Rheological behavior of a pectic fraction from the pulp of cupuassu (Theobroma grandiflorum)

Rheological examination of water-soluble pectic fractions (W-1 and PW-1) isolated from the pulp of cupuassu (Theobroma grandiflorum) were evaluated to determine the influence of starch on the water-soluble pectin. Pectin gels (1–3%, w/w) were prepared at pH 3.0 in the presence of high sucrose concentrations (55–65%). Small deformation measurements of storage (G′) and loss (G″) moduli at 25 °C showed that increasing the pectin and the sucrose concentrations of the gels both resulted in an increase of G′. In general, stronger gels were those obtained for fraction W-1, in terms of viscoelastic properties as well as thermal stability, suggesting that starch could be cooperating in the formation of water-soluble pectin gels.