the weight of the original material corresponding to five grams of the
dry substance. The original composition of the sample is therefore
expressed by the following numbers:
Per cent.
Sucrose 11.1
Reducing sugars 0.7
Water 76.5
Fiber (insoluble matter) 11.7
=214. Examination of the Bagasse.=—The method just described for the
examination of canes may be also applied to the analysis of bagasses,
with the changes made necessary by the increased percentage of fiber
therein. On account of the large surface exposed by the bagasse, the
sampling, shredding and weighing should be accomplished as speedily as
possible to avoid loss of moisture.
The optical examination of bagasses is rendered difficult by reason of
the uneven pressure to which the canes are subjected. With fairly good
milling in technical work the bagasses will have at least thirty per
cent of fiber. The method for the polariscopic examination is therefore
based upon that assumption, but the volume of the solution must be
changed for varying percentages of fiber in the bagasse. On account of
the smaller percentage of sugar, it is convenient to take double or
three times the normal weight of the bagasse for examination. Since
large sugar flasks are not commonly to be had the diffusion of the
bagasse may be conducted in a quarter liter flask. In a quarter liter
flask place 52.096 grams of the finely shredded bagasse, very nearly
fill the flask with water and extract the sugar as described for canes
in the foregoing paragraphs. In the weight of bagasse used there will
be, in round numbers, fifteen grams of fiber. When the volume of water
is completed to the mark the actual content of liquid in the flask will
therefore be only 235 cubic centimeters. Fifty cubic centimeters of the
filtrate are placed in a sugar flask marked at fifty and fifty-five
cubic centimeters, the proper quantity of lead subacetate solution
added, the volume completed to the upper mark, the contents of the
flask well shaken, filtered and polarized in a 200 millimeter tube. Let
the reading obtained be four degrees and increase this by one-tenth for
the increased volume of solution above fifty cubic centimeters. The
true reading is therefore four degrees and four-tenths. This reading,
however, must be corrected, because the original volume instead of
being 200 cubic centimeters, is 235 cubic centimeters. The actual
percentage of sugar in the sample examined is obtained by the following
proportion: