2. INTRODUCTION:
Substances that are added to food to maintain or improve the
safety, freshness, taste, texture, or appearance of food are
known as food additives.
Food additives can be derived from plants, animals, or
minerals, or they can be synthetic.
Additives may be intentional as well as unintentional.
Intentional- added with objective to perform a specific
function and increase the preservation of life of product.
Unintentional- have no intended function in adding to the
product but to be a part of that particular product.
3. Objectives of adding an additive :
To reduce wastage and improve keeping quality.
eg:benzoate in sauces, sodium propionate in bread and sorbic
acids in cheese, etc.
To improve and maintain nutritive elements. eg:addition of
vitamins for enrichment, addition of vitamin D to milk,
addition of iodine to salt, etc .
To enhance quality and consumers acceptability of the
product. e.g., addition of colouring agents, emulsifier,
thickeners etc.
To facilitate the preparation of foods e.g., addition of acid to
beverage, sugar in jams, jellies, etc.
8. Chemical Preservatives:
Substances added intentionally to prevent or slow down food
spoilage
They are non toxic to humans as they come under food
additives generally recognized as safe (GRAS)
Substance has capable of inhibiting, retarding and arresting
growth of microbes.
Used to inhibit the growth of food spoilage and foodborne
pathogens.
9. Chemical preservatives are utilized in food preservation in
various ways:
• Directly mixed with food
• Applied to wrappers or containers
• Storage environment of food
• Equipment treatment
The preservatives are classified into following two classes as
Class I and Class II preservatives.
10. Class I preservatives:
Naturally occuring substances.
There is no maximum limit specified under law for their use.
Common Examples are:
Salt,
Sugar,
Dextrose,
Glucose syrup,
Spices,
Vinegar or Acetic acid,
Honey &
Edible vegetable oils.
11. Class II preservatives:
Chemical substances added to the food.
Being chemical substances have maximum limit beyond which
they should not be present in different products.
Maximum limit for these substances under FPO (Fruit
Products order) in different fruit and vegetable products vary
between 40 to 2000 ppm (SO2), 120 to 750 ppm (benzoic
acid) and 50 to 500 ppm (sorbic acid) depending upon the type
and category of foods.
When two or more preservatives are added to the food, their
ratio shall be calculated proportionally to their maximum limit.
12. -Contd..
Examples:
Benzoic acids and its salts
Sulphurous acids and its salts
Nitrates/ Nitrites of Sodium or Potassium
Sorbic acid
Propionates of Ca, Na, lactic acid
Nisin
Methyl/ Propyl parahydroxy Benzoates ,Sodium
Diacetate
13.
14.
15. ORGANIC ACIDS:
Organic acids, which are both naturally present in foods during
fermentation or which are added to foods during processing,
have been used for many years for food preservation. The most
commonly used organic acids include citric, succinic, malic,
tartaric, benzoic, lactic and propionic acids .
Citric acid is found in citrus fruits. It is widely used in
carbonated drinks and as an acidifier of foods. This acid is
more effective than acetic and lactic acids at inhibiting the
growth of thermophilic bacteria.
Malic acid is widely found in fruit and vegetables. It inhibits
the growth of yeasts and some bacteria due to a decrease in
pH.
16. - Contd..
Benzoic acid is the oldest and most widely used preservative.
It occurs naturally in cranberries, raspberries, plums, prunes,
cinnamon and cloves. Disturb enzymatic system
Benzoic acid is primarily used as an antifungal agent in fruit-
based and fruit beverages, fruit products, bakery products and
margarine. Lactic acid is not naturally present in foods, but is
formed during fermentation of sugar by lactic acid bacteria.
Lactic acid inhibits the growth of spore forming bacteria at pH
5.0 but does not affect the growth of yeast and molds.
17. Sorbic acid:
Sorbic acid and sodium and potassium sorbate are used to
inhibit the growth of moulds and yeasts by disrupting cell
membrane function/inhibiting enzymes/inhibiting bacterial
spore germination . The activity of sorbic acid increases as the
pH decreases. Sorbic acid and its salts are tasteless and
odourless when used at levels below 0.3%
Commonly used level: 0.05-0.2%
Propionic acid :
occurs in foods by natural processing. It is found in Swiss
cheese at concentrations of up to 1%. It is effective against
moulds and bacteria by disrupting cell membrane function.
-Contd..
18. -Contd……
Nisin
It is a natural preservative. Having activity against specific
bacteria, which disrupts cell wall synthesis. Used in cheese,
cooked meat etc.
