Rheological characterization of gum and starch nanoparticle blends

Commercial interest on the application of starch nanoparticles (SNP) in food is rapidly growing. Since gums are commonly used in food processing for their texturizing functionality, it is important to understand the influence of SNP on gum rheology. λ-Carrageenan and xanthan gum were selected in this study due to their wide range of applications in food systems. SNP isolated from waxy (0% amylose) and high amylose maize (71% amylose) were used. Binary blends consisting of 0.5% (w/v) gum and different concentrations of SNP were prepared and their flow behaviors evaluated using a rheometer. The starch source, concentration and thermal stability of the SNP influenced the viscosity and viscoelastic properties of the gum-SNP blends, in particular in the low elasticity λ-carrageenan. The blends containing high concentrations of high amylose maize SNP, when compared to waxy SNP, showed higher viscoelastic stability at temperatures up to 90°C, possibly due to their higher thermal stability.