Árbók Háskóla Íslands - 02.01.1955, Page 67

SUMMARY.
Relatively few data have as yet been published on vitamin
content of foods produced in Iceland. In the past few years, how-
ever, — initiated by the Nutrition Council — fairly extensive
estimations have been made of ascorbic acid in Icelandic food-
stuffs and biologic materials. The results of these investigations
are presented in this publication. Part I deals with fresh food-
stuffs, Part II with cooked and preserved foods, and finally, in
Part III, some observations relative to vitamin C nutrition are
presented and discussed.
Method. The ascorbic acid determinations were made by a
photoelectric colorimeter using 2:6 dichlorophenol-indophenol
as indicator (34; 35). By this method interference from non-
specific reducing substances is more easily controlled than by
the titration method. Only in few cases (notably extracts from
certain berries) did such interference cause any remarkable
difficulties.
PART I
Vitamin C content of fresh foods.
Potatoes. Six among the most common varieties of potatoes
grown in Iceland were examined repeatedly after storage for
different length of time, and several other varieties were exa-
mined less frequently. The results are shown in tables 1 and 2
and in figs. 1—4. The loss amounted to roughly 50% at the end
of two months storage after harvesting, but after storage for
5—6 months more, the further loss was in the range of 30—35%
only. Thus, in late spring about one third of the original vitamin
content was still retained.
9