Gelation Behavior of Concentrated Locust Bean Gum Solutions

The gelation of locust bean gum in concentrated sucrose solutions has been studied as a function of temperature, LBG and sucrose concentrations. A critical gelling concentration of approximately 1% w/w LBG in 60% w/w sucrose was measured. The gelation rate initially increased with decreasing temperature until a maximum in gelation rate was found close to −5 °C. Along with the large temperature hysteresis between the temperature for maximum gelation rate and the melting temperature (>44 °C), it is proposed that the cross-linking was controlled by nucleation and growth processes rather than reversible pairwise cross-linking. The slow evolution of LBG cross-links was detected at lower frequencies through an increase in the storage modulus, while at higher frequencies a decrease in the storage modulus was observed. This decrease at higher frequencies was associated with a reduction in chain entanglements during the initial stages of gelation. In addition to cross-link formation through association of 1,4-link...