Jewish World Review
http://www.jewishworldreview.com | (KRT)
At last, science may have solved one of the most vexing problems of the modern age: how to make a cup of decaf coffee that tastes good.
By altering the genes of the coffee plant, Japanese scientists have found they can reduce the caffeine content by 70 percent, they reported Wednesday in the journal Nature.
The scientists say it will take a few more years before they have a product ready to market.
Currently, coffee beans go through a punishing ordeal to remove their caffeine. They are soaked in solvents or scraped in machines, losing not only their caffeine, but many of the compounds that make coffee smell and taste so good to millions of people.
Bad as most decaf tastes, it still accounts for about 20 percent of the sales of coffee in the United States. Many people try to avoid caffeine because too much can cause sleep problems, jitters and upset stomachs.
If the new technology works as hoped, genetically engineered decaf would taste more like full-strength, high-octane coffee.
Unlike more controversial genetic engineering feats in which genes from one species are added to another (flounder genes to tomatoes, for example), these coffee beans will simply have an existing gene turned off, said lead researcher Hiroshi Sano of the Nara Institute of Science and Technology in Nara, Japan.
Plants produce caffeine, possibly useful for repelling insects, in a series of chemical steps that the researchers call a pathway. Each step requires a different substance called an enzyme.
"There are three enzymes necessary, and we knock out one of these," Sano said.
The recipe for making that enzyme is held in a gene - a stretch of DNA. But Sano said researchers don't have to get rid of the gene, they just have to keep it from working.
Sano and his colleagues did not do anything to alter the DNA. Instead, they focused on a related substance, called messenger RNA, which begins carrying out the DNA recipe.
What they did, said Sano, was inactivate the piece of RNA needed for making the enzyme by adding a second, synthetic piece of RNA designed to stick to the first. They inserted this synthetic RNA into plant cells by adding it to bacteria and then "infecting" the coffee plant leaves.
So far, Sano said, he has not created a full-grown coffee plant with beans; he only has some shrubs. By examining the leaves, he estimates that the plant is producing 70 percent less caffeine than its unaltered brethren.
Sano focused on one of the three enzymes needed for the plant to make caffeine. Competitors elsewhere are busily working on blocking the other two.
One of those competitors, John Stiles, is trying to commercialize the process through a Hawaii-based company called Integrated Coffee Technologies.
Stiles said one potential hazard to making genetic decaf is the buildup of unknown chemical byproducts. By stopping the pathway part way through, he said, scientists might find a build-up of some intermediate product that would otherwise have been converted to caffeine.
That product might have adverse health effects or might alter the taste of the coffee.
Stiles said he is working on blocking the first step in the pathway part way so the only chemical that could build up is the starting product, a chemical called xanthosine, which he said is common in foods and is harmless.
Sano said he and his colleagues have found no intermediate harmful chemicals from their process.
Stiles also notes that getting 70 percent of the caffeine out may not fly with consumers. Existing processes for making decaf take out as much as 97 percent. Sano said he is not sure why he has not gotten rid of 100 percent of the caffeine, but he is working on the problem.
He said he and others could extend the method to create other improved foods or other products.
Plants evolved to survive, and many that are full of vitamins also contain traces of bitter and toxic alkaloids. In most cases, it appears that health benefits seem to outweigh the damage from the toxins, but someday, Sano said, genetic engineering could take the toxins out altogether.
Sano points out that most genetic engineering done today is designed to help make more money for the producers, increasing the yields of food. He said his project is among the few aimed at the consumer by providing new choices.
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