [2487-01 -6] which is used as both a pre- and postemergent herbicide to control broad leaf weeds (42). Carbamate derivatives of 3-methylphenol based compounds are used as insecticides. The condensation of 3-methylphenol with formaldehyde yields a curable phenoHc resin. Since 3-methylphenol is trifunctional with respect to its reaction with formaldehyde, it is possible to form a thermosetting resin by the reaction of a prepolymer with paraformaldehyde or other suitable formaldehyde sources. 3-Methylphenol is also used in the production of fragrances and flavors. It is reduced with hydrogen under nickel catalysis and the corresponding esters are used as synthetic musk (see Table 3). 

The main commercial apphcations for sahcylate esters are as uv sunscreen agents and as flavor and fragrance agents. Several have apphcation as topical analgesics. A number of sahcylate esters of commercial interest and their physical properties are hsted in Table 8. 

Isoamyl saUcylate is perhaps the most important ester of saUcyhc acid for perfumery purposes. Generally, it is manufactured by the transesterification of methyl saUcylate. It has a characteristic flowery aroma and is useful in soap fragrances. The May 1996 price was 5.30/kg (18). Other saUcylates of commercial interest as flavor and fragrance agents include isopropyl, isobutyl, phenethyl [87-22-9] and 2-ethyIhexyl saUcylates. 

Polyunsaturated fatty acids in vegetable oils, particularly finolenic esters in soybean oil, are especially sensitive to oxidation. Even a slight degree of oxidation, commonly referred to as flavor reversion, results in undesirable flavors, eg, beany, grassy, painty, or fishy. Oxidation is controlled by the exclusion of metal contaminants, eg, iron and copper addition of metal inactivators such as citric acid minimum exposure to air, protection from light, and selective hydrogenation to decrease the finolenate content to ca 3% (74). Careful quality control is essential for the production of acceptable edible soybean oil products (75). 

Alitame (trade name Adame) is a water-soluble, crystalline powder of high sweetness potency (2000X, 10% sucrose solution sweetness equivalence). The sweet taste is clean, and the time—intensity profile is similar to that of aspartame. Because it is a stericaHy hindered amide rather than an ester, ahtame is expected to be more stable than aspartame. At pH 2 to 4, the half-life of aUtame in solution is reported to be twice that of aspartame. The main decomposition pathways (Fig. 6) include conversion to the unsweet P-aspartic isomer (17) and hydrolysis to aspartic acid and alanine amide (96). No cyclization to diketopiperazine or hydrolysis of the alanine amide bond has been reported. AUtame-sweetened beverages, particularly colas, that have a pH below 4.0 can develop an off-flavor which can be avoided or minimized by the addition of edetic acid (EDTA) [60-00-4] (97). 

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... 

Benzyl alcohol, [100-51 -6] C H CH20H (bp, 205.4°C at 101.3 kPa), produced by the hydrogenation of benzaldehyde is used in color photography as a parenteral solution preservative as a general solvent and as an intermediate in the manufacture of various benzoate esters for the soap, perfume, and flavor industries (see Benzyl alcohol and P-phenethyl alcohol). 

Ben /ben ate [120-51-4] CgH COOCH2CgH, mp, 21°C, cff , 1.118 bp, 323—324°C at 101.3 kPa , 1.5681. This is a colorless, oily liquid with a faiat, pleasant aromatic odor and a sharp, burning taste. It occurs naturally iu Pern and Tolu balsams, is spariugly volatile with steam, and is iusoluble iu water. Benzyl benzoate is prepared commercially by the direct esterification of benzoic acid and benzyl alcohol or by reaction of benzyl chloride and sodium benzoate. The pleasant odor of benzyl benzoate, like other benzoic esters, has long been utilized iu the perfume iadustry, where it is employed as a solvent for synthetic musks and as a fixative. It has also been used iu confectionery and chewing gum flavors. 

