Explain changes in gluten proteins during dough formation, Biology

Assignment Help:

Changes  In Gluten Proteins During Dough Formation

Initially, gluten is formed when flour and water are mixed together. The proteins in the flour, glutenin and gliadin cross  link, using water as a vehicle to form gluten. Enhancing this gluten structure  is important relative to developing a gas retaining structure in the chapati/bread.   When the hydrated bread flour is mixed and kneaded, the gluten proteins orient themselves aligns and partially unfolded. This enhances hydrophobic interaction and formation of disulphide bridges through -S-S- interchange reactions.  A  3-dimensional viscoelastic protein network is established, as the initial gluten particles transform into this membrane (film), thus serving to entrap starch  granules and other flour components.  Cleavage  of disulphide bridges by reducing agents such as cysteine,  destroys the cohesive structure of hydrated gluten and  bread dough ;  the addition of  agents  such  as  bromates,  increase  toughness    and elasticity. "Strong" flours from certain wheat varieties require long mixing time and give very cohesive dough. "Weak flours"  are less effective and  gluten network breaks down when the energy  or duration of mixing exceeds a certain level, probably because of -S-S-  bonds  are ruptured (especially in absence of  air). 

Dough strength  appears  to  be  related to a  large   content  of  high molecular   weight glutenins including totally insoluble  "residue proteins". From experiments with "reconstituted" wheat flours  of varying  gliadin and glutenin  ratios, it can be  postulated  that the  glutenins are responsible for the  elasticity,  cohesiveness and  mixing  tolerance  of  dough  whereas  gliadins   facilitate fluidity,   extensibility  and  expansion  of  the  dough, thus contributing  to a larger bread loaf volume. A proper balance of the proteins is essential for bread making.  Excessive  cohesion (glutenins)  inhibit \the expansion of trapped CO2 bubbles  during fermentation,  the rise of the dough and the subsequent  presence of  open  air cells in the bread  crumb.  Excessive extensibility (gliadins) results in gluten films that are weak and permeable; thus retention of CO2 is poor and dough collapse may occur.

 


Related Discussions:- Explain changes in gluten proteins during dough formation

Explain the results of coarctation of aorta, Explain the Results of Coarcta...

Explain the Results of Coarctation of Aorta? Early hospital death in isolated coarctation is around 2 to 10 per cent. In many reports, mortality for older babies approaches 0.

Do all mammals have a placenta, Do all mammals have a placenta? Mammals...

Do all mammals have a placenta? Mammals of the monotreme group (echidnas, platypus,) are oviparous, egg-laying, and they do not have a placenta. Mammals of the marsupial group

Explain calvin cycle, Calvin cycle (the aka Calvin-Benson Cycle or the Car...

Calvin cycle (the aka Calvin-Benson Cycle or the Carbon Fixation) is the series of biochemical, enzyme-mediated reactions during which the atmospheric carbon dioxide is reduced an

What is the tertiary structure of a protein, What is the tertiary structure...

What is the tertiary structure of a protein? What are the main kinds of tertiary structure? The tertiary protein structure is a spatial conformation additional to the secondary

Main opportunistic diseases that can affect aids patients, Q. What are the ...

Q. What are the main opportunistic diseases that can affect AIDS patients? Among the opportunistic diseases that affect HIV contaminated people during the AIDS stage some are:

Why is it important to study biology, Why is it important to study biology?...

Why is it important to study biology? By studying biology, you can create informed decisions on issues that impact you and society, like environmental issues, health, and tech

How the respiratory system in aquatic molluscs characterized, Q. How is the...

Q. How is the respiratory system in aquatic molluscs characterized? What adaptive respiratory structure do terrestrial molluscs present? In terrestrial molluscs the rich vascul

What is heme degradation, Bile pigments exist in both the animal and plant ...

Bile pigments exist in both the animal and plant kingdoms, and are building by breakdown of the cyclic tetrapyrrole structure of heme. In the animals this pathway is an excretory

Explain different amino acids found in proteins, How many different protein...

How many different proteins, each composed of 8 amino acids, can be constructed using the 20 different amino acids found in proteins?

Photochemical stage of the photosynthesis process, Q. What are the procedur...

Q. What are the procedures of the photochemical stage of the photosynthesis process? Photolysis of water, with liberation of molecular photophosphorylation and oxygen of ADP, w

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd