Explain starch gelatinization, Biology

Assignment Help:

Starch gelatinization

Undamaged starch granules are insoluble in cold water but can imbibe water  reversibly i.e. they can swell slightly and then return to their original size on drying, when starch is heated with excess of water, the molecular order of the granule is gradually and irreversibly destroyed at the gelatinisation temperature, which is approximately in the  range of 60-70°C for most of the starches. Amylose is preferentially leached out of the network and gets solubilized, however, some leaching of amylose can also occur prior to gelatinization. When further heated, starch granules are disrupted and partial solubilization is achieved. Total gelatinization usually occurs over a temperature range with larger granules generally gelatinizing first. At temperatures below 100° C, true molecular solution is not achieved and the swollen hydrated granules consisting of mainly amylopectin remain.  Continued heating of starch granules in excess water results in further granule swelling, additional leaching of soluble components (primarily amylose) and eventually, total disruption of granules especially with the application of shear forces,. This phenomenon results in the formation of a starch paste. The melting temperature of the crystallites is 190°C. Gelatinization is an endothermic process (10 mJ/mg), i.e. a chemical reaction accompanied by the absorption of heat.   

 


Related Discussions:- Explain starch gelatinization

Zoonoses disease-cryptococcosis, Cryptococcosis An opportunistic infect...

Cryptococcosis An opportunistic infection, caused by Cryptococcus neoformans is affecting immunocompromised individuals mainly with impaired cell mediated immunity. The disease

Explain the s1m filament theory of muscle contraction, Explain the s1M fila...

Explain the s1M filament theory of muscle contraction. What is special of "FlavrSavr" variety of tomato? Why is it preferred to its normal native variety? Illustrate a label

What are the cells that produce the myelin sheath, What are the cells that ...

What are the cells that produce the myelin sheath? Of which substance is the myelin sheath formed? In the central nervous system (CNS) the myelin sheath is made by apposition o

Studying the main parts of a flower, Studying the main parts of a flower ...

Studying the main parts of a flower Study specimens of large easy flowers such as tulips or lilies. Count the stamens and observe how they are arranged about the central pistil

Nutrition education for prevention of vitamin a deficiency, Define Nutritio...

Define Nutrition Education for prevention of vitamin a deficiency? Ignorance, you may recall studying earlier, is an important determinant of vitamin A deficiency. There is, th

State the testing of ketones in urine, State the Testing of Ketones in Urin...

State the Testing of Ketones in Urine Ketones are also known as ketone bodies. Ketone bodies are catabolic products of free fatty acids and three ketone bodies that can be dete

Difference between diabetes mellitus and diabetes insipidus, Q. What is the...

Q. What is the difference between diabetes mellitus and diabetes insipidus? What are the characteristic signs of diabetes insipidus? Diabetes mellitus is the disease caused by

Reflex action, REFLE X ACTION - Marshel Hall discovered reflex ac...

REFLE X ACTION - Marshel Hall discovered reflex action. Best & Taylor defined it. Reflex action is functional unit of CNS. It is sudden, immediate involuntary acti

Factors affecting normal blood sugar levels, Q. Factors Affecting Normal Bl...

Q. Factors Affecting Normal Blood Sugar Levels? Earlier in our discussion, we learnt that insulin is the most important factor responsible for normal blood sugar levels. Now we

Explain an open circulatory system, Why, even though they have an open circ...

Why, even though they have an open circulatory system, can flying insects like flies beat their wings with great speed? In insects the circulatory system is open but this syste

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