1,1,6-Trimethyl-l ,2-dihydronaphthalene (TDN): A Possible Degradation Product of Lutein and beta-Carotene*
نویسنده
چکیده
Carotenoids are unstable compounds and are easily degraded to a variety of products in the presence of oxygen and light as well as at elevated temperatures. Ohloff (1972) hypothesised that carotenoids are precursors of aromatic compounds such as C13-norisoprenoids. Recently, several C13-norisoprenoids have been identified upon liberation from their bound forms in grapes and wines (Sefton et at., 1989; Winterhalter, Sefton & Williams, 1990). One of these, 1,1 ,6-trimethyl-1,2-dihydronaphthalene (TDN) (2), is regarded as an important contributor to the bottle-aged kerosene-like character of aged Weisser Riesling wines (Simpson, 1978; Simpson & Miller, 1983; Marais, Van Wyk & Rapp, 1992). In general, when this flavour is present at high intensities it has a detrimental effect on wine quality. The degradation products of the following carotenoids have been investigated: beta-carotene (Day &
منابع مشابه
Timing of cluster light environment manipulation during grape development affects C13 norisoprenoid and carotenoid concentrations in Riesling.
Sunlight exposure of winegrape clusters is frequently reported to increase C(13)-norisoprenoids in resulting wines, but the timing and mechanism of this influence is not well understood. Fruit zone leaf removal was applied to Vitis vinifera cv. Riesling at three timings: 2, 33 and 68 days past berry set (PBS), and compared to an untreated control. Free and total 1,1,6-trimethyl-1,2-dihydronapht...
متن کاملPigment Changes Associated with Application of Ethephon ((2-Chloroethyl)phosphonic Acid) to Fig (Ficus carica L.) Fruits.
The application of (2-chloroethyl)phosphonic acid (Ethephon) to ;Mission' fig fruits (Ficus carica L.) during late period II of their development stimulated ripening and change in color from green to bluish black within 8 days. Chlorophylls a and b decreased rapidly within 4 days after Ethephon treatment, and degradation continued at a decreasing rate for an additional 4 days, at which time the...
متن کاملFour-directional-development thin-layer chromatography of lipids using trimethyl borate.
Solvent mixtures containing trimethyl borate virtually eliminated the pronounced interconversion of 1,2- and 1,3-dipalmitins during their resolution by thin-layer chromatography on Silica Gel G. With trimethyl borate, an average of 1-2% of 1,2-dipalmitin was converted to 1,3-dipalmitin. A four-directional-development TLC procedure incorporating trimethyl borate resolves cholesteryl glucoside, c...
متن کاملPlasma appearance of labeled beta-carotene, lutein, and retinol in humans after consumption of isotopically labeled kale.
The bioavailability of carotenoids from kale was investigated by labeling nutrients in kale with 13C, feeding the kale to seven adult volunteers, and analyzing serial plasma samples for labeled lutein, beta-carotene, and retinol. Ingested doses of labeled carotenoids were 34 micromol for beta-carotene and 33 micromol for lutein. Peak plasma concentrations, areas under the plasma concentration-t...
متن کاملDe novo synthesis and degradation of Lx and V cycle pigments during shade and sun acclimation in avocado leaves.
The photoprotective role of the universal violaxanthin cycle that interconverts violaxanthin (V), antheraxanthin (A), and zeaxanthin (Z) is well established, but functions of the analogous conversions of lutein-5,6-epoxide (Lx) and lutein (L) in the selectively occurring Lx cycle are still unclear. We investigated carotenoid pools in Lx-rich leaves of avocado (Persea americana) during sun or sh...
متن کامل