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Biotechnol Lett (2013) 35:375382 DOI 10.1007/s10529-012-1088-z
ORIGINAL RESEARCH PAPER
Soy peptides enhance yeast cell growth at low temperatures
Sayuri Kitagawa Masahiro Sugiyama
Takayasu Motoyama Fumiyoshi Abe
Received: 10 September 2012 / Accepted: 31 October 2012 / Published online: 5 December 2012 Springer Science+Business Media Dordrecht 2012
AbstractPurpose of work To elucidate the mechanisms of high performance by soy peptides during yeast fermentation in low temperature stress conditions and to identify a type of soy peptide that is suitable for yeast fermentation at low temperatures during brewing.
The growth of a tryptophan auxotrophic yeast strain in a medium containing soy peptide (SP) was
compared with that in a medium containing an equivalent composition of free amino acid mixture. At low temperature (10 C), the cells grew in the medium containing SP but not in the medium containing the free amino acid mixture. Free tyrosine and phenylalanine inhibited the uptake of free tryptophan at low temperatures whereas most of the tyrosine and phenylalanine were present as oligopeptides in SP. The cells could transport free tryptophan without being inhibited by free tyrosine and phenylalanine at low temperatures in the medium containing SPs. Soy peptide-AM that lacks free tyrosine and phenylalanine was more effective in promoting cell growth compared with a highly hydrolyzed version.
Keywords Brewing Low temperature stress
Soy peptide Tat2 Tryptophan YPH499
Introduction
Soy peptides (SPs) are obtained via the hydrolysis of soy protein isolates and they are utilized widely for the production of isotonic drinks and functional foods because of their physiological functions (Maebuchi et al. 2007; Maebuchi et al. 2011; Hori et al. 2001). In addition, the application of SPs in the fermentation industry has also been reported (Izawa et al. 2007; Ito et al. 2012). SPs are widely used as nitrogen sources in various fermented food products. For example, SPs are
S. Kitagawa (&)
Soy Protein, Processed Foods R & D Center, Fujioil Co., Ltd., 1 Sumiyoshi-cho, Izumisano-shi, Osaka 598-8540, Japane-mail: [email protected]
S. KitagawaLife Science and Bioengineering, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
M. Sugiyama T. Motoyama
Food Science Research Institute, Research & Development Division, Fujioil Co., Ltd., 4-3 Kinunodai, Tsukubamirai-shi, Ibaraki 300-2497, Japane-mail: [email protected]
T. Motoyamae-mail: [email protected]
F. AbeDepartment of Chemistry and Biological Science, College...