The effect of microwave blanching on the flavora attributes of Peanuts, Kinetyka suszenia - artykuły
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Abstract
SCHIRACK, ANDRIANA VAIS. The Effect of Microwave Blanching on the Flavor
Attributes of Peanuts. (Under the direction of K.P. Sandeep.)
The use of microwave technology as an alternative blanching method for
peanuts could potentially reduce energy costs and processing time, and lead to
products with better nutrient retention. However, an off-flavor was found in peanuts
which were microwave-blanched at high temperatures. As a result, the objective of
this research has been to determine the impact of different microwave blanching
parameters on the properties of roasted peanuts, and to characterize the off-flavor
observed during high-temperature microwave blanching using a descriptive sensory
panel and analysis of volatile flavor compounds. The processing parameters best
suited for microwave blanching of peanuts were determined based on energy
absorbed during processing, internal and surface temperatures, loss in moisture
content, and blanchability. The best blanchability resulted from higher process
temperatures and lower final moisture content. However, peanuts which reached
the highest internal temperatures during blanching also developed an off-flavor,
which was characterized by increased intensities of stale/floral and burnt/ashy notes.
Solvent extraction / solvent assisted flavor evaporation (SAFE), gas
chromatography-olfactometry (GC/O), gas chromatography-mass spectrometry
(GC/MS), aroma extract dilution analysis (AEDA), threshold testing, and model
systems were used to examine the chemical compounds which may be responsible
for this microwave-related off-flavor. Analysis revealed an increased formation of
guaiacol, phenylacetaldehyde, and 2,6-dimethylpyrazine in the off-flavored peanuts
as compared to a process control, which led to the burnt and stale/floral
characteristics noted by descriptive sensory panel. These compounds were only a
small fraction of over 200 aroma-active compounds which were found to contribute
to roasted peanut flavor using GC/O. This research illustrates the importance of the
relative concentrations of the many aroma-active compounds found in peanuts.
These findings could aid in training sensory panels to evaluate processing-related
off-flavors, because guaiacol and phenylacetaldehyde could be used as chemical
standards to define the burnt/ashy and stale/floral off-flavors which can occur during
high temperature processing. Through this project, it was determined that it is
possible to achieve acceptable blanchability in peanuts using microwave blanching
while minimizing the possibility of an off-flavor.
THEEFFEGTOFMICROWAVEBLANCHINGONTHEFLAVORATTRIBUTES
OF
PEANUTS
By
AndrianaVaisSchirack
to theGraduateFacultyof
NorthCarolinaStateUniversity
in
partial
fulfillmentoftherequirements
forthedegreeof Doctorof Philosophy.
FOODSCIENCE
Raleigh
2006
Approvedby:
Dr.K.P.
Sandeep
ChairofAdvisoryCommittee
Di.MaryAnneDrake
Dr.TimothySanders
Dr.DonnWard
A dissertation
submitted
Dedicated to my husband, Pete
ii
BIOGRAPHY
Andriana Schirack is originally from Columbus, Ohio, where she attended
Ohio State University as an OSU Medalist Scholar and National Merit Scholar.
Andriana graduated with a B.S. in Food Science in December, 1997 after completing
an internship in product development of infant formula with Ross Laboratories. In
2000, Andriana completed a master’s program in Food Science at North Carolina
State University with a minor in statistics. During this time, she was also employed
as an aseptic processing technician in the dairy plant. From 2000 to 2003, Andriana
was an Assistant Food Scientist at Jim Beam Brands in Clermont, Kentucky, where
she was trained in analytical chemistry for technical problem solving and developed
new beverages for global launch as part of the product development team. She
began her Ph.D. program in the summer of 2003 under the direction of Dr. K.P.
Sandeep, and has been very active in the national IFT Student Association and the
NCSU Food Science Club. Andriana and her husband, Pete, will move to
Minneapolis, MN where she will begin work at General Mills as an R&D Scientist.
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