Analysis of aged gelatin by AFlFFF-MALS: Identification of high molar mass components and their influence on solubility

Gelatin is an important product for several industries and its solubility dramatically influences its functional properties. In order to be able to predict the gelatin behaviour, a new technique for its analysis has been developed with an Asymmetrical Flow Field-Flow Fractionation coupled to a multi-angle light scattering. The AFlFFF-MALS analysis showed the gelatin molar mass ranging from 5 × 104 to 2 × 107 g mol−1. This technique also permitted to follow aggregation of gelatin samples after process in an oven at 75 °C. Between 0 and 4 days, some huge aggregates appeared. Their size and density increased without changing gelatin solubility. From 8 to 30 days, the molar mass and density of these aggregates increased leading to partial gelatin insolubilisation in water. This phenomenon is supposed to be due to cross-linking of the gelatin macromolecules.