Milling & Baking News - October 19, 2004 - 29

When two are better than three
Claiming unique dietary benefits and already highly popular in Japan, a diglyceride
(D.A.G.) oil has been introduced in the United States by Archer Daniels Midland Co.,
Decatur, Ill., under the Enova brand. It is made by lipase-catalyzed esterification of
glycerol with fatty acids from soy and canola. After refining, the oil contains about
55% 1,3 diglyceride, 25% 1,2 diglyceride and 20% triglyceride plus monoglyceride.
Based on the way fats are absorbed in the gut, researchers claim D.A.G. oil is
converted into energy instead of being deposited in adipose tissue. In the body,
ingested fat (a triglyceride) is hydrolyzed by pancreatic lipase (specific for the
No. 1 and No. 3 positions of glycerides) to form two molecules of fatty acid
and one of 2-monoglyceride. These are absorbed into the gut wall where
a lipid synthetase reforms them into triglycerides and passes them on.
The fat molecules are transported as chylomicrons (tiny fat droplets)
in the lymph system to adipose (fatty) tissue, where they are deposited.
If the body uses up its stores of energy-producing materials such as carbohydrates, the fat is withdrawn from the adipose tissue, transferred to the
liver and then "burned" to provide energy.
The key to this process is that lipid synthetase requires 2-monoglyceride as the building block
for reforming triglycerides. In its absence, free fatty acids are delivered to blood serum, then transported directly to the liver where they are "burned." In the case of D.A.G. oil, 1,3 diglyceride is
hydrolyzed completely by pancreatic lipase. MBN

cis form of fatty acids, increase L.D.L. What
is not clear yet is whether various forms and
chain lengths of trans acids differ in their effects. For now, they are all grouped together
in the new labeling regulations requiring
the declaration of more than 0.5 grams per
serving. While the cis form of monounsaturated acids (oleic acid) is highly beneficial,
the trans form (elaidic acid) is now considered a bad actor. To further complicate
things, C18:2 (cis 9, trans 11), which forms
during hydrogenation of linolenic acid, has
shown anti-carcinogenic properties.

Modified vegetable oils
Oilseed cultivars with a fatty acid composition differing from that of the parent plant
are now available. These are produced by
two different methods: 1 - artificial mutation such as treating seeds with radiation or
chemical mutagens, followed by selection
of improved plant (or animal) stock by the
agriculturalist; or 2 - bioengineering, a
more precise method, which introduces a
specific gene into the seed DNA to produce
the desired end-product change(s).
Olive oil is the prototypical monounsaturated oil containing about 80% oleic acid.
Canola (low-erucic acid rapeseed, or LEAR)
oil contains about 60% oleic acid. It was developed by artificial mutation of rapeseed,
which is natively high in erucic acid. The
oleic acid content of other major vegetable
oils produced in the United States (soybean,
sunflower, corn and cottonseed) is much
30 / Milling & Baking News, October 19, 2004

lower, ranging from 18% to 25%.
Artificial mutation and selection were
used to make TriSun80, a sunflower variety
with 80% oleic acid in the oil. Bioengineering
has produced a soybean whose oil contains
75% oleic acid. In both instances, the increase
in monounsaturated fatty acid comes at the
expense of polyunsaturated acids.
Polyunsaturated fatty acids are more
susceptible to oxidation than monounsaturated forms, so high-oleic vegetable oils
have greater oxidative stability than the
comparable ordinary types. They are the
oils of choice for combination with "hard"
fats in making "no trans" shortenings, providing high monounsaturate content along
with oxidative stability.

No-trans shortenings
As medical science learned of the effects
trans fatty acids have on serum lipoproteins, public health concerns led the F.D.A.
to issue a rule requiring inclusion of trans
fat content as part of the Nutritional Facts
panel on food labels, effective Jan. 1, 2006.
Advocates of this label addition intend it
to motivate consumers to seek foods with
lower levels of trans fat.
For many reasons, it is technologically impossible to completely remove
trans fats from oil-containing foods. But
it is possible to minimize it to less than
0.5 grams per serving.
Bakers have become accustomed to the
functionality of shortenings based primar-

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Because of their altered structure, diglyceride fats (D.A.G.) enter the body's energy
cycle immediately, while conventional triglyceride fats (T.A.G.) are stored as body fat.

ily on blends of partially hydrogenated
vegetable oils. The challenge is to make
fats with essentially the same properties
during processing and in the finished
product but with no (or reduced levels of)
trans fat. Three factors must be considered:
1 - the hard fat component, 2 - the liquid
oil used and 3 - the method(s) of combining the two.
Partial hydrogenation converts a liquid oil to a plastic fat. The unsaturated
fatty acids are hydrogenated (making
saturated fatty acids) or isomerized
(shifting the double bonds to the trans
configuration). Both changes raise the
melting point and the solid fat content
(S.F.C.) of the oil/fat. To make a no-trans
shortening, the high-melting fraction is
supplied as a hard fat, one containing
primarily saturated fatty acids. A number of options are available:
* Full hydrogenation of vegetable oil
converts all the fatty acids to saturated acids.
Complete hydrogenation (Iodine Value, or
I.V. = 0) is not commercially feasible; most
"fully hydrogenated" oils have an I.V. of
about 5. The remnant unsaturated acid is
primarily elaidic acid (C18:1, trans-9) and
positional isomers. This is the most common
type of hard fat used in no-trans fats.
* Vegetable stearines are made by
fractionating oils to obtain the high-melting point triglycerides. For example, in
making cottonseed-based salad oil, "winterization" (a low-temperature process)
removes fully saturated triglycerides; this
may be used as a hard fat. Palm oil often
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Milling & Baking News - October 19, 2004

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