Conversion of Valencene to Nootkatone

Hunter, G. L. K.; Brogden, William B.

doi:10.1111/j.1365-2621.1965.tb01858.x

Cited by 54 publications

(27 citation statements)

References 5 publications

(2 reference statements)

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“…The largest fraction by weight, representing approximately 90% of all citrus oil compounds, is total monoterpene hydrocarbons (including d‐limonene; Hunter and Brogden 1965a). Other hydrocarbons present in orange peel oils include the sesquiterpenes, such as valencene (Hunter and Brogden 1965a, b). Previous findings also suggested that the fruity aromas in citrus oils, which are specific to different varieties, contain oxygenated terpenes (Stanley 1962).…”

Section: Other Important Components Of Citrus Fruitmentioning

confidence: 99%

“…Although representing a small portion of all citrus oils, esters, such as ethyl butyrate in orange essence, provide the characteristic aroma to citrus fruits (Wolford and others 1963; Ikeda and Spitler 1964; Shaw 1979). Terpene aldehydes and ketones are important flavoring constituents in lemons, oranges, and grapefruits (Stanley and others 1961; MacLeod Jr. and Buigues 1964; Hunter and Brogden 1965b). Other volatile flavoring constituents and citrus oils include alcoholic compounds, such as linalool and octanol, which are in trace amounts in lemon, lime, grapefruit, and tangerine (Attaway and others 1962; Hunter and Moshonas 1965; Hunter and Moshonas 1966).…”

Section: Other Important Components Of Citrus Fruitmentioning

confidence: 99%

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History, Global Distribution, and Nutritional Importance of Citrus Fruits

Liu¹,

Heying²,

Tanumihardjo³

2012

Comp Rev Food Sci Food Safe

472

292

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Although the mysteries of its history and origin remain unsolved, worldwide cultivation and high-demand production for citrus fruit (genus Citrus in family Rutaceae) make it stand high among fruit crops. Growth of the citrus industry, including rapid development of the processing technology of frozen concentrated orange juice after World War II, has greatly expanded with international trade and steadily increased consumption of citrus fruits and their products during the past several decades. Characterized by the distinct aroma and delicious taste, citrus fruits have been recognized as an important food and integrated as part of our daily diet, playing key roles in supplying energy and nutrients and in health promotion. With low protein and very little fat content, citrus fruits supply mainly carbohydrates, such as sucrose, glucose, and fructose. Fresh citrus fruits are also a good source of dietary fiber, which is associated with gastrointestinal disease prevention and lowered circulating cholesterol. In addition to vitamin C, which is the most abundant nutrient, the fruits are a source of B vitamins (thiamin, pyridoxine, niacin, riboflavin, pantothenic acid, and folate), and contribute phytochemicals such as carotenoids, flavonoids, and limonoids. These biological constituents are of vital importance in human health improvement due to their antioxidant properties, ability to be converted to vitamin A (for example, β-cryptoxanthin), and purported protection from various chronic diseases.

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Section: Other Important Components Of Citrus Fruitmentioning

confidence: 99%

Section: Other Important Components Of Citrus Fruitmentioning

confidence: 99%

History, Global Distribution, and Nutritional Importance of Citrus Fruits

Liu¹,

Heying²,

Tanumihardjo³

2012

Comp Rev Food Sci Food Safe

472

292

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“…Nootkatone is an oxidized sesquiterpene, which is obtained by the oxidation of (+) valencene (Figure a; Fraatz et al ., ). Valencene is present in various citrus species, for example in the essential oil of Valencia orange ( Citrus x sinensis ) (Hunter and Brogden, ,b). Valencene imparts a woody citrus characteristic and is economically important because it gives a juicy impression in citrus flavourings and fragrances.…”

Section: Introductionmentioning

confidence: 99%

Valencene synthase from the heartwood of Nootka cypress (Callitropsis nootkatensis) for biotechnological production of valencene

Beekwilder

Houwelingen²,

Cankar³

et al. 2013

Plant Biotechnology Journal

117

136

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Summary Nootkatone is one of the major terpenes in the heartwood of the Nootka cypress Callitropsis nootkatensis. It is an oxidized sesquiterpene, which has been postulated to be derived from valencene. Both valencene and nootkatone are used for flavouring citrus beverages and are considered among the most valuable terpenes used at commercial scale. Functional evaluation of putative terpene synthase genes sourced by large‐scale EST sequencing from Nootka cypress wood revealed a valencene synthase gene (CnVS). CnVS expression in different tissues from the tree correlates well with nootkatone content, suggesting that CnVS represents the first dedicated gene in the nootkatone biosynthetic pathway in C. nootkatensis The gene belongs to the gymnosperm‐specific TPS‐d subfamily of terpenes synthases and its protein sequence has low similarity to known citrus valencene synthases. In vitro, CnVS displays high robustness under different pH and temperature regimes, potentially beneficial properties for application in different host and physiological conditions. Biotechnological production of sesquiterpenes has been shown to be feasible, but productivity of microbial strains expressing valencene synthase from Citrus is low, indicating that optimization of valencene synthase activity is needed. Indeed, expression of CnVS in Saccharomyces cerevisiae indicated potential for higher yields. In an optimized Rhodobacter sphaeroides strain, expression of CnVS increased valencene yields 14‐fold to 352 mg/L, bringing production to levels with industrial potential.

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“…Since grapefruit material is limited on the world market, synthetic (+)-nootkatone produced from (+)-valencene is predominantly used in commercial applications, also for the flavour market [5]. Chemical oxidation of valencene requires the use of tert-butyl chromate [6], which is a carcinogenic substance. Alternatively non-carcinogenic tert-butyl peracetate [7] or tert-butyl hydroperoxide can be used which are highly flammable and corrosive compounds.…”

Section: Introductionmentioning

confidence: 99%

A chicory cytochrome P450 mono-oxygenase CYP71AV8 for the oxidation of (+)-valencene

et al. 2010

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a b s t r a c tChicory (Cichorium intybus L.), which is known to have a variety of terpene-hydroxylating activities, was screened for a P450 mono-oxygenase to convert (+)-valencene to (+)-nootkatone. A novel P450 cDNA was identified in a chicory root EST library. Co-expression of the enzyme with a valencene synthase in yeast, led to formation of trans-nootkatol, cis-nootkatol and (+)-nootkatone. The novel enzyme was also found to catalyse a three step conversion of germacrene A to germacra-1(10),4,11(13)-trien-12-oic acid, indicating its involvement in chicory sesquiterpene lactone biosynthesis. Likewise, amorpha-4,11-diene was converted to artemisinic acid. Surprisingly, the chicory P450 has a different regio-specificity on (+)-valencene compared to germacrene A and amorpha-4,11-diene.

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Conversion of Valencene to Nootkatone

Cited by 54 publications

References 5 publications

History, Global Distribution, and Nutritional Importance of Citrus Fruits

History, Global Distribution, and Nutritional Importance of Citrus Fruits

Valencene synthase from the heartwood of Nootka cypress (Callitropsis nootkatensis) for biotechnological production of valencene

A chicory cytochrome P450 mono-oxygenase CYP71AV8 for the oxidation of (+)-valencene

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