ATSUSHI TANIGAWA (1), Hisao Kuroda (1), Masahide Sato (1), Tatsuro Shigyo (1)
(1) Frontier Laboratories of Value Creation, Sapporo Breweries Ltd., Yaizu, Shizuoka, Japan
During brewing low malt or non-malt beer-like beverages, we sometimes
observe sluggish fermentation. Sluggish fermentation tends to increase
off-flavors such as sulfur compounds, and they are generally considered
to be caused by the deficiency of certain essential nutrients derived
from malt. We previously reported several phenomena caused by the
shortage of nutrients such as amino acids and vitamins. For example,
reduction of tryptophan or vitamin B6 levels in wort induces
the production of indole (2009 ASBC Annual Meeting). Many research
projects on the nutrition of yeast such as amino acids, vitamins,
minerals, and lipids have been conducted; however, previous reports are
mainly focused on the additional effect on wort equipped with
high-gravity brewing or low malt quality. In this study, we used an
omission test to evaluate the essential nutrients on yeast propagation
and fermentation. First, we made a synthetic medium consisting of
maltose syrup, amino acids, and vitamins. Second, we performed yeast
propagation and fermentation test using these media and measured yeast
physiological state and products such as esters and organic acids. We
then compared the essential nutrients between the propagation process
and the fermentation process, and found that they are not necessarily
identical. For example, shortage of inositol level induces irregular
budding during both propagation and fermentation; on the other hand,
thiamine and Vitamin B6 are necessary for the production of
suitable levels of beer flavor such as esters during fermentation, but
not during propagation. In this presentation, we summarize the nutrient
conditions necessary for yeast propagation and fermentation, and propose
typical nutrient conditions required for appropriate propagation and
fermentation.
Atsushi Tanigawa received an M.S. degree from the Department of
Agricultural and Environmental Biology, Tokyo University. He found
employment with Sapporo Breweries, Ltd. in 2005 as a microbiologist in
the Frontier Laboratories of Value Creation.
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