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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!