Self-aggregation of gelatine above the gelling temperature analysed by SEC–MALLS

The molar mass distribution of porcine skin gelatine was analysed by size exclusion chromatography combined with multi-angle laser light scattering (SEC–MALLS), refractive index detection and optical rotation detection. A change in molar mass distribution, interpreted as a reversible aggregation of gelatine chains at temperatures well above the gelation temperature was observed. It is concluded that apart from covalent linkages between α-gelatine chains, there exists an additional interaction, of order kT, which causes physical aggregation. It is shown that this aggregation does not involve extensive formation of helices. Self-aggregation of gelatine may have profound consequences for its thermodynamic behaviour in mixtures.