2023 Fiscal Year Final Research Report
Mechanism of slow saccharification that enables long-term, low-temperature multiple-parallel fermentaion in sake brewing.
Project/Area Number |
21K05460
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Review Section |
Basic Section 38050:Food sciences-related
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Research Institution | Tokyo University of Agriculture |
Principal Investigator |
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Project Period (FY) |
2021-04-01 – 2024-03-31
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Keywords | オリゴ糖 / 清酒 / 発酵 / 糖化 / 糖転移 |
Outline of Final Research Achievements |
We investigated the details of saccharification necessary to establish the long-lasting, low-temperature fermentation that is a characteristic of traditional sake brewing. From the structural elucidation of oligosaccharides in sake and the analysis of the formation and degradation mechanisms of oligosaccharides in vitro and in fermentation mash, it was clarified that characteristic oligosaccharides in sake include both transglycosylation products and starch degradation products. Both alpha-glucosidase A and B of Aspergillus oryzae are involved in the formation and degradation of the oligosaccharide in sake. Inhibition tests revealed that branched oligosaccharides are slowly degraded in fermentation mash and make a certain contribution to the supply of sugar for alcohol fermentation.
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Free Research Field |
食品科学
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Academic Significance and Societal Importance of the Research Achievements |
本研究により、伝統的な清酒製造において、醪末期のアルコール発酵を支える糖の供給には分岐構造をもつオリゴ糖の緩慢な分解が一定の寄与をしていることが示された。この分岐構造を持つオリゴ糖の生成には、麹菌のα-グルコシダーゼAとBによる糖転移と分解が関わる。また、一部のオリゴ糖は澱粉分解により直接生成しており、澱粉の微細構造中に隣接した分岐が存在することを初めて明らかにした。その他に清酒中から新規のオリゴ糖や配糖体を発見した。以上の成果は伝統的な清酒醸造の科学的理解となるだけでなく、今後の清酒製造技術の発展の基盤となる有益な知見である。
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