Study of Inulin as Cryo- and Lyoprotector of Bovine Plasma Proteins

RODRIGUEZ FURLAN, LAURA TERESA; PÉREZ PADILLA, ANTONIO; CAMPDERRÓS, MERCEDES

Calorimetry

INTECH

Año: 2012;

The aim of this study was to investigate whether the oligosaccharide inulin is able to act as cryo- and lyoprotector of bovine plasma proteins during freeze-drying. The saccharide behavior was comparatively studied considering, glucose and sucrose. The thermal stability of the protein was investigated as a function of the saccharide type and concentration, and between pH 4-8. The effect of these variables on phase transition, crystallization temperatures, thermal stability and miscibility into the matrix was evaluated by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The results suggested that transition temperatures increased with the molecular weight of the saccharide, conferring inulin a stabilizing effect at higher storage temperature, while thermal protein properties (denaturation temperature and enthalpy) showed that endothermic transition shifted to higher temperatures, being also the stabilizing effect: inulin> glucose >sucrose. Furthermore it was demonstrated that the protein unfolding was irreversible, being the experimental result adequately interpreted by a two state model. The T´g of the protein frozen solution and the water plasticizing effect, were estimated by means of Miller/Fox and Gordon/Taylor theoretical models for the multi-component system. The SEM micrographs showed the homogeneity of the matrixes protein-saccharides. This integration state of the blends could justify the increase of the transitions in samples protected with saccharides. The findings of this study clearly illustrates that inulin appear to have very good protection and stabilizing properties of bovine plasma proteins. Considering the benefic effect of inulin on nutrition since it is a prebiotic, this saccharide is a valuable functional ingredient for food formulations including plasma proteins.