Biomedical Engineering Reference
In-Depth Information
(e.g., soybean) contain linolenic acid in amounts that can affect flavor, color, and
odor. With the potential for increasing revenues, decreasing waste disposal costs,
and improving emulsification, glandless cottonseed oil and lecithin products are
economically attractive.
Most cottonseed grown for commercial use has gossypol-containing
glands.
48,56,57
Cottonseed products or blends containing gossypol intended for human
use in the U.S. must contain no more than 0.45% free gossypol. The dark-brown
color caused by gossypol in cottonseed meal, oil, and lecithin also limits its use in
foods. Changes in oil extraction processes have produced oil that contains consid-
erable amounts of free gossypol pigments in crude phospholipids causing color and
toxicity problems.
Corn Lecithin
Patents for commercial preparations of corn phosphatides and for products containing
lecithin (cosmetics, ointments, foaming agents, and rust inhibitors) were issued during
the 1930s through the 1950s.
62-64
The growth in demand for corn sweeteners may
make other products of the corn-refining industry, such as lecithin, more available
and competitive. Similar compositions were noted for the major phospholipids of
phosphatidylcholine, phosphatidylinositol, and phosphatidic acid. Glycolipids repre-
sent a higher proportion of polar lipids in corn than in soybean lecithin and
t
he
percentages of minor components, like stearylglycoside esters, are more than twice
that of soybean. Both the glycolipids and phospholipids of corn have lower percent-
ages of linolenic acid and are more saturated than those of soybean. Linoleic acid
varies from 42 to 70% depending on the variety of corn. This genotypic effect on
fatty acid composition of phospholipids introduces the possibility that lecithin with
selected content of these nutritional components can be obtained by corn breeding.
Other Potential Sources of Lecithin
Other potential sources of lecithin include canola/rapeseed, sunflower seed, peanut,
palm kernel, xenophytic curcurbit seed, cereal grains including wheat, barley, and
rice, and olive, mango, and avocado fruit. Nonconventional sources include palash
(
Butea monosperma
), papaya (
Caricapapaya
), jangli bodani (
Sterculia factida
),
coriander (
Coriandrum sativum
), and carrot (
Daucus carota
) seed. Phosphatidyl-
choline, phosphatidylethanolamine, and phosphatidylinositol have been identified as
major components in all of these sources.
48,49,61,65-74
Minor components include
lysophosphatidylcholine, lysophosphatidylethanolamine, phosphatidic acid, phos-
phatidylglycerol, glycolipids, and triglycerides. Differences were noted among
minor phospholipids which could alter the functionality of lecithin derived from
these seed sources. Canola lecithin has been shown to contain a greater amount of
glycolipids than sunflower and soybean lecithin.
Natural Emulsifiers in Eggs
Whole liquid egg contains 11.5% fat, while liquid yolk contains 30.6%. Dried egg-
white contains 92% proteins and 8% salts and sugars. The egg yolk solids contain
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