Description
Aspergillus oryzae molds convert rice starches and proteins into fermentable sugars and amino acids.
Technical
Koji inoculation involves cultivating Aspergillus oryzae on steamed rice, producing α-amylase (EC 3.2.1.1) and acid protease (EC 3.4.23.18) that hydrolyze starch into maltose and proteins into peptides/amino acids. The process creates koji-kin, a living enzyme culture used in multiple fermentation applications.
Culinary Significance
Fundamental to Japanese fermented foods like miso (soybean paste), shoyu (soy sauce), and sake (rice wine), providing umami depth through glutamic acid production.
Science
Primary Reaction
Starch → Maltose + Dextrins (via α-amylase)
Parameters
Temperature
32°C optimal
25°C to 40°C range
Time
48 hours
36 hours – 60 hours
Equipment
Wooden trays (traditional)Perforated stainless steel tanksHumidity-controlled incubators