Description
Surgical removal of hemoglobin-rich tissues to eliminate metallic/bitter flavors in fish.
Technical
Targets the nephric and circulatory remnants along the dorsal midline containing iron-porphyrin complexes. Hemoglobin oxidation accelerates rancidity via Fenton reactions.
Culinary Significance
Critical for premium sashimi/sushi where pure umami expression is paramount.
Science
Primary Reaction
Hemoglobin autoxidation (Fe2+ → Fe3+)
Parameters
Temperature
1°C optimal
-2°C to 4°C range
Time
5 minutes/fillet
2 minutes/fillet (skilled) – 15 minutes/fillet (novice)
Equipment
Hagane tweezers (high-carbon steel)Flexible boning knife (15° angle)Chiku-bocho (bamboo cutting board)Ice slurry bath