Gluten quality makes all the difference for good and healthy bread time after time.

Knowing the quality of your flour is as fundamental as following the recipe when making wholemeal bread of a consistent high volume and crumb structure.

In this issue’s film, Jan shows the big difference in bakery performance between three types of wholemeal wheat flour. What we need to do as bakers is put a finger on the difference before baking begins.

Quality in the protein
Analyses of flour quality typically focus on total protein content. In standard white wheat flour, a high protein content is considered a reliable indication of good quality. But the same rule of thumb does not apply to wholemeal flour.

The reason is that much of the protein exists in the flour’s bran content. While the bran proteins contribute to the flour’s nutritional profile, along with fibre and minerals, they have no influence on baking functionality. So a test that simply measures protein quantity in whole grain flour can be misleading.

Simple gluten analysis
In our bakery lab at DuPont, we use a series of simple tests to evaluate protein quality. This involves looking specifically at the gluten, the composite of proteins that builds the elastic network responsible for dough strength and bread volume. Analysing the gluten gives a clearer picture of how wholemeal flour is likely to perform in bread-making.

Here are two of the most common tests:

• Wet gluten
  Flour and a salt solution are mixed to make a dough. After resting for an hour, the dough is gently kneaded under a stream of tap water to wash out the starch and other soluble components.
  Eventually, only an insoluble mass remains – the gluten, which is then weighed and evaluated for extensibility.
• Sedimentation
  Flour and a lactic acid solution are shaken together in a glass cylinder, causing the gluten to bind water and swell. The solution is left to rest and the speed of sedimentation evaluated. There is a positive correlation between slow sedimentation and relative gluten strength.

Fibre interference
Due to the water-binding ability of the fibre in wholemeal flour, the test results may be distorted by fibre interference. All the same, a better picture of flour quality will be obtained than from a purely quantitative assessment of protein content.

Consider the ash
Another important aspect to consider is ash content – comprising the minerals primarily located in wheat bran – which indicates the flour extraction rate. In principle, a wholemeal flour should have an extraction rate as close to 100% as possible, including all parts of the bran, germ and endosperm. However, this brings another challenge: the negative effect of bran particles on flour baking performance.

The ultimate flour quality test, of course, is to bake and look. In a small-scale bakery trial, all is revealed. 
With these test results in hand, the need to optimise your wholemeal bread recipe becomes apparent – enabling you to ensure consistent quality every time you bake.

Still in doubt? Talk to your miller or ask about the opportunities to conduct a flour analysis in our lab.