Amerindians used biotechnology

http://www.stabroeknews.com/index.pl/article?id=56529494

Amerindians used biotechnology
Stabroek News, Monday, September 24th 2007

Dear Editor,

The late Sir Everard F im Thurn (MA. Oxon,1852-1932) published (1883) a
work entitled: Among the Indians of Guiana: Being Sketches Chiefly
Anthropologic from the Interior of British Guiana. There are detailed
descriptions of how cassava bread is made, with variations under
different conditions when the cassava is scarce. However, we want to
focus on the earliest recorded incidence of 'biotechnology' procedures
in British Guiana. (This is from my contemporary readings of our
national historical documentation - I am of course subject to
correction by evidence to the contrary by the experts in this field.)

On Page 263 of the abovementioned work we read: "Cassava bread which is
to be transformed into paiwari, is made as that for other purposes; but
it is thicker, and is baked, or rather burned, until it is quite black.
It is then broken into smaller fragments, and is mixed with water in a
large jar or pot The larger fragments are picked out and chewed by the
women, who do this while moving about and performing their usual
household work; and the masses are again replaced in the jar. As soon
as this jar is sufficiently filled, its contents, after being well
stirred, are slightly boiled, and are then poured into the trough. More
and more is added to the liquor in the trough until it is full.

"The mixture is then allowed to stand for some days, until it is
sufficiently fermented - a process which is said to be much accelerated
by the mastication of the bread. Sometimes a little juice of sugarcane
is added to sweeten the liquor.

The result is a brownish liquor - looking like coffee with a great deal
of milk in it - with a sub-acid, but not unpleasant taste. Some of the
True Caribs, it is said, and some of the Brazilian tribes, manage to
prepare paiwari, and to procure a proper degree of fermentation, by
simply boiling, without resorting to the very disagreeable but more
orthodox chewing process; but paiwari produced in this way is said to
be of very inferior flavour."

"In some parts of the country, instead of paiwari, both for festivals
and for ordinary occasions, a much pleasanter drink is used. This is
casiri, which is made of sweet-potatoes and sugar-cane. A little
cassava is sometimes added. Generally, though not always, it is
prepared simply by boiling the ingredients, and allowing them to
ferment. It has a pretty pink colour, due to the sweet potatoes; and
when well made it tastes not unlike thin claret…"

For those who love to eat and have done some science, we would remember
that digestion of food begins in the mouth - ie chewing breaks down the
size of the food particles to smaller and smaller-sized ones. This
chewing is necessary so that we can have the maximum surface area of
the food exposed to the saliva - produced by the salivary glands in the
mouth. This chewing therefore also maximises the efficiency of the
catalytic process that occurs in the presence of saliva. The saliva
produced in the mouth contains an enzyme called human salivary amylase
also called ptyalin (among other chemicals) which is mainly called
alpha amylase that breaks down a complex carbohydrate such as starch
(polymer of glucose) into simple sugars (monosaccharide, disaccharide
or tri-saccharide e.g. such as glucose, maltose, maltotriose,
respectively, and "limited dextrin"). The alpha amylase enzyme is
present in very small amounts in the saliva. Usually, in any biological
enzymatic process only a small amount of the catalyst is needed. The
alpha amylase enzyme (like other enzymes) here works best at a
particular pH (ie a measure of acidity or alkalinity) range (in this
case slightly alkaline, 7.4). (Incidentally, the saliva also contains
another enzyme called lysozyme that lyses (breaks down) bacteria, in
addition to other anti-bacterial compounds.)

This saliva helps to sterilise any bacteria that would remain on any
improperly washed or handled cassava. Hence the saliva destroys any
bacteria present as well as breaking down starch to form glucose,
maltose, maltotriose and "limited dextrin"- done by alpha amylase and
lysozyme, respectively.

The stirring mentioned above also allows for maximum exposure to the
enzymatic processes - thereby maximising the efficiency of the
catalytic breakdown of starch into maltose. The heating to a slight
boiling denatures (kills) the enzymes - thereby stopping the catalytic
action of the enzyme (alpha amylase). This phase of the production
process is over. The heating to a boiling also acts as sterilization
step - since heat kills bacteria, viruses, and other living
micro-organisms that may also be present.

The sterilised maltose is now ready for the next step - fermentation of
simple sugar i.e. maltose into alcohol. (Incidentally, from cane sugar
we extract the sucrose (a disaccharide) which is then fermented to give
alcohol.). Unfortunately, I found no detailed record of how the
fermentation process was/is initiated, controlled, and stopped. Maybe
those with this knowledge or experience can kindly let us know.

We see from the above that the old making of paiwari is indeed complex
science - and the participants involved intuitively must have some
understanding of the biological chemistry or biochemistry involved.
Today such a complex process would be in the realm of applied science,
ie biotechnology, since it involved the use of biological materials in
a complex production process.

Next time, we see Amerindians I hope that we have more respect for
their immense knowledge. If we look carefully without prejudice, we can
learn a lot from them. They do have a lot to teach us - we just have to
be open-minded.

I taught biochemistry at UG, regrettably I was not aware at time that
there was a good local example of the application of early
biotechnology in Guyana. I never learnt about this until I was doing
some research about the Rupununi Uprising. Who knows what other gems
are there to be discovered and recorded before they are lost.

These liqueurs (paiwari and casiri) can probably be produced for
commercial exploitation using alpha-amylase. Besides the use of sweet
potatoes in casiri, fruits such as 'jamoon,' gooseberry, tamarind,
and/or other local fruits can be used to make flavoured liqueurs. This
would provide an additional market for cassava-based products. This
would be a good enterprise for DDL or some adventurous group of young
entrepreneurs.

Hope that next time we can all celebrate Amerindian Heritage month with
a new found respect for their contribution and knowledge - in addition
to their knowledge in forestry, botany, zoology, and their
environmental awareness.

Yours faithfully,

Seelochan Beharry, PhD