Food Lipids: Chemistry, Nutrition, and Biotechnology

of any specific triglyceride having a specific structure (i.e., which fatty acid was on
which carbon of the glycerol backbone). In the majority of cases, such knowledge
would have been of academic interest only, since these structured fats were simply
not available in any great proportion in a given fat system. Aside from cocoa butter
and some of the other more exotic tropical fats, most fats used in foods consist of
a random assortment of triglycerides driven by the types and levels of fatty acids in
their composition, so that such knowledge would have no direct bearing on a formulator’s
capabilities.
Although many pioneering studies were conducted on synthesized and purified
structured triglycerides to ascertain their physical chemical properties, especially
those related to their melting characteristics and crystal forms, the quantities synthesized
were not sufficient to be utilized in real food systems.
Recently, a great deal more effort has been expended to study structured triglycerides
in foods, and these researches have led to the market introduction of
synthesized species that have been almost exclusively targeted at the confectionery
market for the replacement of cocoa butter, with the additional benefit of producing
reduced-calorie products. These products take advantage of the effects of positional
isomerism on the glycerin backbone to address the specific physical properties required
in the final food product, and to utilize the differences in caloric contribution
of the various fatty acids used to arrive at a lowered caloric intake. These novel
ingredients, however, are costly to manufacture. Each one requires a series of synthetic
steps along with requisite purification procedures. With a final price to the end
user that remains at several dollars per pound, the ultimate use of novel ingredients
is restricted to specific niche markets in the food industry; a significant move toward
their use in a wide array of food products cannot yet be projected.
It is the foregoing type of research, however, that is needed to drive our understanding
of the functionality of triglyceride structures in food systems. With the
advent of the tools provided by genetic engineering, the opportunity to create new,
structured triglycerides in the seed oil of an agricultural crop at costs much closer
to a commodity seed oil base than to that of a synthesized product is very real. The
goal, then, is to develop knowledge that relates structure to function so that a specific
structure can be utilized for a specific end use. When this has been achieved, it is
also likely that the total amount of fat required in any given food system will be
reduced to levels well below those currently required using the various random
systems as they occur in nature. The end result will very likely take us to the reduction
in total fat intake that is so strongly recommended by health care professionals.
2. Laurate Canola: A Case Study
The first genetically engineered oil approved for food use was developed by Calgene
over a period of approximately 10 years, through the use of techniques discussed
earlier. The product was ultimately brought to market using the common and usual
name, laurate canola. The specific composition of this oil was given earlier (Table
3). Initial functional screening of this new oil was conducted to see if it would serve
as a cocoa butter replacement in coating and confectionery products. Although laurate
canola did not contain the same levels of laurate as the coconut and/or palm kernel
products currently used for these applications, all the C12 and C14 fatty acids occurred
exclusively at the sn-1 and sn-3 positions of the glycerin molecule, and this
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.