Food Additives

Despite their association with modern-day food production, food additives have been used for centuries in preserving and improving the appearance and colour of food.

Syllabuses 2002

Topic Experimental NotesFood Additive PreservativesPreservatives

(e.g. nitrates (III), nitrates (V), sulphur dioxide, sulphates (IV), benzoic acid and benzoates)

AntioxidantsAntioxidants(e.g. BHA & BHT)

Flavour agentsFlavour agents(e.g. MSG and saccharin)

TextureTexture(e.g. emulsifying agents)

AppearanceAppearance(e.g. colouring agents)

Nutritional valueNutritional value(e.g. vitamins)

Principle of BHA/BHTPrinciple of BHA/BHTantioxidant to retard atmospheric oxidation of oils and fats

Syllabuses 2002

Topic Experimental NotesThe possible menace of food additives

The side effects of MSG, the toxicity of nitrates (III) and sulphur dioxide, and the potent carcinogenic nature of nitrates (III) and saccharin.

An awareness that the use of food additives is monitored by research findings and by legislation.

Content

Preservatives

Flavouring Agents

Colouring Agents

Emulsifiers, Stabilizers and Thickeners

Nutrients

Antioxidants

Harmful Effects of Food Additives

Monitoring of Use of Food Additives

Preservatives

Flavouring Agents

Colouring Agents

Emulsifiers, Stabilizers and Thickeners

Nutrients

Antioxidants

Harmful Effects of Food Additives

Monitoring of Use of Food Additives

Preservatives

Nitrates (III) and Nitrates (V)

Sulphur Dioxide and Sulphates (IV)

Benzoic Acid and Benzoates

Sorbic Acid and Sorbates

Propanoic Acid and Propanoates

Nitrates (III) and Nitrates (V)

Sulphur Dioxide and Sulphates (IV)

Benzoic Acid and Benzoates

Sorbic Acid and Sorbates

Propanoic Acid and Propanoates

Flavouring Agents

Spices Monosodium Glutam

ate Esters Saccharin Artificial Flavouring Common food Flavo

uring

Spices Monosodium Glutam

ate Esters Saccharin Artificial Flavouring Common food Flavo

uring

Preservatives

Flavouring Agents

Colouring Agents

Emulsifiers, Stabilizers and Thickeners

Nutrients

Antioxidants

Harmful Effects of Food Additives

Monitoring of Use of Food Additives

Colouring Agents

Natural Colourings Synthetic Colourings

Natural Colourings Synthetic Colourings

Preservatives

Flavouring Agents

Colouring Agents

Emulsifiers, Stabilizers and Thickeners

Nutrients

Antioxidants

Harmful Effects of Food Additives

Monitoring of Use of Food Additives

Emulsifiers, Stabilizers and Thickeners

Carboxymethymethylcellulose

Xanthan Gum Pectin Dextrins Sodium Alginate

Carboxymethymethylcellulose

Xanthan Gum Pectin Dextrins Sodium Alginate

Preservatives

Flavouring Agents

Colouring Agents

Emulsifiers, Stabilizers and Thickeners

Nutrients

Antioxidants

Harmful Effects of Food Additives

Monitoring of Use of Food Additives

Nutrients

Vitamins Minerals & Iodine

Vitamins Minerals & Iodine

Preservatives

Flavouring Agents

Colouring Agents

Emulsifiers, Stabilizers and Thickeners

Nutrients

Antioxidants

Harmful Effects of Food Additives

Monitoring of Use of Food Additives

Antioxidants

Ascorbic Acid and Ascorbates

BHA and BHT

Ascorbic Acid and Ascorbates

BHA and BHT

Preservatives

Flavouring Agents

Colouring Agents

Emulsifiers, Stabilizers and Thickeners

Nutrients

Antioxidants

Harmful Effects of Food Additives

Monitoring of Use of Food Additives

Harmful Effects of Food Additives

Allergies Hyperactivity Long-term illnesses Controversy over BHA

and BHT Side Effects of MSG Toxicity and Potent

carcinogenic Nature of Nitrates (III)

