Experiment Station Record, Volume 92, January-June, 1945 Page: 151
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1945] FOODS-HUMAN NUTRITION 151
chlorophenolindophenol method adapted for use with an Evelyn photoelectric colorimeter.
Carefully selected paired samples were analyzed in the raw and the cooked
state. Weights of raw and cooked samples (the latter after cooking and after
standing) were ascertained to permit computation of the values in the cooked
samples to the raw basis. The raw mature potatoes, representing samples of different
varieties and origin, contained from 3.6 to 14.0r mg. ascorbic acid per 100
gram.; Louisiana new potatoes contained from 51 to 61 mg. per 100 gram. Steaming
in the skins was the only method of preparation which resulted in no loss of
ascorbic acid. French-fried potatoes showed a small loss when the temperature of
the fat was kept constant. It is pointed out that ordinarily there is great variation
in temperature during this cooking process and that potatoes so prepared cannot
be considered a reliable source of ascorbic acid. Baked potatoes lost 20 percent
of their ascorbic acid during baking and this loss increased to 59 percent after 43
min. on the steam table. Potatoes pared, cut in halves or sixths, and baked without
added fat or salt lost 20 percent during baking, and this increased to 48 percent
after 38 min. on the steam table. Mashed potatoes and creamed potatoes lost 39
percent of their ascorbic acid during the steaming and 95 percent after preparation
and standing on the steam table.
Effect of refrigeration on ascorbic acid content of canned fruit juices after
opening, F. I. SCOULAR and H. WILLARD (Jour. Amer. Dietet. Assoc., 20 (1944),
No. 4, pp. 223-225).-A total of 57 cans, varying in capacity from 6 to 46 oz. and
representing 19 commercial brands of canned fruit juices, was obtained in local
grocery stores in Denton, Tex., from March to July 1943 and opened for analysis
of the contents in June and July. Ascorbic acid, determined by the dye titration
method, in the nine brands of grapefruit juice, four of orange, two of pineapple,
and four of apple juice averaged, respectively, in the freshly opened juices, 29.9,
34.6, 9.8 and 1.7 mg. per 100 gm. These juices were stored, after opening the cans,
on the top shelf of a refrigerator operated under home-use conditions where the
temperature varied from 7 C. in the early morning to 22' late in the afternoon.
Each juice was stored in three ways, namely, in the can covered with an oiled-silk
refrigerator dish cover, in the open can, and in a glass jar with the lid but no
rubber. The ascorbic acid lost by each of the canned fruit juices during the refrigeration
was found, however, to be similar for the three methods of storing.
After 1 day of refrigeration, the average percentage loss of ascorbic acid from
the freshly opened cans was 3.0 for grapefruit, 3.7 for orange, 1.1 for pineapple,
and 24.1 for apple juice. The grapefruit juice was also sampled after several
days of refrigeration, and lost only 5.6 percent of its ascorbic acid even after 3 days.
Synthesis of vitamin C in stored apples, C. WEST and S. S. ZILVA (Biochem.
Jour., 38 (1944), No. 1, pp. 105-108, illus. 1).-Vitamin C was found to be synthesized
in Bramley Seedling apples during storage at 3; the capacity for such
synthesis diminished with age of fruit.
The ascorbic acid requirements of school-age girls, V. M. ROBERTS, M. H.
BROOKES, L. J. ROBERTS, P. KOCH, and P. SHELBY (Jour. Nutr., 26 (1943), No.
5, pp. 539-547, illus. 1).-In this extension of an earlier investigation (E. S. R.,
88, p. 862), 30 preadolescent girls between the ages of 6 and 12 yr. living in a
suburban home for girls served as subjects. Preliminary determinations of the
food intakes of 6 of the subjects for a week showed daily ascorbic acid intakes
ranging from 31 to 94 mg. and averaging 59 mg. Blood ascorbic acid levels of
these subjects ranged from 0.46 to 0.97 mg. per 100 cc. Readjustments were made
in the diet to lower the ascorbic acid content to about 22 mg. daily, most of this
being contained in the noon meal. The girls were divided into 6 groups and were
given daily supplements of ascorbic acid in amounts increasing by 10 mg. in each
group from 10 mg. to 60 mg. The amount of reduced ascorbic acid in the blood
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U.S. Department of Agriculture. Agricultural Research Administration. Office of Experiment Stations. Experiment Station Record, Volume 92, January-June, 1945, book, 1947; Washington D.C.. (digital.library.unt.edu/ark:/67531/metadc5064/m1/164/: accessed December 18, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.