![]() ![]() Theobromine can also occur as a degradation product of caffeine and although some radioactivity in theobromine was detected after treatment, this was minimal in both cases ( Fig. We found traces of radioactivity in theophylline, the first degradation product of caffeine, in both cases (results not shown). The exogenous radiolabelled caffeine was degraded in both AC and MN plants ( Fig. (For methods, see supplementary information.) ![]() The radioactivity incorporated into metabolites was analysed after 4, 21 and 48 h of incubation by using HPLC coupled to ultraviolet and radioactivity detection systems 9. To test this, we infiltrated AC1 and MN leaves under vacuum with 14C-caffeine or 14C-adenine to monitor their degradation or their conversion to caffeine, respectively, in these plants. 1a), the immediate precursor of caffeine 8, indicating that these plants might be deficient in the enzyme caffeine synthase, which acts on theobromine. We found that AC plants accumulated theobromine (about 6.1 mg g −1 dry weight Fig. The leaves and other parts of the fruit were also very low in caffeine. The seeds of these plants showed a mean caffeine content of 0.76 mg g −1 dry weight Mundo Novo (MN), a commercial cultivar of C. ![]() They were detected during routine high-performance liquid chromatography (HPLC) of methanolic extracts of seeds. We found that three of these Ethiopian plants (designated here as AC1, AC2 and AC3 in honour of the geneticist Alcides Carvalho) were almost completely free of caffeine. arabica is an autogamous (over 95% self-pollinating) allotetraploid (2 n = 4× = 44), whereas all other coffee species are diploid and allogamous (none is self-pollinating).īiotechnological attempts have also been made to interfere with caffeine production by preventing the expression of genes that encode key enzymes in the caffeine biosynthesis pathway 4, culminating in the production of a transgenic Coffea canephora with a 50–70% reduction of caffeine in the leaves 5.Īs part of a genetic breeding programme to reduce caffeine, initiated in 1987 at the Instituto Agronômico de Campinas, we have studied 3,000 coffee trees, representing 300 C. arabica have failed owing to a strong genetic barrier 2, 3: C. Attempts to transfer the caffeine-free property from wild coffee species of Madagascar, which produce an inferior beverage, to C. Coffea arabica is the most cultivated and consumed coffee in the world. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |