Extraction of gelatin from fish skins by high pressure treatment

High pressure, at 250 and 400 MPa, for 10 or 20 min, was applied at either of two stages: during pre-treatment in acid at 10 °C to facilitate destabilisation of acid labile crosslinks, or during extraction in water at 45 °C to accelerate collagen hydrolysis. The resulting gelatins were evaluated in terms of yield of extraction, molecular weight distribution by SDS-PAGE, and viscoelastic properties of gelatin newly dissolved and after overnight cold maturation. Pressure level and time of treatment induced noticeable changes in molecular weight distribution and consequently affected viscoelastic properties. The use of high pressure to extract gelatin from fish skins is a useful alternative to the conventional procedure. Its utility lies basically in that the longest phase of the treatment can be drastically shortened, thus making it possible to produce a gelatin of high gelling quality in only a few minutes.