Overall about wheat flour

FLOUR - SPECIFICATION INDICATORS

 

1. MOISTURE

Moisture content is determined by heating a flour sample in air oven and compare the weight of the sample before and after heating. The amount of weight loss is the moisture content.

Moisture content results are expressed as a percentage. Example: 13.5%

Moisture is also an indicator of flour storability. Flour is high moisture content (over 14.5%) attracts mold, bacteria, and insects, all of which cause deterioration during storage.

Flour with low moisture content is more stable during storage.

 

2/. PROTEIN

Protein content is determined through high temperature combustion in protein analyzer.

Since protein is the major flour compound that contents nitrogen, the protein content can be determined by measuring the amount of nitrogen released during burning.

Protein content results are expressed as a percentage. Example: 11.5%

Protein content is the key specification for flour purchasers since it is related to many processing properties such as water absorption and Gluten strength.

Protein content can also be related to finished product attributes, such as texture and appearance.

Low protein flour is desired for tender products like cakes, steamed buns, etc.

High protein flour is desired for product with chewy texture such as sandwich, noodles, etc.

High protein flour content usually requires more water and longer mixing time to achieve optimum dough consistency.

 

3/. ASH

Ash content is determined by high temperature incineration in an electric muffle furnace. When a sample is incineration in an ash oven, the high temperature drives out the moisture and burns away all the organic material (starch, protein, and oil), leaving only the ash.

Ash content results are expressed as a percentage of initial sample weight. Example:  0.53%. Flour ash is usually expressed on a common moisture basic of 14%.

Ash in flour can affect color, imparting a darker color to finished products.

Some special products (Pau, Noodles) require a particular white flour call for low ash content.

 

4/. WET GLUTEN

Wet gluten content is determined by washing the flour sample with a salt solution to remove the starch and other soluble from sample. The residue remaining after washing is the Wet Gluten

Wet gluten content results are expressed as a percentage on 14% moisture basic.

Example:  35% for high protein flour, strong gluten or 22% for low protein flour, weak gluten.

During centrifugation, the gluten is forced through a sieve. The percentage of Gluten remaining on the sieve is defined as the Gluten Index, which is an indication of gluten strength. A high Gluten index indicates strong Gluten.

 

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