CHEMISTRY PROJECT

FOOD PRESERVATIVES

Jesse vinu
12-D
23
 BONAFIDE CERTIFICATE
This is to certify that this project work is done
by
……………. ………………………………. of class XII-D
during the academic year 2022-2023.
DATE: _______________ P.G.T
in____________________
United Indian School
Kuwait

Submitted for SENIOR SECONDARY SCHOOL

CERTIFICATE PRACTICAL Examination held
at United Indian School, Kuwait
Examiner
Date: ___________________
 ACKNOWLEDGEMENT
I am overwhelmed in all humbleness and gratefulness to
acknowledge my gratitude to all those who have helped me
to put these ideas, well above the level of simplicity and into
something concrete.
I would like to express my special thanks to my teachers
Mrs.Mary Litty and Mrs.Elizabeth Mani ,as well as our
Principal who gave me the golden opportunity to work on
this wonderful project on the topic ‘CHEMICALS IN
CIGARETTES’
, This project offered me an opportunity for
research, as a result of which I could gather so many
valuable information.
The support and guidance of my parents and friends played
a significant role in completing this project with utmost
satisfaction. My deepfelt gratitude to my parents who
helped me a lot in gathering different information, collecting
data and guiding me from time to time in making this
project, despite of their busy schedules. A special mention
of gratefulness to my friends for precious support.
INDEX
 INTRODUCTION:
A preservative is a substance or a chemical that is added
to products such as foods , vegetables, beverages,
pharmaceutical drugs, paints, biological samples,
cosmetics, wood and many other products to prevent
decomposition by microbial growth or by undesirable
chemical changes. In general, preservatives is
implemented in two modes chemical and
physical .Chemical preservatives entails having chemical
compound to the product .Physical preservatives entails
processes such as refrigeration or drying preservative
food additives reduce the risk of foodborne infection,
decrease microbial spoilage, and preserve fish attributes
and nutritional quality. Some physical technics for food
preservatives include dehydration, freezing drying and
refrigeration, Chemical preservatives and physical
preservatives techniques are sometimes combines
 FOOD PRESERVATIVES
Food preservatives include food processing
practices which prevents the growth of
microoraganism such as yeast abd slow the
oxidation of flat that cause rancidity. Food
preservatives may also includes processes that
inhibites visual deterioration such as the enzymatic
browning reaction in apples after they are cut
during food preparation. By preserving food , food
waste can be reduced, wich is an important way to
decrease production costs and increase the
efficiency of food system, improve food security and
nutrition and contributes towards environmental
sustainability .For instances, it can reduce the
environmental impact of food production
 WHY DO WE NEED TO PRESERVE ?
Food is so important for the survival so food
preservation is one of the oldest technologies used
by human beings to avoid its spoilage different
ways and means have been found and improved for
the purpose. Boiling, freezing and refrigation,
pasteurizing, dehydration, pickling are the
traditional few sugar, minerals salt and salt are
often used as preservatives food. Nuclear radiation
is also being used now as food preservatives.
Modified packaging techniques like vacuum packing
and hypovaric, packing also work as food
preservatives
Preserving food also offers the opportunity to have
a vide variety of food year-round SO that the
nutritive value, flavour and colour of the foods
remain intact
 THE NECESSITY TO PRESERVE
1)to preserve the nature characteristics of food
2) To preserve the appearance of food
3)To increase the self value of the food for the
storage.
4)the varies of food can be enjoyed in any different
area and any seasons
5)the supplyment of food can be increased.
6)The waste of food will be reduced.
7) people can taste food from any location.
8) can stored the food more easily.
PRESERVATION METHODS

There are the basic principals through many of the

preservation methods use multiple mechanisms

>Acidity
>Moisture
>Temperature
>Oxygen
If you are infamiliar with any of these ill give you a
general idea of what each method does.

PH LEVELS
Microorganisms,such as botulism, cannot grow at a
pp of 4.6 or lower . Changing the acidity of a food
( as in fermentationwill halt the growth of
microorganisms
Moisture
Microrganisms need moisture to grow depending
on how much moisture is removed will slow down
or halt the growth of microorganism

TEMPERATURE
Temperature can either be increased ( as in freezing
)to affect the growth of microorganisms. When
raised high enough, the temperature can destroy
the microorganism ,and lower it with hault the
growth.

