Gluten content, gas retention and physical properties of starch in selected flours

Essay by krammerUniversity, Bachelor's August 2005

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Gluten content, gas retention and physical properties of starch in selected flours.


This experiment has three parts; properties of starch, gluten content of flour and gas retention of doughs. One objective of this experiment is to assess the properties of starch using a microscope before and after gelatinisation. Potato starch was found to be the quickest forming gel and pre-gelatinised starch was the most viscous. The second part of this experiment measured gluten quantity of four flours. Rice flour was found to contain no gluten and is perfect for those with celiac disease but not for baking due to lack of elasticity. Gas retention in doughs is closely related to gluten quantity. There was some fluctuation of the results in the third part of the experiment making the data somewhat unreliable. This could be due to gas leakage and human error. However the data shows that gluten flour produces the most gas, followed by bread flour, then cake flour and lastly rice flour.

This data is used to assess the suitability of flours to the baking of breads and cakes.


This experiment was divided into three components. The first method examined the properties of starch granules. The second method assessed gluten quantity and the last measured gas retention in doughs. These are labelled part A, B and C respectively.

Starch consists of amylose and amylopectin. "The overall behaviour of a starch is the relative amounts of amylose and amylopectin" (McWilliams, 2001). Mostly starches contain more amylopectin than amylose. Amylopectin makes up 75% of the starch in cereals (McWilliams, 2001).

The size of granules varies for different types of starch. Wheaten starch granules measure10-35m this is small in comparison to potato starch, which is approximately 100m (McWilliams, 2004). I believe there will be a difference in gelation rate...