954 FOODS AND FOOD ADULTERANTS. 
extracted with water; the extract is evaporated to a sirupy consistency, treated 
with alcohol, decolorized by means of lead acetate, the excess of which is removed 
with H,SO,. The sugar thus prepared is inverted and the invert sugar determined 
with Fehling’s solution. 
Hassall.'—The sugar is dissolved out of the sample with cold water, inverted by 
boiling with dilute H,SO,, and then estimated with copper solution. 
Mansfeld.2—The residue from the fat determination is extracted for three hours 
with 100 cc of 80 per cent alcohol, and the extract made up to 150 ce. Fifty ce are 
evaporated to dryness. After weighing, the residue is dissolved in water, made up 
N 
to 100 cc, heated one-half hour on the water bath with 10 ec 5HCl, neutralized 
with NaOH, and diluted to 250 cc. The invert sugar is then gravimetrically deter-. 
mined with Fehling’s solution. 
Determination of sugar by direct weighing.—Hassall.'—Dissolve a weighed quan- 
tity of cocoa containing sugar in cold water and collect the residue on a filter. This 
residue is dried on the water bath and weighed. 
100— per cent of insoluble matter—per cent of soluble matter. 
Per cent of soluble matter — (per cent of moisture + the approximate 
per cent of soluble matter in cocoa) = per cent of sugar. 
Herbst.?—The residue from the fat determination is extracted with boiling 50 per 
cent alcohol as long as the extract is colored. This extract is evaporated to dryness 
and treated with cold water, which dissolves the sugar. This solution is evaporated 
to dryness, the residue dried in hydrogen and weighed. 
Determination of commercial glucose in chocolates.—In regard to the determination of 
the sugars used for sweetening chocolates, M. Schreeder* writes as follows: 
“The detection and estimation of less than 5 per cent of commercial glucose in 
presence of cane sugar by means of copper solution is uncertain, because commercial 
cane sugar often contains an equivalent amount of reducing sugars. The optical 
determination by Clerget’s method is more satisfactory, since only a small percent- 
age of commercial glucose is necessary to appreciably lessen the degree to which the 
inverted solution rotates to the left. The evidence obtained by Clerget’s method 
can be strengthened by determining the dextrin which would be present in the 
residue after fermentation, if commercial glucose were present in the original 
material.” 
Determination of starch.—Asborth® has published a method, according to which he 
adds Ba(OH), to the boiled starch, with which it forms a compound which is insol- 
uble in dilute alcohol. Dr. Mansfeld’s modification of this method is given below. 
Ass. Swiss Anal. Chem.*—The sample, free from fat and sugar, is boiled with water 
for four hours and the resulting starch solution is inverted with sulphuric acid; the 
excess of acid is removed by basic acetate of lead; the filtrate is freed from lead with 
H.S and the reducing sugars determined by means of Fehling’s solution. The 
starch may also be determined by treating the powder in a Reischauer’s pressure- 
flask, inverting, etc. 
Bensemann.’—Two grams of the substance, after extraction and washing with cold 
water, and while still moist, are mixed with 200 ce of water and 20 ce HCI, sp. gr.1.12. 
The mixture is heated for at least three hours on the water bath, cooled, and filtered. 
After making the filtrate alkaline with NaOH, a freshly prepared soiution of 4 grams 
of copper tartrate, 2 grams of tartaric acid, 30 ce of soda lye, sp. gr. 1.13, and 100 
1 Op. cit., note 2, p. 940 of this work. 
? Op. cit., note 1, p. 950 of this work. 
3 Op. cit., note 4, p. 950 of this work. 
‘Zeitsch. f. angew. Chem., 1892, 173. 
5Rep. anal. Chem., 8, 20. 
6 Op. cit., note 3, p. 949 of this work. 
7 Op. cit., note 4, p. 949 of this work. 
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