Food preservation and additives ppt

Food Preservation & Additives
Nidhi Choudhary

Food Preservation?
A process by which certain foods like fruits and
vegetables are prevented from getting spoilt for a long
period of time.
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Why do we need Preserve Food ?
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Food preservation prevents the food from being spoiled by the action
of enzymes and microorganisms.
It increases the safe storage period of foodstuffs.
It increases the availability of out of season foodstuffs.
Reaches areas where the food item is not grown. In some areas of
Rajasthan which are desert areas and in Himalayan regions that are
covered with snow most of the time, very few foods can be grown.
Availability of some preserved food can add to the variety and
nutritive value of meals e.g for inclusion of dehydrated peas, green
leafy vegetables, canned fruits etc. in the meals is a good idea in such
areas.
Compelling Reasons to Preserve Food
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Food preservation in some cases produce a different form.e.g grape
when dried produce raisins and with preservative, grape squash can
be made.
Economy.Food bought when they are most plentiful, are cheaper and
of good quality and money can be saved by buying and preserving
food at this time.
It makes the transportation of the food materials easier e.g. if you dry
green leafy vegetables such as mint, coriander, spinach, etc, their
weight and volume reduces, thus making their storage easy.
Food preservation is essential because it extends the length of time
during which the food is nutritionally viable and safe to eat.
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Principles of Food Preservation
1) Prevention or delay of microbial decomposition
(a)By keeping out microorganisms (asepsis)
• Nature provides protective coverings around the food in the
form of shells of nuts, die skins of fruits and vegetables, the
shells of eggs, and the skin or fat on meat or fish.
• These protective coverings act as a preservative factor,
thereby preventing or delaying microbial decomposition.
• Even in the food industry several aseptic methods are adopted
to prevent the contamination of foods during its processing.
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•In the canning industry, the load of micro-organisms determines
the heat process necessary for the preservation of food. This is
better known as aseptic canning.
• In the dairy industry, the quality of milk is judged by its bacterial
content.
• Packaging of foods is also an application of asepsis.

(b) By removal of microorganisms (Filtration)
•Filtration is a method used for the complete removal of microorganisms
and is successfully applied only to clear liquids such as water, fruit juices,
beer, soft drinks and wine.
• The filter used in this method is made of asbestos pads, unglazed
porcelain and similar materials.
• This filter is sterilised and made “bacteria proof” before being used as a
filtration device.
• The liquid is filtered by forcing it under pressure through the filter.
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Asbestos Pads Unglazed Porcelain

(iii) By hindering the growth and activity of micro-organisms
•This may be done by low temperature or drying or by providing
anaerobic conditions or by chemicals,
•Low temperature at which foods are preserved in cold storage
slows down and sometimes prevents bacterial activity.
•Drying of foods is a very effective method of avoiding spoilage of
food, since micro-organisms cannot flourish in the absence of
moisture.
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•Certain chemicals like sodium benzoate and potassium meta bi-
sulphite may be used for preservation, but they should be used with
great care as an excess of any of them may result in poisoning.
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•When anaerobic (absence of oxygen) conditions are created, some aer

(iv) By killing the micro-organisms using heat or radiation
By Radiation
•In this process gamma rays or high speed electrons are used to
destroy the micro-organisms.
•Both types of radiations are termed as ionised radiations
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By Heat
•Coagulation of proteins and inactivation of their metabolic enzymes by
application of heat leads to destruction of micro-organisms present in foods.
•Exposure of food to high temperature also inactivates the enzymes present in
the food. Foods can be heated either at temperature below 100oC
(pasteurization) at 100oC (boiling) or at temperature above 1000C
(sterilization).
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Pasteurization of juice
Boiling
Pasteurization of Milk
Sterilization

2) Prevention or delay of self decomposition of food
A) By destruction or inactivation of food enzymes by Blanching
•The inactivation affects many plant enzymes which otherwise might
cause toughness and change in colour.
• All plant and animal tissues contain enzymes which are highly active at
room temperature and above.
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B) By delaying of chemical reactions e.g by prevention of
oxidation by means of antioxidant.
•Rancidity of fats is an excellent example of undesirable oxidation
and leads to the deterioration in flavour of foods that may contain
only small quantities of fat. Oxidation also leads to a loss of ascorbic
acid.
•Plant and animal tissue fibre is softened, the surfaces of cut non-
acid fruits are oxidised and become darkened as a result of enzyme
action, thereby changing the colour, texture and nutritive value.
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3)Prevention of damage caused by insects, animals and mechanical
causes.
•Use of fumigants in dried fruits, cereals etc checks the damage caused by
insects and rodents.
•Wrapping of fruits, providing cushioning trays, using light pack and good
packaging material checks the damage to fresh food commodities during
handling and transportation.
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Fumigants

BLANCHING:
Blanching is a process where vegetables are exposed to boiling water or steam
for a brief period and then rapidly placed in ice water to prevent cooking.
Blanching stops the food's enzyme action and destroys any microorganisms
present on the vegetables surface reducing your risk of food poisoning.
Blanching is a unit operation prior to freezing, canning, or drying in which
fruits or vegetables are heated for the purpose of inactivating
natural/endogenous enzymes; modifying texture; preserving color, flavour,
and nutritional value; and removing trapped air.
If not blanched, enzyme activity can occur even under refrigerated, frozen and
dried conditions.Enzymes can also be active during the come uptime for
retorted canned products.
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Contd…

Principles of Food Preservation can be
broadly classified in two types
1) Bactericidal Methods
2) Bacteriostatic Methods
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1.Bactericidal Methods
This method of food preservation involves killing all/most
bacteria.
1. Food Preservation by High Temperature
a. Pasteurization
b. Sterilisation
c. Canning
d. Boiling
2. Food Preservation by Radiation
3. Food Preservation by Filtration
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2.Bacteriostatic Methods
This method of food preservation would prevent the growth of
bacteria, but leaving some bacteria alive.
1. Food Preservation by Low Temperature
a. Refrigeration or Chilling
b. Freezing
2. Food Preservation by Dehydration / Drying
3. Food Preservation by Osmotic Pressure
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Techniques of Food Preservation
1)Physical Methods
2)Chemical Methods
3)Biological Methods
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1.Physical Methods
Those methods that utilise physical treatments to inhibit, destroy, or remove
undesirable microorganisms or endogenous enzymes without involving
antimicrobial additives or products of microbial metabolism as preservative factors.
1.Food Preservation by Low Temperature
a. Refrigeration or Chilling
b. Freezing
2. Food Preservation by High Temperature
a. Pasteurization
b. Sterilisation
c. Canning
d. Boiling
3.Food Preservation by Dehydration / Drying
4.Food Preservation by Radiation
5.Food Preservation by Filtration 22

2.Chemical Methods/Chemical Preservation
Chemical food preservatives are substances which, under certain
conditions, either delay the growth of microorganisms without
necessarily destroying them or prevent deterioration of quality
during manufacture and distribution.
1. Preservation by Preservatives
2. Preservation by Osmotic pressure
3. Food Additives
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Difference between Preservatives and Food additives
Additive is a substance that is added to another substance in
order to affect the characteristics of that substance. Generally,
they are added to improve the characteristics (flavour, colour,
shelf life, etc.) of the substance. Preservative is also a type of
additive which is added to the substance in order to prevent or
delay spoiling.
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Biopreservation refers to extended storage life and enhanced
safety of foods using the natural antimicrobial compounds that are
of plant, animal and microbial origin and have been used in
human food for long time, without any adverse effect on human
health .
Biopreservation reduces the amounts of chemical preservatives as
well as the intensity of heat treatments, both of which can
otherwise negatively affect the food quality.
Common method we use :-
• Fermentation
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Biological method/Biopreservation

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Food
Preservation by
low temperature

