ABSTRACT
The lipidic material is constituted mainly of triacylgly-
cerols that are the major components, and numerous
minor compounds of different chemical nature. These
minor components can be divided into glyceridic and
nonglyceridic compounds. The minor glyceridic com-
pounds are di-and mono-acylglycerols, oxidized
triacylglycerols, triacylglycerol polymers, phospholi-
pids, and glycolipids. The nonglyceridic minor com-
ponents are compounds of very different polarity, such
as hydrocarbons, tocols, prenols, aliphatic alcohols,
steroidal alcohols, steroidal aldehydes, steroidal acids,
fatty acids, volatile compounds, pigments, and phe-
nols. Furthermore, esters of fatty acids with short-and
long-chain and steroidal alcohols are present in some
food matrices. For determining the nonglyceridic minor com-
pounds, usually the glyceridic material is eliminated
by saponification. Saponification consists in transform-
ing the glyceridic compounds and fatty esters in soaps,
glycerin, and other alcohols, by heating with a solution
of alkali in ethanol. The subsequent addition of water,
extraction of the aqueous solution with organic sol-
vents, followed by evaporation of the organic solvent
yields a residue called the unsaponifiable matter, which
is constituted of numerous nonvolatile compounds
belonging to several chemical families. Each of these
families can include various classes of compounds;
e.g., hydrocarbons are constituted of alkanes, alkenes,
and terpenic and polycyclic aromatic hydrocarbons.
