ITEM

NAME OF THE TEST

PROCEDURE

RESULT

INFERENCE

1

Fruit
juice

Biuret’s
test 

Fruit juice +
Biuret’s reagent

Colour changes
from light blue to
purple

Protein is
present.

Grease test

To a brown
paper, add a few
drops of fruit
juice.

No translucent
spot

Fats and oils are
absent or are in
negligible mounts.

Ninhydrin
test

Fruit juice +
Ninhydrin reagent
+ boil for 5
minutes

Colourless
solution changes
to pink, blue, or
purple colour

Amino acids are present.

2

Saliva

Biuret’s
test

Saliva + Biuret’s
reagent

Colour changes
from light blue to
purple

Proteins are
present.

Grease
test

On a brown
paper, add a drop of saliva.

Ninhydrin
test

Saliva +
Ninhydrin
reagent + boil for 5 minutes

Colourless
solution changes
to pink, blue, or
purple colour

Amino acids are present.

3.

Sweat

Biuret’s
test

Sweat + Biuret’s
reagent

No colour change 

Proteins are
absent.

Solubility
test

Sweat + Water 

Oily appearance

Fats/oil may be present

Ninhydrin
test

Sweat +
Ninhydrin
reagent + boil for 5 minutes

No colour change,
solution remains
colourless

Amino acids are
absent.

4.

Urine

Biuret’s
test

Few drops of urine + Biuret’s
reagent

Colour changes
from light blue to
purple

Proteins are
present.

Solubility
test

Few drops of urine + Water

Little bit of
oily appearance

Fats may or may not be
 present.

Ninhydrin
test

Few drops of urine +

Colourless
solution changes
to pink,

Amino acids are
present.

Ninhydrin
reagent + boil for
5 minutes

blue, or purple
colour depending
on the type of amino acid