Physicochemical properties of carboxymethylated flamboyant (Delonix regia) seed gum

The worldwide high consumption of food additives has encouraged to perform research on new species producers of gums or hydrocolloids that can compete with those that are traditionally used, such as flamboyant (Delonix regia) seed gum, a species considered underutilized and of ornamental type. Flamboyant tree seeds were used to obtain a native gum (flamboyant gum (FNG)), which was modified by carboxymethylation (CFG), this reaction was confirmed using Fourier transformed infrared (FTIR) spectroscopy and colorimetric titration. Swelling index and dispersion were evaluated in a range of 30 90 degrees C. The apparent viscosity (mu) was evaluated with a rheometer. Compression strength of the gel (CSG) was measured with a texture analyzer and calorimetric profile with differential scanning calorimetry (DSC). The CFG had a degree of substitution of 0.33 and the FTIR analysis indicated the presence of carboxy-ether groups in the CFG. The modification of the FNG increased dispersion by 66%. Both gums exhibited shear-thinning behaviors although carboxymethylation caused a decrease in viscosity. The DSC showed a state crystalline in the FNG and a state amorphous in the CFG. The modification of the FNG favored hydrogen bridge interactions with water but decreased intra-catenary interactions in the polysaccharide.