Rheological behavior of gums extracted from flamboyan (Delonix regia), pixoy (Guazuma ulmifolia) and leucaena (Leucaena leucocephala) seeds: Potential ingredients for use as additives in food

Abstract

Gums or hydrocolloids are important ingredients in the food industry due to their use as thickeners, stabilizers, gelling agents and texture enhancers in the foods in which they are used. In this study, gums rheological behaviors from seeds of flamboyant (Delonix regia), pixoy (Guazuma ulmifolia), and leucaena (Leucaena leucocephala) at several concentrations were evaluated. The flow and viscoelasticity curves of dispersions in water at 0.5, 1.0 and 1.5% were determined and adjusted to different mathematical models. In the three gums, at low concentrations the best behavior adjustment was obtained with the power law model, while at high concentrations the rheological behavior was adjusted to the Cross model. Viscosity decreased with increasing shear rate and flow index values (n) indicated a shear thinning behavior (n <1) for all concentrations evaluated. The values of the consistency index (K) were higher for the dispersions of the pixoy gum (0.71-1.79) than for the other gums (0.10-0.61) in all concentrations studied. The elastic modulus was greater than modulus viscous and both moduli were little dependent on the frequency in the range studied to pixoy gum, associated with gel type behavior, while flamboyant and leucaena had a macromolecular solution behavior type.