Two pectin samples A and B with high methoxyl content were purified, taking into account their contents in methoxylic and carboxylic acid groups. Their chemical compositions were investigated by analysis of neutral sugars by gas chromatography and determination of the degree of methoxylation by high performance liquid chromathography. For sample A, a higher content in total neutral sugars and a higher degree of methoxylation were determined. Intrinsic viscosities, [eta] = 3.68 dL/g and [eta] = 3.56 dL/g, were determined at pH 7.0 for samples A and B, respectively. At pH 3.0, lower values were determined. Gelation was investigated in relation to sample concentration and temperature, measuring the storage modulus, G', and loss modulus, G", as a function of time. At pH 3.0, pectin A showed higher rates of gelation, as a function of both concentration and temperature.
Pectin; degree of methoxylation; gelation
