1994 Fiscal Year Final Research Report Summary
The Study on the Mechanisms of Freeze-tolerance of Yeast in Frozen-dough.
| Project/Area Number |
05680021
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
家政学
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| Research Institution | Nara Women's University for Scientfic Research |
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Principal Investigator |
KAWAI Hiroyasu Nara Women's University Dept. of Food Science and Nutrition, Professor, 生活環境学部, 教授 (80026525)
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| Co-Investigator(Kenkyū-buntansha) |
YOKOIGAWA Kumio Nara Women's University Dept. of Food Science and Nutrition, Associate Professor, 生活環境学部, 助教授 (60230637)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Freeze-tolerant yeast / Freeze-sensitive yeast / Torulaspora delbrueckii / Freeze-tolerance of yeast / Mechanism of Freeze-tolerant of Yeast / Frozen-dough |
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| Research Abstract |
This study was undertaken to clarify the mechanism of freeze-tolerance of yeast by analyzing the composition of lipid and the content of intracellular trehalose of a freeze-tolerant yeast Torulaspora delbrueckii D2-4 and a freeze-sensitive strain 60B3 which was derived from D2-4 by mutation. It was found that the total content of phospholipid and its composition together with the ratio of sterol to phospholipid of D2-4 differed apparently from those of 60B3, the results indicating that the difference of lipid composition between the two strains may attribute to reflect the freeze-sensitivity of yeast. Then, the relation between freeze-tolerance and trehalose content of yeast cells was investigated. It was observed that the intracellular content of trehalose of D2-4 was higher than that of 60B3, and that the freeze-tolerance ratio changed in parallel with the change of trehalose content occurred under various growth conditions. The result suggested the participation of trehalose in yeast cells with their freeze-tolerance. The trehalose content of compressed bakers' yeast commercially available for a freeze-dough process varied with the specimens, but their survival ratio after freezing at -20ﾟC for 1 week was found to depend on their trehalose content, thus an important role of intracellular trehalose to protect yeast cells from freeze-injury was suggested.
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