Physicochemical characterizations of gum Arabic modified with oxidation products of ferulic acid

Gum Arabic is a natural polysaccharide with valuable properties that enable its use in many industrial fields. Nevertheless, its application field may be enlarged to new properties. One way consists of the modification of the polysaccharide through an enzymatic process based on the oxidation of a phenolic compound. This work aims then to study the impact of the presence of ferulic acid oxidation products onto gum Arabic on its properties as its color, thermal properties, rheological and interfacial behaviors. For instance, modified gum Arabic powder underwent a change of color from white to orange and a glass transition was reported contrary to native gum. Though its rheological behavior did not change, its solubility decreased from 42.5 ± 2.6 to 10.6 ± 0.1% w/v. However, the amphiphilic behavior of functionalized gum Arabic seemed to be different from the one of native gum Arabic. For a given concentration, the surface tension of the modified polymer was lower (31.2 ± 0.8 mN m−1 for native gum Arabic against 52.5 ± 2.4 mN m−1 for the modified gum at 1% w/v). Finally, modified gum Arabic presented important antioxidant properties. The modification of gum Arabic with phenolic compounds appeared then as a promising way to produce a polysaccharide with new properties that could enlarge the field of its potential applications and could make it an interesting food ingredient.