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Properties of heated aqueous starch dispersions dependent on the preparation conditions
Author(s) -
Ulbrich Marco,
Flöter Eckhard
Publication year - 2017
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.201600381
Subject(s) - starch , solubility , aqueous solution , chemical engineering , polymer , chemistry , fraction (chemistry) , dispersion (optics) , shear (geology) , degradation (telecommunications) , centrifugation , mass fraction , materials science , chromatography , organic chemistry , composite material , telecommunications , physics , optics , computer science , engineering
The solution state of starch was investigated depending on several factors. Impacts on the preparation of aqueous starch pastes were examined with respect to solubility and molecular characteristics of the starch existent in the two phases. Different initial molecular states of the starch (native potato and three acid‐thinned [AT] products), different disintegration temperatures (95, 125, and 155°C) as well as a high‐shear aftertreatment of the dispersion using an Ultra‐Turrax were tested systematically. Centrifugation of the dispersion was carried out to separate the soluble (supernatant) and the swollen (sediment) phase. The molecular composition of the starch polymers dissolved in the supernatant was characterized using SEC‐MALS. With the purpose of a detailed analysis of the AM‐fraction, the starch was enzymatically debranched prior to characterization. The sediment of pastes prepared without high‐shear aftertreatment was also obtained, completely dissolved, and subsequently analyzed in the same way. The starch solubility increased basically when both increasing degree of modification and temperature. Enhancing disintegration temperature as well as a high‐shear aftertreatment of the paste promoted in particular the relative solubilization of the highly branched molecule fraction. Indeed, a slight molecular degradation of that fraction due to exposure to high temperature (heat‐induced) or shear (mechanical input) was assumed in certain cases, but evidence for concurrent molecular degradation of the AM was not found.