What You Need to Know
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.
Fundamental to Japanese fermented foods like miso (soybean paste), shoyu (soy sauce), and sake (rice wine), providing umami depth through glutamic acid production.
Key Parameters
Temperature
32°C
25°C - 40°C
Time
48 hours
36 hours - 60 hours
Equipment
Wooden trays (traditional)Perforated stainless steel tanksHumidity-controlled incubators
Steps
- 1.
Shio-koji (Japan): Tenderizing marinade via protease activity
- 2.
Amazake (Heian period Japan): Sweet non-alcoholic beverage from starch conversion
The Science
Primary Reaction
Starch → Maltose + Dextrins (via α-amylase)