Soluble aggregates obtained from heat‐treated suspensions of commercial whey protein concentrate with 74.4% w/w protein were characterised. The effect of protein concentration (7 and 8% w/w), pH (7.0, 7.5 and 8.0), and heating time (0, 5, 10, 15, 20 and 30 min) at 80 °C were evaluated. Whey protein concentrate suspensions with the highest protein concentration (8% w/w) and the lowest pH (pH 7.0) had the highest steady shear viscosity and absorbance values, indicating the effect of the soluble aggregate content (high concentration) and the aggregate size (at lower pH values). According to principal component analysis, samples with 8% w/w and pH 7.0 were grouped in a plot region that confirmed the behaviour observed by confocal microscopy. Those whey protein concentrate suspensions could have soluble aggregates with a strong probability of interacting with cations (in cold gelation applications such as microencapsulation) and with each other (in film‐formation during coating).

-The stress-strain of samples deformed until failure and the relaxation response after 50% deformation of the initial height under constant stress were obtained. Uniaxial compression and stressrelaxation tests enabled satisfactory differentiation of the mechanical resistance of gels with different alginate and carrageenan concentrations. Higher values for initial force at the beginning of the relaxation test were associated with higher calcium uptake by the gels. An increment of failure stress during the uniaxial compression tests for higher concentration of calcium in the gel structure was also observed. The maximum amount of cation uptake was higher than the theoretical value for saturation of all the carboxylic groups available in alginate molecules due to structural rearrangements. Stress-relaxation tests indicated that the residual stress of the gel increased with κ-carrageenan concentration.

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