Maturation of fermented rice-koji miso can be monitored by an increase in fatty acid ethyl ester

• Published in: Bioscience, biotechnology, and biochemistry biotechnology, and biochemistry, 2004-01, Vol.68 (1), p.250-252
• Main Authors: Yamabe, S. (Tokyo Dietitian Academy (Japan)), Kaneko, K, Inoue, H, Takita, T
• Format: Article
• Language: English
• Subjects: ASPERGILLUS ORYZAE; Biological and medical sciences; ESTERS; Esters - analysis; Esters - metabolism; fatty acid ethyl ester; FATTY ACIDS; Fatty Acids - analysis; Fatty Acids - metabolism; FERMENTATION; fermented soybean paste; Food Microbiology; Fundamental and applied biological sciences. Psychology; Glycine max; LINOLEIC ACID; Linoleic Acid - metabolism; lipid change; Lipid Metabolism; Lipids - chemistry; MONITORING; MUTATION; natural fermentation; OLEIC ACID; Oleic Acid - metabolism; Oryza - metabolism; Oryza sativa; rice-koji miso; SOYFOODS; TRIGLYCERIDES; Triglycerides - metabolism
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1271/bbb.68.250

A mixture of steamed soybean and boiled rice with seeded Aspergillus oryzae was naturally fermented without addition of yeasts or Lactobacilli, and kept matured for 12 months at room temperature. Chemical analysis of this rice-koji miso sample for lipid changes during maturation showed that triacylglycerol was gradually decomposed into free fatty acid, with distinct formation of fatty acid ethyl ester which, six months after the start of fermentation, came to account for 35.0% of total lipid. The ester was constituted primarily with linoleic acid (ca. 50%) and oleic acid (ca. 20%), no appreciable change in this proportion being observed during maturation. Also, the proportion was unique in that this did not reflect the fatty acid composition in a mixture of the two materials. It is possible to monitor the maturation of the rice-koji miso by following up the increase with time in fatty acid ethyl ester.