Effect of inulin and agave fructans addition on the rheological, microstructural and sensory properties of reduced-fat stirred yogurt

- Inulin and fructans improved the sensory attributes of reduced-fat yogurt.
- Inulin formed gelled structures while fructans covered the casein micelles.
- Close agreement existed between sensory perception and viscoelasticity of yogurts.

The effect of medium chain inulin (IN) and agave fructans (FR) at concentrations of 20, 40, and 60 g L−1 on the microstructural, rheological and sensory properties of reduced milk-fat (RIN or RFR, 13 g of milk fat L−1) stirred yogurts were investigated in comparison with those of a full-fat control (FC, 26 g of milk fat L−1) yogurt. Scanning electron micrographs revealed that RIN and RFR showed different protein network arrangements than FC. FR tended to cover the casein micelles, while IN formed secondary gelled structures. RIN40 and RFR60 exhibited sensory characteristics (viscosity, creaminess, flavour and overall acceptability) that were deemed superior than those of FC. The loss tangent values in the linear and the stress values corresponding to the crossover point between the storage and loss moduli in the non-linear viscoelastic regions provided indicators that closely agreed with sensory evaluation perceptions.