The most common form of casein is sodium caseinate. As a food source, casein supplies amino acids, carbohydrates, and two essential elements, calcium and phosphorus.
Casein contains a high number of proline residues, which do not interact. There are also no disulfide bridges. As a result, it has relatively little tertiary structure. It is relatively hydrophobic, making it poorly soluble in water. It is found in milk as a suspension of particles, called casein micelles, which show only limited resemblance with surfactant-type micelles in a sense that the hydrophilic parts reside at the surface and they are spherical.
However, in sharp contrast to surfactant micelles, the interior of a casein micelle is highly hydrated. The caseins in the micelles are held together by calcium ions and hydrophobic interactions. Any of several molecular models could account for the special conformation of casein in the micelles. Another model suggests the nucleus is formed by casein-interlinked fibrils. Finally, the most recent model proposes a double link among the caseins for gelling to take place.
The isoelectric point of casein is 4. Since milk's pH is 6. The purified protein is water-insoluble. While it is also insoluble in neutral salt solutions, it is readily dispersible in dilute alkalis and in salt solutions such as aqueous sodium oxalate and sodium acetate.
The enzyme trypsin can hydrolyze a phosphate-containing peptone. Report this Document. Flag for inappropriate content. Download now.
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Need an account? Click here to sign up. Download Free PDF. Chemistry Investigatory Project on Food Adulteration. Jump Cuts. A short summary of this paper.
Download Download PDF. Translate PDF. Madhu Saxena, PGT Chemistry and our lab attendant for their able guidance and support in completing my project. I would also like to extend my gratitude to the principal Mrs. Jyoti Gupta for providing me with all the facility that was required.
Certiicate 2. Acknowledgement 3. Objective 4. Introduction 5. Theory 6. The report is found worthy of acceptance as final Project report for the subject Chemistry of class XIIth sci. Gupta sir for guiding me immensely through the course of the project. He always envinced keen intrest in my project.
My sincere thank goes to our principal sir for his co-ordination in extending every possible support for the completion of this project. I must thanks to my classmates for their timely help and support for completion of this project. Last but not the least, I would like to thank all those who had helped directly or indirectly towards the completion of this project. To study the digestion of starch by saliva.
To study the effect of temperature on the digestion of starch by saliva. To study the effect of pH on the salivary digestion of starch. The act of chewing stimulates the excretion of saliva. Saliva mixes up with the food and helps its digestion. That is, the enzyme ptyalin or amylase present in human saliva hydrolyzes the big molecules of food into many molecules. For example, starch into mono-saccnaricies maltose and glucose; proteins into amino acids and fats into fatty acids and glycerol.
Thus saliva not only helps in digestion of food but also convert into energy generating substances. Further, enzyme and their activity are very sensitive to temperature and pH. Even a slight variation in these two factors, can disturb the action of enzymes. In other words, digestion of food by salivary amylase is also effected by temperature and pH and can be verified experimentally. For example, hydrolysis of starch can be verified by testing it with iodine solution.
Starch forms blue coloured complex with iodine. If no starch is present in a system it will not give blue colour with iodine. Test tubes 2. Test tube stand 3. One dropper 4. Beaker 5. Stop watch 6. Starch 7. Iodine solution 8. Thermometer 9. Dilute HCl solution Dilute NaOH solution. Collection of Saliva:- Rinse mouth thoroughly with cold water and ensure that it does not contain any food particles.
Now take about ml of lukewarm water in the mouth and keep for about three minutes so that saliva mixes up well with it. Spit this into a beaker.
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