What is micronised wheat

The micronising process involves the treatment of grain by infrared irradiation, and is not to be confused with ultra-fine grinding by the ' Micronizer' fluid energy mill. When infrared rays penetrate they cause the molecules of the material to vibrate at a frequency of 60,000 to 150,000 megacycles per second. This results in rapid internal heating and a rise in water vapour pressure. The grains become soft and turgid causing them to swell and fracture. Immediate rolling or flaking gelatinises the starch, considerably enhancing digestibility and feed value of the grain.

Micronising drastically reduces the counts of bacteria and moulds. The counts from two sample wheats are given below:

Sample

Count per g

Bacteria

Mould

Untreated wheat

540,000

1200

Micronised wheat

<100

<10

The effect on the milling is less efficacious. For example, in a measured experiment a control wheat conditioned to 15% moisture content (m.c.), yielded 67.3% flour, and a micronised wheat similarly conditioned yielded only 36.4% of flour. The micronised wheat flour produced was of poor colour, and clean-up of bran was unsatisfactory. It was concluded that micronised wheat was unsuitable for the normal roller-mill process to produce white flour.

The flour from micronised wheats would not be suitable for normal bakery products since the gluten quality would be spoilt by the heat generated in the micronising procedure but often finds use where the thickening properties of the gelatinised starch have value, e.g. soups.

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