Test for Carbohydrates : Iodine Test - Components of Food , Science, Class 6 Video Lecture

hello friends this video on components
of food part 4 is brought to you by exam
fear calm no more fear from exam this
might be a very common scenario at your
home sometimes now when you do not want
to eat bread your mom might be telling
at eat bread it has a lot of
carbohydrates now the next question that
might bother you is how do I know that
it has carbohydrates so what is the
proof that the bread has carbohydrates
okay so that is what we will do in this
section now you are given the food icon
so let's say you are given a potatoes in
a plate and you are asked does it
contain fat behind carbohydrates so what
would you see whether it contains or not
so you might say that you are not sure
because just looking at the food item
just looking at the potatoes they don't
really tell you anything that it is rich
in carbohydrates or proteins or fats or
minerals or vitamins so you are really
not sure what it doesn't contain so that
is where we will talk about some
specific tests to prove if a food item
contains carbohydrates or not now even
before that what exactly are
carbohydrates we know that they are
nutrients but when you look at them
chemically they are made up of carbon
hydrogen and oxygen so that is why they
are called carbohydrate Caribou is from
carbon hydro is from hydrogen and it
also contains oxygen so these are the
three important constituents of all
carbohydrates now some examples of
carbohydrates are starch - glucose
fructose say you lose these are all
examples of carbohydrates now in your
higher classes you will learn that some
carbohydrates are simple carbohydrates
so they are very simple structure their
chemical structure is very simple
whereas some car
hybrids are like of very complicated so
many small units of simple carbohydrates
they join together to form complex
carbohydrates so you will learn about
all those in higher classes so here you
can just look at these examples no
different carbohydrates different types
of carbohydrates are present in
different products for example when you
talk about starch starch is present in
high amount in food items like potatoes
means cereal grains basically so they
are very rich source of starch you talk
about fructose they are present in
fruits that that's why the name tractors
from from fruits so you talk about
lactose that is present in milk so milk
also is a source of carbohydrate so milk
not only provides calcium it also
provides carbohydrates glucose you can
find it in honey cellulose cellulose is
found in plants especially the green
leafy vegetables which we obtained from
plants so these are all examples of
different types of carbohydrates and all
of them are found in huge amounts of
different types of food items now some
examples of food items which contain
carbohydrates are potatoes banana actual
corn wheat rice sugar cane glucose so
these are all examples of food items
which contain a lot of carbohydrates or
you can say which are rich source of
carbohydrates now this is something
which I am telling you that potato is a
rich source of carbohydrate or wheat is
a rich source of carbohydrate but how do
you prove that yes is potato contains
carbohydrates so for that we perform a
test for iodine test so we make use of
iodine and we perform an experiment
which proves whether a food item
contains carbohydrates or not so what we
need to do iodine things the questions
first of all we need to prepare and I
solution so how do we prepare that
iodine solution so for that we would
need a few drops of iodine added to
water and that's how we prepare the
iodine solutions as you can see here in
this beaker you have some water you add
a few drops of two to three drops of
iodine to it now as soon as you add this
iodine solution what happens you will
get an iodine solution that is iodine
diluted with water so it has maximum
amount of water and only a few drops of
iodine the moment you add the iodine
what happens the color of the water
changes to a purple in color a slight
light purple so that's how you get this
iodine solution now what are we going to
do with this iodine solution take a
slice of potato or whatever food item
you want to check for carbohydrates you
take that food item a sample of it in a
plate now take some iodine solution this
solution which you have prepared so put
a few drops of this iodine solution on
the potato after a couple of seconds or
after a couple of minutes what do you
see you observe a change in color in
this area so that that area where you
had put the iodine solution so there you
observe a change in color and this
appearance of a blue-black color
indicates the presence of starch so if
you get a blue-black color then that
means the archer is present there and if
there is no blue-black color that means
starch is not present so when you
perform this iodine - sweet potato what
happens obviously a blue-black color
appears because starch is present in
potato so we see that the iodine test is
positive for potato so wherever the
iodine test is was it positive that
means starch is present and if the
iodine test is negative that means
starch is not present so positive test
would mean that this new black color
will appear after adding iodine solution
if this color does not have
that means the iodine taste is negative
and that means that starch is not
present in that particular food item so
you see this is a very simple test so
you can just prepare iodine solution put
that ironing solution in various food
items you want to try it out with all
the vegetables and fruits you can just
do that and you will be able to see this
change in color only in a few of them
and only those contain typo metrics
others don't now if you take up other
substances like bread rice maize or
potato for all of them we see that the
iodine test comes out to be positive
that means for all of them when you add
a few drops of iodine you can see a
bluish black color on the food item
thank you please visit www.payoor.com to
watch more educational videos with a
better experience please do not forget
to Like and subscribe to our YouTube
channel for latest updates thank you
once again