The use of low temperatures to preserve foods is based upon the fact that the
activities of food- borne microorganisms and enzyme reactions can be
slowed down and/or stopped at temperatures above freezing and generally
stopped at subfreezing temperatures.
Low temperature can be produced by:
1.Refrigeration or chilling
2.Freezing
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Chilling
•Chilling is a temporary or short term method of
preservation.
•Preservation of foods at temperatures above
freezing and below 15ºC is known as refrigeration
or chilling.
•It is used to reduce the rate of biochemical and
microbiological changes and hence to extend shelf
life of fresh and processed foods.
•It causes minimal changes to sensory
characteristics and nutritional properties of foods.
•Chilled food is usually kept just above 0ºC.
Because the temperature is low, the rate of
bacterial growth is reduced but not stopped
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•Chilled foods can be a single food or a food product such as a
ready meal (e.g. Lasagne, Cottage Pie). These cook-chill foods are
prepared, cooked and chilled rapidly. Once cooked they must be
blast-chilled to a temperature below 5 o C within 90 minutes. They
must then be stored at these temperatures until they are reheated
for use.
•Cook-chill foods can only be stored for a few days, although if
special packaging is used their shelf life can be extended to up to
14 days. The food should be reheated until the centre reaches at
least 72oC and eaten within two hours.
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Chilling

Categories of chilled food
According to storage temperature range:
•-1ºC to 1ºC (fresh fish, meats, sausages, smoked meat and ground
meat).
•0ºC to 5ºC (pasteurised milk, canned meat, cream, yoghurt, salad,
sandwiches, baked foods, soups and sauces).
•0ºC to 8ºC (Soft fruits and fruit juices, cooked rice, hard cheese
and butter).
•8ºC to 12ºC in the wine industry. The must is kept at this
temperature between 6 and 24 hours.
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Advantages of Chilling
•Chilled foods taste closer to fresh foods than frozen, canned or dried
foods.
•There is little loss of flavour, colour, texture, shape or nutritional
value.
•Fresh foods can be kept at maximum quality for a longer time.
•The consumer can be offered a much larger range of fresh and
convenience foods.
Disadvantages of Chilling
•Only a temporary, short term method of preservation.
•Specialist storage equipment is needed – a fridge kept at below 5 o C.
Commercial stores must be below 2 o C.
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Freezing
•Freezing process is a combination of the beneficial effects of low
temperature at which micro-organisms cannot grow, chemical changes
are reduced and cellular metabolic reactions are delayed.
•Freezing turns liquids, such as water, into solids, such as ice. As micro-
organisms need liquid as well as warmth to grow, this makes freezing a
long term method of preservation.
•Bacteria are not destroyed by the freezing process they are ‘dormant’
(this means that they don’t multiply once frozen). it is important to
remember that bacteria will be reactivated by the thawing process.
•Quick freezing is best for food as it produces smaller ice crystals so
there is less damage to cell walls
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Freezing methods
Factories where food is frozen use three basic methods:
1. Plate freezing: Flat products such as burgers and fish fingers, are
frozen between two plates.
2. Blast freezing: Freezing air is blasted over irregular shaped
foods such as vegetables and prawns.
3. Cryogenic or immersion freezing: Food is immersed or sprayed
with liquid nitrogen. This is an expensive method and is usually
only used for delicate foods such as raspberries.
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Principles of Freezing
•Extreme cold (0ºC to -18ºC colder):
a. Stops growth of microorganisms
b.Slows chemical changes, such as enzymatic reactions.
•Preservation is achieved by a combination of low temperatures,
reduced water activity and, in some foods, pre-treatment by
blanching.
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Changes during freezing
•Loss in texture is the main problem that occur during freezing.
Water in inter cellular spaces of fruits and vegetables freezes and
ice-crystals are formed which cause adjacent cell walls to rupture.
•Freezing causes negligible change to pigments, flavours or
nutritionally important components, although these may be lost in
preparation procedures like Blanching.
•Freezing causes death of 10% to 60% of the microbe population
and the %age gradually increases during frozen storage.
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Advantages of Freezing
•Many foods can be frozen.
•Good natural color, flavour and nutritive value can be retained.
•Texture usually better than for other methods of food preservation.
•Foods can be frozen in less time than they can be dried or canned.
•Simple procedures.
•Adds convenience to food preparation.
•Long term method of preservation (weeks & months rather than
days)
•Little change in flavour or structure compared to canned or dried
food
•Very little nutritional loss – most vitamin B and C is retained.
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Disadvantages of Freezing
•Quick & controlled freezing is needed or large ice crystals will form and
break the cell walls of some foods.
•Vegetables need to be blanched (immersed quickly in boiling water) or
enzymes will continue to work and change the flavour and texture of the
food.
•Specialist storage equipment is needed – a freezer kept at below -18 o C.
•Long term stores must be below -26 o C.
•Flavours of garlic, spices and herbs often become stronger during
freezing.
•Cell damage can occur in soft fruits such as strawberries and the
colloidal structure of some food products, such as sauces, can collapse
when frozen.
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PRESERVATION BY
HIGH TEMPERATURE

Food Preservation by High Temperature/By heat/ By Thermal
processing
Thermal processing is defined as the combination of
temperature and time required to eliminate a desired
number of microorganisms from a food product.
The term "thermal" refers to processes involving heat.
Heating food is an effective way of preserving.
The basic purpose for the thermal processing of foods is
•to reduce or destroy microbial activity,
•reduce or destroy enzyme activity, and
•to produce physical or chemical changes,
•to make the food meet a certain quality standard.

Types Thermal Processing
There are three main temperature categories employed
in thermal processing:
Blanching
Pasteurization
Sterilization.
•Mild processes :Blanching ,Pasteurisation
•More severe processes :Canning, Baking, Roasting,
Frying
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PASTEURIZATION
•Pasteurization is the application of heat to a food product in order to destroy
pathogenic (disease-producing) microorganisms, to inactivate spoilage-
causing enzymes, and to reduce or destroy spoilage microorganisms.
•The high-temperature–short-time (HTST) treatments cause less damage to
the nutrient composition and sensory characteristics of foods and therefore
are preferred over the low-temperature–long-time (LTLT) treatments.
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Pasteurization
Milk Pasteurizing Temperatures
Temperature Time
63°C
72°C
89°C
90°C
94°C
100°C
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For 30 min (low temperature long time LTLT)
For 15 sec (primary high temperature short time,HTST method)
For 1.0 sec
For 0.5sec
For 0.1 sec
For 0.01sec

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PASTEURIZATION
The heat treatment of pasteurization is not severe enough to render a product
sterile, additional methods such as refrigeration, fermentation, or the
addition of chemicals are often used to control microbial growth and to
extend the shelf life of a product.
For example, the pasteurization of milk does not kill thermoduric bacteria
(those resistant to heat), such as Lactobacillus and Streptococcus, or
thermophilic bacteria (those that grow at high temperatures), such as
Bacillus and Clostridium. Therefore, pasteurized milk must be kept under
refrigerated condition.
Liquid foods such as milk, fruit juices, beers, wines, and liquid eggs are
pasteurized using plate-type heat exchangers.
Plate-type heat exchangers are effective in rapid heating and cooling
applications. After the pasteurization process is completed, the product is
packaged under aseptic conditions to prevent recontamination of the product

The temperature and time requirements of the pasteurization process
are influenced by the pH of the food.
When the pH is below 4.5, spoilage microorganisms and enzymes are the main
targets of pasteurization. In the pasteurization process for fruit juices is aimed at
inactivating certain enzymes such as pectin esterase and poly galacturonase. The
typical processing conditions for the pasteurization of fruit juices include heating
to 77 °C and holding for 1 minute, followed by rapid cooling to 7 °C . In addition
to inactivating enzymes, these conditions destroy any yeasts or molds that may
lead to spoilage.
When the pH of a food is greater than 4.5, the heat treatment must be severe
enough to destroy pathogenic bacteria. In the pasteurization of milk, the time and
temperature conditions target the pathogenic bacteria Mycobacterium
tuberculosis, Coxiella burnetti, and Brucella abortus. The typical heat treatment
used for pasteurizing milk is 72 °C for 15 seconds, followed by rapid cooling to
7 °C.
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Advantages of Pasteurization:
• It does not produce an unpleasant cooked flavour..
• Some Harmful pathogens especially TB bacteria are destroyed.
• It inactivates enzymes such as phosphatase and lipase in milk
which adversely affect the quality of milk.
• It increases shelf-life of a product such as Milk and other dairy
products.
• Save time.
Disadvantages of Pasteurization:
• Strict monitoring must be observed.
• Processors / marketers are able to sell more than 10 day old milk
as fresh milk!
• Doesn’t kill heat resistant pathogen.
• Reduction in the nutrition content.
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STERLISATION
Sterilization is a controlled heating process used to completely eliminate
all living micro-organisms, including thermoresistant spores in milk or
other food.
It can be achieved by:
1)Moist heat
2)Dry heat
3)Filtration
4)Irradiation
5)by chemical methods
The aim of sterilization is the destruction of all bacteria including their
spores.

