The glucans of Ramalina celastri: relation with chemotypes of other lichens

The aim of this work is to demonstrate that the phase behaviour of the gelatin/maltodextrin gel can be controlled by means of the molecular weight distribution of the polymeric constituents and the cooling rate. In doing so, the technique of small deformation dynamic oscillation was used to monitor the mechanical strength of the binary gels and their melting profiles upon subsequent heating. Introduction of high molecular weight fractions induced a transformation from weakened deswelled gels to reinforced composite gels. The phase inversion point from gelatin to maltodextrin continuous gels was manipulated by decreasing the length of molecular chains of the protein and/or increasing that of the polysaccharide. The formation of maltodextrin continuous structures was further assisted by quenching the binary solutions from high temperature as opposed to slow cooling. For a given concentration of gelatin, it was possible to reduce to a third the amount of maltodextrin required for phase inversion in the mixture.