Fjölrit RALA - 22.03.1979, Side 77

-71-
(J. Augustin et al., 1975). Such a relationship exists un-
doubtedly for other varieties as well.
Cooking always destroys a large part of the vitamin C
amount. A study done in Finland on 1200 food rations.showed
that 34% of the vitamin C in uncooked food is destroyed on
cooking (P. Reine, 1977). This reduction varies greatly de-
pending on the food product or from 17 to 96%.
Sigurjónsson's results show that the vitamin C content
of peeled potatoes decreases by 20% during boiling. Experi-
ments done by A.A.M.B. Domah et al. showed that increasing
the salt concentration (NaCl) in the water which the pota-
toes are boiled in, causes a still further reduction.
Browning of boiled potatoes may cause up to 70% of the
vitamin C to be destroyed (0. Pelletier et al., 1977).
9. Minerals:
No research on the mineral content of potatoes is known
to have been carried out in Iceland.
10. Contaminants:
Research carried out at the A.R.I. on the nitrate and
nitrite content of vegetables has shown that a consideráble
amount of nitrate may be found in potatoes.
It is likely that there is a definite relationship be-
tween nitrogen fertilization and nitrate in potatoes. Other
environmental factors, such as type of soil and climate, prob-
ably also play an important role, as well as the variety of
potato in question. It is also possible that the size of the
potato affect the nitrate content.
IV. Research Projects to be Desired
The growth and consumption of potatoes in Iceland is con-
siderable. It may therefore be said that the time has come for
extensive research on the nutritional value of those varieties
grown here. If such research is carried out it is necessary
to take into consideration the many factors affecting the
different nutrients.