Effects of Mucilage on the Pasting, Thermal and Retrogradative Properties of Native and Modified Starches Obtained from Ipomoea Batatas

Abstract

This study investigates the effect of mucilage on the pasting, thermal and retrogradative properties of native, pregelatinized and acid modified starches obtained from ipomoea batatas. Dispersions of mucilage with each starch was carried out in a ratio 1:20, 1:10, 1:5, 3:10 and 2:5 respectively. Native starch (SPS) had a higher peak viscosity, trough, breakdown, final viscosity and enthalpy (?H) as compared to pregelatinized starch (PPS) and acid modified starch (APS) in the order SPS > PPS > APS. Parameters such as pasting temperature, syneresis, onset, peak and conclusion temperature were in the order APS > PPS > SPS. Pregelatinized starch had a higher set back and peak time as compared to other starches in the order PPS > SPS > APS. Generally, dispersions of SPS, PPS and APS in mucilage followed similar trends as described above with increase in peak time, pasting temperature and ?H as the mucilage concentrations increased and a decrease in peak viscosity, trough, breakdown, final viscosity, set back, syneresis (except SPS), onset, peak and conclusion (except APS) temperature as the mucilage concentration increases.

Keywords: Ipomoea batatas starch, pregelatinized, acid modified, dispersion, mucilage