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dough tensile properties, dough quality, rheology, wheat flour
Measuring the tensile properties of dough is one of the most important techniques used to assess the quality of flours used for bread making. The introduction of ICC standard 180 Haubelt Flourgraph E 7 has the aim of introducing new equipment using a universal technique to quantify the values of measured variables that would characterise rheometric elements as: dough formation, properties of dough formation and its visco-elastic properties. The aim of this multinational collaborative study is to measure the performance of this equipment for the validation of the draft standard. The ring test for E 7 was organised and performed under the responsibility of Haubelt Laborgeräte GmbH. Ten laboratories participated in the ring, performing the test method on 5 flours of different rheological properties in addition to one sample investigated in duplicate (blind). Results were collected by the Haubelt company and the data forwarded to ICC's technical director for statistical evaluation of accuracy (trueness and precision) of measurement for energy, resistance to extension and extensibility at the intervals of 45, 90, and 135 minutes of resting time according to the requirements of ISO 5725 part 1, 2 and 6. The relationship between standard deviations and mean values can sufficiently be described by a linear regression. This means that for repeatability and reproducibility no fixed value can be derived. Calculation of the average repeatability and reproducibility as percentage of the mean may help to summarise the results of this ring test in a simple and condensed manner.
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