Cereal Chem 60:381 - 387. | VIEW
Differential Scanning Calorimetry of Heat-Moisture Treated Wheat and Potato Starches.
J. W. Donovan, K. Lorenz, and K. Kulp. Copyright 1983 by the American Association of Cereal Chemists, Inc.
Native potato and wheat starches were heat-treated at 100 C for 16 hr at moisture contents between 18 and 27%. Differential scanning calorimetry of the treated samples showed a broadening of the gelatinization temperature range and a shifting of the endothermal transition toward higher temperatures, compared to the untreated starches. The enthalpy of this transition decreased with increasing moisture content. The change was greater for potato than for wheat starch. The endotherm of the treated samples was biphasic, suggesting that two types of organized structure were present in the granules. For some samples, only one part of the biphasic endotherm coincided with loss of birefringence. Changes in the endotherm produced by defatting the starches were different when defatting was performed before rather than after heat treatment. When samples were heated in the calorimeter with small amounts of added water, the most extensively modified wheat starch showed three order-disorder transitions in addition to the gelatinization transition. These transitions were those for melting of amylopectin crystallites, of the amylose-lipid complex, and of an unknown structure. The treated potato starch did not show the latter two transitions.