Potato Washing-Good for Monkeys and Humans?

If you go to Germany, you may come across asparaginase-treated cookies
labelled “low in Acrylamide”. This sounds good. Even if you didn’t know what it was,
most would guess that the less Acrylamide, the better. But what is Acrylamide? Studies
have shown that Acrylamide may be a human carcinogen, thus, reduced amounts of
Acrylamide in our snack foods sounds very appealing. However, this cookie may not be
that simple, and in order to understand why, we must understand what Acrylamide is and
why these cookies have less of it.
In 2002, Swedish scientists discovered high amounts of Acrylamide in fried and
baked foods such as potato chips, French fries and bread. This compound is reported
as carcinogenic in rats and at the levels ingested by humans, may be linked to ovarian
cancer in women. Since the discovery of this potentially carcinogenic substance in our
favourite snack foods, scientists have tried to figure out how to reduce Acrylamide
formation. So, how does Acrylamide come to be in our favourite snack foods?
It turns out that starchy foods, coupled with the high temperatures of frying
or baking, produce this undesirable compound, Acrylamide. This process is called
the Maillard reaction and in addition to creating Acrylamide, it is responsible for the
browning which occurs when foods are baked or fried. Starchy foods, such as potatoes,
contain amino acids. One of these amino acids in particular is responsible for the
formation of Acrylamide-this amino acid is called asparagine. Asparagine is often
found in a free state, meaning it is not incorporated in a protein. This allows it to react
with other substances. When heated to high temperatures, the asparagine reacts with
reducing sugars to form Acrylamide. Boiling foods does not produce Acrylamide because
the temperatures involved are not as high as frying or baking. Therefore, to reduce the
formation of Acrylamide, scientists have tried to reduce the amount of asparagine or
reducing sugars in foods such as potatoes before the heating process.
In order to reduce the amounts of the reactants, scientists have thought of a simple solution-wash the potatoes! Studies have shown that simply soaking potatoes in
water before baking or frying significantly reduces the amount of Acrylamide formed
because it dissolves some of the sugar required to form Acrylamide. Even better, soak
them in an asparaginase solution. In August of 2007, Novozymes launched the first
commercial asparaginase for food applications. They claim that soaking potatoes with
asparaginase before heating can reduce levels of Acrylamide by up to 90% in French
fries, bread and other snack foods. Asparaginase is an enzyme which breaks asparagine
(one of the components of Acrylamide) into aspartic acid and ammonia. Neither of
these reacts to form Acrylamide. Therefore, asparaginase eliminates free asparagine
and no asparagine is available to react with reducing sugars to produce Acrylamide.
Sounds perfect, and so far, studies have shown that soaking potatoes in
asparaginase before baking or frying is a very effective and safe way of reducing
Acrylamide formation. Proponents of asparaginase-treated products claim that this
process does not affect the nutritional properties, the taste of the final product or even
the browning process because the Maillard reaction which causes browning still takes
place with aspartic acid (the product when asparagine is broken down by asparaginase).
In the United States, the use of asparaginase is generally recognized as safe and it has
also been approved in Europe. In October 2007, DSM Food Specialties launched the
first “acrylamide-free” product in Germany. They released cookies which were treated
with PreventASe, their commercial asparaginase.
Some Canadians however, are sceptical about using an unfamiliar enzyme in
food processing and are not convinced of the carcinogenic risks of acrylamide, the
compound with the bad reputation that had us looking for asparaginase in the first place.
On the contrary, Health Canada has concluded that there are no foreseeable nutritional
risks associated with the use of asparaginase in this capacity. Thus, earlier this year,
they conducted an online consultation asking the public for their opinion on allowing
food manufacturers to use asparaginase. So now it is up to us to decide if we want to eat
asparaginase-treated fries with reduce levels of acrylamide, or if we want our fries the old
fashion way, sans asparaginase. The results of the consultation will be available shortly
on the Health Canada website.
Hitherto, a less controversial use of asparaginase and cancer-related health is
in the treatment of a type of leukemia. Here, the exposure to the enzyme is completely
different from that of asparaginase in food manufacturing. In this case, asparaginase is
injected and takes away circulating asparagine by breaking it down into aspartic acid
and ammonia. Since leukemic cells cannot produce their own asparagine they rely on
circulating asparagine. Asparaginase deprives leukemic cells of circulating asparagine
causing cancerous cells to die. In this case, the benefits of asparaginase outweigh its
risks. For now, soaking your potatoes in water before deep-frying or roasting, is a good
way to lower Acrylamide levels at home. One day, asparaginase-treated potatoes may
become widespread once we understand all the risks involved.
Fifty years ago, researchers in Japan studying animal behaviour laid out potatoes
on a sandy beach for a group of macaques. They observed a female macaque, named
Imo, washing one of the potatoes in the water. Soon after, other macaques were seen
washing potatoes as well. While the macaques may have just been trying to get rid of the sand embedded in the potato, Imo may have been on to something. It seems simple potato
washing can also greatly reduce the amount of possible carcinogenic chemicals in our
French fries!

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