Potatoes… - Bayer CropScience

Some examples of the use of starch as a renewable raw material (from left to right):
Wallpaper paste
Carrier bags
(Photo: novamont)
America and Asia than in Europe. The production
of potato starch for non-nutritional
purposes is predominantly an activity of
Western European nations (although Asia
also uses a smaller amount of potato starch
for industrial purposes).
Each year, more than 9 million tonnes
starch are produced in the European
Union, of which around a fifth derives
from potatoes and the rest from maize and
wheat. Potato starch production in the EU
is fixed by quotas: the total amount is almost
2 million tonnes, of which the largest
share goes to Germany (656,000 tonnes),
followed by the Netherlands (507,000
tonnes) and France (265,000 tonnes). More
than 40% of the starch produced in the
Community is used for non-food purposes.
Native potato starch shows a higher
viscosity than starch from wheat or maize.
It possesses good water-uptake and
swelling properties, as well as low thermal
and electrical conductivity. Its chemical
make-up comprises the carbohydrates
amylose and amylopectin, each of which is
suited to its own set of purposes, although
for most uses, the branched amylopectin
molecule is a more valuable starting material
than the linear amylose. The average
ratio of amylose to amylopectin in potato
starch lies between 1:4 and 1:5.
Late varieties preferred
For starch production, simple late-ripening
potato varieties are preferred. Around 400
varieties of this type exist around the
world. Their starch content of 17 to 20% is
markedly higher than that of food potatoes
(around 10%). On arriving at the starch
factory, the tubers are first washed to
remove any earth still sticking to them.
Next, they are rasped and processed to produce
a slurry, from which the potato starch
is separated and dried in a succession of
steps. The result is a highly pure native
starch with a moisture content of around
20%. A side-product of this process is
potato pulp, which can be returned to the
agricultural production cycle in the form
of protein-rich animal feed.
From glue to fuel
The potato starch is processed further to
produce raw materials for the paper, chemical,
pharmaceutical and textile industries.
The feel, smoothness and shine of the
paper that brings this “Courier“ article to
you could well be attributable to materials
from processed potato starch. Adhesives
derived from potato starch are also valued
in medicine, because they are entirely free of
health concerns: that’s why such adhesives
are found in plasters and dressings. And
many a stamp remains stuck to a holi day
postcard thanks to starch and water.
Potato starches can also be processed
into films, carrier bags, disposable cutlery
and packaging materials. These bio-materials
can replace petroleum oil-based products;
they are capable of being sprayed,
formed or expanded into various shapes
and containers. For example, your last
tee-off at golf may well have been done
from a starch-based tee. Bioplastics would
be especially valuable in restricting the use
of mineral oils and reducing waste if they
were to be used more widely in short-lived
products such as food-packaging, carrier
bags, rubbish sacks and plant pots.
Depending on how they are formulated,
materials based on plant starches are biologically
degradable; composting them
brings the starches back into the production
cycle. At present, the worldwide
capacity for producing bioplastics is less
30 COURIER 1/08