Program Book - Master Brewers Association of the Americas

P-139
Effective use of yeast nutrients to improve yeast nutrition and
fermentation performance
SYLVIE VAN ZANDYCKE (1), Christoph Tenge (2), Moritz Pöschl
(2)
(1) Lallemand Brewing, Las Vegas, NV; (2) TU München
Weihenstephan, Freising, Germany
Sufficient yeast nutrition is a crucial factor for yeast propagation,
fermentation and the physiology of the yeast culture. In addition
to sugars and a nitrogen source, the yeast requires minerals,
trace elements, vitamins, sterols and fatty acids. In all-malt
worts the availability of essential nutrients is largely dependent
on the malt quality and the wort production process. In regard
to this the nutrient supply is typically sufficient in the majority
of cases. However, although previous reports have focused on
zinc deficiency it is likely that worts could also be deficient in
the number of other ions and nutrients. Worts produced with
adjuncts or sugar supplements show a different composition, in
some cases the nutrients are often incorrectly balanced, which
can result in poor yeast growth and abnormal fermentation
performance. To counteract such issues, technological approaches
are possible. One solution is the addition of the deficient nutrients
by supplementation with commercially available yeast nutrients. In
this study the effect of nutrient supplementation on fermentation
performance was assessed. Different nutrient mixtures, including
commercially available supplements as well as novel nutrient
compositions, were tested during pilot fermentations. All maltworts
and worts supplemented with maltose syrup were fermented in
parallel batches. Fermentation profiles, the production of volatiles,
yeast growth, yeast vitality and the resulting beers were analyzed in
each instance. The data obtained indicated that supplementation
with yeast nutrients enhanced fermentation performance. These
results could even be observed in worts which would typically be
deemed as having a sufficient nutrient supply. The effect was also
observed to increase over the following yeast generations (serial
repitching). Thus a deterioration of the yeast culture over several
generations can be prevented by altering the nutrients available to
the yeast. By comparing the different wort compositions, it could
be observed that increasing the concentration of nutrients is more
valuable when added to low nutrient worts. In addition beneficiary
effects during serial repitching were also observed in high nutrient
worts. It is suggested that a better supply of nutrients may reduce
yeast stress under high gravity conditions resulting in the improved
physiological condition of the yeast culture over several generations.
Differences in fermentation performance could also be seen by
comparing the various nutrients. The results depended on the
precise composition of the nutrient. Supplementation with a single
nutrient did not show a significant improvement in fermentation
performance. Surprisingly the addition of zinc was not observed to
influence yeast performance during fermentation. Thus our results
indicate that adding a defined composition of nutrients is typically
most effective in improving fermentation performance, yeast and
beer quality.
Sylvie Van Zandycke studied biochemical engineering and
fermentation at the Institute Meurice (Brussels, Belgium); she
completed her degree in September 1996. During that time, she
obtained an Erasmus studentship for a 6-month project on brewing
yeast cell aging at Oxford Brookes University. She obtained her Ph.D.
degree on oxidative stress and aging in Saccharomyces cerevisiae
in July 2000 at Oxford Brookes University. In March 2000 Sylvie
was employed as project manager for SMART Brewing Services. She
was involved in contract research, microbiological analysis, and
development of methods and kits for the brewing industry.
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She also took part in organizing international courses, symposia,
and congresses for the brewing industry. In 2004 Sylvie left the
United Kingdom for Canada and accepted a post at Lallemand
Inc. as project manager for their Genetic Identification Laboratory.
She was involved with both yeast and bacteria QC and R&D,
and her main focus in research was developing new methods
for microorganism identification and characterization, as well
as detection of contaminants in alcohol production processes.
Since February 2007 Sylvie has occupied the position of brewing
fermentation manager for Lallemand to service and support the
brewing industry worldwide.
P-140
Ocean beer
JING-IONG YANG (1)
(1) National Kaohsiung Marine University, Taiwan
Seaweeds are rich in natural bioactive compounds. In particular,
seaweed polysaccharides such as agar are present in the cell walls
of some red algae and are composed of agarose and agaropectin.
Agar was easily extracted from red algae and widely used as food
and gelling agents according to the historic records of more than
a thousand years in China and Japan. In recent years, agarooligosaccharide
structures and bioactivities, which are derived from
red seaweed polysaccharide, have been widely investigated. Many
beneficial health properties of agaro-oligosaccharides are attributed
to their antioxidant activities such as scavenging free radicals and
inhibiting lipid peroxidation in various chemical assays. In addition,
agaro-oligosaccharides have demonstrated in vitro and in vivo
hepatoprotective effects. In this study, a marine bacterium strain,
YT, with agar-degrading ability was isolated from the seashore of
Kaohsiung, Taiwan. The YT agar-degrading enzymes were used to
digest red algae and produce water-soluble oligosaccharides with
functional properties (antioxidant activities).The oligosaccharides
were then employed as adjuncts and added to a wort made from
desalted deep sea water. Since deep sea water processing requires
advanced technology, only the U.S., Japan, Korea, Norway
and Taiwan have been begun to obtain deep sea water from a
depth of more 200 m below the surface of the ocean. After yeast
fermentation, a novel type of beer, ocean beer, is produced.
Jing-Iong Yang has worked in the National Kaohsiung Marine
University, Taiwan, since 2001. He is an associate professor in the
Seafood Science Department of KMU. His current research focuses on
the functionality of foods and beverages. Jing-Iong received his B.S.
degree in agricultural chemistry and M.S. degree in food engineering
from the National Taiwan University in 1991 and 1996, respectively.
From 1996 to 2000 he studied at Karl J. Siebert’s laboratory
(brewing chemistry major) at Cornell University and was awarded a
Ph.D. degree in food science and technology.