by Thomas Ziolko, Bühler AG
Too much residual starch in bran means foregoing profit for millers
Bühler offers two ways out of the ‘residual starch dead end’ with its online measuring technology: the NIR Multi Online Analyzer MYRG or the Online Color and Speck Measurement MYHB. Both methods measure and report an increase in residual starch without loss of time making prompt correction possible.
In the grain milling industry the term extraction rate describes the amount of flour that can be made from 100 kg of grain. In modern milling operations, yield calculators continually monitor production and determine the degree of extraction. The goal of every miller when producing white, low-ash flour is to separate as much of the endosperm from the husk (bran) as possible. Bran is considered a by-product in milling and can be used as an additive for feed or sold as is.
Optimum extraction rate
Flour particles that stick to the bran as residual starch in the separation process are considered a loss by the miller. The higher the extraction rate, the higher the yield and thus also the miller’s profit.
However, it should be noted that as the extraction rate increases, more edge and husk particles are released from the grain along with the flour starch. With a higher extraction rate, the flour becomes darker and has higher ash content. Millers will do everything they can to achieve the optimal extraction rate based on the desired type of flour and customer requirements. This includes trying to avoid too high of a residual starch content in the bran which means lower yields.
Of course, other parameters that influence the baking properties must also be taken into consideration.
Polarimetric determination
But how can the miller determine whether ‘his’ bran has too much residual starch? An initial indication is that yield drops or the ash content in the flour is low. If the miller determines this is true, he can use polarimetric starch determination according to Ewers (ISO 105020:1997) in the lab to determine the residual starch content in the bran. This method dissolves the raw starch in the test sample in hot, diluted hydrochloric acid.
After precipitation of the spurious substances, the optical rotation of the raw starch solution is polarimetrically measured and the starch content is calculated based on the rotation angle.
This is an old method and has its pitfalls: A conventional value results because other optically active carbohydrates (particularly water soluble ones) can be detected as well. It is also time-consuming and requires chemicals, which is why very few millers use this method regularly. Sometimes the samples are sent to an external laboratory.
The reverse way is also a possibility: The ash in the bran is measured. Most millers simply eyeball whether there is too much starch in the bran - the lighter it is, the more residual starch it contains.
Read the full article, HERE.
Too much residual starch in bran means foregoing profit for millers
Bühler offers two ways out of the ‘residual starch dead end’ with its online measuring technology: the NIR Multi Online Analyzer MYRG or the Online Color and Speck Measurement MYHB. Both methods measure and report an increase in residual starch without loss of time making prompt correction possible.
In the grain milling industry the term extraction rate describes the amount of flour that can be made from 100 kg of grain. In modern milling operations, yield calculators continually monitor production and determine the degree of extraction. The goal of every miller when producing white, low-ash flour is to separate as much of the endosperm from the husk (bran) as possible. Bran is considered a by-product in milling and can be used as an additive for feed or sold as is.
Optimum extraction rate
Flour particles that stick to the bran as residual starch in the separation process are considered a loss by the miller. The higher the extraction rate, the higher the yield and thus also the miller’s profit.
However, it should be noted that as the extraction rate increases, more edge and husk particles are released from the grain along with the flour starch. With a higher extraction rate, the flour becomes darker and has higher ash content. Millers will do everything they can to achieve the optimal extraction rate based on the desired type of flour and customer requirements. This includes trying to avoid too high of a residual starch content in the bran which means lower yields.
Of course, other parameters that influence the baking properties must also be taken into consideration.
Polarimetric determination
But how can the miller determine whether ‘his’ bran has too much residual starch? An initial indication is that yield drops or the ash content in the flour is low. If the miller determines this is true, he can use polarimetric starch determination according to Ewers (ISO 105020:1997) in the lab to determine the residual starch content in the bran. This method dissolves the raw starch in the test sample in hot, diluted hydrochloric acid.
After precipitation of the spurious substances, the optical rotation of the raw starch solution is polarimetrically measured and the starch content is calculated based on the rotation angle.
This is an old method and has its pitfalls: A conventional value results because other optically active carbohydrates (particularly water soluble ones) can be detected as well. It is also time-consuming and requires chemicals, which is why very few millers use this method regularly. Sometimes the samples are sent to an external laboratory.
The reverse way is also a possibility: The ash in the bran is measured. Most millers simply eyeball whether there is too much starch in the bran - the lighter it is, the more residual starch it contains.
Read the full article, HERE.
The Global Miller
This blog is maintained by The Global Miller staff and is supported by the magazine Milling and Grain
which is published by Perendale Publishers Limited.
For additional daily news from milling around the world: global-milling.com
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