Peach decalactones

Glycerol Urea Canned pear, peach Decalactones, ethanol... 

R)- -Decalactone contributes much of the characteristic taste and aroma of peach and many other flavours. Chemically synthesised T -decalactone has been cheaply available for a long time, but the consumer demand for naturally flavoured food and beverages that arose in the mid 1980s created a strong demand for the (RJ-lf -decalactone isomer as a natural food flavour molecule. This definition of natural grade required its production by entirely enzyme-based steps. In turn this led to the development of a number of biotransformation processes to make natural f -decalactone. 

The value of T -decalactone is enhanced by its use as a species characteristic flavom for some flavoms such as peach, and as an important flavour contributor to a variety of other products. 

Some representatives of y-lactones are y-valerolactone 150, y-decalactone 151 with peach-like flavour, (Z)-6-dodecen-4-olide 152, 3-methyl-4-octanolide (whiskey lactone) 153 and 3-hydroxy-4,5-dimethyl-2(51T)-furanone (sotolone) 154 (Structure 4.46), found in fenugreek, coffee and sake [1-4, 21-23, 62]. 

Peaches and nectarines are members of the same species (Prunus persica). There is controversy over whether nectarine is a separate and distinct fruit or merely a variety of peach [68]. Nectarines lack skin fuzz or pubescence. Approximately 100 volatile compounds have been identified in peaches and nectarines, including alcohols, aldehydes, alkanes, esters, ketones, lactones and terpenes [14, 15, 17, 64, 65, 68-71]. Among them, lactones, particularly y-decalactone and d-decalactone, have been reported as character-impact compounds in peaches and nectarines where they process a strong peach-like aroma [66]. Lactones act in association with Ce aldehydes, aliphatic alcohols and terpenes (Table 7.2,... 

Approximately 75 volatile compounds have been identified in juices prepared from plums Prunus domestica) [35]. Lactones from Ce to C12 are the major class of compound in plums [78]. The distribution of plum lactones differs from that found in peaches in that the C12 y-lactones are found in higher concentrations than the corresponding Cio y-lactones and d-decalactone (Fig. 7.2) [78]. GC sniffing has uncovered benzaldehyde, linalool, ethyl nonanoate, methyl cin-namate, y-decalactone and d-decalactone as volatile compounds contributing to plum juice aroma (Table 7.2, Figs. 7.1, 7.2, 7.4, 7.5) [35]. 

Decanolide (y-decalactone), which imparts a powerful fruity, especially peach-like aroma has a market volume of several hundred tons per year. In the early 1980s, natural 4-decanolide was an extremely expensive, rare natural flavour (price in excess of US 10,000 per kilogram). The subsequent introduction and optimisation of its biotechnological production has resulted in a steady decrease of the price to approximately US 300 per kilogram and an increase of the market volume to several tons per year [8]. 

The closely related 5-decanolide (5-decalactone), not only found in many fruits but also found in dairy products, exhibits a creamy-coconut, peach-like aroma [49] and can be synthesised from the corresponding a,(3-unsaturated lactone 2-decen-5-olide found in concentrations of up to 80% in Massoi bark oil using basidiomycetes or baker s yeast [229]. After about 16 h of fermentation, 1.2 g 5-decanolide was obtained. At the same time, the minor lactone in... 

Primus persica (L.) Batsch. Tou Ren (Peach) (leaf, flower, fruit) Malic acid, citric acid, octalactone, leucoanthocyanins, tannins, hexalactone, hectalactone, benzyl alcohol, nonalactone, decalactone, ethanol, hexanol, acetadehyde, benzaldehyde, acetic acid, pentanoic acid, hexanoic acid.50 Astringent, febrifuge, parasiticide, diuretic, sedative, vermifuge. 

Higher molecular weight lactones, such as y-decalactone, 6-dodecalactone, y-jasmolactone, occur in fruit (peach and apricot aromas) but have been not found in wine, at least in very small traces by gas chromatography/ mass spectrometry (GC-MS). If they are detected in higher quantities, then these lactones were undoubtedly added illegally, a case for prosecution (10MI3,07MI27). 

Decalactone FEMA No. 2360 4-Hydroxydecanoic Acid Lactone 170.25/C10Hi8O2/ CH3(CH2)5CHCH2CH2C=0 1 o colorless to pale yel liq/ fruity, peach s—prop glycol veg oils ins—water/ 281° 1 mL in 1 mL 95% ale... 

Decalactone Ricinolic acid, cor-rolic acid, Massoia lactone or 11-hydroxy hexadecanoic acid Candida species, Clador-sporium sua-volens, baker s yeast Peach, buttery... 