•Sterilisation is used to treat all types of food products. These include milk,
juices, beer and many others.
•In heat treatment processes, various time/temperature combinations can be
applied, depending on the product properties and shelf-life requirements
•Food products filled in sealed containers are exposed to temperatures
above 100°C.
•Temperatures above 100°C, usually ranging from 110-121°C depending
on the type of product, heat must be reached inside the product.
•Products are kept for a defined period of time at temperature levels
required for the sterilization.
•It depending on type of product and size of container.

Sterilization with moist heat:In sterilisation with moist heat, temperatures
generally range from 110 to 130°C with sterilization times being from 20 - 40min.
For example, canned foods are sterilised in an autoclave at about 121°C for 20min.
Sterilization with dry heat:For killing bacterial endospores by dry heat, longer
exposure times (e.g. up to 2 hours) and higher temperatures (e.g. 160 – 180°C) are
required than with moist heat.
Sterilization by chemicals :Chemicals means may also be applied. Ethylene oxide
is used to sterilize food, plastics, glassware, and other equipment.
Sterilization by filtration: Solutions containing thermolabile compounds can be
sterilised by filtration through mediums such as nitrocellulose membranes,
kieselguhr, porcelain, asbestos.
Sterilization by UV-radiation: UV irradiation is used to keep rooms partially
sterile. Bacteria and their spores are killed quickly, but fungal spores are only
moderately sensitive to radiation. Ionising radiation (X ray, gamma radiation) is
used to sterilise food and other compact materials.
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Oven
Autoclave
Dry heat Sterlization
Moist heat Sterlization

UHT (Ultra-High Temperature) sterilization:
•UHT (Ultra-High Temperature) sterilization has a heat treatment of over
100°C during very short times; it is especially applicable to low viscous
liquid products
•UHT sterilization is used for low viscosity liquid products (milk, juices,
cream, wine, salad dressings), foods with discrete particles (baby foods,
tomato products, fruits and vegetables juices, soups).
•UHT treatment is only possible in flow-through equipment .The basis of
UHT, or ultra-high temperature, is the sterilization of food before
packaging, then filling into pre-sterilized containers in a sterile
atmosphere.This requires aseptic processing.
•There are two principal methods of UHT treatment: Direct heating and
Indirect heating.
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•Canning is a method of preservation of food in which
the food is processed and hermetically sealed in
containers (of metal, glass, thermo stable plastic, or a
multi- layered flexible pouch) through agency of heat.
•Canning provides a shelf life typically ranging from
one to five years, although under specific
circumstances it can be much longer.
•Heating is the principle factor to destroy the
microorganisms and the permanent sealing is to prevent
re-infection.
CANNING

•The high percentage of water in most fresh foods makes
them very perishable. They spoil or lose their quality for
several reasons.
•Microorganisms live and multiply quickly on the surfaces
of fresh food and on the inside of bruised, insect-damaged,
and diseased food. Oxygen and enzymes are present
throughout fresh food tissues. Proper canning practices
minimize the effects of these microorganisms.
• The main objective of canning is to preserve the food by
the application of heat so that it can be safely eaten at a
later time. Safety of the consumer is the primary concern
when food is canned.
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Why is Canning done?

Containers for Canned foods
Must be:-
1. Capable of being hermetically sealed to prevent
entry of microorganisms.
2. Impermeable to liquids and gases, including
water vapour .
3. Maintain the state of biological stability (i.e,
commercial sterility) that was induced by the
thermal process alone or in combination with
other chemical and physical processes.
4. Physically protect the contents against damage
during transportation, storage and distribution.
5. The various materials used for canning tin, steel,
plastic and glass containers with metal closures
etc.
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Important Canned Food
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Low acid foods: Meat, fish,
poultry, dairy fall into a pH
range of 5.0 to 6.8. This large
group is commonly referred to
as the low acid group
High acid foods: Such as
pickled products and
fermented foods. The pH
values range from 3.7
down to 2.3, also Jams and
Jellies are in this
classification.
Acid foods: With pH values
between 4.5 and 3.7. Fruits
such as pear, oranges, apricots
and tomatoes fall in this class

Microbial spoilage in Canned food

Advantages
1. Canning alters food chemically by changing the moisture, pH, or
salinity levels to protect against microbes, bacteria, mould, and yeast.
2. It also limits food enzyme activity.
3. Can keep canned foods on shelves from 1-2 years or longer
4. Can be economical when using home grown or locally grown produce.
5. Canning your own food is an excellent way to reduce your
environmental impact.
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Disadvantages
1. Glass jars can be break.
2. Seals can be broken causing spoilage.
3. Canning is time consuming.
4. Most canning is done in the heat of summer and can increase air
conditioning costs.
5. Canned food does not taste as good as fresh food does.
6. It also requires a significant investment of time and equipment.

What is Food Irradiation?
Food irradiation is a cold, non-chemical process that exposes
food to ionizing radiation that can penetrate food to kill, or
prevent reproduction of microorganisms, insects and pests.
Insects require a lot less irradiation than bacteria and viruses
Radiation Kills Microorganisms w/o Raising Food Temperature
Does not and cannot make foods radioactive.
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Which Foods are Irradiated?
Wheat flour – control of mould/pest
White potatoes – inhibit sprouting
Pork – kill Trichinia parasites
Fruit and Vegetables – insect control; increase shelf life
Herbs and Spices - sterilization
Poultry – bacterial pathogen reduction
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•Food irradiation reduces or removes pathogens, such as bacteria and moulds, that
spoil food and cause food poisoning and other illness. For example, irradiation can
kill Escherichia coli, Campylobacter and Salmonella bacteria. These bacteria make
millions of people sick and send thousands of people to the hospital each year.
•Animal feed also can contain Salmonella. Irradiation can prevent the spread of these
bacteria to livestock.
•Food irradiation slows down the aging of foods such as fruits and vegetables by
delaying sprouting.
•Irradiating dry foods like spices and grains allows them to be stored for a long time.
It also allows shipping of grains and spices over long distances.
•Food irradiation can be used to protect agriculture from the import of invasive pests
such as insects and worms. The radiation kills or sterilizes pests, preventing new
bugs from infecting crops.
BENEFITS OF FOOD IRRADIATION

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Food irradiation cannot remove all food dangers:
•Irradiating food does not get rid of dangerous toxins that are already in
food. In some cases, the bacteria themselves are not dangerous, but they
produce toxins that are. For example, Clostridium botulinum bacteria
produce a toxin that causes botulism, a dangerous illness. Food irradiation
can control the spread, growth, and survival of the C. botulinum bacteria,
but cannot remove the toxin produced by C. botulinum.
•Food irradiation can slow, but does not stop, fruit and vegetables from
aging. Aging can lower their nutritional value, taste and flavour.

