lab report

FOOD NUTRITION BASICS LABORATORY REPORT LAB 3 PROTEINS DUE DATE Next FNB Practical NAME (CAPITALS) ______________________________GROUP LETTER___________ This work is the product of my own efforts and has not been copied from any other sources except where full acknowledgement has been given. Signed________________________________________ Student No._____________ Introduction The principle involved in this experiment is denaturation. It involves loss of ordered structure and can be caused by changes in pH value, salt concentration, surface effects or temperature. Denaturation occurs because the bonding interactions responsible for the secondary structure and tertiary structure are disrupted. In tertiary structure there are four types of bonding interactions between side chains including hydrogen bonding, salt bridges, disulfide bonds, and non-polar hydrophobic interactions. which may be disrupted. Therefore, a variety of reagents and conditions can cause denaturation. The most common observation in the denaturation process is the precipitation or coagulation of the protein. A. Denaturation of egg white. Result TubeContentsObservationsAwhite placed in water bath at 60C.Bwhite placed in water bath at 80C.-When the solution boiled on 3.30 minutes,the colour changes in yellow to white. -Boiled on 6.30 minutes, it becomes thick -Boiled on 11.11,it appeared some solid.CAdd 4 dropwise 1M Acetic acid in egg white.-The colour becomes creamy. -lump and white precipitates can be observed.DAdd 51 dropwise 5M NaCl in egg white.-The solution becomes cleanlyEAdd an equal volume of distilled water in egg white.-No observation change. -The egg white with distilled water just separated. Discussion In this experiment, by the differences of temperature, acid and NaCl, egg white will denature in such situation. The result shows that as temperature rises, the molecules have more kinetic energy. They vibrate more rapidly and collide with each other more frequently. Therefore from