Physicochemical Properties of Starch Binary Mixtures with Cordia and Ziziphus Gums

Abstract

The effect of gum Cordia (GC) and gum Ziziphus (GZ) on the physicochemical properties of wheat, potato, and chickpea starches was investigated. Native or acetylated gums were mixed with starch at 2% or 5%. Starches were analyzed using rapid viscoanalyzer (RVA), differential scanning calorimeter (DSC), texture analyzer, and rheometer. In the presence of gums, the data showed clear variations between the starch gels. The effects of gum acetylation on the starch characteristics were significant. According to the starch type, the peak viscosity of the gels increased depending on the gum type or concentration. With the exception of the potato starch, when gums were added, the gelatinization temperature of the starches increased. Gum acetylation significantly increased starch–gel elasticity (high G′), particularly at the 2% concentration. GC-starch gel hardness was ranked as follows: chickpea–5% native gum > wheat–5% native gum > potato–0% gum, whereas GZ followed the order of: chickpea–2% native gum > wheat–2% native gum > potato–2% native gum. Both the gums promoted reduction in syneresis for the wheat and chickpea starches. Although there was no clear trend, the Ea of the native starches was lowered overall as a result of the gums, indicating the limited effect of temperature on the rheological properties of the blends.