Wheat falling number

Levels of the enzyme a-amylase in wheat grains also affect breadmaking quality. Flour for bread-making requires low levels of a-amylase and this is favoured by a dry ripe dormant grain. The Falling Number (Hagberg) Test is used to determine a-amylase levels. A... 

While malt flour is not suitable for bread making it is added to wheat flour in small quantities to feed the yeast, open out the texture and improve the flavour. This practice has declined in recent years for several reasons. When British bread flour was mainly made from Canadian wheat with a Hagberg Falling Number of around 600 the addition of... 

The Hagberg Falling Number test only just qualifies for this section as it is an effective way of measuring the a-amylase activity of wheat or flour. It has the considerable advantage that it is unaffected by any added fungal a-amylase. In addition, it only requires a supply of distilled water and electricity - there is no need for chemical glassware or any reagents. 

When Canadian wheat flour was the norm in British bakeries, with a falling number as high as 600, it was desirable to introduce malt flour to increase the a-amylase to feed the yeast and open up the structure of the crumb. 

In a year when there has been rain during harvest, causing wheat to sprout, the falling number becomes very important. An example of such a year was 1987, when rain in East Anglia meant that the winter wheat in that area was largely unfit for bread making. In contrast the spring... 

Larvae can cause yield loss due to shrivelled grain. Hagbeig Falling Number can also be reduced so of particular importance in quality wheat crops. 

Most bread recipes include diastatic barley malt flour. Diastatic malt contains high levels of a- and P-amylases and proteases that mainly hydrolyze damaged starch granules and proteins, respectively. These enzymes gradually and slowly provide substrate for the fermenting of yeast. Diastatic malt is especially important in those formulations where sugar is not used, such as in French breads. Many commercial hard-wheat flours are supplemented with diastatic malt in order to adjust their diastatic activity, usually measured by the falling number assay (Chapter 15). The quantities used vary from 0.1% to 1.25% (Doerry 1995, Kulp and Ponte 2000, Stauffer 1990). 

In order to avoid the difficulties of naturally occurring variations in study conditions, Fall et al. (1988) studied the emission of sulfur gases from several plant/soil systems using a flux chamber. The study was designed so that emissions from soil could be separated from emissions from plants. Variable amounts of carbon disulfide were emitted from wheat. The effects of light and temperature were observed. Further work was proposed so that systematic investigation could accurately measure the contributions of a number of sulfur compounds under varying conditions. 

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