Читать книгу Foods and Their Adulteration - Harvey Washington Wiley - Страница 123

—Mention has already been made of the fact that by melting a fat and cooling it slowly towards its solidifying point, certain constituents of the fat which have a higher melting point separate first, leaving those constituents with a lower melting point still in a liquid condition. Those portions of an oil or fat which separate first under such conditions, are the constituents of the product which is known as stearin, while the part that remains liquid is the constituent known as olein. Lard stearin is made principally for the manufacture of mixtures and is a by-product of the highest grade of lard oil. Lard stearin is made as follows: The lard is melted and kept in a crystallizing room at from 50 to 60 degrees F., until it is filled with the crystals of the separated stearin. The product is then wrapped in the form of cakes with cloth. Each package contains from 10 to 20 pounds. The cakes are then placed in a large press with suitable arrangements to facilitate the escape of the oil and maintain the low temperature. The pressure is applied very gradually at first, and as the process advances, with increasing power. The high grade oil obtained in this way is known as prime or extra lard oil and is used for illuminating and lubricating purposes. The resulting solid product, which is principally stearin, is used as one of the adulterants of lard, that is, in making a mixture which is sometimes called lard, composed of lard stearin and cottonseed oil.

Fig. 10.