FST261
EXPERIMENT 7: FORMATION OF GLUTEN IN DIFFERENT TYPES OF FLOUR Introduction (4M) Methods (2 M) Results (4M) Discussion (4M) Conclusion (3M) References (1M) Questions (1M) Format (1M) TOTAL (20M)
NAME: 1. 2. 3. 4. 5. 6.
AFIQAH NAIMI BINTI MOHAMAD NURUL NURIANI BINTI KHAIRULAMAR KHAIRULAM AR NADZRATUL AUFA BINTI MOHD FAISAL NOOR HIDAYAH BINTI MOHAMAD RAFII SYAHIRAH AQILAH BINTI SHAHRAN NUR ASHIKIN BINTI ZAMAN
(2015847642) (2015822486) (2015870426) (2015882782) (2015891798) (2015856214)
GROUP
: AS1164A2
DATE OF EXPERIMENT
: 14TH DECEMBER 2016
DATE OF SUBMISSION
: 21ST DECEMBER 2016
FST261 1.0 INTRODUCTION This experiment was conducted to study about gluten, its importance in bread making and its presence in all-purpose flour. It is also done to observe the formation of gluten in different types of flour. Wheat flour is a predominant ingredient in numerous food products, bread, cakes, doughnuts, cracker, cookies, pasta and noodles. Generally, the quality of wheat flour depends on total protein, gluten, amylase, amylopectin (Chen, Zhu, & Zhao, 2017). Wheat (Tritichum aestivum L.) is one of the most cereal grain used worldwide (Boita et al., 2016). The major protein present in flour is glutenin and gliaden. Gluten is a general name for the proteins found in wheat (wheatberries, durum, emmer, semolina and einkorn), rye, barley and triticale – a cross between wheat and rye. Gluten helps foods maintain their shape, acting as glue that holds food together. Gluten can be found in many types of foods, even ones that would not be expected (celiac.org). There are several tests to test wheat flour. The physical tests conducted are to determine flour colour and wheat kernel characteristics specified by wheat processors. The laboratory milling test is used to evaluate the milling performance of wheat and to produce flour for other laboratory tests. Wheat and flour specifications often require specialized testing to determine how flour will perform during processing. Several tests evaluate dough and gluten strength properties. The
wet
gluten
test
measures
the
amount
of
gluten
protein
in
flour
(WheatFlourTestingMethods.pdf). Next, the chemical tests are AOAC method, acid insoluble ash and ash content. Nowadays, there are many types of flour such as normal wheat flour, high protein flour, rice flour and cake. However, all these different flour have a different usage. First, normal wheat flour is used as an all-purpose flour, in which it is able to make all sorts of foods. Second, high protein flour is normally used for baking of breads as is contains a high amount of gluten. Third rice flour is used in the making of rice noodles and pancakes. It is also known for its properties of thickening soups and stews and gluten-free. Last but not least, cake flour is used in baking of cakes as it is relatively lacking of gluten. The hypothesis that can be made is that high protein flour has the most amount of gluten.
FST261 2.0 MATERIALS / APPARATUS
Normal wheat flour
High protein wheat flour
Cake flour
Rice flour
Mixing bowl
Plastic plate
Spatula
Balance
Measuring cylinder , 25 mL
3.0 METHODS 1. About 55 gram of each type of flours was weighed and put into mixing bowls. 2. Accurately 25 mL of water was added to each bowl of flour and mixed. 3. The dough was kneaded for about 5 minutes each. 4. The texture, appearance, color, elasticity and flexibility were noted for each dough ball. 5. The dough ball was placed under the faucet and ran cold water over it. The dough ball was squeezed to drain white, starchy water. 6. This step was continuously repeated under running w ater until no more starch come out. 7. How the dough shrinks in size, changes color and became thread-like was noted. These were the gluten threads. The white as the starch was the water that drains from the dough ball and was washed out of the dough ball.