Is Irradiated Food Safe To Use?
•Yes, irradiated foods are safe. Irradiation makes meat and poultry safer by reducing
the numbers of harmful bacteria and parasites.
•Food irradiation does not make foods radioactive. The radiant energy passes through
the food. The food itself never contacts the source of the radiant energy.
•Below10 kGy they are no known toxicological , microbiological, or nutritional
problems.
•Irradiated foods are wholesome and nutritious. Nutrient losses caused by irradiation
are less than or about the same as losses caused by cooking and freezing.
•Public health agencies worldwide have evaluated the safety of food irradiation over
the last fifty years and found it to be safe.
•In 37 countries more than 40 food products are irradiated.
•In some European countries, irradiation has been in use for decades.
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Sterilization
Pasteurization
Disinfestation
Sprout Inhibition
Delay of Ripening
Physical Improvements
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IRRADIATION PROCESSES

How Food Irradiation Works?
Food irradiators use one of three kinds of radiation: gamma rays (from
cobalt-60 sources), electron beams, or x-rays.
All three methods work the same way.
Bulk or packaged food passes through a radiation chamber on a conveyor
belt. The food does not come into contact with radioactive materials, but
instead passes through a radiation beam, like a large flashlight.
The ionizing radiation sends enough energy into the bacterial or mould cells
in the food to break chemical bonds. This damages the pathogens enough
for them to die or no longer multiply, which reduces illness or spoilage.

Advantages
1. It can kill many insects and pests that infest foods.
2. It can delay or stop normal ripening and decay processes so that foods can be
stored for longer.
3. It can kill dangerous micro organisms in foods
4. Disease causing germs are reduced or eliminated.
5. Nutritional value of the food is preserved
6. Decreases incidence of food borne illness
7. Reduced spoilage in global food supply
8. Increased level of quality assurance
9. Minimize Food Losses
10.Increase Energy Saving
Disadvantages
1. It can only be used on a very limited range of foods.
2. It is still a relatively expensive technology.
3. Vitamin E levels can be reduced by 25% after irradiation and vitamin C by 5-10%.
4. It is ineffective against viruses.
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What is Dehydration?
Dehydration is the process of removing
water from food by circulating hot air
through it, which prohibits the growth of
enzymes and bacteria
Dehydration is the extraction of moisture
from food products like fruits, vegetables,
skim milk, potatoes, soup mixes, and meats.
It inhibits the growth of microorganisms
and imparts a long storage life.
Moisture removal also results in
concentration of food and the osmotic
pressure is increased.
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•Dehydration inhibits microbial growth and enzyme activity, but;
The processing temperature is usually insufficient to cause their inactivation.
Therefore any increase in moisture content during storage, result in rapid
spoilage.
•Drying causes deterioration of both the eating quality and the nutritional value
of the food.
The design and operation of dehydration equipment aim to minimize these
changes.
•Dehydration is one of the oldest methods of food preservation and was used by
prehistoric peoples in sun-drying seeds.
•The North American Indians preserved meat by sun-drying slices, the Chinese
dried eggs, and the Japanese dried fish and rice.
•This is a modern development of smoking and drying.
•Modern dehydration techniques have been largely stimulated by the advantages
dehydration gives in compactness; on the average, dehydrated food has about
1/15 the bulk of the original or reconstituted product.
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• Control of bacterial contaminants in dried foods requires
High-quality raw materials having low contamination.
Adequate sanitation in the processing plant.
Pasteurization before drying.
Storage conditions that protect from infection by dust, insects, and rodents or
other animals
•Foodstuffs may be dried in air, superheated steam, vacuum, or inert gas or
by direct application of heat.
•Air is the most generally used drying medium, because it is
Plentiful and convenient and permits gradual drying,
Allowing sufficient control to avoid overheating that might result in
scorching and discolouration.
•Air may be used both to transport heat to the food being dried and to carry
away liberated moisture vapour
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Points to remember in dehydration

Loss of moisture content produced by drying results in increased
concentration of nutrients in the remaining food mass.
The proteins, fats, and carbohydrates in dried foods are present in larger
amounts per unit weight than in their fresh counterparts, and the nutrient value
of most reconstituted or rehydrated foods is comparable to that of fresh items.
The biological value of dried protein is dependent, on the method of drying.
•Prolonged exposure to high temperatures can render the protein less useful in
the diet.
•Low-temperature treatment, may increase the digestibility of protein.
Some vitamins are sensitive to the dehydration process. For example, in dried
meats significant amounts of vitamin C and the B vitamins—riboflavin,
thiamine, and niacin—are lost during dehydration.
Retention of ascorbic acid (vitamin C) is markedly improved by packaging at
temperatures up to 49 °C (120 °F); the packaging gas may be either nitrogen
or air.
Effect of dehydration on Nutrients
82

•Shrinkage occurs on the surface first and then
proceeds to the inner layers. With quick high
temperature drying of food, the surface becomes dry
and rigid long before the center dries out.
•Dried food pieces may also contain cracks and pores
of various diameters. The shrinking and pore clogging
by the solutes is known as core hardening. It can be
minimised by gradual drying with low surface
temperature.
•Foods that lack good structure and are high in sugar
content, give an impression of retaining moisture
even after the drying process. Fruits like grapes and
figs have high sugar content and lack good
structure, hence appearing moist even after
dehydration.
•Complete prevention of these changes is impossible.
They can be minimised by using appropriate83
Changes during drying

Methods of Dehydration
Drying can be done by two processes:
•Natural drying
•Mechanical dehydration or artificial drying based on source of
energy.
Natural drying takes place under the influence of sunlight and wind
and is of three types: sun, solar and shade drying.
Mechanical drying includes the methods of drying by
(1) heated air - e.g.Spray drying etc
(2) direct contact with heated surface e.g. drum drying,
(3) application of energy from a radiating microwave or dielectric
source. e.g Microwave drying.
In natural drying there is no control over temperature, air flow and
humidity whereas in artificial drying, these conditions are well
controlled. 84

Drum or Roller drier – Liquid foods, purees and mashes are dried by
this method. The food to be dried is applied, as a continuous thin layer,
on to the surface of a revolving drum or between a pair of drums moving
in opposite directions heated by steam.
Vacuum drier-Liquid foods dehydrated by vacuum drying have a
puffed structure and are easily dis-solved in water. Drying under vacuum
is beneficial to fruits and vegetables too. There is minimum flavour
change and heat damage because low temperature is used in this method.
Freeze drying: Freeze drying benefits heat-sensitive products by
dehydrating in the frozen state without intermediate thaw. Freeze-drying
of meat yields a product of excellent stability, which on rehydration
closely resembles fresh meat.
Spray drying : Spray dried that is, atomized into a fine mist that is
brought into contact with hot air, causing an almost instant removal of
moisture content.Dairy products are dehydrated by spray drying.
85

Advantages of Drying
•Preservation is the main reason but not the only reason for
dehydrating foods.
•Food may be dehydrated for other reasons also to decrease weight and bulk;
to retain size and shape of original food; to produce convenience items.
•Dehydration/ drying is cheaper than the other methods of preservation with
less requirement of equipments.
•Storage of dried food products does not require special facilities like
refrigeration etc.
•Dried food products are simple to store and pack because of their low
volume.
Dehydrated foods, are less popular because of some undesirable changes in
colour, taste and flavour during storage and distribution. Dehydration
techniques have been improved to overcome most of these defects.
86

Osmotic dehydration is the removal of water by immersing the
food in a solution of salt or sugars of high osmotic pressure.Water
is transferred from the food to the solution by virtue of the
difference in osmotic pressure.
88
(Osmotic pressure is the pressure that we need to apply to stop the
flow of solvent molecules from a dilute solution to a concentrated
solution through a semi-permeable membrane).

Preservation by High Osmotic Pressure
The principle of osmosis is used to preserve jams, jellies and pickles. In
this process, water tends to draw out from microbes (plasmolysis) and
makes it dehydrated, thus killing them. But yeasts and moulds are
relatively resistant to high osmotic pressure. Hence, preserved foods like
pickles tend to spoil if not stored properly.
89

1 High Concentration of Sugar
Sugar is used to preserve fruits. Preserving fruits in honey
to avoid spoilage is a well known practice. Nowadays jams
and jellies prepared from fruits have a high concentration
of sugar and it acts as a preservative. Pectin, acid and
sugar are essential to prepare jam. Jam or jelly are
prepared by adding commercially prepared pectin and it
also reduces the cooking time. Jellies are clear substances
made of fruit juice or the extract of a fruit.
Sugar acts in the following ways:
•Sugar draws the water out of food therefore making it
unavailable for microorganisms.
•As a result of water loss, microbial metabolism is
stopped.
•Hence, the growth of microorganisms is stopped.
90

Preparation of jam:
1. Fruits like apples are cooked with skin and made into pulp with the
strainer for making jam.
2. Equal quantities of sugar and pulp are taken to make jam.
3. After it is cooked, it is transferred to a sterilized bottle and allowed to
cool.
Honey
Honey is a natural preservative in its original state and was one of the
earliest preservatives used by ancient civilizations. It has a high
concentration of sugar that draws out the water out of yeast or bacteria
cells which contaminate the food.
91

2. High Concentration of Salt
Foods are also preserved by the principle of osmotic
pressure in salting and pickling. Most commonly used
preservative is sodium chloride. Required quantity may
be added to slow down or prevent the growth of
microorganisms or enough to permit lactic acid
fermentation to take place.
Sodium chloride preserves the food by the following
principles:
•It causes the high osmotic pressure and hence
plasmolysis occurs.
•It dehydrates foods by drawing out and tying up
moisture, as it dehydrates microbial cell.
•It ionizes to yield the chlorine ion which is harmful to
organisms.
•It reduces the solubility of oxygen in the moisture.
•It sensitizes the cell against carbon dioxide.
•It interferes with the action of proteolytic enzymes.
92

Pickling:
In pickling, food is placed in edible liquids like
brine, vinegar or vegetable oil which inhibit or
kill microorganisms.Sometimes, food is heated
along with pickling agent so that it gets saturated
with it.
Pickles may be broadly divided into three
groups:
•Sweet pickles e.g., tomato sweet pickle, mango
sweet pickle.
•Sour pickles e.g., mango pickle, lime pickle.
•Fermented pickles e.g., cucumber pickle,
cabbage pickle, chilli pickle, meat and sausages.
The important preservative agents in pickles
are salt, vinegar, sugar, oil, spices and
condiments. Each has a specific role in
preservation.
93

PRESERVATION BY
PRESERVATIVES
94

Preservatives
•Preservatives are chemical agents which serve to retard, hinder or
mask undesirable change in food. Preservatives help in retaining the
original quality of food and delaying their spoilage. These changes
maybe caused
•by microorganisms,
•by the enzymes of food,
•by purely chemical reactions
•Partial prevention of the spoilage can be achieved through the use of
refrigeration, drying, freezing and fermentation.
•The use of chemical additives or preservatives will prolong the shelf
life of the food even further.
95

96
Chemical Preservatives
Class I Preservatives Class II Preservatives
Salt,Sugar,Honey,VinegarAnd
Vegetable oils
Benzoic acid and its Sodium & Potassium
salts
Sorbic acid and its Sodium & Potassium
salts

The Preservatives are also classified as Organic and Inorganic
Preservatives used in Fruits And Vegetables.
Organic Preservatives
•Benzoic acid
•Esters of P- Hydroxy -Benzoic acid
•O- chlorobenzoic acid
•Salicylic Acid
The Preservative permitted in fruits and vegetables in India are
Sodium Benzoate , Sulphites and Sorbic Acid.
97
Inorganic Preservatives
Sulphur Dioxide used in
the form of Sulphites

• Sulphur dioxide is the only permitted preservative used in the form
of sulphites.
•In India, sodium benzoate, sulphites and sorbic acids are permitted
preservatives used in fruits and vegetables.
•Dried fruits are treated with sulphur dioxide to conserve the colour
and to prevent the growth of microorganisms
•Sodium benzoate is preferred to benzoic acid because of its solubility
and used in tomato ketchups, sauces, jams, jellies, pickles and fruit
juices .
•Sorbic acid and its salts are effective against yeasts and moulds but
less effective against bacteria. They are good preservatives for foods
with high fat content e.g., low fat spreads and processed cheese
98

Food quality is an important concept because the food people choose
depends largely on quality.Quality is difficult to define precisely, but it
refers to the degree of excellence of a food and includes all the
characteristics of food that are significant and that make the food
acceptable.
Food Quality can be evaluated by Sensory and Objective methods:
•Appearance, colour, and flavour are largely subjective or sensory
methods of evaluation.
•Nutritional and Bacterial quality are Objective methods. These two
qualities can be measured by chemical analysis, by measuring bacterial
counts, or using other specific tests
INTRODUCTION
100

SENSORY EVALUATION
Sensory evaluation is defined as “a scientific discipline used to invoke,
measure, analyze, and interpret reactions to characteristics of foods and
materials as they are perceived by the senses of sight, smell, taste, touch,
and hearing”
• It can be carried out by the following steps:
1. look at the food and describe the overall appearance
2. smell the food and describe its aroma
3. cut the food and feel its texture
4. chew the food and describe the taste and mouthfeel
101

102
Sensory characteristics – the qualities of a food identified by the senses. How
it looks, tastes, smells, sounds and feels when eaten.

1.Appearance
Surface Characteristics of food products contribute to the
appearance.
Fudge with glossy surface is rated high.
Interior appearance can also be evaluated.
Lumps in a pudding or gravy which are not desirable can be
judged by eye.
Example: Muffins
Peaked, rounded, tunnels on the inside, size of air cells, etc
103

2.COLOUR
The colour of foods adds to their attractiveness and appeal.Color often
used as a sign of freshness or spoilage. Subjective measurement of color
may be done like the one below.
•Ripeness of fruits like banana, tomato, guava, papaya, and plum can be
assessed by colour.
•Strength of coffee and tea is judged in part by the color of the beverage.
•The color of roast beef is used as an index to doneness.
•Toast , dosa and chapati which are too brown are likely to be rejected in
anticipation of scorched bitter taste. 104

105
Chapatti
Dosa
Plum
Papaya
Tomato
Coffee
Tea
Toast

3. FLAVOUR :
Flavour is produced by a combination of taste
and aroma
• Taste – The taste buds on our tongue enable us
to detect the different tastes of food. Taste buds
in the different areas of the tongue are not
equally sensitive to all taste stimuli and at least
some taste cell respond to more than one
stimulus.
Example: sweet, salty, sour , bitter, spicy, bland,
buttery, nutty.
• Aroma/Odour – The odour of the food
contributes immeasurably to the pleasure of
eating.
Involves the sense of smell – Detected by the
nose
Example: fragrant, burnt, floral, fishy, fruity.
106

4.MOUTHFEEL:
The word "mouthfeel" refers to the sensations that are experienced
inside the mouth while eating or drinking.
Texture, Consistency, Tenderness and Hot or Cold sensation can
be felt in the mouth.
Temperature:
•Influence of temperature on taste is not uniform. Taste buds can
be put out of action by both high and low temperatures.
•Increasing temperature appears to increase the response to
sweetness and decrease it to saltiness and bitterness.
•Decreasing temperature appears to increase the response to
bitterness and decrease the response to sourness .
•Taste sensations are less intense as the temperature of the food is
lowered below 20 C and raised above 30 C
•The best example is Ice-cream. Ice-cream doesn't taste sweet
when it is frozen but only when we melt it in the mouth. Also
melted ice cream is hard to drink because it is extremely sweet.
Same as many beverages like coffee taste bitter when cold that is
why we like having coffee, tea , cocoa served hot.107

Texture:
Texture refers to those qualities of a food that can be felt with the fingers, tongue, palate,
or teeth.
Foods have different textures, such as:
Crisp crackers or potato chips , Crunchy celery , Hard candy ,
Tender steaks , Chewy chocolate chip cookies , and Creamy ice cream .
108
The texture of a food can change as it is stored,
for various reasons:
•If fruits or vegetables lose water during storage,
they wilt or lose their turgor pressure
•Crisp apple becomes unacceptable and leathery
on the outside.
•Bread can become hard and stale on storage.
•Products like ice cream can become gritty due
to precipitation of lactose and growth of ice
crystals if the freezer temperature is allowed to
fluctuate, allowing thawing and refreezing.

