The
link between Halloween, corn, and pumpkins
has
more to do with harvest time than vampires or
ghosts. But there is a lot of biology in
Halloween,
and
it’s not because biology is scar
|
Because of the time of the harvest, several food crops have been pulled into the Halloween traditions. Let’s talk about two of them - from more of a biological point of view.
Jack O’ Lanterns
The pumpkin is native to North and parts of South America,
but Halloween originated in Europe. So how did the pumpkin get so involved with
the holiday?
Besides making great pies, Native Americans had been eating
pumpkin for thousands of years. They are healthy as can be, with lots of fiber,
vitamin A, and potassium; plus they are low in fat. But their health value goes
beyond what even the natives might have considered.
The
point is that pumpkin flesh is useful for
preventing
or treating diaper rash. But the
picture
is a blatant attempt to keep you on the
page longer. |
It turns out that the seeds (aka pepitas) have some
amazing talents. In ostriches,
they are being used to prevent and treat gastrointestinal worm infections. In fact, pumpkin seeds have been used for centuries to expel
parasites. The question still remains as to how they do this.
Even without a worm infection, pumpkin seeds can do you much
good. While they are often considered a waste product (or more politely termed,
an “agro-industrial residue”) from production of canned pumpkin, the ground or
pressed seeds have much potential as food additives. A study from the Journal of Food Science in June, 2012 has determined the amount of bioactive
compounds (components of foods that have actions beyond their caloric
value) in the seeds of various pumpkin species - it turns out they are a superfood.
Pumpkins have high levels of carotenoids and tocopherols,
the building blocks of vitamins. The fats are mostly polyunsaturated, which is
better for us, and they tend to have a relaxing effect on gastrointestinal and
bladder sphincters, so they can been used to treat irritable bowel and bladder.
Stingy
Jack carried his lantern and wandered the
countryside
– a spirit with no place to go. For
spending
a life of drinking and debauching, he looks
to
be a fine physical specimen.
|
This is all very interesting, but it doesn’t explain Jack O’
Lanterns and Halloween. I like the story of Stingy Jack as a viable
connection. In brief, Stingy Jack lived in Ireland. He was fond of drink and
gambling. These led him into a series of bets with the Devil for the fate of
his soul. In each case, Stingy Jack was able to trick the Devil into both giving
him something he wanted, and putting Stingy Jack’s soul out of the Devil’s
reach.
Once
Stingy Jack died, heaven didn’t want him because of his transgressions, and Hell
couldn’t take him because of his deal with the Devil. So he was forced to wander
the Earthly night, using only a coal ember in a hollowed out vegetable to light his way. He became Jack of
the Lantern = Jack O’ Lantern.
The Irish would hollow out potatoes or turnips and put hot
coals in them to ward off Stingy Jack in the night. If big enough, they would
carve out faces in their lanterns to ward off the spirit of Stingy Jack. So where does a pumpkin fit into this
story?
The largest pumpkins are of the variety C. maxima. The current record is over 1818 pounds (824.6 kg). However, they are tough to use as Jack O’ Lanterns, as their rinds can be 10 inches (25cm) thick, requiring electric saws to get into and hollow them out. I think Stingy Jack can be warded off without resorting to power tools.
Candy Corn
Candy corn was invented in the 1880’s by a candy
manufacturer named the Wunderlee Candy Company. It was instantly popular with
the largely agrarian society of that time; a much larger portion of the
population were farmers, and they enjoyed the sweetness of bringing in their
corn harvest.
Pouring three differently dyed mixtures into molds one after
another resulted in the layered effect, a revolution for the time. Dried corn
(like in the picture below) are indeed yellow, white, and orange, just like the
candy. The order is different, but that may have had more to do with possible
mixing of the layers than with a misremembered early life on the farm by the
inventor, George Renninger.
Some companies now sell Indian candy corn as well, and the
colors of even the traditional candy corn remind one of the colors in Indian
corn. Indian corn is sometimes called flint corn because it has a thicker,
harder shell, hard as flint. Indian corn isn’t as sugary as sweet corn for
roasting or boiling, but it can be used for popcorn and is actually preferred
for making hominy. In some future post we should talk about the use of corn in
the discovery of genes that can jump around in the chromosomes.
The corn endosperm is full of starch as it matures, but
sweet corn has a recessive mutation which slows the conversion of sugars to
starch. This makes it sweeter, but once it is picked, the ears mature rapidly
as a survival mechanism and the glucose is converted to starch. This is why it
is it is best to eat sweet corn as soon as possible after it has been picked.
As a long chain of glucose molecules, starch is not sweet;
the glucoses are not available to our taste buds. Break down the starch into
smaller units, and then it becomes something tasty, like candy corn. You can achieve this
breakdown with heat (boiling the corn will break up some of the starch), but it
is more likely that this will be done with enzymes.
This enzyme activity is good for us; it gives us corn syrup,
which is the main ingredient in candy corn! Even more amazing, we owe our corn
syrup (and thus our candy corn) to bacteria and fungi, because they are the
sources of the enzymes industry uses to break down the cornstarch.
To make corn syrup, mix some cornstarch (the dried and
powdered endosperm) with some water and add a healthy portion of alpha-amylase.
This enzyme is secreted by bacteria and can be isolated from their growth
medium. The alpha-amylase breaks
starch chains into short oligosaccharides (oligo
= few, sackaron = sugar). This is a
little sweeter than starch, but is hard to work use.
To make it even sweeter and more liquid (starch doesn’t melt
in water as well as glucose; it is less soluble),
a second enzyme is added. Glucoamylase
is isolated from a fungus called Aspergillus.
This enzyme chops up the oligosaccharides into individual glucose molecules.
Now it is sweet and liquid enough with which to work.
There
have been health concerns about HFCS, including that it promotes obesity. The
latest research suggests that there is no relationship between HFCS
specifically and increased obesity. However, other concerns are more grave. A recent review of studies
about epigenetics (epi = beyond) and
autism proposes links between HFCS and heavy metals. HFCS may be low in zinc,
and zinc is crucial for heavy metal detoxification as well as controlling the
expression of some learning genes. This may be exacerbated by mercury or high
levels of copper in HFCS. But good
old candy corn still uses regular corn syrup.
But this isn’t the end of corn in the process. The molds
used to make candy corn are pressed out of cornstarch. The powdery substance is
compressible enough to hold a shape, but can be disrupted with minimal force
(give it a whack). The finished product is turned out, the cornstarch becomes
powder, and can be reused to make new molds. This Halloween candy turns out to
be very corny.
Next week we will return to our investigation of immune system functions, beneficial diseases, and immune system malfunctions - did you know plants have immune responses?
El-Boghdady NA (2011). Protective effect of ellagic acid and pumpkin seed oil against methotrexate-induced small intestine damage in rats. Indian journal of biochemistry & biophysics, 48 (6), 380-7 PMID: 22329239
Thais Ferreira Feitosa, Vinícius Longo Ribeiro Vilela, Ana Célia Rodrigues Athayde, Fábio Ribeiro Braga, Elaine Silva Dantas, Vanessa Diniz Vieira and Lídio Ricardo Bezerra de Melo (2012). Anthelmintic efficacy of pumpkin seed (Cucurbita pepo Linnaeus, 1753) on ostrich gastrointestinal nematodes in a semiarid region of Paraíba State, Brazil Tropical Animal Health and Production DOI: 10.1007/s11250-012-0182-5
No comments:
Post a Comment