Breakfast. Asparagus frittata with goat cheese.
Solid frittata. The eggs were soft (a sign of not being overcooked) and jammed with asparagus tips, which is my favorite part of the stalky plant. The tender spears melted in my mouth, and accompanied with several hefty servings of salty smoked salmon; it was a pretty nice way to start the day.
I specifically mentioned asparagus tips because it is the most tender part of the plant; it also happens to be the most photosynthetic (now you know). We’ve all experienced the curious effect of eating asparagus; the particular smell in our urine, which sort of smells like stale cat urine.
The reason for this? Asparagusic acid. Metabolism of this compound in the human body creates a methanethiol like by-products; which are analogous to products produced by skunks. Not all individuals can detect methanethiol, and not all individuals produce it when chowing down on asparagus.
Immediately after harvesting, asparagus begins to lose its moisture and sugar content, along with the polymerization (forming repeating chain links) of woody lignins from the base up. This is the primary reason why the base of the asparagus is usually the least tender and the most difficult to eat. It can be boiled to a pulp, but our bodies still cannot digest the higher amounts of fiber. A trick into determining where exactly the fibrous area ends and the tenderness begins is to just bend the asparagus. Where it snaps cleanly is where the fibers usually end.
So what are woody lignins and why do they form?
Lignins are secondary cell wall complexes that form within the cell walls, between celluose and pectin components of plant cells. According to several studies, lignins are required to to conduct water movement effectively in the cell. Lignin is more hydrophobic, which leads me to believe that increased lignin production is a mechanism for asparagus to redistribute and protect its water losses. Location formation of lignins can be explained by the genetic tendencies of the plant.
Based on these studies, it seems prudent that buying fresh asparagus most likely means treating it somewhat like fish: eating it as soon as possible as to avoid the loss of sugar (the sweetness in asparagus), the crunch (turgid plant cells), and the lack of lignin formation (less indigestible nasty fibrous parts). Harold Mcgee recommends storing asparagus upright, with its base in water and a bit of sugar, in order to counteract the subsequent loss of glucose and moisture.
Certain fungi and bacteria are able to digest lignin (they contain ligninases) that can degrade the polymer. An interesting application would be to utilize safe doses of such fungi or bacteria in an aqueous suspension to revitalize old, fibrous asparagus. Well-known lignin degradation reactions involve a great deal of oxidation, usually by white rot or brown rot fungi. Whether or not these types of fungi are food grade or safe to eat is beyond me. But an interesting concept nonetheless.