The Washington times., 1901-09-08
THE POTATOES food VALUE
What the Agricultural Department
Knows About the Tuber.

Uncle Sam has been prying into the
inner life of the humble potato and
after most thorough and rigid inves-
tigation declares in the Yearbook of
the Department of Agriculture that the
potato is a deserving and extremely
valuable member of the community.
Scientific investigation has shown
that the practice. which has become SO
general, of serving potatoes with meat
and other similar foods which contain
liberal amounts of protein is based
upon correct principles, one food sup
plying the deficiencies Of the other Po-
tatoes and other foods containing car
bo-hyGrates are sometimes objected to
on the ground that they are starchy
foods and do not supply much nitro
genous material 1t should be remem-
bered, however, that the potato does
contain a by no means inconsiderable
amount of protein, and further that
carbohydrates are an essential part of
well regulated diet. The digestion
experiment referred TO shows that po-
tatoes properly cooked furnish such
material in a digestible form. They
many years without harmful results
and therefore the conclusion that un-
g der ordinary circumstances they are
other than a useful and wholesome
food seems unwarranted-
The potato called in different regions
white potato. Irish potato, English po-
tato or round potato, was first intro
duced into Europe between 1880 and
1855 by the Spaniards and afterward
by the English about the time of Raj
eigh's voyages TO Virginia. 1t is COM
monty believed to be a native of Chile.
Wild potato plants closely resembling
those cultivated today are still found
there, though it is a fact worthy of
mention that, as the potato has been
modified by cultivation, it has largely
lost the power of producing seeds. and
the cultivated potato differs from the
wild in seldom producing seed-bearing
fruits.
-, When first visited by Europeans the
aborigres IN Chile and adjacent re-
gions cultivated the potato for its edi-
BILE tubers and had apparently long
done so. It was probably introduced
into the United States, especially Vir-
ginia and North Carolina, toward the
end of the sixteenth century. 1t is not
surprising that the new foodstuf should
have grown rapidly into public favor
when we remember its prolific yield,
superior keeping qualities. ease of
propagation, and agreeable favor.
The potato tuber is in reality modi-
fed stem, being shortened and thicken-
ed to serve as 4 storehouse for reserve
material for the propagation of new
plants. The outer skin, which is dry
in appearance and usually grey or
brown in color. corresponds to the bark
of the rest Of the plant. The portion
Underneath the skin when exposed 10
the sunlight turns green and gives the
plant an unpleasant favor. The outer
and inner skin are usually removed
when the potato Is peeled. The flesh
makes up the bulk of the potato.
The valuable qualities of the potato
were speedily recognized and there are
early recoris Of attempts to determine
its food value by means of chemical
analyses. In 1855 Pearson reported |
experiments and observations on the |
constituent parts of the potato root"
Einhof In 1905 published analyses of the |
potato, as did also Vauquelin in 1877. |
In America, analyses of the potato |
were reported some fifty years ago by |
Emmons. These investigations were |
useful at the tir1e although they were |
not made by the method usually fol- |
lowed today. This was necessarily the |
case, as the subject of the chemistry |
of nutrition is of comparatively recent !
growth.
In later years many studies of the |
composition and food value Of the po- |
tato have been made in this and other |
Countries. AS shown by recent analy- |
ses, the skin Of the potato constitutes |
on an average % per cent of the whole |
end the cortical layer S.5 per cent.
1t is difficult to peel potatoes SO that |
the skin only is removed Whether |
both skin and cortical layer or only the |
former should be called refuse in our |
current sense of the word is perhaps a |
question. As potatoes are commonly |
eaten, good deal of the flesh, or edible |
portion, is rejected with the skins. |
When they are baked with the skins |
on, the amount of edible portion thus |
thrown away may be small When |
they are pared for boiling, the amount |
wasted may be much larger. When |
they are rough from defects in growth. |
or from shrinking or shriveling after /
keeping over winter. the amount of |
flesh cut off in the peellng is larger
still. just how much this loss OF the |
edible portion Of potatoes will average |
in the ordinary household no one can
say exactly. 1t may be estimated at |
20 per cent Of the whole and the edible |
portion left as so per cent
The edible portion of the potato is
made up OF 7S.3 per cent water, % per |
cent protein (totaI nitrogenous matter), |
OIL per cent fat, 1874 per cent carbo- |
hydrates principally starch), and l per
cent ash or mineral matter OF the
-hydrates, 0.+ per cent is made up
of crude ibre, and materials. which in |
some of their notifications constitute
the cell walls Of plants and gives them |
rigid structure. These figures. like
others for composition of food materials
represent general averages, from
which there are wide variations In in
diyidual specimens. Though the skin.
cortical layer and flesh differ somewhat
in composition. they all resemble more
or less closely that of the whole tuber.
When potatoes are stored they un-
dergo a shrinkage. According to tests
made at the Michigan Agricultural Ex-
pertinent Station, this amounted to lie
per cent when they were kept in stor-