Program Book - Master Brewers Association of the Americas

esponsible for the microbrewery plant of UCC and involved in the
brewing research that is carried out there. Alexander is a member of
the ASBC and Verband ehemaliger Weihenstephaner (VEW).
O-26
Functional components in malting and brewing
MORITZ KRAHL (1), Werner Back (1), Stefan Kreisz (2)
(1) TU Munich-Weihenstephan, Freising, Germany; (2) Novozymes
A/S, Bagsværd, Denmark
Nowadays our nutrition is mainly based on only three cereals,
wheat, rice and corn, they contribute over 75% to the world’s
starch production. At the same time diseases caused by wrong
or unbalanced diet are becoming a severe problem in Western
countries. In this regard the enrichment of functional components
in the malting process with the objective to provide their beneficial
health effects to the consumer is a very important field. The
malting process is influenced by the quality of the raw material
and by several process parameters (e.g. moisture, temperature and
time), and the enrichment of functional components depends on
the same variables. To reduce the necessary number of trials for
the evaluation of the optimal conditions for enrichment of various
components we use software for the “design of experiments” (DOE).
This software (Design Expert, Stat-Ease Inc.) supports several
different statistical approaches, like various “Factorial Designs”
or “Response Surface Methods” (RSM). RSM was developed for
process optimization in technical fields, but it has been successfully
used in various biotechnological applications including brewing
applications. With RSM the interactive effects of various process
conditions are modeled empirically. One group of the functional
components we investigated are the arabinoxylans. This type
of dietary fiber is known to provide health benefits. In order to
investigate this group of substances it was necessary to establish a
method for the determination of water-soluble and water-insoluble
arabinoxylans. The method we used consists of acidic hydrolysis of
the arabinoxylans, followed by HPAEC/PAD detection. Using this
method we were able to enrich water-soluble arabinoxylans in wheat
malt. Other methods we used are AOAC Method 991.43 for the
determination of total and soluble dietary fiber and AOAC Method
999.03 for the determination of fructans and oligofructose. Another
interesting group of components are the flavanols. We established a
method for the characterization of flavonols like rutin, vitexin and
quercetin by HPLC separation, and the technique we used for the
specific detection of catechins and procyanidins is based on postcolumn
derivatization. This method has helped us to determine
optimum malting parameters for the enrichment of these functional
components in buckwheat malt. Additionally changes in the vitamin
B 1 and B 2 content of cereals were monitored during the whole
germination and malting process of different cereals as well as the
changes in water-soluble arabinoxylan and fructan.
Moritz Krahl was born in 1980 in Schwetzingen/Germany. After
attaining the German Abitur (A-level certificate) in 2000, he
started studying brewing and beverage technology at the Technical
University of Munich, Weihenstephan. In 2005 he graduated with a
Dipl.-Ing. degree and has since then been working as a Ph.D. student
at the Chair for Technology of Brewing 1 in Weihenstephan.
Technical Session VIII: Sensory
Moderator: Lauren Salazar, New Belgium Brewing Company, Fort
Collins, CO
Lauren Salazar is the sensory specialist and a QA team member
at New Belgium Brewing Company, where she has been employed
for 10 years and sensory-focused for over 8 years. She developed
the sensory program from a basic production check to its
present program and is responsible for all facets, from design to
implementation to re-engineering. Other areas of interest and fun
at the brewery include intrabrewery flavor training, new product
development, specialty beer program, and wood barrel project
blender. Together with her husband, Eric Salazar, they make up the
wood barrel project team at NBB, with Lauren doing the blending
and Eric doing just about everything else! Lauren is a judge at the
World Beer Cup and Great American Beer Festival, has sat on panels
at the CBC, and has presented short courses for the RMMS, MBG,
AHA, ASBC, and MBAA. Lauren received her BSW degree from the
University of Georgia and holds a certificate from the University of
California, Davis, for applied sensory science and consumer testing.
O-27
Comparison of iso-α-acid sensory thresholds obtained via a
change-point model and standard ASTM methods
ANNETTE FRITSCH (1), Kathryn Kolpin (1), Thomas
Shellhammer (1)
(1) Oregon State University
This study compared proposed threshold values of iso-α-acids
(iso) and tetrahydro-iso-α-acids (tetra) collected by time-intensity
methods to threshold values determined by the ASTM 1432
ascending forced-choice method. The difference threshold, or just
noticeable difference, is the amount of change in concentration from
a constant stimulus that can be reliably identified by an observer.
A trained panel evaluated seven concentrations of iso and tetra in
an unhopped lager by a time-intensity procedure. Concentration
dependent attributes were peak intensity, duration, area under the
curve, and decreasing area. Two lines were fit within a compound
to the panelist’s per concentration-dependent data. This included
a flat line to a change-point and a positively sloped line after a
change-point. At concentrations greater than the change-point,
the panelists could reliably detect changes in the attribute due
to increases in concentration. Therefore, we hypothesized that
the change-point value represented a difference threshold for the
compound in the unhopped lager beer. Thresholds, according to
the ASTM 1432 ascending forced-choice method, were collected
for tetra and iso in the unhopped lager beer, and the change-point
values of iso and tetra for each of the time-dependent attributes were
compared to these threshold values. Eleven panelist’s data were
compared. One-sample t-tests within panelist were used to compare
the per-panelist threshold values to the change-point concentrations
per compound (α = 0.10). Accordingly, the change-point parameter
did not adequately predict the threshold value as measured by the
forced-choice method for either iso or tetra in the unhopped lager
beer.
Annette Fritsch is pursuing a Ph.D. degree at Oregon State
University. She received a B.S. degree in food science from The Ohio
State University in 2001 and a M.S. degree from Oregon State in
2007. She was employed by Givaudan Flavors Corporation from
2001 until 2004 as a product developer. During her employment, she
functioned as a manager, team leader, and customer contact. She has
been a member of ASBC since October 2004 and was awarded the
Ecolab Scholarship by the ASBC Foundation in 2005 and the Brian
William’s Scholarship in 2006 and 2007.
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