Experiment Station Record, Volume 57, July-December, 1927 Page: 13
xvii, 1002 p. ; ill. ; 24 cm.View a full description of this book.
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1927] AGRICULTURAL AND BIOLOGICAL CHEMISTRY 13
With the hard filters recommended in the first filtration, very clear solutions,
giving lower results than those from large-pored filters, were obtained. The
mutarotation of lactose was found to be eliminated by 3 minutes', but not by
1 minute's boiling. The prescribed heating was found without effect on sucrose
readings. The results are to be calculated from the expressions
S (percentage of sucrose) (D-4)7(05) C = 10 - [(1 + 0.82P) X
0.26034]; F==percentage of fat; P=percentage of protein; D=direct reading;
and I==invert reading.
Control testing of wood and pulp, E. P. CAMERON (Canad. Chem. and
Metall., 10 (1926), No. 11, pp. 255-257).-The methods for testing wood and
pulp, consisting of the determinations of crude cellulose, resistant cellulose,
lignin, and resins, are outlined, and their importance in the pulp and paper
industries is discussed. These methods are regarded as highly empirical and
of little definite chemical significance, but they have a definite meaning in
terms of the paper making possibilities of the wood and pulp examined, and
as such are extremely valuable to both the paper maker and the pulp producer.
Studies of commercial sauerkraut with special reference to changes in
the bacterial flora during fermentation at low temperatures, L. A. PRIEM,
W. H. PETERSON, and E. B. FRED (Jour. Agr. Research [U. S.], 34 (1927), No. 1,
pp. 79-95, figs. 4).-The literature is reviewed briefly, certain inconsistencies in
the published statements concerning the bacteria of sauerkraut fermentation
being pointed out. The successive changes in oxygen tension, in pH, in concentration
of fermentable carbohydrates, etc., whereby quite different bacterial
flora may at different stages of the fermentation become prominent and
persist for a time, are noted.
The samples examined were mostly taken from four vats, each of about 40
tons capacity, through spigots placed at the sides and near the bottoms of
the vats to avoid disturbing the sauerkraut in drawing the juice. Samples
were at first taken frequently, later about once a month. Some samples,
obtained from another factory, had been in the vats from 41 days to 1 year.
Temperatures were followed in the vats and in the juice samples as drawn.
They were low, never rising above 10.5 C., which condition resulted in a
relatively slow bacterial development and fermentation. The study covered
a period of 5 months. Acidity as lactic acid increased slowly, amounting to 1
per cent after 3 months and 1.3 per cent after 5 months. Bacteria increased
rapidly from the second to the twentieth day, after which a large drop was
noted. Three hundred and seventy pure cultures were picked from platings,
most of these organisms fermenting arabinose, xylose, and fructose, though
they caused but little change in litmus milk. Nearly all of these forms were
catalase-negative.
Representative cultures, mostly rods with a few cocci, were studied further
for fermentation characteristics. Most of these were Gram-positive, about
two-thirds formed gas from glucose, and about the same number formed mannitol
from fructose, several new mannitol-forming strains being found. Quantitative
determinations of the fermentation products of 6 mannitol-forming
cultures were made, lactic acid being the principal product, with a variation
from 36 per cent produced from glucose to 79 per cent produced from arabinose.
These large percentages of lactic acid could not have arisen from a direct
pentose cleavage, but must have involved some synthesis from two or more
molecules. The d and I lactic acids were usually formed in, approximately
equal quantities, but one culture yielded an excess of the levorotatory form.
Acetic acid, ethyl alcohol, carbon dioxide, and mannitol were also formed in
quantities varying with the sugar and with the culture used.
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General Index to Experiment Station Record, Volumes 51 to 60, 1924-1929 (Book)
A topical, alphabetically arranged index to volumes 51-60 including experiment station records, publications reviewed, and foreign publications. In has a list of all editorial notes from the referenced volumes.
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United States. Office of Experiment Stations. Experiment Station Record, Volume 57, July-December, 1927, book, 1928; Washington D.C.. (https://digital.library.unt.edu/ark:/67531/metadc5099/m1/30/: accessed April 24, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.