| Project/Area Number |
04454077
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
製造化学・食品
|
|---|
| Research Institution | KYUSHU UNIVERSITY |
|---|
Principal Investigator |
HATANO Shoji Kyushu Univ., Food Sci. & Technol. Professor, 農学部, 教授 (30038260)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
MIYAMOTO Takehisa Kyushu Univ., Food Sci. & Technol. Assoc. Prof., 農学部, 助手 (70190816)
YOSHIMOTO Makoto Kyushu Univ., Food Sci. & Technol. Assoc. Prof., 農学部, 助教授 (90182831)
|
|---|
| Project Period (FY) |
1992 – 1993
|
| Project Status |
Completed (Fiscal Year 1993)
|
| Budget Amount *help |
¥6,700,000 (Direct Cost: ¥6,700,000)
Fiscal Year 1993: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1992: ¥5,700,000 (Direct Cost: ¥5,700,000)
|
|---|
| Keywords | Baker's yeast / Freeze tolerance / Bake off system / Actin / Glycolytic system |
|---|
| Research Abstract |
After a 7-d-frozen storage, the viability and CO_2 productivity of conventional baker's yeast decreased to 35% and 25% of those of unfrozen cells, respectively. A freeze-tolerant yeast for frozen dough method kept 75% viability even after the same storage, but the CO_2 productivity decreased to 30%. The CO_2 productivity and DNase I inhibitory activity of action of the cell-free extracts prepared immediately after thawing from 7-d-frozen-stored yeasts largely decreased. Only in the freeze-tolerant yeast, however, the productivity and the activity were increased by incubating the frozen-stored cells at 30 ﾟC after thawing. The increase tool place in actin before in CO_2 productivity. These results suggest that glycolytic system and actin in yeast cells are subject to damages during frozen storage. Both the yeasts released A_<262>-absorbing substances and Ca^<2+> during frozen storage. In cell-free extracts of both yeasts, two peaks of actin were detected by a gel filtration. These two peaks decreased in the extract of the conventional yeast prepared after frozen storage. In contrast, the freeze-tolerant yeast did not decrease the peak of actin deven after the same storage. Both yeasts decreased hexokinase and pyruvate kinase activity after the frozen storage. The decrease was greater in the conventional yeast than the tolerant one. Phosphofruktokinase was eluted at a fraction of higher molecular weight side of the enzyme. The peak moved to the lower molecular weight side after the frozen storage in the conventional yeast. The decrease in hexokinase and pyruvate kinase activity adn the dissociation of phosphofructokinase from enzyme complex cause the decrease in CO_2 productivity after frozen storage.
|
