Foods and Their Adulteration: Origin, Manufacture, and Composition of Food Products; Description of Common Adulterations, Food Standards, and National Food Laws and RegulationsWiley, Harvey Washington
Science
Foods and Their Adulteration: Origin, Manufacture, and Composition of Food Products; Description of Common Adulterations, Food Standards, and National Food Laws and Regulations
Wiley, Harvey Washington
Food; Food adulteration and inspection
Creatin figures are very interesting and of much value in determining
the source and value of an extract. Creatin is the principal amido-body
found in meat, consequently we expect to find it or creatinin, its
hydrated form, in still larger quantities in meat extracts. In several
cases which came under our notice where the extract acted suspiciously,
the creatin values were nil, and in such cases grave doubts exist as to
the source of the extract. Our best extracts give high creatin as well
as high meat base figures.
The xanthin bases and ammonia nitrogen figures present a variety of
problems. While the xanthin bases are desirable constituents, ammonia
in any amount is not. It is questionable whether the ammonia figures
obtained by the magnesium oxid method do not give too high results (W.
D. Bigelow).
=Gelatine.=--Gelatine is a substance obtained from the nitrogenous
portions of bones, hide, horns, hoofs, connective tissue, tendons
and other nitrogenous matter of the animal. One of the principal
constituents of these bodies is a substance known as collagen. When
this is heated either under pressure or without pressure it is changed
to gelatine. Glue is unrefined gelatine or impure gelatine to which
usually some substance has been added to increase its holding power.
A type of gelatine known as isinglass is made from the bladders of
sturgeons.
The general process of manufacturing gelatine is as follows (Whipple,
Technology Quarterly, Vol. XV, No. 2, June, 1902):
“The hide scraps are first macerated and subjected to the action of
a solution of lime or caustic soda in pits for two or three weeks.
This dissolves most of the blood and saponifies the fats. The excess
of lime or soda is then largely removed by washing and the solution
steamed to dissolve the gelatine, but an excess of heat is avoided.
Sulfurous acid is used to bleach the gelatine. When of sufficient
strength, the gelatine is allowed to harden in molds or on slabs, and
is ultimately dried in sheets on wire nets. Bone gelatine is made in a
somewhat similar manner. The bones are crushed, boiled, treated with
hydrochloric acid, and the gelatine is dissolved as before, washed,
bleached and dried in sheets. The process requires a number of weeks.”
Gelatine is also made from bones, fresh as well as old, and from the
residues of bones used in the manufacture of buttons. The thin slices
of the bones are treated with acid until all the phosphate of lime is
extracted. They are then treated with lime and the gelatinous residue
is then dissolved in warm water and purified for use.
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