The Potato Root
We
grow a lot of potatoes in this country: 33 billion pounds to be exact.
That’s about 142 pounds of potatoes per person every year. About half
are used fresh to make baked potatoes, potato skins, mashed potatoes,
canned
potatoes, potato soup, potato salad and Mr. Potato Heads. All of these
uses
of fresh potatoes pose no more of a sulfite danger than any other fresh
food.
You just have to beware of other ingredients that might be added to
such
dishes. The other half of our potato crop is processed into french
fries,
frozen hash-browns, potato flour and dehydrated mashed potatoes. I hate
to
break the news, but most of those processed potatoes contain sulfites.
Potatoes have a slight temperature problem. If they
are stored at temperatures
below 45 degrees, the starches can convert to sugars and they can turn
brown.
If they are frozen, browning can become an issue. I guess that’s why
your grandmother told you to keep your potatoes in the cupboard and out
of
the refrigerator. Any product that contains a frozen potato may have a
color
problem requiring sulfites. Dehydrated potatoes have similar issues
that
are solved by sulfite preservatives. Potato flours go one step further
and
use sulfur dioxide to bleach the final product, giving it a nice white
appearance
like other flours.
French
fries are the kings of processed potatoes and most fries are prepared
in
a potato factory and frozen before being sent to your local burger
stand.
The burger people simply dump them into a deep fat fryer for final
cooking
and serve them to you hot. At the factory, potatoes are cooked under
pressure
until the skin softens. When the pressure is suddenly released, the
skin
is jolted loose and it easily peels off in a stream of water jets. The
potato
skin is used either as cattle feed or to produce methane gas to help
run
the potato plant. The peeled potatoes are inspected and sent to the
cutting
machines. The cutting machines are centrifugal pumps that accelerate
the
potatoes to 50 mph and shoot them into stationary blades. Out pops
french
fries. The fries are inspected by automated machinery for size, spots
and
color. Those that pass are blanched in vats of hot water. If necessary,
a
sugar dip improves the sugar content of the potatoes. Then the fries
are
dried to controlled water content by blasts of hot air. Finally, they
are
"par fried" for about a minute and a half in very hot cooking oil. At
this
point, they are blast frozen and boxed for shipment. Somewhere in this
process,
sulfites are added because french fries wind up with an effective
sulfur
oxide concentration of about 13 ppm. For a super-sized bag, this means
2730
micrograms of sulfur dioxide. No thank you, I’ll pass.
Now, the potato industry must have some real muscle.
You will remember that
the FDA banned sulfite preservatives on salad bars in 1986. In 1990,
they
proposed to do the same thing for fresh potatoes intended to be cooked
and
served unpackaged and unlabeled (like french fries). In a protracted
court
battle, the potato industry challenged the FDA ruling and prevailed on
procedural
grounds. I’m not exactly sure what all of that means, except this is
many years later and sulfites are still all over french fries. My
advice
to sulfite sensitive people is simple. When it comes to potatoes,
unless
it is baked whole in its own skin, don’t eat it.
Of course, you also have to watch out for dehydrated
potatoes. Dehydrated
spuds are used to make instant mashed potatoes. They are easy to
recognize
when they are in a box on the grocery shelf. But when you’re eating
away from home, you have to ask where the mashed potatoes come from
before
you eat them. Dehydrated potatoes have a cousin, potato flour. You
should
read ingredient labels and avoid potato flour. Like a fool, I switched
from
ordinary hamburger buns to Hawaiian buns to avoid high fructose corn
syrup.
Unfortunately, the Hawaiian buns had a few grams of potato flour that
spawned
several headaches before I realized what was going on. Potato flour is
a
sulfited starch that causes trouble for me about 24 hours after eating
and
lasts for an additional 24 hours. It’s hard to relate your pain to
something
that you ate 48 hours earlier.
What
about potato chips? The bags state "No Preservatives" but can you
really
believe them? I honestly could find no information on how potato chips
are
commercially manufactured. I guess the industry protects its secrets.
So,
I ate a few of Lay’s Classic chips one day, and a few more on following
days until I was staring at a full dinner plate of chips. No headache,
no
problem. Thank you Frito-Lay for not using sulfur preservatives. Of
course,
after you dine on a full plate of potato chips, it’s a long time
before you want another chip.
Potatoes are a good source of starch just like corn.
And like corn, they
can be refined to produce food starches, maltodextrins and dextrose. In
fact,
potato starch is more common than corn starch in Europe where American
maize
has never caught on. In the United States, many factories have been
built
to refine potatoes over the past century. But potato refining is a
somewhat
messy business and environmental pressure combined with competition
from
corn have depressed American potato refining. Maybe depress is too weak
a
word. There is only one raw potato refining plant left in all of the
USA.
But don’t fret; the potato waste from french fry and chip factories
can be economically refined. So, refined potatoes have begun a
comeback.
Some french fries are now coated with potato starch to keep them crisp
for
longer periods.
Since refined potatoes are much less common in North
America than refined
corn, you won’t run across potato starch on food labels very often.
When you do, it will probably be on a soup can. However, food labels do
regularly
specify just "food starch" or "modified food starch". Such an
ingredient
could be corn starch, wheat starch, potato starch or any starch. The
food
manufacturer then has the freedom to use whatever starch is cheapest,
most
available or works best. Of course, in practice, it will usually be
corn
starch if the item was produced in America. As far as the oxides of
sulfur
are concerned, the worst starch is corn starch. So, using the corn
starch
SOx values for "food starches" is both realistic and conservative. The
same
comments apply to generic dextroses and maltodextrins.
When we assign a number to the SOx value of an
ingredient like "food starch",
we are just making a guess. We would like to hope that it is a good
guess
or even an educated estimate, but we don’t really know for sure. An
SOx value is simply an average of the effective sulfur oxide content of
a
large number of samples. A particular sample might differ from the
group
average just like the height of any human may differ from the average.
So,
remember this when you look at the nutrition label on a can of soup and
calculate
a sulfur content. It’s only a guess. To be more accurate, you would
have to contact the manufacturer or run some chemical tests. And even
then,
what could you say for sure about next month’s can of the same soup?