Healthy Beans And Your Coffee Health
The world's caffeine addicts got some good news this week when it was announced that the genes involved in coffee quality have been identified. Since 2001, CIRAD and the Agricultural Institute of Paraná in Brazil (IAPAR) have been working on joint research into understanding the biological processes - flowering, fruit ripening, etc - that determine coffee's distinctive characteristics. Some compounds (sugars, fats, caffeine, etc) are known to play a role in coffee quality. Their accumulation in the plant, and particularly in the beans, is a determining factor. Sucrose is considered to play a crucial role in coffee organoleptic quality, since its breakdown during roasting releases several aroma and flavour precursors.how coffee beans ripen. Using molecular biology and biochemistry techniques, they have characterized the key enzymes in the sucrose metabolism during coffee bean development. The quality of coffee makes a big difference at market, which is good news for all concerned as coffee is still the second most traded commodity in the world behind only petroleum.
The work showed that an enzyme, sucrose synthetase, is responsible for sucrose accumulation in coffee (Coffea arabica) beans. Unlike in other plants, invertases play only a minor role in this metabolism. Sucrose synthetase exists in the form of at least two similar proteins with the same biological function - isoforms -, but which are coded by two different genes: SUS1 and SUS2. The researchers were supported in their work, by the University of Campinas in Brazil (Unicamp).
Expression of those genes was analysed within the various tissues of developing coffee beans (pulp, perisperm and endosperm). The results showed that sucrose accumulation in coffee beans, towards the end of ripening and just before picking, is controlled by isoform SUS2. Isoform SUS1, for its part, seems to be involved in sucrose breakdown and thus in energy production. In effect, its expression is systematically detected during the early stages of cell division and expansion in young tissues.
A second phase comprised a study of the nucleotidic diversity of these genes, so as to account for the variations in bean sucrose content between the various Coffea species or within the same species. The genes were mapped and tested to determine their role in that variability. The aim was to identify early markers of sucrose content that would guarantee end product quality.
The first application of these results was a study of the relations between shading, which is known to improve coffee quality, and sucrose metabolism enzymes. To this end, IAPAR set up a field trial. The results showed that sucrose synthetase and sucrose phosphate synthetase, another enzyme in the sucrose metabolism, show greater enzymatic activity in the beans of coffee trees grown in the shade than in those grown in full sunlight. In the case of sucrose synthetase, this activity is correlated with the increase in SUS2 gene expression seen in the beans of shaded plants. However, the final sucrose content of the beans is not higher for shaded plants. The quality of shaded coffee may thus result from the reorientation of the sugar metabolism towards the synthesis of other compounds, such as fats, which may also be involved.
Coffee can work wonders
Recent research has found that two to four cups of coffee a day can contribute to a reduced risk of inflammation and cardiovascular disease, due to its high antioxidant content, BBC Television reported.
Antioxidants scavenge unstable molecules (free radicals) in the body. Free radicals contribute to oxidative stress, which, over time, can cause inflammation and other unhealthy changes in cells.
A study of more than 27,000 post-menopausal women concluded that coffee's antioxidant properties might well inhibit inflammation and, consequently, development of cardiovascular disease.
It appears that routine coffee consumption, particularly decaffeinated coffee, substantially lowers the risk of type 2 diabetes.
Among a group of 890 older women, a history of consuming caffeinated coffee throughout their life appears to have helped the preservation of cognitive skills - such as thinking, memory and comprehension - possibly due to long-term caffeine exposure.
An extensive trial - the Nurses' Health Study - found that low levels of caffeine intake reduced the risk of Parkinson's disease in women who used post-menopausal hormone therapy. In women who didn't use this treatment, moderate to high caffeine intake decreased the risk of Parkinson's.
However, the study found that six or more cups of coffee per day increased the risk of Parkinson's in women who used hormone therapy.