Food Lipids: Chemistry, Nutrition, and Biotechnology

systems. Key to assessing the opportunity is understanding the needs of the margarine
and spreads industries.
Margarines and spreads are prepared by blending fats and oils with other ingredients,
including water, milk, edible proteins, salt, flavorings, coloring. Spreads
are differentiated from margarines by their lower fat content. By FDA regulation, a
product must contain at least 80% fat to be labeled margarine; products with lower
fat levels must be labeled as spreads. As consumers have become more concerned
about overall fat consumption, spreads have become increasingly popular. The key
to the formulation of both margarines and spreads is to provide a solid, spreadable
fat with appropriate melting characteristics. This is achieved by using partially hydrogenated
vegetable oils, which have had a portion of their unsaturated fatty acids
converted to both saturated fatty acids and less saturated, trans fatty acids. Saturated
and trans fatty acids have higher melting points than unsaturates and provide the
requisite functional properties for the finished product. The specific oils used and the
degree to which they are hydrogenated vary as a function of specific marketing
objectives for the particular product.
In Europe, some margarines contain an oil portion consisting of a liquid vegetable
oil blended with one that has been fully hydrogenated—a formulation ploy
seen increasingly in the United States. Unlike partially hydrogenated oils, fully hydrogenated
oils do not contain any trans fatty acids. This allows for the manufacture
of margarines that are trans-free but also contain higher levels of saturates than those
containing partially hydrogenated oils. European manufacturers also use more tropical
oils in the manufacture of margarines and spreads than firms in the United States,
since European consumers are not as concerned as U.S. consumers about tropical
fats.
As of this writing, several companies are actively pursuing the development of
seed oils that contain levels of saturated fatty acids high enough to permit the elimination
of needs for hydrogenation, with the concomitant production of trans fatty
acids. As an integral part of this higher production of functional, saturated fatty acids,
it is also necessary to have the desired fatty acids in a low polyunsaturated fatty acid
background, to assure the ultimate stability of the finished formulation. To compete
in the large markets involved under these two sets of conditions of composition, one
must also strive for a resulting plant with agronomic vigor and oil yields comparable
to those of existing sources of commodity oils.
B. The Discovery of Novel Utility
1. Conventional Wisdom Versus Structured Triglycerides
Most of the body of knowledge that has been built up over the years on the functionality
of lipids in food systems has been based on experiments designed around
variations of naturally occurring fats and oils. The functional performance of these
fats, from whatever source, was related back to specific analytical characteristics that
still enjoy wide use in the industry: solid fat index, iodine value, and fatty acid
composition. In addition to these characterizing values, a number of analytical tests
were routinely performed on the fats that were indicators of their quality, or their
ability to withstand the stresses of temperature and shelf-life requirements. These
included free fatty acid content, peroxide value, color, and odor. None of these tests,
however, related the functional performance of the fat to the presence (or absence)
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.