Transcript Food Additives

Food Additives
Foods, Facts & Fallacies
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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!