last time you ate bread, perhaps you checked how much fiber was in a slice—but
did you think about how much phytic acid it contained? You’re not alone. Nearly
every culture in the world eats bread, but few people consider the potential
risks and benefits associated with the phytic acid it contains.
to a team of researchers at several universities in Turkey, they may not have
team recently used Minitab Statistical Software to study the interactions
between the main ingredients in bread and the effect they have on its phytic acid
level. Their findings, detailed in the Turkish Journal of Field Crops, may give
bakers more control over bread’s nutritional value.
acid—which is found in grains, legumes, and nuts—has numerous health benefits. But
the compound’s antioxidant properties, and abilities to reduce excessive
amounts of iron and decrease the risk of colon cancer, are sometimes
overshadowed by its capacity to inhibit mineral absorption.
more people learn that insufficient dietary fiber can lead to diseases, the
demand for high-fiber foods is rising. In response, bakers enriched their bread
by increasing the amount of bran in their recipes—a change that also boosts the
amount of phytic acid the bread contains.
how can bakers give people the higher-fiber bread they want while keeping
phytic acid levels at an acceptable level?
at Baskent, Gazi, and Ankara Universities in Turkey decided to investigate the
best way to manipulate the bread-making process to suit nutritional needs.
team used Minitab Statistical Software and a statistical technique called Design
of Experiments to measure the effect of input variables (wheat bran, yeast, and
fermentation time) on phytic acid. Specifically, they employed a Box-Behnken
design (BBD), a type of “response surface design” widely used in industry to
find optimal levels for input variables based on experimental data.
their experiments, the researchers set three levels for each input variable. They
held one factor at the center level while applying different combinations of levels
for the other variables, and measured the effects of each combination on phytic
acid level. They then repeated the process with each of the remaining two
factors held at the center level. The experimental design they selected let
them collect the data they needed with the lowest number of experimental runs, while
still representing all possible factor combinations.
analysis of a response surface design typically includes graphs that reveal how
different levels of the input variables affect the outcome. When the Turkish
scientists analyzed their data and looked at the graphs created by Minitab,
they discovered that the amount of bran and fermentation time influenced the
level of phytic acid, while the amount of yeast, either alone or in any
interaction, did not affect it significantly.
contour plot lets you visualize the effects of two predictor variables on a
response variable. In the plot below, the predictors Fermentation Time and
Yeast Amount appear on the X-Y axes, and the different color bands represent
the amount of phytic acid in the resulting bread when the percentage of wheat
bran in the flower is held at 10%.
analysis indicates that the amount of phytic acid increases or decreases
proportionately with the amount of wheat bran added. Applying the optimal
fermentation time—which they found to be 60 minutes—after selecting the wheat
type with the lowest phytic acid content, produces bread that balances the
compound with the desired nutrition.
results of their work may not bring phytic acid into broad consumer awareness
in the same way people know about fiber, fat, and carbohydrates. But as bread
companies build on their research fine-tune their own formulations, the hope is
that most of us will never need to worry about the amount of phytic acid in one
of the world’s most popular foods.
This story was adapted
from an article
published in the 2012 issue of the Turkish Journal of Field Crops.