Tenderness:
In fruits and vegetables depends on how easily the cells separate.
The quality of food being easy to cut or chew.
Meat tenderness is influenced by –
Amount of muscle (The more muscle the more toughness)
Amount of marbling (The more marbling the less toughness)
109

110
Consistency:
Temperature may affect consistency of food.Thinness or thickness
of a product.Measured in terms of “pourability”
5.Psychological Factors:
These factors contribute to acceptability of foods. Food is accepted
when there is pleasant condition.
•Taste bias is a like or dislike that is linked to past positive or
negative experiences.
•Label terms, brand names, advertising, peers, and setting also
cause taste bias

SENSORY EVALUATION TEST
Different sensory test are employed foe food evaluation.The test are
grouped into four types:
1. DIFFERENCE TEST
2. RATING TEST
3. SENSITIVITY TEST
4. DESCRIPTIVE TEST
111

113
A. DIFFERENCE /DESCRIMINATION TEST
Difference tests are used to determine if there is any
difference between or among samples. The three basic types
of difference tested are:
•Simple difference
•Directional and Quantitative difference
•Quality preference difference

Prepare two different samples of the food product you
wish to test.
Compare one attribute, e.g. which one is sweeter?
Record the response from the tasters.
115
A. DIFFERENCE TEST
A1.Paired comparison test

Prepare three food samples, two of which are the same.
Using one of the two identical samples as control, as the
taster to decide which of the other two remaining sample
as the control.
Record the tasters’ responses.
117
A2.Duo-trio Test

Prepare three food samples, two of which are the same.
Arrange the samples in a triangle.
Ask the tasters to decide which of the samples is the
odd one out.
Record the responses from the tasters
Two Samples A and B can be presented in two
combinations AAB and BBA and for replication in six
different-
AAB,ABA,BAA,BAB,ABB and BBA.
A3.TRIANGLE TEST
120

2B.RATING TEST
B1. Ranking test
Used to determine how several samples differ on the
basis of a single characteristic.
Panellist are presented all samples with code number
and are asked to rank.
The Panellist are asked to rank the coded samples
according to there preference.
121

Sensitivity tests are done to assess the ability of
individual to detect different tastes, odour and feel the
specific factors like hotness.
These tests are used to select and train panel members
for evaluating the quality of products containing spices,
salt and sugar. Eg., tomato ketchup or sauce.
C1.SENSITIVITY THRESHOLD
TEST
122

Most food companies have a panel that is trained on
each of their products
To train a panel takes several weeks to months
There are several different methods of training:
•Quantitative Descriptive Analysis
•Sensory Spectrum
•Flavour Profile
DESCRIPTIVE TEST
123
contd..

What are Food
Additives?
❧❧ Some of the food we eat are fresh. They are not
processed.
❧ Most foods, however, are processed.
❧ In food processing , small amounts of certain chemicals are
often added.
❧ These are called food additives.
❧ Any substance that becomes part of a food product either
directly or indirectly during some phase of processing, storage
or packaging.
❧ Basically, a food additive is something that doesn’t
normally occur in the food we eat — it has to be added…126

In general various definitions have been given.
➢ According to WHO (1965), ‘Food Protection
Committee of the National Academy of Sciences
(1959)
‘It is a substance or mixture of substances, other than the basic
food stuff, which is present in food as a result of any aspect of
production, processing, storage or packaging. This term does
not include chance contamination.’
127
FOOD ADDITIVES

The use of food additives is not a modern-day
invention. The practice probably started when man first
discovered that fire would cook and thereby preserve
his meat. Later he realised that the addition of salt
would preserve without cooking. In ancient times,
cloves were placed in hams to inhibit the growth of
bacteria.
128
History

Food additives are added to foods in precise amounts during processing.
They are Technologically justified for:
• Maintaining the nutritional quality of the food
• Enhancing the keeping quality or stability of food thereby reducing food
wastage
• Making food attractive to consumers in a manner which precludes deception
• Providing essentials aids in food processing
In some products, they are so essential that additives are used in certain
organic foods
In some countries, lots of food is lost because it “ goes off” due to microbial
growth before it can be eaten. Food poisoning also shows the dangers of
contaminated food and without the use of preservatives; it would quite likely
be more common.
129
WHY USE FOOD
ADDITIVES?

1. To provide nutrition – to improve or maintain the
nutritional quality of food.
2.To maintain product quality and freshness – Fresh foods
do not stay that way for long periods of time; they rapidly
deteriorate, turn rancid and spoil. Food additives delay
significantly this deterioration and prevent spoilage caused
by growth of microorganisms, bacteria and yeast and also by
oxidation (oxygen in air coming into contact with the foods).
130
PURPOSE OF FOOD ADDITIVES

3.To aid in the processing and preparation of foods –
Additives impart and/or maintain certain desirable qualities
associated with various foods.
4. To make foods appealing – the majority of food additives are
most often used for this purpose. Unless foods look appetizing
and appeal to our senses, they will most likely go uneaten and
valuable nutrients will be lost.
131
PURPOSE OF FOOD ADDITIVES

Types of additives
Additives may be:
• Natural – found naturally, such as extracts from
beetroot juice , used as a colouring agent;
• Manmade versions – synthetic identical copies of
substances found naturally, such as benzoic acid (E210),
used as a preservative;
• Artificial – produced synthetically and not found
naturally, used as a preservative in some dairy products
and in semolina and tapioca puddings.
132

Why not keep to natural additives?
Some artificial colours have almost disappeared from
foods as companies realised that many consumers prefer
food products to contain natural colours.
At present there is not the variety of natural additives
required to perform all the functions of additives
necessary.
Manmade additives may prove more efficient at
preserving, and some natural colours fade in some products
133

Additives are very important for the processed food industry.
Natural additives are came from plants and animals while
other additives are artificial sing various chemicals.
Common types of additives are:
• Preservatives
• Colouring
• Flavouring
• Nutrient
The FDA makes sure that food additives used by food
manufacturers safe and approved for regulated use.
134

1.Acids, bases and buffers:
•Food acids are added to make flavours "sharper",
and also act as preservatives and antioxidants.
Common food acids include vinegar, citric acid,
tartaric acid, malic acid, fumaric acid, and lactic
acid.
•Acids, bases and buffers control the acidity or
alkalinity of food, for safety and stability of
flavour.
2.Anti-caking agents:
Anti-caking agents ensure free movement or flow of
particles, e.g. in dried milk or table salt.
Calcium Phosphate, Silica Gel in curing mixes and
Stearate are examples of anti-caking agent.
135
CLASSIFICATION of FOOD ADDITIVES

3.Antifoaming agents:
•Anti-foaming agents prevent or disperse
frothing, e.g. in the production of fruit juices.
•Antifoaming agents are added to cooking oils
to prevent excessive frothing during deep
frying. These agents are included in many
foods, such as Diet Pepsi, Diet Coke, and
Sprite.
•There are many types of defoamers including
oil based, water based, silicone based used
agents are insoluble oils, polydimethylsiloxanes
and other silicones, certain alcohols, stearate
and glycols.
136

