Coagulation of Proteins Essay Sample
Curdling of protein refers to lodging together. like a blood coagulum. normally as a consequence of denaturation or coming out of solution due to abnormal ionic strength or a alteration of dissolver. Definite features of the proteins are changed when they are coagulated. among which is loss of solubility in H2O and dilute salt solutions. In some cases and under certain conditions the curdling procedure may be reversible. ( Campbell. et. Al. 1979 ) 4A. 2. 2 Chemistry behind Coagulation
Ovalbumin the chief protein in egg white is a ball-shaped protein denatured by heat. this means reaction is more rapid with an addition in temperature of warming. Since heat is absorbed during curdling of egg proteins. the reaction is endothermal. Egg white coagulated by heat alterations from a transparent syrupy solution to a opaque white gel. the H2O of white trapped by the protein. ( De Mann. 1986 ) 4A. 2. 3 Chemistry behind Opalescence
Opalescence is a type of dichroism seen in extremely spread systems with small opacity. The material appears yellowish-red in familial visible radiation and blue in the scattered visible radiation perpendicular to the transmitted visible radiation. The phenomenon is named after the visual aspect of opals ( Fennema. 1996 ) . There are different grades of iridescent behaviour. One can still see through a somewhat iridescent stage. The more atoms and the bigger the atoms are. the stronger the dispersing arising from them and the cloudier the peculiar stage will look. At a certain concentration the sprinkling is so strong that all light go throughing through is scattered. so that it is non crystalline any more ( Fennema. 1996 ) .
4A. 2. 4 Different Factors that Influence Coagulation of Proteins
Curdling is influenced by factors such as heat. whipping. pH and besides usage of sugar and salt. Heat should be slow and mild. The egg white coagulates. and go solid at temperatures 62-65C. Egg yolks begin to clot at 65C and go solid at 70C. Beating should be done easy because when an energy is applied. the protein begins to denature which will take to curdling. As the pH lessenings and becomes more acidic. curdling of the egg white occurs more readily. The more sugar added. the greater the heat required to convey about the curdling ; it besides increases the heat stableness of the proteins. The add-on of salt lowers the temperature at which curdling takes topographic point. ( Belitz. 1977 )
Materials and Methods
* Egg Whites
* Distilled Water
* 0. 1M Na chloride solution
* 0. 1M Ca chloride solution
* 0. 1M Ferric Chloride solution
* 0. 1M sucrose solution
* 1. 0M sucrose solution
* 0. 01M hydrochloric acid solution
* 0. 1M hydrochloric acid solution
* Filter documents
* pH metre
* Test tubing
Dilute 25ml egg white with 75ml distilled H2O. Stir easy but exhaustively.
Procedure ( Schematic )
Filter utilizing a filter paper
Add 10ml of the albumin solution and 5ml of each of the coagulator to each trial tubing. Use distilled H2O as controlled
Record the pH of the solution incorporating distilled H2O and 0. 01M and 0. 1M HCL
Topographic point all in a beaker of H2O. heat easy.
Note the temperature at which iridescence develops.
Dilute 1 egg white ( somewhat beaten ) with 3 volumes of distilled H2O ; stir easy but exhaustively and filter. Concluding volume should achieve at least 100ml. To each of a series of trial tubings. add 10ml of the albumin solution and 5ml of each of the solutions listed supra. Use distilled H2O as control. Record the pH of the solution incorporating distilled H2O and 0. 01M and 0. 1MHCl. Topographic point all in a beaker of H2O. heat easy. Note the temperature at which iridescence develops. Consequences and Discussion
Test Solution | Temperature for Opalescence ( C ) | pH value| 0. 1M Na chloride solution| 63C| -|
0. 1M Ca chloride solution| 63C| -|
0. 1M Ferric Chloride solution| 69C| -|
0. 1M sucrose solution| 63C| -|
1. 0M sucrose solution| 66C| -|
0. 01M hydrochloric acid solution| 61C| 3. 04 pH|
0. 1M hydrochloric acid solution| -| 2. 31 pH|
Distilled H2O ( control ) | 64C| 8. 78 pH|
As seen in the tabular array. most of the temperature for iridescence scopes from 60C-70C this is because egg white thickens at temperature 62C-65C harmonizing to Belitz. Besides. as said by Belitz an add-on of acid requires greater sum of heat to clot ; this is shown in the tabular array where 0. 1M hydrochloric acid solution which have a pH of 2. 31 didn’t signifier iridescence even for a longer clip or in higher temperature. 0. 1M Na chloride solution which has a temperature for iridescence of 63C. the low temperature is due to the salt content because an add-on of salt lowers the temperature at which iridescence takes topographic point. Generalization and Recommendation
Curdling of proteins depends chiefly on the intense of the heat temperature usage. besides on the whipping and add-on of salt. sugar and acid. Not all coagulators could organize iridescence this is because at a certain concentration the sprinkling is so strong that all light go throughing through is scattered. so it is non crystalline any longer. Procedures must be decently conducted. Proper handling of stuffs and instruments is a necessity. Correct measuring obtained from the instruments must be checked. Cleanliness must be extremely observed in making the experiment.
Vickie A. and Christian W. . 2008. Necessities of Food Science. Dallas. Texas: Springer. B. Srilakshmi. . 2003. Food Science. New Delhi: New Age International Ltd. . Publishers. Anonymous. Date accessed: February 9. 2013. Proteins.
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