Rheology of oil in water gel emulsions formulated with gellan gum

LORENZO G.; ZARITZKY N.; CALIFANO A.

BOGOTÁ

Congreso; VII Congreso Iberoamericano de Ingeniería de Alimentos (CIBIA VII); 2009

This work has the objective of analyze and model the effect of gellan gum as stabilizer on the rheological behavior of low-in-fat o/w gel emulsions with different lipid phase concentration. High and low acyl gellan gums were analyzed in the range between 0.1-0.5% using three different oil concentrations (10, 20, 30%). Rheological analysis consisted in dynamic oscillatory measurements (within the linear viscoelastic range) and creep-recovery assays. Low acyl gellan gum resulted inadequate to perform these gel emulsions since their gelification kinetics was slower than the creaming velocity of the emulsion (low gelification temperature). High acyl gellan gum gel emulsions showed a “strong gel like” behavior with a storage modulus (G’) independent of the frequency even in those samples with low hydrocolloid content. Oil concentration slightly affected the elastic behavior of the emulsions, and it became less significant with the increase of gum content. Application of a superposition principle allowed to generate a master curve of G’, G’’ vs. frequency, obtaining the corresponding shift factors. Dynamic data measured in the present work were successfully modelled using Baumgaertel-Schausberger-Winter equation to predict the mechanical relaxation spectrum. Satisfactory prediction of other mechanical properties was validated using creep experimental data.