FST261 4.0 RESULTS
Table 7.1: Observation of Dough Ball Sample
Texture
Normal wheat flour
Hard
High protein wheat
Soft
flour Cake flour
Paste
Rice flour
Fine
Appearance
Can form a dough ball Can form a dough ball Can form a dough ball Powdery
Colour
Elasticity
Flexibility
Cream
Not elastic
Flexible
Cream
Elastic
Flexible
Cream
Not elastic
Not flexible
White
Not elastic
Not flexible
Table 7.2: Observation of Gluten Formation Gluten Sample Colour
Size
Unchanged
Shrink
Brown
Shrink
Cake flour
Unchanged
Unchanged
Rice flour
Unchanged
Unchanged
Normal wheat flour High protein wheat flour
FST261 5.0 DISCUSSION Gluten is defined as mixtures of proteins remain after washing the dough with water. It is made up from glutenin and gliadin with the ratio of 1:1. Both proteins can separate gluten or wheat flour according to their solubility. Gliadin is soluble in aqueous ethanol whereas glutenin is soluble in dilute acid and alkaline solution (Williams and Philips, 2012). Flour is the main ingredient in baking. It provides a good structure for the bakery product. Four different types of flour were used in this experiment which is n ormal wheat flour, high protein flour, cake flour and rice flour. Based on the observation, normal wheat flour have hard texture and it can form a dough ball. The colour of the dough ball is cream and it is not elastic. Besides, the dough ball from this wheat flour is flexible. Meanwhile, the texture for high protein wheat flour is soft. Dough ball can be formed using this type of flour. High protein wheat flour is cream in colour. It also has good elasticity and very flexible among the other types of flour. Next, the texture of cake flour is like a paste after being mixed with water. Dough ball cannot be formed using this flour. It is cream in colour and it is neither elastic nor flexible. Lastly, the texture of rice flour is fine. Dough ball cannot be formed as it is powdery. The colour of this flour is white and it is not elastic and flexible. The second observation is the gluten formation. For normal wheat flour sample, the colour is unchanged and the size of dough ball became shrinking. As for the high protein wheat flour, the colour is brown and the size became shrinking. Next, cake flour sample has the same colour before it is put under the running tap water which is cream and the size also remain the same. Rice flour also has no change in terms of colour and size. From the result obtained, it shows that more gluten is present inhigh protein wheat flour. It is because the dough ball from high protein content is elastic and flexible than the other types of flour. Function of gluten is to make the dough elastic and have a good structure to the baked product. The presence of gluten is also proven by the changes in size of the dough ball after being put under running tap water. The dough ball shrinks because of the removal of starch water and water soluble components in the dough ball (Wieser, 2007). Gluten is also present in normal wheat flour but not as much as in the high protein wheat flour.
FST261 According to the observation, cake flour is said to have a very small amount of gluten. This is related to the function of cake flour which is to produce a fine, delicate and velvety structure to the cake. Flour with high amount of gluten is not suitable to make cake because it will provide a tough and elastic structure to the cake. Rice flour is gluten-free flour. It is commonly used by the Asians to make variety food products such as rice noodle and can also replace wheat in baked goods (Brown, 2010).
FST261 6.0 CONCLUSION In conclusion, gluten is present in all types of flour. The hypothesis made was also accepted. Gluten can be high or low content based on the flour. It can give different texture, appearance, colour, elasticity and flexibility of dough based on the flour that to be used in food production. Based on the table 7.1, observation of dough ball stated that normal wheat flour and high protein wheat flour have high content of gluten as it give hard texture, very slightly elastic and have flexibility than cake flour and rice flour. It is supported by the result of table 7.2 which stated that normal wheat flour and high protein wheat flour also give different colour and size as they are creamy in colour and the size become smaller than normal dough after running under the tap water compare to the low content of gluten, cake flour and rice flour which have white colour but become loss existence when undergo the running tap water. The uses of gluten can be applied in many aspects in food making. For example, gluten gives bread its elasticity, texture and structure. Addition of gluten resulted in a significant decrease of the dough development time, whereas samples with powdered eggs and soy proteins were more difficult to hydrate and the bread with a high gluten gives a better resilience and adhesiveness compare to the breads with egg protein which is less brittle (Patrascu, Banu, Vasilean, & Aprodu, 2016).
7.0 QUESTIONS 1.
List the major protein present in wheat flour?
Albumins and globulins, Gluten, Gliadins,Glutenins 2.
What is gluten?
Gluten is a general name for the proteins found in wheat,rye,barley and triticale a cross between wheat and rye. Gluten helps foods maintain their shape, acting ad a glue that holds food together. 3.
Which flour has greater gluten content?
High protein wheat flour
FST261 4.
Which flour do you think is suitable in breadmaking? Why?
Cake flour because the cake flour has the least protein and yields extra-light baked goods
8.0 REFERENCES 1. Williams P.A and Philips G.O. 2012. Gums and Stabilisers for the Food Industry 16, Royal Society of Chemistry, 115. 2. Herbert Wieser. 2007. Chemistry of Gluten Protein. Food Microbiology, 42 (2), 115-119. 3. Amy Christine Brown. 2010. Understanding Food Principles and Preparation, Cencage Learning. 373. 4. Boita, E. R. F., Oro, T., Bressiani, J., Santetti, G. S., Bertolin, T. E., & Gutkoski, L. C. (2016). Rheological properties of wheat flour dough and pan bread with wheat bran. Journal of Cereal Science, 71, 177-182. doi: 10.1016/j.jcs.2016.08.015 5. Chen, J., Zhu, S., & Zhao, G. (2017). Rapid determination of total protein and wet gluten in commercial wheat flour using siSVR-NIR. Food Chemistry, 221, 1939-1946. doi: 10.1016/j.foodchem.2016.11.155 6. Patrascu, L., Banu, I., Vasilean, I., & Aprodu, I. (2016). Effect of gluten, egg and soy proteins on the rheological and thermo-mechanical properties of wholegrain rice flour. Food Sci Technol Int . doi: 10.1177/1082013216665722
