Physicochemical characterization and functional properties of galactomannans from mesquite seeds (Prosopis spp.)

In the present study, the physicochemical and functional characteristics of galactomannans (GM) from mesquite seeds were investigated and compared with the characteristics of a commercial GM. The mesquite gum was extracted with water at room temperature, and its physicochemical parameters, thermal constants and functional properties were determined. The results showed that mesquite GM had contents of 2.56% moisture, 4.54% protein and 0.06% ash; trace levels of fat; 95.40% total carbohydrate; +63.48 optical rotation; an intrinsic viscosity of 12.36 dL/g and a molecular weight of 1.2 x 10(6) g/mol. The sugars detected were mannose (Man) and galactose (Gal), with a Man: Gal ratio of 1.50. The curves obtained by calorimetry indicated a transition temperature (Tg), melting temperature (Tm) and heat capacity (Cp) very similar to those of the guar GM. The evaluation of the functional properties of the mesquite GM revealed a solubility of 92.10%, an emulsion capacity of 95% and an emulsion stability of 92.24%. The polysaccharide extracted from the mesquite seeds is a GM with physicochemical and functional properties similar to those reported for other legume seed gums, allowing us to conclude that mesquite GM has the potential for use in the food industry. (C) 2012 Elsevier Ltd. All rights reserved.