Urbana, Illinois
March 3, 2008
If you're allergic to soy, help is
on the way. Two University of
Illinois studies show that fermenting soy dramatically
reduces its potential allergenicity and also increases the
number of essential amino acids in soy products, making them a
healthy and a safe choice for consumers.
"When we fermented soy seeds, flour, or meal by introducing
certain microorganisms, inmmunoreactivity was significantly
reduced--by as much as 99 percent. This shows that we have the
potential of developing nutritious, hypoallergenic soy
products," said Elvira de Mejia, a U of I associate professor of
food science and human nutrition.
The scientist achieved these results when she challenged the
blood plasma of persons allergic to soy with protein extracts
from both fermented and unfermented soy products. Plasma samples
were obtained from the World Health Organization.
"Why do we see this reduced immunoreactivity? During the
fermentation process, proteins are broken down into very small
pieces, pieces that can't be identified by the antibodies that
produce the allergic reaction," de Mejia explained.
Because of soy's health benefits, de Mejia would like to make
sure soy foods can be safely eaten by all people. Soy is a
source of high-quality protein, oil, B vitamins, fiber, and
essential fatty acids, and it also contains phytochemicals that
may help prevent chronic diseases, including heart disease, some
cancers, osteoporosis, and diabetes, she said.
And, although soy allergy affects only 0.5 percent of the
population, that figure may be rising. Because soy is used as in
ingredient in many food products, de Mejia said that a technique
that can eliminate its allergenicity is widely sought.
In the two U of I studies, which were done in collaboration with
the Instituto de Fermentaciones Industriales (CSIC) in Madrid,
Spain, soy was subjected to both solid and liquid fermentation
by exposing samples to a number of microorganisms, including
bacteria, molds, and yeast.
L. plantarum-fermented soy flour showed the highest reduction in
immunoreactivity--96 to 99 percent--depending upon the
sensitivity of the human plasma, the scientist said.
"Our next step will be to optimize the fermentation conditions
to produce zero-tolerance allergens," she said.
De Mejia noted that fermentation had also improved the essential
amino acid composition in the soy products and produced new
peptides that may be beneficial.
"We want to evaluate some of the bioactive peptides that were
produced during fermentation because we believe they may have
other benefits. In particular, we're interested in their effect
on lipogenesis, so we'll be testing these hydrolysates in
adipose cells," she said.
The increase in the number of small bioactive peptides was
attributed to partial digestion of large soybean peptides by
enzymes secreted by the microorganisms used in fermentation, she
said.
Plaimein Amnuaycheewa, a master's degree student in de Mejia's
lab, is currently working on the allergenicity project, and
Cristina Martinez-Villaluenga, a Marie Curie fellow, is working
with allergenicity and adipogenesis.
Papers on this research were recently published in Food
Chemistry and in the Journal of Agricultural and Food Chemistry.
Co-authors for both articles are Juana Frias, Young Soo Song,
Cristina Martinez-Villaluenga, and Concepcion Vidal-Valverde.
The studies were funded by the USDA Future Foods Initiative and
the Illinois Soybean Association.
Author: Phyllis Picklesimer |
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