Toxicity of sulphur dioxide

Potent carcinogenic nature of saccharin

Allergies Hyperactivity Long-term illnesses Controversy over BHA

and BHT Side Effects of MSG Toxicity and Potent

carcinogenic Nature of Nitrates (III)

Toxicity of sulphur dioxide

Potent carcinogenic nature of saccharin

Preservatives

Flavouring Agents

Colouring Agents

Emulsifiers, Stabilizers and Thickeners

Nutrients

Antioxidants

Harmful Effects of Food Additives

Monitoring of Use of Food Additives

Monitoring the Use of Food Additives

By Research By Legislation

By Research By Legislation

Preservatives

Flavouring Agents

Colouring Agents

Emulsifiers, Stabilizers and Thickeners

Nutrients

Antioxidants

Harmful Effects of Food Additives

Monitoring of Use of Food Additives

Nitrates (III) and Nitrates (V)

Nitrates (III) and nitrates (V) of sodium and potassium

Slow down microbial growth

Maintain the pink colour of meat

Prevent botulism in canned foods

Sulphur Dioxide and Sulphates (IV)

Maintain the colour and the vitamin C content of the food

Prevent fruit tissues from browning

Provide an acidic medium that is not favourable for microbial growth

Benzoic Acid and Benzoates

Preventing mould and yeast from growing

Widely used in jams, fruit juices, oyster sauce(蠔油 ), margarine(黃油 ), non-alcoholic beverages and pickled(醃菜 ) products

Sorbic Acid and Sorbates

Prevent mould formation

Mainly used in cheese and in flour confectionery(糖果 )

Propanoic Acid and Propanoates

Prevent the formation of mould in bread.

Used in chocolate products and cheese.

Spices

CinnamonCinnamon and gingerginger are examples of natural spices

Chemicals which stimulate our taste buds

Commonly used in chicken broth, oyster sauce, soup bases for instant noodles, many fast foods and restaurants dishes.

Monosodium Glutamate (MSG)

Does not add any taste to foodBut is a flavour enhancer. It can bring out the flavour of food, particularly meat productsCommonly used in chicken broth, oyster sauce, soup bases for instant noodles and dim sums(點心 ).

Side Effects of MSG

Esters

The sweet smell in fruit is due to the presence of ester compounds

Naturals fruit flavours can be extracted from fruits and other plant materials

Most fruit flavouring used in the food industry are synthetic compoundssynthetic compounds

Esters are used in ice-cream and many fruit juicese.g. ethyl ethanoate which has a pineapple flavour.

Saccharin

Kind of sweetener

Used as a sugar substitute or diet sugar.

Saccharin has no food value

Sweetness about 500500 times that table sugar

Artificial Flavouring

Although flavourings can be extracted from natural sources, the demand for flavouring in the food industry has outstripped the supply. Therefore, artificial flavours are being produced.

Artificial flavouring are closely resembles the natural product.

Common food Flavouring

Flavour 中文 Food Additive

Camphor 樟腦 Bornyl acetate

Cinnamon 桂皮 Cinnamaldehyde

Ginger 薑 Ginger oil

Grape 葡萄 Methyl anthranilate

Lemon 檸檬 Citral

Orange 橙 Orange oil

Pear 梨 Amyl butyrate

Peppermint 胡椒薄荷 Menthol

Rum 朗姆酒 Ethyl formate

Spearmint 留蘭香 Carvone

Spicy 辛辣 Ethyl cinnamate

Vanilla 香子蘭 Ethyl vanillin

Wintergreen Methyl salicylate

Natural Colourings

CaramelCaramel→Brown colouring→Used in oyster sauceCaroteneCarotene→Yellow dye present in carrots→Used to colour butter and margarineChlorophyllChlorophyll→Green dye extracted from plants→Used to colour edible oils

Synthetic Colourings

Indigo carmineIndigo carmine→Purple blue dye combination with yellow colouring→Used for confectionery, candies and liqueursTartrazineTartrazine →Yellow dye →Used in Pudding Powders, candies, ice-cream and pop drinksSunset YellowSunset Yellow→Orange dye→Used in candies, honey-like products, sea salmons and crabs( 蟹 )

