Effect of sugar addition on the elongational and shearing deformation behavior of sesame paste systems

Abstract

The structural characteristics of series of mixtures of sesame paste with different sugars were studied using various rheological techniques. The sugars employed were sucrose and fructose in powder form; maltose and isoglucose in the form of corn syrup. The sesame paste was prepared either from unroasted or roasted sesame seeds. The rheological measurements were carried out using uniaxial compression to determine the Young's modulus of elasticity, lubricated squeeze flow viscometry to determine elongational viscosity as well as dynamic and creep small deformation tests. Roasted or unroasted sesame paste exhibited higher values of Young's modulus comparing to the sesame paste-sugar systems. Significant differences were recorded in the elongational viscosity values of the resulting sesame paste-sugar mixtures. The behavior of a concentrated fluid was observed for all systems. The viscosity of the sesame paste-sugar systems was affected by the concentration of sugar in the mixture and the temperature of measurement as well. Overall, results indicated that the structure of the sesame paste-sugar systems examined was mainly affected by the ratio of the sesame paste to sugar content present in each mixture.