Characteristics of fish gelatin-anionic polysaccharide complexes and their applications in yoghurt: Rheology and tribology.

In this study, the rheological and tribological properties of complex solutions comprising of fish gelatin (FG)-Arabic gum (AG), FG-xanthan gum (XG), and FG-κ-carrageenan (κC), respectively, were measured, as well as the effects of the complex on the physical properties of yoghurt. Results showed that with increased XG and κC concentrations, the viscosity of FG-XG and FG-κC complex solutions both increased. It was also found that the lubrication properties of FG-anionic polysaccharide (AP) solutions decreased with the increased AP contents. The applications of FG-AP complexes (FG:AP = 9:1) improved firmness, water holding capacity and viscosity of yoghurt by the formation of large aggregates, but gels were easily destroyed at high frequency. Moreover, compared with gelatin, FG-AP complexes made yoghurt better lubrication properties during low and medium sliding speed, especially for FG-XG complexes. Thus, FG-AP complexes have the potential to be applied in producing yoghurt with good quality.