著者

阿部 真紀 小針 清子 秋田 修 アベ マキ コバリ サヤコ アキタ オサム Maki Abe Sayako Kobari Osamu Akita

雑誌

実践女子大学生活科学部紀要

巻号頁・発行日

vol.49, pp.7-14, 2012-03-10

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Aspergillus oryzae is widely used to produce fermented food such as sake, soy sauce and miso in Japan. Since these fungi have been used for food fermentation for a long time, these economic strains for food fermentation are thought as "domesticated strains." The origin of these strains is thought to be a contaminant from natural environment. We isolated many A. oryzae like strains from field using the autoclaved rice as medium. Isolated strains were confirmed as A. oryzae by the genomic structure of aflatoxin homologous gene cluster. The amount of mycelium in rice koji prepared by isolated strains did not show the significant differences compared with those of commercial strains. The activities of enzymes such as α-amylase, glucoamylase, acid carboxypeptidase, acid protease and neutral protease in rice kojiprepared by isolated eight strains and commercial strains were analyzed. Some of the isolated strains showed the similar enzyme activities to those of the commercial strains. From these results, it is suggested that the present commercial A. oryzae strains originate from A. oryzaeliving in the natural environment.

著者

阿部 真紀 小針 清子 秋田 修

出版者

実践女子大学

雑誌

実践女子大学生活科学部紀要 (ISSN:13413244)

巻号頁・発行日

no.50, pp.171-176, 2013-03

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Many kinds of salted-koji( rice-koji soaked in salted water) for pickle preparation have cometo be sold in market recently. We assayed salt and alcohol concentrations of five commercialsalted-koji. Salt concentrations were 10.2% to 13.2% and alcohol concentrations distributedfrom 2.2% to 5.7%.In addition we assayed germination ability of koji-mold (Aspergillus oryzae) and enzymeactivities remaining in five commercial salted-koji and homemade salted-koji. Homemadesalted-koji maintained the germination ability, but no commercial salted-koji showed thegermination ability.Most of the saccharifying enzyme activities of commercial salted-koji were lower than theactivities of homemade salted-koji. On the other hand, commercial salted-koji E and D had thehighest acid protease and neutral protease activities respectively in all samples. We examinedthe effect of pasteurization and ethanol on enzyme activities by using homemade salted-koji.Many kinds of salted-koji( rice-koji soaked in salted water) for pickle preparation have cometo be sold in market recently. We assayed salt and alcohol concentrations of five commercialsalted-koji. Salt concentrations were 10.2% to 13.2% and alcohol concentrations distributedfrom 2.2% to 5.7%.In addition we assayed germination ability of koji-mold (Aspergillus oryzae) and enzymeactivities remaining in five commercial salted-koji and homemade salted-koji. Homemadesalted-koji maintained the germination ability, but no commercial salted-koji showed thegermination ability.Most of the saccharifying enzyme activities of commercial salted-koji were lower than theactivities of homemade salted-koji. On the other hand, commercial salted-koji E and D had thehighest acid protease and neutral protease activities respectively in all samples. We examinedthe effect of pasteurization and ethanol on enzyme activities by using homemade salted-koji.