Food Additives Foods, Facts & Fallacies YSCN 0006 lramsden/fff.html.

Food Additives

Foods, Facts & Fallacies

YSCN 0006

http://web.hku.hk/~lramsden/fff.html

Additives

What do we eat?Fresh food versus processed food.Changing patterns of food consumption.Longer storage and processingNeed to maintain food quality

What are additives?

Substances added to food that are not naturally present

Not nutritiveOriginal aim usually preservationLater to enhance food appearanceand enhance food quality

Types of Additives and their Functions

Food Regulation

US GRAS systemGenerally Recognised As Safe Introduced in 1958 to approve established

food ingredientsNew additives must be approved by FDADelaney Clause to prohibit any substance

known to cause cancer

Additive Testing

Relies on animal tests to NOELNo Observable Effect Level = highest dose

of additive with no effect on animalReduced by a factor of 100 to give safety

margin for humans

E number system

European system for approved food additives

E classification shows the additive is safe for use in food

Internationally recognised and also used in other countries

E numbersE number Additive

100-180 Colouring agents

200-297 Preservatives

300-321 Antioxidants

322-385 Emulisfiers

400-495 Texture modifiers

500-578 Processing aids

620-640 Flavour enhancers

900-1520 Coating agents, sweeteners

Earliest Additives Preservatives Sodium Chloride, Salt Used for 10,000 years to

preserve meat products Salt reduces water availability

for bacteria to grow Crude salt is contaminated

with sodium nitrate Additional use of smoke

Traditional AdditivesUsed for thousands of year

Salt and saltpetre Smoke Honey Vinegar Herbs & Spices Natural food colourings Calcium carbonate

E 250 Sodium NitriteSodium nitrate contaminant of crude saltFound to cause pinkish colour in meatSodium nitrite more effectiveOn high temp cooking can be converted to

carcinogenic compounds nitrosoamines.Potent inhibitor of anaerobic metabolismPrevents growth of major food pathogenClostridium botulinum

Clostridium botulinum

Common soil bacteriaAnaerobe can only grow well when no oxygen present

Spores heat resistant to 120°C for 3minsBacteria produces protein toxin1µg fatal, respiratory paralysis and cardiac failure

Meat colour

Fresh meat ~ purplish red Exposed meat, bright red oxymyoglobin Later turns to metmyoglobin, gray or brown

Nitrite reacts to form nitrosomyoglobin After cooking – nitrosohaemochrome pinkish red in colour

Cured meat Pickled in salts,

Salt, sodium nitrite, ascorbic acid, sugar Meat submerged in strong solution Or injected by machines with multiple needles 10 days at 4°C

SmokingWood fire, produces anti bacterial compounds

Provides surface coating and protectionColour and flavourHams, heated to 60°C

Not sterile, must be refrigerated, But can be eaten raw

Bacon, only heated to 52°C Cannot be eaten raw

Sausages Ground meat, low quality off-cuts

Natural casing, eg. sheep intestine Stuffed + spices, salt, sugar, ice Sodium nitrite to inhibit Clostridium botulinum

Frankfurters, hot dogs

Meat comminuted Ground very finely to form meat emulsion 30% fat, 10% water stuffed in cellophane casings to form links smoked or cooked to 75°C De-skinned, passed through hot water and skins

peeled off by machine.

Spoilage

Become slimy Surface growth of yeasts and bacteria

Turn green lactobacter releasing hydrogen peroxide Reacts with nitrosohaemochrome oxidises it to a green colour

More PreservativesE200 Sorbic Acid, soft drinks, yoghourt.E210 Benzoic acid, jams, creams

E220 Sulphites, SO2 wine, vegetables, drinks

E230 Diphenyl, fruit E234 Nisin, cheese E239 Hexamine Fish E280 Propionic acid Bread

Antioxidants

Chemical preservationMost important for fats

E300 Ascorbic acid (vitamin C) E306 Tocopherol (Vitamin E) E320 BHA meat products, dairy products E321 BHT meat products, dairy products

Flavour

Artificial Sweeteners sucrose 1 cyclamate 30 saccharin 300 aspartame 180 sucralose 600 alitame 2000 thaumatin 2500

Artificial FlavoursMimics of natural flavours using complex

mixes of pure chemicalsSynthetic banana flavour

amyl acetate amyl butartae ethyl butartae isoamyl acetate isoamyl butarate linalool + 15 others in lesser quantities

Flavour enhancer

E621 monosodium glutamateamino acid - glutamine

19th century Increased urbanisation & food processing

Adulteration Use of cheap substitutes Colour & flavour enhancers

Sometimes dangerous 1857 survey of confectionary found colours: Lead chromate Mercuric sulphide Copper arsenite

Food ColoursPreserved Vegetables

Chlorophyll, green pigment in plants is unstable

Green colour from copper salts due to cooking under acid conditions in copper pans

ConfectionaryColouring to enhance consumer appeal

Natural Inorganic Synthetic

Natural ColoursCaramel, brown from burnt sugar,

most widely used colour, not always classified as an additive

Carotenoids, orange/yellowsAnthocyanins, reds & bluesBetalaines, red/purpleTurmeric, root of turmeric plant, yellowCochineal, insects from cactus, scarlet

Synthetic ColoursYellow Tartrazine E102

Sunset yellow E110Red Red 2G E128

Ponceau 4R E124 Amaranth E123

Blue Brilliant Blue FCF E133Green Food Green S E142Brown Chocolate Brown E155

Dye problemMany organic chemicals with bright colours

found to be carcinogenicFlat shape allows them to interfere with

DNA helixUsually found by effects on people making

them not those eating theme.g. Butter yellowNot allowed to be used in foods

Bread

Flour whitening calcium carbonate

Anti caking agents ammonium citrate

Dough enhancers stearate

Leavening agents baking powder

EmulsifiersStabilise mixtures of food componentsOil and waterNatural emulsifier - E322 lecithinSynthetic

E 471 Glyceryl monostearate E442 Ammonium phosphatide E435 polysorbate

Thickeners Non-starch polysaccharides Bind water to form gels Algal origin

Alginates, agar, carrageenans

Plant origin Guar gum, Locust Bean gum

Modified celluloses, methyl cellulose

Bacterial origin Xanthan gum

Is It Safe

Better than the alternativeFood degradation by biological or chemical

action - very unsafe!