4.Antioxidants:
•Prevent food containing fat or oil from going rancid due
to oxidation, developing an unpleasant odour or flavour;
•Prevent the browning of cut fruit, vegetables and fruit
juices (and so increase shelf life and appearance). For
example, vitamin C, also known as ascorbic acid, or
E300, is one of the most widely used antioxidants.
•Very-beneficial in preventing spoilage in animals fat
caused by oxidation.
137

5.Bulking agents:
Bulking agents such as starch are additives that increase the bulk-
volume of a food without affecting its taste. Eg.potassium bitartrate.
6.Food colouring:
•Restore colour lost during processing or storage, e.g. marrowfat peas
•Ensure that each batch produced is identical in appearance or does
not appear ‘off’.
•Reinforces colour already in foods, e.g. enhance the yellowness of a
custard.
•Give colour to foods which otherwise would be colourless (e.g. soft
drinks) and so make them more attractive.
138

Natural food colours:
•Caramel (dark brown)colouring, made from caramelized sugar,
used in cola products and also in cosmetics.
•Annatto, a reddish-orange dye made from the seed of the
Achiote.
•A green dye made from chlorella algae.
•Betanin extracted from beets.
•Turmeric orange yellow
•Saffron Paprika
•Elderberry
139
CLASSIFICATION of FOOD
ADDITIVES

Artificial food colours:
•Brilliant Blue, E133 (Blue shade)
•Indigotine, E132 (Dark Blue shade)
•Fast Green, E143 (Bluish green shade)
•Allura Red AC, E129 (Red shade)
•Erythrosine, E127 (Pink shade)
•Tartrazine, E102 (Yellow shade)
•Sunset Yellow, E110 (Orange shade)
140
CLASSIFICATION of FOOD
ADDITIVES

7.Colour retention agents:
Colour retention agents are food additives that are added to food to
prevent the colour from changing. Many of them work by
absorbing or binding to oxygen before it can damage food
(antioxidants). For example, ascorbic acid (vitamin C) is often
added to brightly coloured fruits such as peaches during canning.
8.Emulsifiers, Stabilisers:
➢ Emulsifiers- help mix ingredients together that would normally
separate, e.g. Lecithins (E322).
➢ Stabilisers- prevent ingredients from separating again, e.g. Agar
and Pectin( E440).
141

9.Flavour and Flavour Enhancers:
•Flavours are additives that give food a particular taste or smell, and
may be derived from natural ingredients or created artificially.
Examples are salt, sugar, and vanilla, which are used to complement
the flavour of certain foods.
Synthetic flavouring agents, such as benzaldehyde for cherry or
almond flavour, may be used to simulate natural flavours.
•Flavour enhancers enhance a food’s existing flavours . They may
be extracted from natural sources ( through distillation , solvent
extraction, maceration, among other methods ) or created artificially.
e.g. monosodium glutamate (E612) is added to processed foods.
For example some soups, sauces and sausages.
142

143
Natural Food colour Synthetic Food Colour
Almond
flavour and
fragrance
with
benzaldehyde
Natural flavour enhancer
Synthetic flavour enhancer

144
10. Flour treatment agents:
•Flour treatment agents are used to help the manageability of dough
during baking. These improve flour performance in bread making.
•Newly milled flour without further treatment does not make good
bread. Flour treatment agents help mature the flour and give a
smooth texture. This gives the flour a more uniform appearance
and eases the handling of the dough under different conditions like
fermentation.
•These are used to ensure good loaf volume and improve the crumb
structure, softness and colour. Vitamin C, or ascorbic acid, (E300)
is the most commonly used flour treatment agent.

11. Glazing agents:
Glazing agents produce a protective coating and impart a
polish/sheen on the surface of a food such as confectionery or
citrus fruit or even baked goods (for appearance and shelf-life)
e.g Stearic acid (E570),Beeswax (E901),Carnauba wax (E903)
etc.
12. Humectants:
•Prevent food from drying out
•Glycerine, Sorbitol, and Mannitol are called humectants and
are used in foods such as coconut and certain confections to
help retain moisture.
145

13 Tracer gas:
Tracer gas allow for package integrity testing to prevent foods from
being exposed to atmosphere, thus guaranteeing shelf life.
14 Preservatives:
•Prevent the growth of micro-organisms which could cause food
spoilage and lead to food poisoning.
•Extend the shelf-life of products, so that they can be distributed
and sold to the consumer with a longer shelf- life.
•Salting and sugaring are two of the oldest methods of preserving
food.
For example Meats are often treated with nitrite and nitrate (E249
to E252) during the curing process
147

148
Sugaring Salting
Curing meat by nitrite

15.Sweeteners:
Sweeteners are added to foods for flavouring. Sweeteners other
than sugar are added to keep the food energy (calories) low, or
because they have beneficial effects regarding diabetes mellitus,
tooth decay, or diarrhea.
Intense sweeteners, e.g. saccharin, have a sweetness many times
that of sugar and therefore are used in small amounts, e.g. in diet
foods, soft drinks, sweetening tablets;
Bulk sweeteners, e.g. sorbitol, have a similar sweetness to sugar
and are used at similar levels.
149

• Only certain additives are allowed for use
• Amounts are controlled & must be noted on the label
• Maximum amounts used are small & must serve a
useful purpose
• Are safety tested by the industry & these tests are
monitored by Health Protection Branch of Can.
• Monitoring usage of additives is ongoing.
150
Government controls

•All additives must be listed on food labels
•The names (or the identification number) and the functions of the
additives used in a prepackaged food must be listed on the food label
•Additives must appear on the food label in descending order of
quantity (greatest amount first)
•International Numbering System for food additives
– It is an internationally agreed numerical system for identifying
food additives
•E number
– Additives are given the prefix “E” if they have been accepted as
safe for use within the European Union
151
Food labelling and food additives

154
Legislation in World
Type of Additive E Number
Colouring Most begin with 1
Preservatives Most begin with 2
Flavourings Not numbered
Antioxidants E300 – 321
Emulsifiers and E322 and some numbers
stabilisers between E400 and E495
Sweeteners Most begin with 4 or 6

100-199 Colors
200-299 Preservatives
300-399 Antioxidants and Acidity regulators
400-499 Thickeners, Stabilisers and Emulsifiers
500-599 Ph regulators, Anti-caking agents
600-699 Flavour enhancers
700-799 Antibiotics
900-999 Miscellaneous
1100-1599 Additional chemicals
155
E-numbers (food labels)

•Extend the life of processed foods so they can be transported,
stored or kept on the shop shelf for longer, maintain a standard
quality.
•Make the products more attractive to the consumer.
156
Advantages of Food Additive

157
Disadvantages of
Food Additives

1.Artificial Sweeteners
Artificial sweeteners are used in many diet foods and beverages to
enhance sweetness while reducing calorie content.
Common types of artificial sweeteners include Aspartame, Sucralose,
Saccharin and Acesulfame -K.
Aspartame, (E951) more popularly known as Nutrasweet and Equal, is
found in foods labeled "diet" or “sugar-free”.
Aspartame is a neurotoxin and carcinogen. Affect short-term memory,
the components of this toxic sweetener may lead to a wide variety of
ailments.( Brain tumour, diseases like Lymphoma, Diabetes, multiple
sclerosis, Parkinson's, Alzheimer's, Fibromyalgia, and Chronic fatigue,
Emotional disorders like depression etc )
158
Disadvantages of Food Additives
Additives which should
be avoided

Acesulfame-K, a relatively new artificial
sweetener found in baking goods, gum and
gelatin, has not been thoroughly tested and has
been linked to kidney tumours.
Artificial Sweeteners found in:
diet or sugar-free sodas, diet coke, coke zero,
desserts, sugar-free gum, drink mixes, table top
sweeteners, cereal, breath mints, pudding, ice tea,
chewable vitamins, toothpaste.
Artificial sweeteners are generally considered safe
for most people when consumed in moderation.
However, if you experience any negative side
effects after using artificial sweeteners, check
ingredients labels carefully and limit your intake.
159

