Interesterified Fat: A Questionable Replacement
for Trans Fat
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What is interesterified fat? Just as food
manufacturers have started to remove them from
their products, restaurants have been
eliminating them from their menus, and
government entities have begun to ban them,
transfats have
been replaced by a new kind of fat with a
lengthy and unpronounceable name—INTERESTERIFIED
FATS. While these fats may be interesting, the
root word from which their name is derives is
not INTEREST, but
ESTER . Esters are organic compounds formed
from an organic acid and an alcohol.
Interesterification
Interesterification is one of three main fat
modification techniques. The other two
techniques are fractionation and hydrogenation,
which is the process used to produce transfats.
Interesterification is the process of
rearranging the fatty acids in triglyceride
molecules.
Triglycerides form the basic structure
of most fats and oils. They are composed of
glycerol and three chains of fatty acids.
Interesterified fats (IFs) are used in
shortening for baked goods, fat for frying, in
butter substitutes, such as soft margarine. The
interesterification process maintains solid fat
content at ambient temperatures while lowering
the melting point of the fat.
Interestified Fat in Food
While consumers are being regularly informed by
the food manufactures and restaurants that
transfats are being removed from their menus,
very little is being said about the fats that
are replacing transfats. The class of
interesterified fats provides one of the least
expensive options for fats used in baking and
frying. There are two types of interestification--one
that uses chemical
catalysts —usually metals or salts, and
another that uses enzymic catalysts. Use of
chemical catalysts is less expensive than use of
enzymic catalysts, but the chemical catalysts
require manufacturing steps to purify and
deodorize the finished product.
Why should the consumer care about how fats are
made? Interestingly, it appears that changing or
re-arranging the molecules of fats or a
combination of fats during the
interesterification process may affect how the
fats are metabolized in the human body. A recent
joint study conducted in Malaysia and at
Brandeis University indicated that not only
did IFs depress beneficial HDL cholesterol, it
appeared to raise blood glucose levels and
decrease insulin production. Elevation of blood
glucose and suppression of insulin production
are precursors to diabetes. In addition, further
elevation of blood glucose and reduction in
insulin levels could be dangerous to those who
are already have diabetes. Further studies are
needed, but this study has raised real concerns
about the use of IFs to replace transfats,
especially if they are used widely and without
the knowledge of consumers.
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