Question -
Answer -
(a) Test for protein
BiuretтАЩs test тАУ If BiuretтАЩs reagent is added to protein, then the colour of the reagent changes from light blue to purple.
(b) Test for fats and oils
Grease or solubility test
(c) Test for amino acid
Ninhydrin test тАУ If Ninhydrin reagent is added to the solution, then the colourless solution changes to pink, blue, or purple, depending on the amino acid.
| Test | Name of item | Procedure | Result | Conclusion |
| BiuretтАЩs test | Fruit juice | Juice + biuretтАЩs reagent | Change of color from light blue to purple | Presence of protein |
| Saliva | Saliva + biuretтАЩs reagent | Change of color from light blue to purple | Presence of protein |
| Sweat | Sweat + biuretтАЩs reagent | Colour does not change | Absence of protein |
| Urine | Drops of urine + biuretтАЩs reagent | Change of color from light blue to purple | Presence of protein |
| Grease test | Fruit juice | Few drops of juice on brown paper | Translucent spot not observed | Absence of oils and fats |
| Saliva | Few drops of saliva on brown paper | Translucent spot not observed | Absence of oils and fats |
| Solubility test | Sweat | Water added with sweat | Oil presence | Fats or oils can be present |
| Urine | Water added to a few drops of urine | Slight oily presence | Fats may or may not be present |
| Ninhydrin test | Fruit juice | Juice+ninhydrin reagent (boil for few minutes) | Change of color from no color to purple, pink or blue | Presence of amino acids |
| Saliva | saliva+ninhydrin reagent (boil for few minutes) | Change of color from no color to purple, pink or blue | Presence of amino acids |
| Sweat | sweat+ninhydrin reagent (boil for few minutes) | No color change | Absence of amino acids |
| Urine | urine+ninhydrin reagent (boil for few minutes) | Depending upon type of amino acid, colourless solution changes to purple, pink or blue color | Presence of amino acids |
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