2.High-Fructose Corn Syrup(HFCS)
High-fructose corn syrup is a sweetener made from corn.
It’s rich in a type of simple sugar called fructose, which can cause
serious health issues when consumed in high amounts.
HFCS packs on the pounds faster than any other ingredient, increases
your LDL (“bad”) cholesterol levels, and contributes to the
development of diabetes and tissue damage, among other harmful
effects.
It contributes empty calories and added sugar to foods without any of
the important vitamins and minerals that your body needs.
160
be avoided

Found in most processed foods, bread,
candy, flavoured yogurts,
salad dressings, canned vegetables, cereals.
It’s best to skip sugary snacks and foods that contain high-fructose corn
syrup.
Instead, go for whole, unprocessed foods without added sugar, and sweeten
them up with Stevia, yacon syrup or fresh fruit.
161

3.Monosodium Glutamate (MSG)
Monosodium glutamate, or MSG, is a common food additive used to
intensify and enhance the flavour of savory dishes.
It’s found in a variety of processed foods like frozen dinners, salty snacks
and canned soups. It’s also often added to foods at restaurants and fast
food places.
MSG is known as an excitotoxin, a substance which overexcites cells to
the point of damage or death.
MSG affects the neurological pathways of the brain and disengages the
"I'm full" function which explains the effects of weight gain.
Found in Chinese food (Chinese Restaurant Syndrome ) many snacks,
chips, cookies, seasonings, most Campbell Soup products, frozen
dinners and lunch meats.
162
be avoided

Found in Chinese food (Chinese Restaurant Syndrome ) many
snacks, chips, cookies, seasonings, most Campbell Soup products,
frozen dinners and lunch meats.
If you experience any negative side effects after consuming MSG,
it’s best to keep it out of your diet.
Otherwise, if you’re able to tolerate MSG, it can be safely
consumed in moderation without the risk of adverse side effects.
163

4. Trans Fat
Trans fats are a type of unsaturated fat that have undergone
hydrogenation, which increases shelf life and improves the
consistency of products.
A number of potential health risks have been associated with trans
fat intake, and the FDA even recently decided to revoke their GRAS
(generally recognised as safe) status.
Numerous studies show that trans fat increase LDL cholesterol levels
while decreasing HDL (“good”) cholesterol, increases the risk of
heart attacks, heart disease, and strokes, and contributes to increased
inflammation, diabetes, and other health problems.
164
be avoided

165
Found in margarine, chips and crackers, baked goods, fast foods.
You can also make a few simple switches in your diet, like using
butter instead of margarine and swapping out vegetable oils for
olive oil or coconut oil instead.

5. Common Food Dyes/Artificial Food Colouring:
Artificial food colouring is used to brighten and improve the appearance
of everything from candies to condiments may contribute to behavioural
problems in children and lead to a significant reduction in IQ. Animal
studies have linked some food colourings to cancer.
Red dye # 3 (E124)
•Banned in 1990 after 8 years of debate from use in many foods and
cosmetics.
•Has been proven to cause thyroid cancer and chromosomal damage in
laboratory animals, may also interfere with brain-nerve transmission.
•Found in fruit cocktail, maraschino cherries, cherry pie mix, ice cream,
candy, bakery products and more!
166
be avoided

Yellow #6 (E110) and Yellow Tartrazine (E102)
•Banned in Norway and Sweden.
•Increases the number of kidney and adrenal gland tumours in
laboratory animals, may cause chromosomal damage.
•Found in : American cheese, macaroni and cheese, candy and
carbonated beverages, lemonade and more!
Blue #1 and Blue #2 (E133)
Banned in Norway, Finland, and France.
May cause chromosomal damage.
Found in candy, cereal, soft drinks, sports drinks and pet foods.
167

•More research is needed to evaluate the safety and potential health
effects of artificial food colouring for humans.
•Food dyes are found primarily in processed foods, which should be
limited in a healthy diet. Always opt for whole foods, which are
higher in important nutrients and naturally free of artificial food
colouring. 168

6.Sodium Sulfite:
Sulfites are chemicals that are in some foods, either naturally or as
additives.
It is rare, but some people (about 1 in 100, according to the FDA)
are sensitive to these compounds. Their reaction can range from mild
to life-threatening.The majority of these individuals are asthmatic,
suggesting a link between asthma and sulfites.
Individuals who are sulfite sensitive may experience headaches,
breathing problems, and rashes. In severe cases, sulfites can actually
cause death by closing down the airway altogether, leading to
cardiac arrest.
Found in: wine and dried fruit.
169
be avoided

170
7. Sodium Nitrate/ Sodium Nitrite:
Sodium nitrite acts as a preservative to prevent the growth of bacteria while
also adding a salty flavour and reddish-pink color.
When exposed to high heat and in the presence of amino acids, nitrites can turn
into nitrosamine, a compound that can have many negative effects on health.
A higher intake of nitrites and processed meats may be linked to a higher risk of
several types of cancer.
Sodium nitrite is widely regarded as a toxic ingredient, and the USDA actually
tried to ban this additive in the 1970's but was voted by food manufacturers
who complained they had no alternative for preserving packaged meat
products.
Why does the industry still use it? Simple: this chemical just happens to turn
meats bright red.
It's actually a color fixer, and it makes old, dead meats appear fresh and
be avoided

Found in hotdogs, bacon, ham, lunch meat, cured meats, corned
beef, smoked fish or any other type of processed meat.
It’s best to keep your intake of sodium nitrite and processed meats
to a minimum.Chicken, beef, fish, pork, legumes, nuts, eggs are
just a few delicious high-protein foods that you can add to your
diet in place of processed meats.
171

172
8. BHA and BHT (E320)
Butylated hydroxyanisole (BHA) and
Butylated hydroxytoluene (BHT)
BHA and BHT affects the neurological
system of the brain, alters behaviour and has a
potential to cause cancer.
They are oxidants which form cancer-causing
reactive compounds in your body.
BHA and BHT preservatives keeps foods
from changing color, changing the flavour or
becoming rancid.
Found in cereals, chewing gum, potato chips,
and vegetable oils.
be avoided

9. Sulfur Dioxide (E220):
•Sulfur additives are toxic and in USA the Federal Drugs Administration
( FDA) have prohibited their use on raw fruit and vegetables.
•Adverse reactions include bronchial problems particularly in those
prone to asthma, hypotension (low blood pressure), flushing, tingling
sensations or anaphylactic shock.
•It also destroys vitamins B1 and E.
•Not recommended for consumption by children.
•The International Labour Organization says to avoid E220 if you suffer
from conjunctivitis, bronchitis, emphysema, bronchial asthma, or
cardiovascular disease.
•Found in beer, soft drinks, dried fruit, juices, cordials, wine, vinegar,
and potato products.
173
be avoided

10. Potassium Bromate
An additive used to increase volume in some white flour, bread, and
rolls, potassium bromate is known to cause cancer in animals. Even
small amounts in bread can create problems for humans.
Found in bread.
174
be avoided

While certain food additives have been linked to some pretty scary
side effects, there are plenty of others that can be safely consumed as
part of a healthy diet.
Start reading the ingredient labels when grocery shopping to take
control of your diet and determine what’s really being added to your
favourite foods.
Additionally, try cutting back on processed and packaged foods and
incorporating more fresh ingredients into your diet to minimize your
intake of food additives
175
The Bottom Line

Slideshare
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https://www.slideshare.net/Kanchchana/preservation-methods-129552244
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https://www.diet.com/info/facts/additives-and-preservatives
http://www.differencebetween.info/difference-between-preservatives-and-additives
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