In Group 9 various organic acids like lactic acid (Flavis 08.004, FEMA 2611), pyruvic acid (Flavis 08.019, FEMA 2970) and succinic acid (Flavis 08.024, registered in Food Chemical Codex) together with various diesters are found. Beside some diols, numerous lactones such as y-decalactone (Flavis 10.017, FEMA 2360) with peach-like notes and 8-decalactone (Flavis 10.007, FEMA 2361) with a sweet coconut-like profile are represented. 

Chiral y-lactones are important compounds of many fruits and give strawberries, peaches, apricots and many other fruits their characteristic and distinctive notes [74]. Albrecht and Tressl [75] investigated the biogenetic sequence of y-decalactone. These results indicate that (E)-3,4-epoxydecanoic acid, formed from (E)-3-decenoyl-CoA, an intermediate of the P-oxidation of linoleic acid, is the genuine precursor in the biosynthesis of y-decalactone. 

Candida strains convert ricinoleic acid into If-decalactone, which displays the fatty, fruity aroma typical of peaches. Ricinoleic acid (12-hydroxy octadec-9-enoic acid) is the major fatty acid in castor oil (approx. 80 %). The yeast can lipolyze castor oil glycerides and the liberated ricinoleic acid is subsequently metabolized via d-oxidation and eventually converted to 4-hydroxy-decanoic acid (Figure 5). Recently a European patent has been filed (20) essentially covering the same procedure. Shake culture fermentations were carried out on 100 ml scale for one week. The 4-hydroxydecanoic acid formed was converted to )f-decalactone by boiling the crude, acidified (pH 1.5) fermentation broth for a period of 10 minutes. The lactone was isolated via solvent extraction and a yield of some 5 g/1 was obtained. The same lactone was detected as the major volatile component formed when the yeast, Sporobolomyces odorus was grown in standard culture medium (21). Although the culture medium displayed an intense fruity, typical peach-like odor, the concentration of y-decalactone amounted to no more than 0.5 mg/1. 

C12H22O2, Mr 198.30, dfd 0.948-0.954, is a colorless to slightly yellowish liquid with a powerful fruity, peach-like and oily odor. It may be produced in the same way as 8-decalactone. T ike that compound, it is mainly used in cream and butter flavors. 

Sn-beta, combined with hydrogen peroxide as oxidant, has the potential to substitute classical oxidants, for example peracids, in BV oxidations. As an example, the oxidation of delfone (2 pentylcyclopentanone) to d-decalactone (tetrahydro-6-pentyl-2H-pyran-2-one) is currently achieved using the corrosive peracetic acid. The resultant lactones have a creamy coconut-and peach-like aroma and are important flavor constituents of many types of fruit, and cheese and other dairy products. The lactones are also used in fragrances the two enantiomers have different aromas. Sn-beta was tested for this BV transformation in a stirred reactor. The desired lactone product was obtained in 86% yield in the presence of the Sn-beta catalyst. (302) This result demonstrated clearly that the combination of Sn-beta and hydrogen peroxide is an environmentally friendly alternative to the commonly used organic peracids, even in asymmetric synthesis. Instead of a stoichiometric amount of carboxyHc acid waste, water is produced as a side product from the oxidant. 

Schnermann and Schieberle [54] reported 13 odorants with the highest flavor dilution factors in milk chocolate as 3-methylbutanal (malty) 2-ethyl-3,5-dimetbylpyrazine (potato chip-like) 2- and 3-methylbutanoic acid (sweaty) 5-methyl-(E)-2-hepten-4-one (hazelnut-like) l-octen-3-one (mushroom-Uke) 2-ethyl-3,6-dimethylpyiazine (nutty, earthy) 2,3-diethyl-5-methylpyrazine (potato chip-like) (Z)-2-nonenal (green, tallowy) (E,E)-2,4-decadienal (fatty, waxy) (E,E)-2,4-nonadienal (fatty) 8-decalactone (sweet, peach-like) and 2-methyl-3-(methyldithio)furan. 

Decanolide (y-decalactone) J X Fruity, peaches O Fat-containing food, cf. Table 5.13... 

In most de novo procedures, the yield of the main compound is usually <100 mg 1 . Better yields are achieved when a substrate biochemically more immediate to the volatile product is used, or when an immediate precursor is included in the culture medium together with the crude substrate, thus obtaining processes that are closer to bioconversion procedures (see next paragraph). For example, the production of the peach-like aroma y-decalactone by Yarrowia lipolytica and various Candida species can exceed 10 g 1 if castor oil is included in the culture [25,26]. 

Lactones have characteristic aromas that contribute to peach, coconut, and dairy flavors and occur in a wide variety of foods. The y-lactones, specifically y-undecalactone and lesser for y-decalactone, possess intense peach-like odors (11). A doubly unsaturated 5-decalactone, 6-pentyl-2//-pyran-2-one, also has an intense peach character (4). As a point of distinction, the Cio-Cn 8-lactones, particularly the creamy-coconut note of 8-decalactone, are flavor constituents of coconut as well as cheese and dairy products (11). 

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