Food Additives
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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 processing Need to maintain food quality What are additives? Substances added to food that are not naturally present Not nutritive Original aim usually preservation Later to enhance food appearance and enhance food quality Types of Additives and their Functions Food Regulation US GRAS system Generally Recognised As Safe Introduced in 1958 to approve established food ingredients New additives must be approved by FDA Delaney Clause to prohibit any substance known to cause cancer Additive Testing Relies on animal tests to NOEL No Observable Effect Level = highest dose of additive with no effect on animal Reduced 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 numbers E number 100-180 200-297 300-321 322-385 400-495 500-578 620-640 900-1520 Additive Colouring agents Preservatives Antioxidants Emulisfiers Texture modifiers Processing aids Flavour enhancers 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 Additives Used for thousands of year Salt and saltpetre Smoke Honey Vinegar Herbs & Spices Natural food colourings Calcium carbonate E 250 Sodium Nitrite Sodium nitrate contaminant of crude salt Found to cause pinkish colour in meat Sodium nitrite more effective On high temp cooking can be converted to carcinogenic compounds nitrosoamines. Potent inhibitor of anaerobic metabolism Prevents growth of major food pathogen Clostridium botulinum Clostridium botulinum Common soil bacteria Anaerobe can only grow well when no oxygen present Spores heat resistant to 120°C for 3mins Bacteria produces protein toxin 1µg 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 cooking – nitrosohaemochrome pinkish red in colour After 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 Smoking Wood fire, produces anti bacterial compounds Provides surface coating and protection Colour and flavour Hams, 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 Turn growth of yeasts and bacteria green lactobacter releasing hydrogen peroxide Reacts with nitrosohaemochrome oxidises it to a green colour More Preservatives E200 Sorbic Acid, soft drinks, yoghourt. E210 Benzoic acid, jams, creams E220 Sulphites, SO2 wine, vegetables, drinks Diphenyl, fruit Nisin, cheese Hexamine Fish Propionic acid Bread E230 E234 E239 E280 Antioxidants Chemical preservation Most 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 cyclamate saccharin aspartame sucralose alitame thaumatin 1 30 300 180 600 2000 2500 Artificial Flavours Mimics of natural flavours using complex mixes of pure chemicals Synthetic banana flavour amyl acetate amyl butartae ethyl butartae isoamyl acetate isoamyl butarate linalool + 15 others in lesser quantities Flavour enhancer E621 monosodium glutamate amino acid - glutamine 19th century Increased urbanisation & food processing Adulteration Use of cheap substitutes Colour & flavour enhancers Sometimes 1857 dangerous survey of confectionary found colours: Lead chromate Mercuric sulphide Copper arsenite Food Colours Preserved Vegetables Chlorophyll, green pigment in plants is unstable Green colour from copper salts due to cooking under acid conditions in copper pans Confectionary Colouring to Natural Inorganic Synthetic enhance consumer appeal Natural Colours Caramel, brown from burnt sugar, most widely used colour, not always classified as an additive Carotenoids, orange/yellows Anthocyanins, reds & blues Betalaines, red/purple Turmeric, root of turmeric plant, yellow Cochineal, insects from cactus, scarlet Synthetic Colours Yellow E102 E110 Red E128 E124 E123 Tartrazine Sunset yellow Red 2G Ponceau 4R Amaranth Blue Brilliant Blue FCF E133 Green Food Green S Brown Chocolate Brown E155 E142 Dye problem Many organic chemicals with bright colours found to be carcinogenic Flat shape allows them to interfere with DNA helix Usually found by effects on people making them not those eating them e.g. Butter yellow Not allowed to be used in foods Bread Flour whitening calcium Anti carbonate caking agents ammonium Dough citrate enhancers stearate Leavening agents baking powder Emulsifiers Stabilise mixtures of food components Oil and water Natural emulsifier - E322 lecithin Synthetic E 471 Glyceryl monostearate E442 Ammonium phosphatide E435 polysorbate Thickeners Non-starch polysaccharides Bind water to form gels Algal origin Plant origin Guar gum, Locust Bean gum Modified celluloses, Alginates, agar, carrageenans methyl cellulose Bacterial origin Xanthan gum Is It Safe Better than the alternative Food degradation by biological or chemical action - very unsafe!
