Structure evolution of carrageenan/milk gels: effect of shearing, carrageenan concentration and nu fraction on rheological behavior

In many cases, a strain-hardening behavior was observed using strain sweep measurements: above the upper limit of the linear domain, stress increased more than proportionally to the strain. Two types of iota-carrageenan were compared: iota with and without nu precursors. The content of the precursor affects the ability to form helical structures. Samples without precursor gave the highest level of helical structures. The carrageenan concentration effect was tested in the range 0.1-0.5 wt%. Differences in sheared and unsheared gel properties, particularly in large strain conditions, are discussed in terms of gelation process, phase separation, carrageenan/milk proportion and carrageenan type. The industrial interest in using either type of carrageenan is discussed.