Food Additives & Preservatives

8/6/2019 Food Additives & Preservatives

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FOOD ADDITIVES & PRESERVATIVES


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Definition of Food Additives:

a chemical added to a particular food

for a particular reason during

processing orstorage which couldaffect the characteristics

of the food, or become

part of the food.


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Additives.

it excludes food ingredients

such as:

y

salt, sugar, flavourings,y minerals, spices orseasonings,

y vitamins, packaging materials,

y veterinary drugs & agricultural chemicals.

y *flavourings: not covered by any legislation


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Common Food Additives:

Ascorbic Acid:

y used in cereals, cured meats & fruit drinks

as an antioxidant, colourstabilizer or as a

nutrient

Artificial & natural flavouring:

y used in cereals, candy, gelatin, desserts,

soft drinks &many oth

er foods as mimic ofnatural flavours


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Additives

Butylated Hydroxytoluene (BHT)y cereal, chewing gum, & potato chips as

an antioxidant. It keeps oils from going

rancid. Gums: (Arabic, guar, locust bean)y used in beverages, candy, cottage cheese,

dough, drink mixes, frozen pudding, ice

cream, salad dressings as stabilizers &thickening agents


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Additives

Sodium Benzoate:

y used in fruit juice, pickles, preserves

y soft drinks to prevent growth ofmicro-

organisms in acidic foods


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Additives use:

raises the nutrient value

prevents cancercausing agents fromforming

anti caking agents bleaching agents: dough conditioners

colouring agents

emulsifiers & stabilizers

as preservatives & prevent fats fromrancidity

to slow growth of microorganisms


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Introduction

Food additives can be divided into two

major groups

y Intentional additives

Chemical substances that are added to food

for specific purpose

Are regulated by strict governmental controls

y Incidental additives

We have little control over incidental or

unintentional additives


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Introduction

The term food additive means any substancethe intended use ofwhich results, or may

reasonably be expected to result, directly or indirectly in its becoming a

component or otherwise affecting thecharacteristics of any food

(including any substance intended for use inproducing, manufacturing, packing,processing, preparing , treating, packaging,transporting, orholding food;


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Introduction

and in including any source of radiation

intended for such use)

Except that such a term does not include

pesticides, colour, additives andsubstances forwhich prior sanction or

approval was granted


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Intentional Additives

Chemicals that are intentionally

introduced to foods to aid in processing

to act as preservatives

or to improve the quality of the food

are called intentional additives

Their use is strictly regulated by national

and international laws


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The purpose of food additives

y To improve or maintain nutritional value

y To enhance quality

y To reduce wastage

y To enhance consumer acceptability

y To improve keeping quality

y To make the food more readily availabley To facilitate preparation of the food


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The use of food additives is in effect a

food processing method

because bothhave the same objective

to preserve the food and/or make it

more attractive

In many food processing techniques, the

use of additives is an integral part of themethod, as is smoking, heating, and

fermenting


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In the following situations additives shouldnotbe used:y To disguise faulty or inferior processes

y To conceal damage, spoilage, or other inferiorityy To deceive the consumer

y If use entail substantial reduction in importantnutrients

y If the desired effect can be obtained byeconomical, good manufacturing practices

y In amount greater than the minimum necessaryto achieve the desired effects


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There are several ways of classifying

intentional food additives

One such method lists the following three

main types of additives

i) complex substances such as proteins or

starches that are extracted form other

foods

y For example: the use of caseinate in

sausages and prepared meats


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ii) naturally occurring, well-defined

chemical compounds such as salt,

phosphates, acetic acid, and ascorbic

acid

iii) substances produced by synthesis,

which may or may not occur in nature,

such as coal tar dyes, synthetic B-carotene, antioxidants, preservatives,

and emulsifiers


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Preservatives

Preservatives or antimicrobial agentsplay an important role in todays supplyof safe and stable foods

Increasing demand for conveniencefoods and reasonably long shelf life ofprocessed foods make the use ofchemical food preservatives imperative

Some of the commonly usedpreservatives such as sulfites, nitrate,and salt have been used for centuriesin processed meats and wine


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Preservatives

The choice of antimicrobial agent has to

be based on a knowledge of the

y antimicrobial spectrum of the preservative

y the chemical and physical properties of both

food and preservative

y the conditions of storage and handling,

ythe assurance of a

high

initial quality of thefood to be preserved


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Benzoic Acid

Benzoic acid occurs naturally in many types ofberries, plums, prunes, and some spices