Carboxymethylcellulose

Used to stabilize batter for coating steaks and fish fillets

Xanthan Gum

Used in Salad dressings, dessert toppings and frozen pizzas

Pectin

Used to make the gel in jams and jellies

Dextrins

Used to emulsify and stabilize cream, mayonnaise(蛋黃醬 ) and salad dressings

Sodium Alginate

Commonly used to emulsify and stabilize ice-cream, yogurt, sauces and syrups(糖水 )

Vitamins

Vitamin Cfor fruit juices

Vitamin Bfor enriched flour

Vitamin Dfor milk and margarine

Minerals & Iodine

Ammonium ferric citrate in infant milk formulations and bread flour

Iodine in iodized salt

Ascorbic Acid and Ascorbates

Ascorbic AcidChemical name of Vitamin C

Reducing in nature

Reduce the amount of dissolved oxygen in food

Ascorbic Acid and AscorbatesAntioxidants for water-soluble fatty products

BHA and BHT

BHA (butylated hydroxyanisole)BHT (butylated hydroxytoluene)Commonly used antioxidants for fat-soluble fatty productsSimilar properties to the natural antioxidant, vitamin E

BHA and BHT

They appear to work by donating the H atom of the –OH group to the free hydroperoxide redical (ROO·) involved in the autoxidation of fats and oil, thereby stopping the chain reactions in oxidative spoilage.

AH + ROO· ROOH + A·where AH represents the antioxidant, and A is a radical derived from the antioxidante.g.

O·

C(CH3)3

OCH3

O·

C(CH3)3

OCH3

Antioxidant radicals from BHA

Allergies

Some people are allergic to certain additives. It is suspected that MSG and Tartrazine may cause rashes, stomach upsets and asthma.

Hyperactivity

In the 1970s, it was suggested by some scientists that food additives may be linked to hyperactivity and attention deficient disease (ADD) in children

Some hyperactive children show improvement when fed with additive-free diets

Well-controlled studies have produced no evidence of these additives causing hyperactivity or learning disabilities in children

Long-term illnesses

Some additives, such as sodium nitrate (III), are suspected to be carcinogens

Some additives are believed to be the causes of some long-term illnesses

Controversy over BHA and BHT

Small amount of BHT shown to prevent cancer

Larger amounts can cause cancer

Side effects of MSG

Some people allergic toMSG

Dizziness Thirst Headache Chest pain Sweating Abdominal discomfort

Chinese RestaurantSyndrome /MSG Syndrome

Toxicity and potent carcinogenic nature of nitrates

Short termDecrease in haemoglobin in blood

Long termMalnutrition

Growth retardation

Impairment of reproductive capacity

reduced lifespan

Toxicity and potent carcinogenic nature of nitrates (III)

In the stomach, nitrates (III) are first converted to nitric (III) acid.NaNO2(aq) + HCl(aq) HNO2(aq) + NaCl(aq)

Under certain conditions, nitric (III) acid reacts with secondary amines, which are released during digestion of proteins, to from nitrosamines.HNO2(aq) + R2NH(aq) R2N-N=O(aq) + H2O(l)

Stomach acid

Secondaryamine

nitrosamine

Toxicity of Sulphur Dioxide

Sulphur dioxide is poisonousAttack respiratory system

Potent carcinogenic nature of saccharin

Bitter aftertaste which renders it unpleasant to some users

High doses cause cancer

Research

Salt, sugar, vitamins and some minerals had long been used as additives to food and are Generally Recognized As Safe (GRAS)

No food additive may be used unless it has been extensively tested on animals

Legislation in World

In USAFood and Drug Administration (FDA) is responsible for monitoring the safety, purity, and wholesomeness of food additives

In UKFood Advisory Committee compiles in European Economic Community, a permitted food additive is assigned a E number.

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 stabilizers E322 and some numbers between E400 and E495

Sweeteners Most begin with 4 or 6

Legislation in Hong Kong

Legislate permissible additives and maximum limits of additives in particular foodsRequire supply of information as to composition of substances used in the preparation of foodCheck on food labelingInspect food- processing industriesTake samples for chemical analyses on foods and food additivesSeize and destroy foodProsecute for false labeling, advertisement, using non-permitted additives or using additives beyond the permissible limits.