OH): The process of saponification may be viewed as the gradual progressive transformation of tristearin, or some analogously constituted substance, into distearin, monostearin and glycerin, or as the similar transformation of a substance analogous to distearin or to monostearin into glycerin.
It is noticeable that with few exceptions the fatty and oily matters occurring in nature are substances analogous to tristearin, i.e.
Amongst these glycerides may be mentioned the following: Tristearin - C 3 H 5 (O C1 8 H350)3.
Some other glycerides isolated from natural sources are analogous in composition to tristearin, but with this difference, that the three radicals which replace hydrogen in glycerin are not all identical; thus kephalin, myelin and lecithin are glycerides in which two hydrogens are replaced by fatty acid radicals, and the third by a complex phosphoric acid derivative.
A fat consisting of the glyceride of one fatty acid only, such as stearin or tristearin, C3H5(O C1811350)3, the glycerin ester of stearic acid, C17H35 C02H.
The natural oils and fats are mixtures of at least two or three different triglycerides, the most important of which are tristearin, tripalmitin, C3H5(0'C16H310)3 and triolein, C 3 H 5 (0C1811330)3.
This is not only due to the fact that they are mixtures of several glycerides, but also that even pure glycerides, such as tristearin, exhibit two melting-points, a so-called "double melting-point," the triglycerides melting at a certain temperature, then solidifying at a higher temperature to melt again on further heating.