Gravity table separation in the production of milling and baking quality wheat from samples containing sprout-damaged grain

Abstract

Gravity tables are able successfully to separate wheat of acceptable Falling Number from a bulk of sprout-damaged grain. However, almost no information is available on the milling, and particularly the baking quality, of wheats treated in this way. The aims of this investigation were to obtain such information and, if necessary, to develop tests for selecting appropriate wheat samples for treatment. Fifteen pairs of samples (before and after gravity separation) of wheat of breadmaking varieties were obtained from the operators of commercial gravity separators. These were subjected to a range of quality testing, including the test baking of bread.

Although gravity separation was extremely successful in improving the Falling Number and specific weight of all of the samples, it was less successful in improving the baking quality of the wheats. Even the treated samples performed less well in the baking tests than would be expected of a good quality breadmaking wheat. In particular, some of the problems associated with the Falling Number were still observed to some extent in bread from the tested samples. Examination of the condition of the protein in the samples did not provide any explanation for the poor baking performance. All but one of the fifteen wheat samples were of the variety Avalon. A number of samples of Avalon of naturally high Falling Number from the 1987 harvest were also test baked. The overall quality of the bread from these samples was comparable with that from the gravity-separated samples. This result, suggests that other problems with the quality of the wheats from the 1987 harvest (and Avalon in particular) may have been to blame.