Composition of fractions from air-classified wheat flour

Sammanfattning: The unique ability of wheat to produce leavened bread is mainly due to the gluten proteins present. As consumers are more and more attracted to bread with high fibre content the use of wheat gluten will also increase in order to obtain bread with good volume and appetizing characteristics. Air-classification is a technological method used to separate particles by size and shape by means of air-streams into two fractions, fine and coarse. When used on wheat flour it is known to alter the flour composition in the fractions obtained compared to the original flour. This method is not widely used in the milling industry but could possibly be of interest if protein rich fractions with favorable protein quality can be produced. These protein rich fractions could be an alternative to commercial gluten additives. The objective of this thesis was to evaluate air-classified flour by means of determination of protein content, wet gluten content, rheological properties and bread volume. The flour was a strong wheat flour and the air-classifier used was a Hosokawa Alpine ATP 50. The rotational speeds used for separating the flour were 5000 revolutions per minute (rpm), 6500 rpm and 8000 rpm. The result showed that the fine fraction from 8000 rpm contained high levels of proteins with good quality. The dough produced from this fraction was strong, contained high levels of wet gluten and had high water absorption. The bread produced from the same fraction had the largest volume.