OXYGEN
Microbial growth can be slowed down when placed
In an anaerobic state (removal of oxygen) in
method such as canning and oil submission.

CURING
You can also stop microorganism growth by drawing
out water with salt. Not can you also preserve meat
at home like salt curd ham and dry cured meat, but
you can also preserve fresh herbs in salt as well

FREEZING

Freezing can reduce water content bt turning the

water into crystalized state. Additionally, it lowers
the temperature of the food to a state where the
bacteria can no longer multiply and grow. However
it doesn’t actually kill the bacteria , it just put it into
dormant state so when food is thawed , the
bacteria will become active and can multiply again .
This is why freezing does not kill bacteria on row
meet, and we still have to cook it. The heat from the
cooking process is what will kill the harmful optimal
whenever more than one mechanism for food
preservation is in play
So for example, it is recommanded that some fruits
and vegetables that had continued enzyme activity
after harvesting need to be balanced before
freezing. You can learn more about this in detail in
my complete guide to home food preservation .
Blanching will destroy the emzyme activity which
can otherwise continue at the frozen temperature.
So in the case of blanching foods for freezing, you
are using three mechanisms .The first is using heat
to kill the enzymes, the second is the lowering
temperature so microorganism cannot multiply, and
they third is removing the water so that the
microorganisms cannot multiply
CANNING
Canning relies on proper pH level , heat and the
removal of oxygen to preserve the food . Tf the pH
level of the food is not acidic enough, those food
need to be pressure canned in order to use heat to
destroy microorganism present present.
If your jars are simply sitting in a pot of boiling
water, the temperature cannot rise above 212
degrees no matter how long they sit there .
Microorganism such as botulism will not die unless
they have reached a temperature of 248 degrees.
Pressure canning is unique in that it allows you to
bring the internal temperature of the food up to
248 degrees .Fahrenheit for specified amount of
time.
Sugar comes into play in the canning process by
absorbing water and making it less available. You
cannot use sugar as a preservative by packing food
in sugar as you do with salt, but sugar does play a
role in extending the self life of canned goods after
the jar has been opened.
The canning process itself relies on acid and pH
levels to preserve the food .We know that botulism
cannot grow a pH of 4.6 or lower, and many fruits
and berries are acidic, naturally falling under this Ph
level, so the need to add sugar isn’t necessary.
However, since sugar helps to absorb water, the
more sugar in the recipe , the longer the shelf life
will be after jar is opened because the reduction in
water will reduce the ability for mold to grow after
the seal is broken . With the health consequence od
gugar in mind , I use low sugar recipes in my work
like strawberry , cherry and apple pie jam and
process them into smallest jars possible . That way,
we have the ability to go through the product
before it has a chance to be bad.
PASTEURIZATION
Most people don’t use pasteurization as a home
preservation method, but like canning it brings the
temperature of the food up to specified
temperature for specified period of time in order to
kill the microorganisms present .Depending on the
product you are pasteurizing, these temperatures
and time will vary.
OIL IMMERSION
You must be very careful when using oil to preserve
food, because oil does create an anaerobic
environment nut this method also relies on
acidity .Botulism can still grow in an abaerobic
environment if the acidity level is not 4.6 or below
FERMENTATION
This method uses three mechanism.The first is
drawing out the water by either salting the
vegetables or using salt water brine.
Second, the vegetables is fully submerged under the
liquid level to cause an anaerobic state.
Lastly, the salt also act to keep the good and bad
bacteria balanced so that the bad bacteria are kept
at bay until the lactic acid is formed .This acid works
to change the Ph level to an acidity where food can
be preserved.
ALCOHOL FERMENTATION
This method initially follows the fermentation
process, but is allowed to continue to fermen tuntill
the yeast that is consuming the sugar in the food
then begins to excrete alcohols
DEHYDRATION
Although heat is used in hedydration it is not high
enough to kill the microorganism . Dehydration
relies on removal of water only.
COLD STORAGE
It is recommended that the root cellar temperature
be in the range od 35-49 degree Fahrenheit in order
to slow microbial growth . Not everyone is able to
use a root cellular , but did you know that you can
use your gardern to store your vegetables over the
winter ?
 CHEMICAL PRESERVATIVES
Chemical food preservatives are also being used for
quite a some time now they seem to be the best
and the most effective for a longer shelf life and are
generally fool proof for the preservation purpose
examples of chemical food preservatives are :

