Fjölrit RALA - 22.03.1979, Síða 73

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3. Carbohydrates:
As mentioned earlier, Friðriksson measured the starch
content of potatoes on a special balance. The average con-
tent turned out to be 13.4%. The Mandel Vitblommig variety
contained the most — 21.2% -- and Konsuragis the least --
9.9%.
The techniques used in the studies carried out by Vest-
dal and Ölafsson on the starch content of potatoes are not
known but they were most likely chemical methods.
The average starch content resulting from ölafsson's
study was 13.4% which is the same as Friðriksson obtained.
The range was 11.6-17.0%.
A comparison of a few results of starch measurements
done by these men is shown in table 4.
A Comparison of Starch Measurements Done by
Friðriksson, ölafsson and Vestdal (%)
Study/Variety Acker- segen Alpha Deo- dara Erd- g°id Gull- augen July Kerr's pink King Edward
Friðriksson 10.7 11.3 14.0 12.5 15.8 12.7 14.0 15.1
Ölafsson 12.5 11.6 17.0 12.8
Vestdal 15.1 12.8 13.0 11.9 16.0 11.7 13.4 12.3
As can be seen from the table, there is considerable
variation in starch content of the same variety. This
variation is most likely due to environmental factors.
The carbohydrate content of potatoes depends on the
variety and on many environmental factors as is true of
most of the nutrients found in potatoes.
Rönsen (1969) believes that carbohydrates may be
regarded as a group of compounds which are in dynamic
equilibrium:
sucrose x glucose + fructose
U 11
starch ^ ■. glucose
The reactions are catalyzed by enzymes and their
effects depend on other compounds and also on tempera-
ture. A rise in temperature causes the starch to break
down to a further extent (Rönsen, 1969).