The influence of pH, temperature and salt on the ethanolic desolvation of dilute cold water fish skin gelatin from aqueous solution

Abstract

Gelatin is a heterogeneous mixture of water-soluble proteins of high molecular weight. It is the degradation product of the protein collagen, a long triple-stranded helical rod which is stabilized by non-covalent interactions and covalent crosslinking. A number of studies have been carried on the desolvation of various types of gelatin of mammalian origin.1,2 Cold-water fish skin gelatin (CWFSG) has a different imino acid composition to mammalian gelatin. The number of proline and hydroxylproline groups in CWFSG is lower and this means that there is less hydrogen bonding. This leads to a different secondary structure. Moreover, the differences in the primary structure of the protein would also be expected to cause differences in other physical properties fish gelatin may exhibit. The objective of this work was to determine the response of CWFSG in aqueous solution, to the non- solvent ethanol under different conditions of pH, temperature and concentration.