Читать книгу Foods and Their Adulteration - Harvey Washington Wiley - Страница 135

—It is possible to mix together the different materials used in making adulterated lard in such a manner as to produce a compound which in some respects resembles the natural product. This compound, however, necessarily differs from the natural product in its physical and microscopic properties and in its reaction with various chemicals which give distinct color with the different fats and oils used as adulterants. The mean properties of thirteen samples of mixed or compound lards are shown in the following table:

Specific Gravity. 35° C.	Melting Point. ° C.	Refractive Index. 25° C.	Rise of Temperature with Sulfuric Acid. ° C.	Water. Percent.	Iodin. Percent.
.9060	40.6	1.4634	46.5	.098	63.58

These lards, in addition to the above properties, show distinct color reaction with sulfuric and nitric acid and with the reagents which are distinctive of cottonseed oil. They are mostly mixtures of lard and tallow stearin with cotton oil or cotton oil stearin.

In addition to the adulterations already mentioned as mixing with cottonseed oil may be added the use of coconut oil. It is not probable that in the United States any adulteration of lard with coconut oil has been made for commercial purposes. Such an adulteration, however, is practiced in some foreign countries. Coconut oil contains considerable quantities of volatile acid, and, therefore, when used as an adulterant of lard, would increase the normal quantity of volatile acid materially. One sample examined by Allen, of England, was found to contain a quantity of coconut oil, amounting to 33 percent.