Coffee Tech: Ripening Synchronization!


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Sep 8, 2003
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"Next time you plunk down $4 for a cup of gourmet coffee, consider thanking the anonymous laborers who harvested the beans that went into it. The best coffees use handpicked beans, "because the fruits of a coffee tree do not ripen uniformly and, thus, there are both mature and immature fruit on the same tree," according to a new US patent (6,727,406).

A dearth of cheap labor has forced many growers to adopt methods in which workers indiscriminately harvest beans from branches, ripe or not. Mechanical harvesting is another option, but mechanical harvesters also don't efficiently distinguish mature from immature beans. And poor quality beans make a poor pot of coffee.

Into this breach (fortified by a strong cup of Kona, no doubt) stepped a group of scientists at the University of Hawaii who determined that coffee beans are climacteric, that is, they boost respiration and ethylene synthesis just prior to ripening. To control these processes en masse, the group has devised a method to eliminate the synthesis of two enzymes critical to ethylene synthesis by introducing sense or antisense nucleic acid sequences into the coffee plant's genome.

The coffee growers can thus regulate the ripening of the fruit. "By application of ethylene to the entire plant, the entire plant will ripen at once, making manual and mechanical harvesting of coffee more productive." Hopefully they'll wash it off before Starbucks gets the beans. "

From The Scientist June 7, 2004