Abstract:
Pectins are polygalacturonic acids with varying degrees of methyl esterification and are widely used to create gels. The commercial pectins studied by the authors were high-methoxyl esterified pectin, low-methoxyl esterified pectin and low-methoxyl amidated pectin. A puncture test was performed at 5 and 20C using a texture analyzer. The compression force was recorded as a function of displacement. The resulting force-displacement measurements were converted to stress-strain to calculate Young’s modulus by assuming incompressibility of the materials in a linear viscoelastic region (LVR). A rheometer was used for the shear flow curve, frequency sweep, amplitude sweep and creep tests, at 5 and 20C. The effects of temperature on storage and loss moduli were obtained. Further to that, a differential scanning calorimeter was used to investigate the melting behavior of pectin gels. The shear elastic moduli of pectin gels in an LVR were compared with Young’s modulus.
