Discrete reduction of type I collagen thermal stability upon oxidation

Komsa-Penkova R, Koynova R, Kostov G, Tenchov B · Biophysical Chemistry

Gives the number that decides what cooking does to collagen structure: non-oxidized type I collagen denatures at 41 degrees C, and oxidation splits that into a second transition at 35 degrees C. The isolated triple helix is therefore unstable near body temperature and cannot survive a simmer — which is why undenatured type II collagen supplements have no counterpart in cooked food.

Population

Acid-soluble calf skin type I collagen (microcalorimetry and scanning densitometry)

Intervention

Metal-dependent free-radical oxidation, then measurement of the denaturation transition

Limitations

Isolated acid-soluble type I collagen in solution, not collagen within intact tissue, which is stabilized by crosslinking and gelatinizes at appreciably higher temperatures. Type I rather than type II. The commonly quoted 60-75 C in-tissue shrinkage figures are from food-science sources we could not verify against a primary indexed citation.