oxidation of phenolic compounds had a pronounced effect on
the gel properties of cuttlefish skin gelatins. The gel strength
of gelatin increased when either extracts oxygenated at very alkaline pH were incorporated (po0.05). At alkaline pH,
phenolic compounds were converted to quinone. Quinone can induce the formation of dimers between amino or
sulfhydryl side chains of polypeptides. Covalent C–NorC–S bonds with the phenolic ring were also found (Strauss &
Gibson, 2004). As a result, quinone could act as a cross-linker for gelatin to form a stronger gel network. However, either
extracts without oxidation could not increase the gel strength of gelatin (data not shown).