Brea Tree (Cercidium praecox) Exudate Gum

BERTUZZI MARÍA A.; SLAVUTSKY ANIBAL M

Emerging Natural Hydrocolloids: Rheology and Functions

John Wiley & Sons, Ltd

Año: 2019; p. 347 - 370

Brea gum is the exudate from the Brea tree (Cercidium praecox) that is widespread in arid and semiarid regions of South America. Brea tree grows in poor soils and can help with degraded environment restoration. Brea gum is obtained through cuts or incisions on the bark. Gum purification includes steps of grinding, dissolution, decantation, filtration, bleaching and drying. Its chemical composition is based in a β-(1??4) xylan backbone heavily substituted by short branch chains containing neutral sugars (arabinose, galactose, rhamnose) and glucuronic acids and their ethers. In water-based solution, the molecule acquires spherical form and presents high solubility and a rheological behaviour practically Newtonian with moderate viscosity at high concentrations. Brea gum contains 5 to 10% of proteins that influence their functional properties. The gum is suitable as stabilizer for systems containing high insoluble solids, as well as emulsions and foams. It acts as a good emulsifier and stabilizer of oil-in-water emulsions. Besides, brea gum forms dense edible films with high water solubility, hence their mechanical and barrier properties are strongly affected by ambient relative humidity. Clay nanoparticle incorporation in the film matrix reinforces the structure and reduces the effect of humidity on film properties. In bread making, addition of 0.5% of brea gum to wheat flour increases the moisture of the crumb. The food safety of this hydrocolloid has been demonstrated and it was approved as food additive. According its physicochemical and rheological properties, this gum could be used as substitute of arabic gum or similar gums in several applications.