The juices are made dilute by adding distilled water to it, in order
to remove colour and to make it colourless so that colour change can be
easily watched and noted down. Now test for food components are taken
down with the solution.
|
Test
|
Observation
|
Inference
|
| ORANGE TEST: |
|
|
| Test for acidity: |
|
|
| Take 5ml of orange juice in a test tube and dip
a pH paper in it. If pH is less than 7 the juice is acidic else
the juice is basic. |
The pH comes out to be 6. |
Orange juice is acidic. |
| Test for Startch: |
|
|
| Take 2 ml of juice in a test tube and add few
drops of iodine solution. It turns blue black in colour than
the starch is present. |
Absence of blue black in colour. |
Orange juice is acidic. |
| Test for Carbohydrates (FEHLING'S
TEST): |
|
|
| Take 2 ml of juice and 1 ml of fehling
solution A & B and boil it. Red precipitates indicates the presence
of producing sugar like maltose, glucose , fructose & Lactose. |
No red coloured precipitates obtained. |
Carbohydrates absent. |
| Test for Iron: |
|
|
| Take 2 ml of juice add drop of conc.
Nitric acid. Boil the solution cool and add 2-3 drops of potassium
sulphocyanide solution .Blood red colours shows the presence
of iron. |
Absence of blood red colour. |
Iron is absent. |
| Test for Calcium: |
|
|
| Take 2 ml of juice add Ammonium chloride
and ammonium hydroxide solution. Filter the solution and to
the filterate add 2 ml of Ammonium Oxalate solution. white ppt
or milkiness indicates the presence of calcium. |
Yellow precipitate is obtained. |
Calcium is present. |