Food Chemistry

14 Edible Fats

and Oils

14.1 Foreword

Most fats and oils consist of triacylglycerides (re-
cently also denoted as triacylglycerols; cf. 3.3.1)
which differ in their fatty acid compositions to
a certain extent. Other constituents which make
up less than 3% of fats and oils are the unsaponifi-
able fraction (cf. 3.8) and a number of acyl lipids;
e. g., traces of free fatty acids, mono- and diacyl-
glycerols.
The term “fat” generally designates a solid at
room temperature and “oil” a liquid. The des-
ignations are rather imprecise, since the degree
of firmness is dependent on climate and, more-
over, many fats are neither solid nor liquid, but
are semi-solid. Nevertheless, in this chapter, un-
less specifically emphasized, these terms based
on consistency will be retained.

14.2 Data on Production

and Consumption

Data on the production of oilseeds and other crops
are summarized in Table 14.0. The world produc-
tion of vegetable fats has multiplied since the time
before the Second World War (Table 14.1). There
has been a significant rise in production since
1964 of soybean, palm and sunflower oils, as well
as rapeseed oil. Soybean oil, butter and edible
beef fat and lard are most commonly produced
in FR Germany (Table 14.1). The per capita con-
sumption of plant oils in Germany has increased
in the past years (Table 14.2).

*Butter is dealt with in Chapter 10.2.3.

14.3 Origin of Individual Fats

and Oils

14.3.1 Animal Fats

14.3.1.1 Land Animal Fats

The depot fats and organ fats of domestic animals,

such as cattle and hogs, and milk fat, which was

covered in Chapter 10, are important animal raw

materials for fat production. The role of sheep

fat, however, is not significant. The major fatty

acids of these three sources are oleic, stearic and

palmitic (Table 14.3).

It should be noted that the fatty acid composition

of individual fat samples may vary greatly. The

fat composition of land animals is affected by the

kind and breed of animal and by the feed. The

composition of plant fats depends on the culti-

var and growth environment, i. e. climate and geo-

graphical location of the oilseed or fruit plant (cf.

Fig. 3.3.1.5). Therefore only average values are

given in the following tables dealing with fatty

acid composition.

In contrast to oil from plant tissue, the recovery

of animal fat is not restricted by rigid cell walls

or sclerenchyma supporting tissue. Only heating

is needed to release fat from adipose tissue (dry

or wet rendering with hot water or steam). The

fat expands when heated, tearing the adipose tis-

sue cell membrane and flowing freely. Further fat

separation is simple and does not pose a technical

problem (Fig. 14.1).

Fig. 14.1.Steps involved in wet rendering

H.-D. Belitz · W. Grosch · P. Schieberle,Food Chemistry 640
© Springer 2009