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This article focuses on the study of the dynamic rheological and structural properties developed in low‐fat stirred yoghurts made with skim milk and multiple emulsions stabilized with carboxymethylcellulose (SYCMC) or amidated low methoxy pectin (SYALMP), in comparison with a full milk‐fat stirred yoghurt control (SYMF). The SYALMP yoghurt exhibited greatest Tanδafter 14 days of storage than the SYMF and SYCMC yoghurts. The SYALMP yoghurt presented the highest lacunarity value and was characterized by a structure composed of highly clusterized casein aggregates. In contrast, the SYCMC and SYMF yoghurts displayed lower lacunarity values and structures characterized by smaller casein clusters. Lower Tanδvalues were associated with lower lacunarity values. PRACTICAL APPLICATIONS Limited work has been done on stirred and set‐style yoghurts, cheeses and, in general, dairy products, where milk‐fat globules are substituted by skim milk combined with multiple emulsions containing polyunsaturated vegetable oils. As a result of this, multicomponent gels formation occurs (made up by milk proteins, polyunsaturated vegetable oils, emulsifiers, hydrocolloids and many possible other ingredients), which give rise to completely different structural arrangements that may display comparable mechanical‐sensory properties with those exhibited by their full milk‐fat counterparts, paving the way for the development of new healthier foods sensory and texturally acceptable to consumers.

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The flow patterns produced by two dual mixing systems composed of independently driven impellers were studied. The dual impellers included a turbine rotating at high speed (Rushton or Smith) and a slowly rotating helical ribbon agitator (HR). Visualizations and power input were used to evaluate mixing performance. The influence of the rotational speed ratio on the flow patterns was evaluated. For high shear-thinning fluids, N T /N HR modifies the flow patterns considerably. Three typical behaviors were found with shear thinning fluids: segregation of two principal flow patterns (N T /N HR < 10), turbine dominance (N T /N HR > 10), and a well-distributed flow pattern throughout the tank (N T /N HR = 10). For low-viscosity fluids, the motionless HR reduced the vortex length and the T-HR systems eliminated vortex when the impellers rotated in opposite directions at N T /N HR = 10. Finally, a relationship between the dimensionless vortex length and the Froude number is proposed for individual turbines as well as for the turbine-motionless HR systems.

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