Gluten

TITTLE : FORMATION OF GLUTEN IN DIFFERENT TYPES OF FLOUR INTRODUCTION Gluten is a protein composite found in foods processed from wheat and related grain species, including barley and rye. Gluten gives elasticity to dough, helping it rise and keep its shape and often gives the final product a chewy texture. Gluten may also be found in some cosmetics, hair products, and other dermatological preparations. Gluten is also defined as a cohesive, elastic protein that is left behind after starch is washed away from a wheat flour dough. Only wheat is considered to have true gluten. Gluten is actually made up of many different proteins. Gluten is the composite of a gliadin and a glutenin, which is conjoined with starch in the endosperm of various grass-related grains. The prolamin and glutelin from constitute about 80% of the protein contained in wheat seed. Being insoluble in water, they can be purified by washing away the associated starch. Worldwide, gluten is a source of protein, both in foods prepared directly from sources containing it, and as an additive to foods otherwise low in protein.True gluten, with gliadin and glutenin, is limited to certain members of the grass family. The stored proteins of maize and rice are sometimes called glutens, but their proteins differ from true gluten. There are also many types of flour in food processing which the gluten is present.

OBJECTIVE To determined the formation of gluten in different types of flour

PROCEDURE

55 g of each type of flours is weighed and put into mixing bowls

25 mL of water is added and mixed to each bowl of flour

The dough mixture is kneaded for about 15 minutes each

The texture , appearance , colour , elasticity , and flexiblity of each dough ball is noted

The dough ball is soaked in a beaker that contain water and the dough is squeeze to drain white and starchy water

The above process is continued until there are no more starch comes out

The gluten threads is observed and the result is recorded

RESULTS 1.1

: OBSERVATION OF DOUGH BALL

SAMPLE Normal

TEXTURE

APPEARANC

COLOUR

ELASTICITY

FLEXIBILITY

Tough

E Berketul2

Yellow

Elastic

Flexible

Tougher

Berketul2

Pale

Elastic

Flexible

wheat flour High protein

yellow

wheat flour Cake flour

Tough

Smooth

Pale

Elastic

Flexible

Rice flour

Soft

Smooth

yellow White

Not elastic

Flexible

1.2

: OBSERVATION OF GLUTEN FORMATION SAMPLE

Normal wheat flour High protein wheat flour Cake flour Rice flour

GLUTEN COLOUR Yellowish White White None

SIZE Large Largerst Small None

DISCUSSION From the experiment , we need to determine the formation of gluten in different types of flour which is normal wheat flour , high protein wheat flour , cake flour and also rice flour. The dough ball and gluten formation also has been observed. Gluten is extracted from flour by kneading the flour, agglomerating the gluten into an elastic network, a dough, and then washing out the starch. Starch granules disperse in running cold water, and the dispersed starch will be sedimented and removed leaving only a threads of gluten. Gluten is forms when glutenin molecules cross-link to form a submicroscopic network attached to gliadin, which contributes viscosity (thickness) and extensibility to the mix. There are also many factors that can affect the gluten development which include extent of mixing

amount of

water added, presence of fats , pH, salt , temperature and etc Through this experiment , the texture , appearance , colour , elasticity and flexibility of dough ball is observed where normal wheat flour and cake flour have tougher texture . Meanwhile, high protein wheat flour has the toughest texture and rice flour contribute to soft texture among all the samples. The appearance that has been seen for all four samples also show that cake flour and rice flour have smooth appearance while both normal wheat flour and high protein wheat flour have curdle appearance. On the other hand , the colour for normal wheat flour , rice flour and both high protein wheat flour and cake flour show yellow , white and pale yellow colour respectively. The elasticity for normal wheat flour , high protein wheat flour and cake flour are also elastic than rice flour which is not elastic at all. Lastly , all the samples is flexible in terms of their flexibility. The observation of gluten formation in all the samples also show that high protein wheat flour has the largest gluten size than normal wheat and cake flour which have large smaller gluten size respectively. The colour of gluten

for normal wheat , high protein wheat and cake flour also show yellowish , white and white in colour respectively. Meanwhile , rice flour did not has gluten at all and the colour of the gluten cant be observed as this flour is dissapeared when it has been washing out together with the starch. The protein content in different types of flour also play an important role where the higher the protein content , the higher the gluten form in certain flour. Among of all this samples , high protein wheat flour has the largest size of gluten than others because it contains lots of gluten-forming proteins, making it suitable for bread-making. The observation of dough ball and the colour of the gluten, is also different as

diferent

ingredients

is

added

to

prepared

the

samples.

For

examples,normal wheat and high protein wheat flour has been added with wheat than cake and rice flour that are added with their own different proportion of ingredient. This will result different texture,appearance,colour and etc of both dough ball and the gluten. However , in this experiment there are many error that has been done that could affect the accuracy of the result .For example , the amount of water added is not uniform as some samples may added with higher amount of water than others . Besides, the weight of the flour also is not same as the process of weighing is not properly conducted by the handler. To minimize these errors various precautions should be taken, care during conducting this experiment must be employed besides three consecutive of weighing were carried out to eliminate the errors of the handlers

CONCLUSION From the experiment , the high protein wheat flour has largest size of gluten while rice flour did not have gluten at all. Thus , different types of flour has different amount of gluten. Hence , the hypothesis is accepted.

QUESTIONS 1. List the major proteins present in wheat flour. - Major protein present in wheat flour are albumin, globulin, gliadin and glutenin (gluten) 2. What is Gluten ? - Gluten is a composite formed from several different proteins. It is found most commonly in wheat and other related grains, such as barley and rye. Adding texture and a characteristic chewiness to baked goods, this ingredient is used in a wide variety of other foods as a thickener and binder, flavor enhancer, and protein supplement. 3. Which flour has greater gluten content ? - High protein wheat flour has greater glutent content 4. Which flour is suitable for bread making ? - High protein wheat flour is suitable for brad making . Because it will increase the stretch in white and mixed flour breads

REFERENCES H. Steinman , Wheat, Gluten Allergy , ( 2012 ) , Gluten Intolerance and Gluten Enteropathy , Retrieved from www.scienceinafrica.co.za P. Barham , The Science of Cooking , ( 2001 ) , Springer Inc Types of Wheat Flour - Flour for Bread Baking , ( 2012 ) , Retrieved from www.germanfood.about.com. What is gluten? What is gliadin? , ( 2012 ) , Retrieved from www.celiac.com