The Asparagus Strikes Back

I concluded last week’s post with countering foul smelling odors in fish.  The upcoming posts will be dedicated to obnoxious aromas in a different category, vegetables.  Before I explore the (minor) negative side effects of consuming veggies, I do want to emphasize that these verdant creatures provide a great deal of nutrition everyone should be thankful for.  Not only would life cease to exist without these highly evolved autotrophs, but imagine how much time you’d spend on the toilet!  We’ll enough with the toilet talk, so let’s explain why asparagus makes your urine smell.

Asparagus is a native Eurasia plant and its culinary history has been documented since the third century.  It was mainly harvested by the Greeks and Romans, but because asparagus’s labor-intensive cultivation, it only became popular in the 18^th century after the Agricultural Revolution.    Unlike many other plants where we consume the flowers, fruits, or leaves, Asparagus is actually the main stalk.  Other plants may have leaves, but asparagus equips itself with small projections.  The branching appendages, called phylloclades, protect immature photosynthetic clusters until they’re ready to follow their energy-generating brethren.

[Source: http://www.worldcommunitycookbook.org/season/guide/photos/asparagus.jpg] 

There are many color variations of asparagus including white and purple.  White asparagus are shielded from direct UV light by remaining underground until harvested.  Once displaced from Mother Earth and exposed to the sun, they convert to yellow or red.  The chromatic color change is due to the absorption of yellow and red wavelengths from the sun…whereas, purple…well, I couldn’t find reliable research about the purple asparagus.  However, I’m going to say they know what’s right with human-equality.

[Source: http://farm4.static.flickr.com/3546/3428907676_f178514cae.jpg]

Like many freshly harvested plants, young asparagus tend to be juicer and noticeably sweeter due to higher concentration of sugar (thus more liquid).  Sugar levels decline as the farming season progresses because of the growing clusters (the apical stem, if Bio1A memory serves me right).  A key indicator for detecting fresh and asparagus is to examine the tip and look for a tightly-closed cluster.  If they tip begins to open up or branch, then it’s a sign of maturity.  However, you can “refreshen” your asparagus by submerging the veggies in a 5-10% dilution of sugar to water for a few minutes before cooking.  Just mix 5-10 grams of sugar with 100 ml of water (sorry, but I’m pro-Metric system). 

The main responsibility of the stalk is to provide support and act as a transport medium for water.  Therefore, asparagus can sometimes be tough due to its well-supported external surface composed of chewy lignin and cellulose.  Some cooks choose to peel their asparagus while others repeated bend and exert physical stress loosening the structure.  I personally like the stemy exterior, it reminds me of eating an artichoke.

Ok, so back to the unusual side effects of consuming asparagus.  The green-spear contains a compound named Asparagusic acid (clever!) that contains sulfur.  The body then metabolizes Aspargusic acid into a funky chemical found in skunks called methanethiol (mentioned in an earlier post).  There have been studies showing some individuals are immune to this odor, and genetic variations account for why some humans can’t smell the by product.  I wonder why this would be a genetic advantage?

Many vegetables and fruits create compounds for natural defense, I bet this is an asparagus’s way to tell you not to eat them.