Food Additives

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Food Additives

• Foods, Facts Fallacies
• YSCN 0006
• http//web.hku.hk/lramsden/fff.html

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Additives

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

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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

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Types of Additives and their Functions
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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

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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

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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

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E numbers
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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

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Traditional Additives

• Used for thousands of year
• Salt and saltpetre
• Smoke
• Honey
• Vinegar
• Herbs Spices
• Natural food colourings
• Calcium carbonate

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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

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Clostridium botulinum

• Common soil bacteria
• Anaerobe can only grow well when no oxygen
  present
• Spores heat resistant to 120C for 3mins
• Bacteria produces protein toxin
• 1µg fatal, respiratory paralysis and cardiac
  failure

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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

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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 4C

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Smoking

• Wood fire, produces anti bacterial compounds
• Provides surface coating and protection
• Colour and flavour
• Hams, heated to 60C
• Not sterile, must be refrigerated,
• But can be eaten raw
• Bacon, only heated to 52C
• Cannot be eaten raw

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Sausages

• Ground meat, low quality off-cuts
• Natural casing, eg. sheep intestine
• Stuffed spices, salt, sugar, ice
• Sodium nitrite to inhibit Clostridium botulinum

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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 75C
• De-skinned, passed through hot water and skins
  peeled off by machine.

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Spoilage

• Become slimy
• Surface growth of yeasts and bacteria
• Turn green
• lactobacter releasing hydrogen peroxide
• Reacts with nitrosohaemochrome
• oxidises it to a green colour

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More Preservatives

• E200 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

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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

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Flavour

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

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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

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Flavour enhancer

• E621 monosodium glutamate
• amino acid - glutamine

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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

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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

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Confectionary

• Colouring to enhance consumer appeal
• Natural
• Inorganic
• Synthetic

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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

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Synthetic Colours

• Yellow Tartrazine E102
• Sunset yellow E110
• Red Red 2G E128
• Ponceau 4R E124
• Amaranth E123
• Blue Brilliant Blue FCF E133
• Green Food Green S E142
• Brown Chocolate Brown E155

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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

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Bread

• Flour whitening
• calcium carbonate
• Anti caking agents
• ammonium citrate
• Dough enhancers
• stearate
• Leavening agents
• baking powder

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Emulsifiers

• Stabilise mixtures of food components
• Oil and water
• Natural emulsifier - E322 lecithin
• Synthetic
• E 471 Glyceryl monostearate
• E442 Ammonium phosphatide
• E435 polysorbate

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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

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Is It Safe

• Better than the alternative
• Food degradation by biological or chemical action
  - very unsafe!