How to Identify Fake or Chemically Treated Fish Maw: 5 Essential Quality Tests
Buyer's guide to detecting counterfeit fish maw: water transparency test, heat elasticity check, smell evaluation, chemical reagent detection, and light transmission.
Test 1: Backlight transmission and natural fibre grain
Hold dried maw against a bright LED light. Authentic fish maw displays natural, irregular collagen fibres, fine branching blood vessels, and varying translucency. Fake gelatin or pork skin replicas appear uniformly dull, plasticky, or feature artificial air bubbles.
Test 2: Cold-water soaking resilience test
Genuine fish maw softens into a springy, pliable, unified sheet after 24 hours in water. Chemically glued scrap maw (拼胶/碎胶压块) falls apart into fragmented clumps or sloughs off a slimy, foul-smelling layer.
Test 3: Detection of hydrogen peroxide bleaching
Unscrupulous traders soak dark or bruised maw in hydrogen peroxide (H2O2) to achieve unnaturally stark white pieces. Authentic dried maw always exhibits a warm ivory, golden-amber, or naturally aged pale yellow hue.
Test 4: Sulfur dioxide (SO2) fumigation olfactory test
Smell the inside of a sealed carton. Authentic product smells solely of clean marine salinity. If there is a sharp, acidic, match-head, or pungent chemical odor, the lot was fumigated with sulfur to hide dampness.
Test 5: Boiling broth testing (化汤检验)
Boil a sample piece in water for 60 minutes, then refrigerate the liquid. Genuine fish maw broth sets into a firm, clear, elastic jelly due to high collagen concentration. Starch-adulterated fake maw liquid remains watery or cloudy.