Benzoates (such as sodium benzoate, benzoic

acid.
>Nitrites (such as sodium nitrite)
>sulphites (such as sulphur dioxide)
>sorbates(such as sodium sorbate)

Antioxidants are also the chemical food

preservations act as free radical scavengers .In
this category of preservatives in food comes the
vitamin C,BHA, bacterial growth inhibitors like
sodium nitrite, sulphur dioxide and benzoic
acid.
Then there is ethanol that is a one of the
chemical preservatives in food, inhibitors like
sodium nitrite, sulphur dioxides and benzoic
acid.
Then there is ethanol that is a one of the
chemical preservatives in food, wine and food
stored in brandy. Unlike natural food
preservatives some of the chemical food
preservatives are harmful. Sulfur dioxide and
nitrites are the examples. Sulphur dioxides
causes irritation in bronchial types and nitrites
are carcinogenic.
PRESERVATION BY CARBON DIOXIDE , SULPHITE
,NITRITE AND NITRATE

CABON DIOXIDE LEVELS

The food preservation processes based on
carbon dioxide use the property that increase
the level of carbon dioxide the ethylene
concentration .Enriched carbon dioxide level
significantly reduce respiration, hinder textural ,
softening and slowing down the biological
processes associated with ripening . To use
these method of preservation , determine the
specific tolerance level of fruit and vegetables .
For instant for cA preservation of avocado , the
optimum level of oxygen is two to three percent
and that of carbon dioxide is three to 10
percent. There is no one setting suitable for all
types of produce and the level of carbon
dioxide is determined based on the stage of
maturify , culitivation pattern and
environmental condition in the region.
Are there benefits to using sulfites in home
dehydration
Sulfites are also used as a food preservatives
both commercial and in the home. In
commercial dehydration this may means using a
sulfur gas to fumigate them .At home it usually
means soaking the produce in a sodium bisulfite
and water mix before dehydration .
Sulfites are primarily used to create a pretty
product by stopping the natural browning
process of produce. Apricots stay that plump
orange and those golden grapes don’t turn
ugly .Sulfites also kill bacteria and fungus, giving
food a longer shield life and they slow natural
breakdown of vitamin c and a, mending to the
claim that sulfites ‘preserve nutrients’. All very
helpful

What does nitrite do in meat products ?

Nitrite prevents the growth of a harmful

bacterium called clostridium botulinum and it
may also have preservation effect on other
harmful and spoilage bacteria . In
addition ,nitrite develops cured meat flavour
and colour and retards the development of
rancidity and off- odurs and off- flavour during
storage of cured meats. Nitrite is responsible
for the characteristic pink colour of cured meat.
In nature, nitrates are readily converted to
nitrites and vice versa. Nitrates and nitrites are
currently authorized as food additive with in
the eu.
These additive function as preservatives in food
and they are both used extensively to enhance
the colour and extent shelf life of processed
meats. Nitrites is considered the activity curing
ingredient responsible for the preservation of
the food in combination with other ingredients
like salt. Nitrate, when added to food, convert
to nitrite before exerting a preservative
function.

IRRADIATION PRESERVATION OF THE FOOD

Food irradiation is the process of exposing food

and food packing to ionizing radiation such as
gamma rays, x- rays without direct contact to
the food product.When ionizing radiation
passes through a food product, some energy is
absorbed by some chemical bond. Some bonds
rupture and produce free radicals which are
highly reactive and unstable through a food
product some energy is absorbed by some
chemical bonds .some bonds rupture and
produce free radicals ,which are highly reactive
and unstable .They instantaneously join with
neighboring compounds and the results are
called radiolytic compounds. Food irradications
is used to remove food saftely by extending
product shelf life. [preservation],reducing the
risk of foodborne illness delaying or eliminating
sprouting or ripening by sterilization of foods
and as a means of controlling insect and
invasive pests. Irradiation extent the self life of
irradiated food by effectively destroying
organism responsible for spoilage and
foodborne illness and inhibiting shrouting
consumers perception of food treated with
irradiation is more negative than prossed by
other means
Food irradiation is perminted in over 60
countries and about 5 lakh meter tons of food
are processed annually worldwide
 The regulation for how food is to be irradiated
as well as the food allowed to be irradiated
very greatly from the country to country
In Australia , Germany and many other
countries of the European union