As an additive, it is used as benzoic acid or asbenzoate

The latter is used more often because benzoicacid is sparsely soluble in water, and sodiumbenzoate is more soluble

The undissociated form on benzoic acid is the

most effective antimicrobial agenty pKa of 4.2; optimum pH range is from 2.5 to 4.0


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Benzoic Acid

y This makes it an effective antimicrobial in high-

acid foods, fruit drinks, cider, carbonated

beverages, and pickles

yIt is also used in margarines, salad dressings,soy sauce, and jams


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Parabens

Parabens are alkyl esters ofp-hydroxybenzoicacid

The alkyl groups may be one of the followingy

Methyl, et

hyl, propyl, Butyl, or

heptyl

Parabens are colourless, tasteless, andodorless (except the methyl paraben)

They are nonvolatile and nonhygroscopic

Th

eir solubility inw

ater depend on th

e natureof the alkyl groupy The longer the alkyl chain length, the lower the

solubility


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Parabens They differ form benzoic acid in that they have

antimicrobial activity in both acid and alkaline pH

regions

The antimicrobial activity in parabens is proportional to

the chain length of the alkyl group Parabens are more active against molds and yeast than

against bacteria, and more active against gram-positive

than gram-negative bacteria

They are used in fruitcakes, pastries, and fruit fillings


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Parabens

Methyl and propyl parabens can be used in

soft drinks

Combinations of several parabens are

often used in applications such as fishproducts, flavor extracts, and salad

dressing


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Hydrogen Peroxide

Hydrogen peroxide is a strong oxidizing agent and isalso useful as a bleaching agent

It is used for the bleaching of crude soya lecithin

The antimicrobial action of ofhydrogen peroxide isused for the preservation of cheese milk

Hydrogen peroxide decomposes slowly into waterand oxygen

y This process is accelerated by increased temp

y The presence of catalysts such as catalase,lacto-peroxidase and heave metals


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Hydrogen Peroxide

Its antimicrobial action increases with temp

When hydrogen peroxide is used for

cheese making, the milk is treated with

0.02 percent hydrogen peroxide followedby catalase to remove hydrogen peroxide

Hydrogen peroxide can be used for

sterilizing food processing equipment and

for sterilizing packaging material used in

aseptic food packaging systems


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Sodium Chloride

Sodium chloride has been used for

centuries to prevent spoilage of foods

Fish, meats and vegetables has been

preserved with salt

Today, salt is used mainly in combination

with other processing methods

The antimicrobial activity of salt is relatedto its ability to reduce the water activity (a

w)

thereby influencing microbial growth


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Sodium Chloride

Salt has the following characteristics:

y It produces an osmotic effect

y It limits oxygen solubility

y It changes pH

y Sodium and chloride ions are toxic

y Salt contributes to loss of magnesium ions

The use of sodium chloride is self-limiting because of its effect on taste


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Acids

Acids as food additives serve a dualpurposey Acidulants

y Preservatives

Phosphoric acid is used in cola soft drinksto reduce the pH

Acetic acid is used to provide tartness inmayonnaise and salad dressings

Similar functions are served by organicacidsy Citric acid, tartaric, malic, lactic acids


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Acids

Straight-chain carboxylic acids,

propionic and sorbic acids, are used for

their antimicrobial properties

Propionic acid is mainly used for its

antifungal properties


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Antioxidants

Food antioxidants in the broadest sense

are all of the substances that have some

effect on preventing or retarding

oxidative deterioration in foods


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Bread improvers

To speed up the aging process ofwheat

flour, bleaching and maturing agents are

used

Benzoyl peroxide is a bleaching agent

that is frequently used

y Other compounds including the oxides of

nitrogen, chlorine dioxide, nitrosyl c

hloride,and chlorine are both bleaching and

improving (maturing) agents


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Bread improvers

Improvers used to ensure that doughwillferment uniformly and vigorously includey Oxidizing agents: Potassium bromate,

potassium iodate, calcium peroxide

There may be small amounts of otherinorganic compounds in bread improversy Including ammonium chloride, ammonium

sulfate, calcium sulfate

Most of these bread improvers can only beused in small quantities, becauseexcessive amounts reduce quality

Food Additives & Preservatives

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