Food Lipids: Chemistry, Nutrition, and Biotechnology

although techniques using pulsed NMR spectrometry allow for similar determinations
of the solid/liquid ratio in a given fat as a function of temperature. Usually, the solids
fat index (SFI) is determined for food fats at a select number of temperatures. The
plots of solids versus temperature have been related over the years to the actual
performance of given fat systems in specific food formulas. The portion of the curve
below 25�C (77�F) relates to the ‘‘hardness’’ of the fat, specifically the resistance to
deformation it provides to the base food, while the solids present between the temperatures
of 25�C and 30�C (86�F) represent the amount of solids typically found at
ambient temperatures and are a measure of the degree of heat resistance provided to
the food product by the fat system. Solids that occur above 37�C (or about body
temperature, 98.6�F) are perceived as ‘‘waxiness’’ in the mouth, although low levels
of solids are acceptable. A rapid rate of solids decrease between ambient temperatures
and body temperature provides a desirable cooling sensation in the mouth and is
deemed a positive for confectionery fat systems. A major use of these fats is in
confectionery coatings, where the lauric fats provide an effect similar to that of cocoa
butter in chocolate, at a much reduced cost.
The major fat used in the manufacture of chocolate is cocoa butter. It is also
one of the most expensive ingredients used in the formula, and because so much of
it must be used to achieve the desired functional effects, it contributes the highest
cost of goods for the total formulation. Aside from a significant contribution to the
final flavor of the chocolate, cocoa butter has some physical properties that make it
unique among the triglycerides found in nature. First of all, it is composed of a very
few sets of highly structured triglycerides (see Table 4).
These triglycerides are essentially composed of only three fatty acids: palmitic
(C16:0, P), stearic (C18:0, S), and oleic (C18:1, O). Practically all the oleic acid
Table 4 Triglyceride Composition
of Cocoa Butter (%)
Triglycerides Percent
POSt 36.3–41.2
StOSt 23.7–28.8
POP 13.8–18.4
StOO 2.7–6.0
StLiP 2.4–6.0
PLiS 2.4–4.3
POO 1.9–5.5
StOA 1.6–2.9
PLiP 1.5–2.5
StLiSt 1.2–2.1
OOA 0.8–1.8
PPSt 8.0
PStSt 0.2–1.5
POLi 0.2–1.1
OOO 0.2–0.9
A, arachidate; Li, linoleate; O, oleate; P,
palmitate; St, stearate.
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.