Agriculture Reference
In-Depth Information
spring. Their texture and sweetness come from a combination of starches and sugars. To
the plant, starches represent food that has been stored for future use, while sugars can be
immediately converted to energy. Starches are chemical compounds that resemble tough
little pellets when raw. After they are heated in combination with a liquid, they soften. (In
this way, what happens when you cook a beet is not all that different from what happens
when you make a simple white sauce.)
Sugars are closely related to starches. (Simple and complex carbohydrates, remember?)
In fact, enzymes produced by the plant can convert starches (stored food) to sugars (usable
food) when doing so is necessary for the plant's survival. This is why parsnips are almost
always sweeter when harvested after a hard frost: the plant, feeling threatened by cold
weather, has started converting its stored food to food that it can use immediately. By con-
trast, a plant such as the carrot, which hails from a more moderate climate, has a higher
ratio of sugar to starch and is sweeter right off the bat.
Properly selected and prepared, all root vegetables turn sweet. But this is only part
of their appeal. What makes root vegetables so fascinating is the diversity of secondary
attributes they possess. In general these fall into two main categories, the sharp and the
col orful. The first typifies the flavors of vegetables such as radishes, kohlrabi, rutaba-
gas, turnips and horseradish and comes from varying concentrations of a mustardy sulfur-
ous compound that in nature functions as a defense mechanism. As with onions, cooking
tames the heat by altering the enzyme that helps create it, as does pickling in an acid such
as vinegar. Pungent as these roots can be in flavor, they are, to varying extents, bland in
appearance (although radishes have thin skins that can be colorful).
Other roots, while lacking inner fire, are among the most vibrantly colored members
of the vegetable kingdom. The most obvious example is the beet, which, depending on
the variety, is colored anything from blood red to golden orange or even pure white. This
color comes from the pigment betalain - or its absence. (Betalain also gives bougainvillea
its distinctively fiery colors.) Unlike most plant pigments, betalain is water-soluble and
will leak readily - as anyone who has cut up beets on a wooden chopping block will sadly
attest. For this reason, beets are usually treated differently than other vegetables - cooked
whole before they're peeled. Once cooked, the corky peel will slip right off (although you
still have to be careful of staining).
We usually think of carrots as being bright orange, colored with a pigment called, ap-
propriately, carotene. But they, too, come in a wide variety of hues. In fact, the familiar
orange carrot probably dates back only to the seventeenth century. Some people believe
that the original carrot was a purplish red color nearly identical to that of the beet. These
