Important source of knowledge at education of scientific subjects
ESTIMATION OF VITAMIN C IN
FRUIT AND VEGETABLE JUICES
• The aim of
checking the relative
amount of vitamin C
in different juices.
WHAT IS VITAMIN C?
Vitamin C, ascorbic acid, a water soluble vitamin, which plays
a major role in the cellular oxidation, especially in the
tyrosine oxidation and reduction processes.
Vitamin C increases body resistance, what is essential to
maintain correct condition of the connective tissue.
It facilitates the absorption of iron.
Its deficiency causes scurvy.
Preparing the solution of starch including iodine
Pour starch to the bowl or beaker . Next, pour hot water
from kettle to the bowl. Then, put the bowl into cold water
and blend the solution quickly. When the solution looks
like a jelly you must add drops of iodine and blend it. The
solution is ready when it stained blue.
PROCESS OF THE
Note the number
being put into
Add the iodine
solution to the
test tube drop by
drop until it
colour into violet-
Add the iodine
to the test tube
Extract Number of drops
of iodine solution
• Lemon and grapefruit
juice were the ones
that changed colour
in the shortest time.
• Tomato juice
required the biggest
amount of iodine
solution to change
VITAMIN C IN DIFFERENT
• All of the examined juices contain vitamin C,
however its content is different.
• The biggest amount of vitamin C in examined
extracts was found in the fresh lemon juice
prepared in the lab as well as in the juice of red
grapefruit which was bought in the shop.
• The least content of vitamin C was reported in
the essence of vegetables such as parsley,
carrot and tomato.
• Vitamin C was also detected in apple and
grapefruit juices containing preservatives.
EXPERIMENT CONDUCTED BY
• Marika Karasek
• PhD Anna