Peanut flour is a dry powder formed after the
partial extraction of oil from the roasted peanut seed. It is used to
add flavor and protein to processed baked goods, nutrition bars and
snacks, as well as to marinades, sauces and dressings. Worldwide,
peanut flours have been limited to use by industrial food processors as
a major food ingredient.
The study was conducted by food
technologist Jack P. Davis and colleagues in the ARS Market Quality and
Handling Research Unit, Raleigh, N.C. ARS is the U.S. Department of
Agriculture's chief scientific research agency.
To gauge how
effectively different commercial peanut flours thicken during heat
processing, Davis used different types of rheological tests.
Rheological measurements involve testing the flow behavior and form
changes of a material and have been shown to relate to the human
perception of texture.
Generally, peanut flours are offered at
fat levels of 12 or 28 percent, and either as light, medium or dark
roasts. Davis found that regardless of roast color, lower-fat peanut
flours thicken more effectively than higher-fat ones.
While
peanuts are about 25 percent protein, peanut flour is about 50 percent
protein. That's because the process of mechanically removing fatty oil
from roasted peanuts enriches the levels of the remaining peanut
components. The resulting flour is naturally low in fat, high in
protein and relatively low in carbohydrates.
Ounce-per-ounce,
low-fat, light-roasted peanut flours were found to promote more
viscosity--or to thicken more effectively--than other peanut flours
when dispersed in water and heated under controlled conditions.
Davis
and ARS research leader Timothy Sanders will report the findings in an
upcoming issue of The Journal of Texture Studies. That data and those
from future studies will help food processors choose the best heat
treatments, based on a particular peanut flour's thickening properties.
_____________________________________________
ARS News Service
Agricultural Research Service, USDA
Rosalie Marion Bliss, (301) 504-4318,
rosalie.bliss@ars.usda.gov
January 25, 2007
--View this report online, plus photos and related stories, at
www.ars.usda.gov/is/pr
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