Their findings suggest that higher concentrations of sulfate and proteins in the carrageenan reinforces the molecular structure, increases thickness, increases elasticity, and prevents water filtration, making the gel stronger. However, the strength between these bonds causes a concentration of force at their intersection which makes it easier to break.
The study suggests that increasing the concentration of sulfate and proteins in carrageenan strengthens its molecular structure, making the gel thicker, more elastic, and less permeable to water.  However, this increased strength also creates a point of concentrated force at their intersection, which makes it easier for the gel to break.