Carotenoids, aroma compounds

Due to oxidative degradation of carotenoids, aroma compounds are also formed, including P-ionone with an odor threshold value of 14 ng/g in water. The formation... 

One of the most important discoveries recently made in the field of carotenoid aroma compounds relates to the class of damascones. Seven naturally occurring members (266) to (272) of this class are known today. The discovery of these new compounds started with the isolation of damascenone (268) from Bulgarian rose oil in 1970 120). Later, the same compound was detected in various tobacco brands 5, 110, 306), tea 491), raspberry oil 708), cooked apples 442), various grape and wine varieties 546, 549), beer 598), coffee oil 179), buchu leaf oil 283) and Roman camomile 638). 3-Hydroxy-(3-damascone (269) was shown to be an important aroma component of tobacco 108, 169, 285) in which it develops a green, rose-floral and sweet Burley-like note (556). (3-Damascone (267) was found in Burley tobacco 110) and rose oil 108), whereas a-damascone (266), accompanied by (3-compound (267) and damascenone (268), was exclusively observed in tea oil 491). Among the known cyclization products (270) to (272), the last two compounds were found in tobacco (779), while ketone (270) was detected in tea 491). 

Selective oxidations are key transformations for the industrial production of a wide range of chemicals. Within DSM, oxidations reactions are used in the synthesis of vitamins and carotenoids, aroma compounds and polymer intermediates. Here we describe the use of both chemocatalysts and biocatalysts used in the industrial oxidation of aliphatic and aromatic systems, alcohols and poly hydroxyl-compounds. 

In the natural world, carotenoid oxidation products are important mediators presenting different properties. Volatile carotenoid-derived compounds such as noriso-prenoids are well known for their aroma properties. Examples include the cyclic norisoprenoid P-ionone and the non-cyclic pseudoionone or Neral. Carotenoid oxidation products are also important bioactive mediators for plant development, the best-known example being abscisic acid. Apo-carotenoids act as visual and volatile signals to attract pollination and seed dispersal agents in the same way as carotenoids do, but they are also plant defense factors and signaling molecules for the regulation of plant architecture. 

Winterhalter, P. and Rouseff, R., Carotenoid-Derived Aroma Compounds, Series, A.S. Ed., American Chemical Society, Washington, 2001, 1. 

Enzell, C. (1985). Biodegradation of carotenoids An important route to aroma compounds. Pure Appl. Chem. 57 693-700. 

Winterhalter B. and R. L. Rouseff (2002). Carotenoid-Derived Aroma Compounds An Introduction. Washington DC Amercian Chemical Society. 

Pharmaceuticals are only a part of natural products derived from filamentous organisms. Filamentous fungi are also grown industrially for the production of natural products other than pharmaceuticals. Organic acids such as citric, itaconic and gluconic acids, carotenoids, taste and aroma compounds, and a variety of industrial enzymes such as amylases, lipases, dextranases and proteases are also extracted from these fungi. 

Scheme 7.5 Formation of some aroma compounds after oxidative cleavage of a acyclic carotenoids (e.g., lycopene, phytofluene and phytoene) and b cyclic carotenoids (e.g. a-carotene and / -caro-tene)...

As there is great interest from the detergent, food and perfume industry in the potent aroma compounds formed by carotenoid breakdown, and as the fi-ionone obtained can be labelled as natural aroma—if natural carotenoids are used—this cleavage reaction might have a high potential. 

The special potential for constructing double bonds stereoselectively, often necessary in natural material syntheses, makes the Wittig reaction a valuable alternative compared to partial hydrogenation of acetylenes. It is used in the synthesis of carotenoids, fragrance and aroma compounds, terpenes, steroides, hormones, prostaglandins, pheromones, fatty acid derivatives, plant substances, and a variety of other olefinic naturally occurring compounds. Because of the considerable volume of this topic we would like to consider only selected paths of the synthesis of natural compounds in the following sections and to restrict it to reactions of phosphoranes (ylides) only. 

Winterhalter, R, Rouseff, R.(2000). Carotenoid-derived aroma compounds. In P. Winterhalter R. Rouseff (Eds.),Carotenoid-derived aroma compounds an introduction (pp. 1-17). Washington, DC ACS Symposium Series 802. 

Gunata, Z., Wirth, J.L., Guo, W. and Baumes, R.L. (2002) C13-norisoprenoid aglycon composition of leaves and grape berries from Muscat of Alexandria and Shiraz culti-vars, In Carotenoid-derived aroma compounds, ACS Symp. Series 802, Am. Chem. Soc., Washington DC. 

Winterhalter, P. 1996. Carotenoid-derived aroma compounds Biogenetic and biotechnological aspects. In Biotechnology for improvedfoods and flavors, ed. G. R. Takeoka, R. Teranishi, P. J. Williams, and A. Kobayashi, 295-308. ACS Symposium Series 637. Washington, DC American Chemical Society. 

Carotenoid-Derived Aroma Compounds Biogenetic and Biotechnological Aspects... 

Enantioselectivity of Biogenetic Routes. The enantiomeric composition of natural aroma compounds is known to reflect the enantioselectivity of their biogenesis (22). Thus, by elaborating the chiral composition of Cp-norisoprenoids in fruits, we expected to obtain some information about step II m the formation of Ci3-notiso-prenoids, i.e. the enzymatic transformation(s) of the primary carotenoid degradation products into labile aroma precursors (cf. Fig. 3). 

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