Testing times

10 April, 2009
Novel tests on wheat, flour, and dough proving and baking are helping identify optimum end-use for flours in Ireland. Ann Marie Foley reports
Page 31 

Athree-year research project, subjecting wheat to a battery of routine and newly devised tests, has identified accurate and rapid methods for bakers and millers to quantify flour's quality and usability.

Dr Eimear Gallagher, Ashtown Food Research Centre (AFRC) Teagasc, Dublin, and Professor Francis Butler, University College Dublin (UCD), headed up the research teams. British Baker caught up with Dr Gallagher as she was monitoring the latest batch of breads at the research centre in Dublin. She explained how the research project began with wheat trials for the Irish Department of Agriculture, Fisheries and Food, in association with Odlums, Ireland's main flour miller. "We test many varieties of wheat grown in various locations around Ireland, but the majority of the tests that had been done before did not use modern methods. Some of the tests we brought in were brand new and some were standard, but new to this programme. For example, we introduced the use of lasers to our programme as a means of real-time monitoring of dough fermentation."

The research centre also looked at wheat from other countries such as Canada, France and the UK for comparison purposes.

In the initial testing, Dr Gallagher and her team fractionated (or separated) milled flour into its individual proteins, using a new Lab-on-Chip method performed by Agilent's Bioanalyser. This method can test 10 samples of flour in 30 minutes and is quicker than traditional methods, such as gel electrophoresis. The method quantifies the molecular weight of proteins in the flour. It reveals firstly that each flour has a unique protein pattern and this, in turn, reveals what bakery products the flour is most suited to. For example, there are low (7%), medium and high (14%) protein flours; the former is best suited for cakes and confectionery and the latter (high protein) for bread and cakes.

The Bioanalyser is specialist equipment that can be used by millers to advise bakers on which flours (or composites) are most suitable for various end-products. AFRC carries out tests for both millers and bakers in Ireland and while its remit is for the Irish food industry, it welcomes visitors to see the tests in action. Research papers are also available on its website (see below).

More established tests such as those on dough, using the extensograph and alveograph, have been used to predict baking properties. Both these pieces of equipment and tests are already in use in bakery businesses.

Laser technology

A totally new test - the structured lighting method - involved shining laser beams on a piece of dough inside a standard proving cabinet. Previously, a specialist machine was used, the Chopin rheofermentometer, which evaluates dough-proving properties within a closed cabinet.

The new test shines lasers vertically and horizontally across the dough as it ferments, so that expansion rates can be measured. Following a series of mathematical calculations, developed by a PhD student, the proving capacity or fermentation properties of dough can be calculated. It is possible to monitor dough density of batters - cake, confectionery and gluten-free. The tests showed that wheat with low dough density at the end of fermentation produced breads with high-volume loaf.

At UCD, real-time dynamic imaging was used to observe the baking properties of confectionery, cakes and biscuits. The tests physically measure how much the product increases in volume during the baking process. Researchers took digital photos, at regular intervals, of products rising in the oven. Colour-coded needles were placed in raw batter, so the rate of rising could be measured against the various colours at different heights.

AFRC is continuing its work, testing wheat, flour and dough by scanning these products with Near Infrared (NIR) technology. This will distinguish between various samples on the basis of composition and these results will be compared with new and routine cereal testing methods, including those already mentioned above.

l For further details of the research - A bag of tricks for millers and bakers CF019-4 and previous bakery research papers CF019 - go to: www.relayresearch.ie.





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