In the soap, perfume, and flavor industries benzyl alcohol is primarily used in the form of its aUphatic esters. Benzyl benzoate [120-51-4] finds widespread use as a fragrance diluent. Benzyl alcohol is frequently employed in bar soap fragrances at 30—40 wt % of the fragrance. Benzyl alcohol is commercially available in five grades (Table 2). 

Yeast (qv) metabolize maltose and glucose sugars via the Embden-Meyerhof pathway to pymvate, and via acetaldehyde to ethanol. AH distiUers yeast strains can be expected to produce 6% (v/v) ethanol from a mash containing 11% (w/v) starch. Ethanol concentration up to 18% can be tolerated by some yeasts. Secondary products (congeners) arise during fermentation and are retained in the distiUation of whiskey. These include aldehydes, esters, and higher alcohols (fusel oHs). NaturaHy occurring lactic acid bacteria may simultaneously ferment within the mash and contribute to the whiskey flavor profile. 

Much work has been reported and summarized ia the Hterature on the matufing of various whiskeys ia charred or uncharred white-oak barrels (4—7). The early Hterature iadicates that total acids, aldehydes, esters, soHds, and color iacreased with aging time and that their concentrations were iaversely proportional to proof. Thus aging at higher proofs (over 127°) yields less color and flavor. The maximum allowable entry proof for straight whiskeys was iacreased from 110° to 125° by the U.S. Treasury Department ia 1962. 

Since the acetal exists in equiUbtium with the aldehyde, it is possible for the aldehyde to be released when water is added in a mixed drink, changing the balance and giving a burst of freshness to a mixed drink. Ethyl esters of terpene alcohols in citms oils and other botanicals, plus the ethyl esters of fatty and volatile acids, are formed during prolonged exposure to ethyl alcohol. Certain beverage alcohol products that need to contain milk, eggs, or other protein containing materials must be developed carefully and the added flavors must be considered to prevent the precipitation of the protein and separation of the product. 

Pyrolytic Decomposition. The pyrolytic decomposition at 350—460°C of castor oil or the methyl ester of ricinoleic acid spHts the ricinoleate molecule at the hydroxyl group forming heptaldehyde and undecylenic acids. Heptaldehyde, used in the manufacture of synthetic flavors and fragrances (see Elavors and spices Perfumes) may also be converted to heptanoic acid by various oxidation techniques and to heptyl alcohol by catalytic hydrogenation. When heptaldehyde reacts with benzaldehyde, amyl cinnamic aldehyde is produced (see Cinnamic acid, cinnamaldehyde, and cinnamyl... 

Nearly all uses and appHcations of benzyl chloride are related to reactions of the active haUde substituent. More than two-thirds of benzyl chloride produced is used in the manufacture of benzyl butyl-phthalate, a plasticizer used extensively in vinyl flooring and other flexible poly(vinyl chloride) uses such as food packaging. Other significant uses are the manufacture of benzyl alcohol [100-51-6] and of benzyl chloride-derived quaternary ammonium compounds, each of which consumes more than 10% of the benzyl chloride produced. Smaller volume uses include the manufacture of benzyl cyanide [140-29-4], benzyl esters such as benzyl acetate [140-11-4], butyrate, cinnamate, and saUcylate, benzylamine [100-46-9], and benzyl dimethyl amine [103-83-8], and -benzylphenol [101-53-1]. In the dye industry benzyl chloride is used as an intermediate in the manufacture of triphenylmethane dyes (qv). First generation derivatives of benzyl chloride are processed further to pharmaceutical, perfume, and flavor products. 

Economic Aspects. There are no pubhshed production figures for cinnamic acid. Most of the manufactured acid is consumed internally to generate a series of cinnamate esters for flavor and fragrance appHcations. With this in mind, it was possible to estimate a 1990 usage in the range of 175 metric tons. The cinnamic acid that does find its way into the marketplace has been sold for 12—14/kg in dmm quantities. 

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