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

Define the uremia and nitrogen disposal, Define the Uremia and Nitrogen Dis...

Define the Uremia and Nitrogen Disposal? In animals, faecal and renal nitrogen were enhanced and decreased uremia was seen in normal and nephrectomised animals. The mechanisms

Define precautions for preparation of phosphate buffers, Define Precautions...

Define Precautions for Preparation of Phosphate Buffers? 1. Glass electrodes should always be dried before and after measuring pH with a tissue paper. 2. The pipettes should

Define the meaning of goitrogens, Define the Meaning of Goitrogens? Goi...

Define the Meaning of Goitrogens? Goitrogens are substances that interfere with iodide metabolism in any way that inhibits thyroid hormone synthesis. As a result, there is augm

Respiration - metabolism of pollen tubes, Respiration - Metabolism of Polle...

Respiration - Metabolism of Pollen Tubes In the unpollinated pistils of Hippeastrum hybridum very high O 2 , tension exists from stigma down through most of the style. During

Explain faecal coliforms - microbiological study of water, Explain the Faec...

Explain the Faecal Coliforms - Microbiological Study of Water? The faecal coliforms include a wide range of bacteria, many of which are not primarily the intestinal bacteria. T

Function of centrioles, FUNCTION In animal cells centrioles play import...

FUNCTION In animal cells centrioles play important role in initiation of cell division by arranging spindle fibres between two poles of cell.Thus they play a role in division o

Muscle cells, explain why it is essential that muscle cells, during anaerob...

explain why it is essential that muscle cells, during anaerobic respiration, convert pyruvic acid(pyruvate) into lactic acid, even though the conversion results in an accumulation

What are the grasslands of north america, What are the grasslands of North ...

What are the grasslands of North America and of South America respectively called? The steppe grasslands of North America are known as prairies. The grasslands of South America

Haversian canals and the volkmann canals of the bones, Q. What are the Have...

Q. What are the Haversian canals and the Volkmann's canals of the bones? Is the osseous tissue vascularized? The Haversian canals are longitudinal canals present in the osseous

Supplementation to prevention of iron deficiency anaemia, Define Supplement...

Define Supplementation to prevention of iron deficiency anaemia? Supplementation with low doses of iron is necessary to prevent anaemia in particular groups of people. Fortifie

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