Wheat flour flowability as affected by water activity, storage time and consolidation.

摘要

The influence of water activity, storage time and consolidation on the flowability of wheat flour were evaluated. Powder flowability was measured using a Jenike shear tester according to the Jenike procedure at four levels of normal consolidating stress within the range of 4.9-17.5 kPa. Flour was placed in a humidity chamber to obtain samples of flour at 0.33 and 0.8 water activity. Instantaneous shear tests were performed at temperature of 20 degrees C on each sample, from which the instantaneous flow functions were obtained. Time consolidation tests on the flour at 0.33 and 0.8 water activity were carried out using a Jenike shear cell and consolidating bench for the consolidation time of 1 and 7 days. Temporal flow functions of the flour were determined to quantify the combined effect of moisture content, time and compression stress.