How To Make A Decaf Coffee Plant

540515222 tpWhy decaf coffee?

Have you ever had a cup of really good decaf coffee?

Me neither.

(Probably because the decaf coffee results from chemical processing of normal coffee beans.)

But why would anyone want coffee without caffeine?

As illustrated by the old Gary Larson cartoon on the left, sometimes you can get too much caffeine. Or maybe you just prefer coffee without the caffeine buzz. Or maybe you are a Mormon.

For whatever reason, there certainly is a very large potential market for coffee beans that naturally have very low or no caffeine.

3720001337 3dee0e6a02Indeed, coffee plant breeders have been trying to develop such varieties for decades, with very little success.

The subject was brought to my attention by an excellent article in the March 15, 2012 issue of Nature magazine. (See reference 1 below.)

It’s a fascinating story about “the enduring quest for a coffee bean without the buzz” and about why it’s been so difficult to produce coffee plants that don’t make caffeine.

Briefly, since it involves a complex metabolic pathway, the biosynthesis of caffeine in coffee plants has been a challenge for plant genetic engineers to effectively eliminate. (Anyway, many people would reject “genetically-modified” coffee.)

Breeding commercially-valuable coffee varieties with other low-caffeine species has also been frustrating.

Perhaps the best chances at obtaining commercially-viable decaf coffee plants will come from mutagenesis. This involves treating coffee seeds with a chemical that increases the probability of genetic mutations occurring and selecting any resulting decaf “mutant” plants. Indeed, about a half-dozen such plants – preliminarily trademarked “Decaffito” – have been found after screening nearly 30,000 potential mutants.

By the way, you can enjoy the complete story, along with informative graphics and a pertinent audio excerpt from the Nature podcast, without having a subscription to Nature. So I highly recommend that you head on over to the Nature website and check it out. (Thank you, Nature!)

449721832 04a59ee1d1But why do some plants make caffeine?

Simply put, it’s a chemical defensive compound that helps the plant to deter herbivory.

Caffeine is one of many plant “secondary compounds”, including nicotine and morphine, called alkaloids that can sometimes have dramatic effects on animals. Some alkaloids are even deadly. (For example, see my previous post regarding “wicked” plants.)

Plants are marvelous biochemists. They not only can produce sugars from CO2, water, and light (photosynthesis) but also can metabolize sugars to make energy or cellulose. All plants can perform such so-called “primary” metabolic pathways.

Secondary metabolic pathways are so-called because only some plants do them, not because they are necessarily secondary in importance to the plant. (“Secondary compounds” is perhaps an unfortunate name for them because many of these compounds are critical to plant survival, especially against herbivores.)

Such natural plant compounds range from vanilla to oil of Wintergreen, from aspirin to cocaine – so many thousands of amazing compounds that it’s way beyond the scope of this blog post.

But I’ll leave you with this parting shot – There is good evidence to suspect that some of these so-called “plant” compounds are actually synthesized by microorganisms, such as fungi or bacteria, called endophytes that live, literally, inside the plant (or “epiphytes” that live in the phyllospere, i.e., on the surface of leaves).

Bottom line: Although many people would surely want to have naturally-decaffeinated coffee, would this leave such coffee plants susceptible to some insect pests?

Reference

1. Borrell, B. (2012) “Plant biotechnology: Make it a decaf.” Nature, Vol. 483, pp. 264–266. (Full Text + Extras)

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