Achievement of wild-type baker's yeast with tolerance to stress and the development of bread processing technology using rice flour

Research Project

Project/Area Number	25560032
Research Category	Grant-in-Aid for Challenging Exploratory Research
Allocation Type	Multi-year Fund
Research Field	Eating habits
Research Institution	Yamagata University
Principal Investigator	NAGAI Takeshi 山形大学, 農学部, 教授 (10385502)
Project Period (FY)	2013-04-01 – 2016-03-31
Project Status	Completed (Fiscal Year 2015)
Budget Amount *help	¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000) Fiscal Year 2014: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000) Fiscal Year 2013: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Keywords	山形県産果樹果実 / 野生酵母 / 冷凍・乾燥耐性 / 米粉パン / 製パン技術開発 / 選抜 / スクリーニング / 製パン性 / 採取 / 分離
Outline of Final Research Achievements	By the acquisition of 2-DG resistant mutants, carbon dioxide and ethyl alcohol production tests, and expandability power test of baking dough using wheat flour, a stain was isolated from pear cultivar Redbartllet fruit. It was identified as S. cerevisiae by the partial 28S rDNA sequence. The optimum growth temperature of the strain was 30℃ and it showed higher fermentation ability in the low-sugar dough. The ability retained under -28℃ preservation, but it extremely decreased in vacuum-packed stain after lyophilization. Using a mixture of rice flour and wheat gluten (8:2), and by the regulation of the appropriate water amounts, it makes it possible to produce high quality of rice bread having a characteristics crust and texture of rice bread and favorable flavor of wild-type yeast. It found that the appropriate water amounts were correlated to the water contents of rice flours. The expansion ratio of the bread decreased with an increasing amylose contents of rice flours.