Transcript Food Additives - jiajie-sciencee

FOOD ADDITIVES
Gan Jia Jie, 2A4
WHAT ARE FOOD ADDITIVES? (I)
Food additives are chemical substances added to foods to improve
flavour, texture, colour, appearance and consistency.
http://www.choice.com.au/reviews-and-tests/food-and-health/food-and-drink/safety/food-additives.aspx
WHAT ARE FOOD ADDITIVES (II)
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Food additives may be natural or artificial.
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Common natural additives include sugar, salt, corn syrup, baking
soda, and pepper.
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Many modern additives, such as vitamins and some flavours, are
made in a laboratory but most of them are exact replicas of naturally
occurring substances and the body is unable to distinguish between
the natural and artificial forms.
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Direct additives are those that are intentionally added to foods for a
specific purpose.
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Indirect additives are those to which the food is exposed during
processing, packaging, or storing. Preservatives are additives that
inhibit the growth of bacteria, yeasts, and molds in foods.
PURPOSE OF FOOD ADDITIVES
Food additives are substances intentionally added to food either directly or
indirectly with one or more of the following purposes:
1.
2.
3.
4.
5.
To maintain or improve nutritional quality
To maintain product quality and freshness
To aid in the processing or preparation of food
To make food more appealing
Control the acidity and alkalinity, and to provide leavening.
COMMON TYPES OF FOOD ADDITIVES
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Colors
Emulsifiers
Flavorings
Gelling agents
Preservatives
Sweeteners
Anti-cake agents
Antioxidants
Acidulants
COLORS
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Color is commonly added to foods, for good visual appeal.
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Food colors are divided into 3 main types:
 Natural Colors
 Nature Identical Colors
 Synthetic Colors
NATURAL COLORS
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These are obtained from natural sources such as grasses, leafy
vegetables, fruit skins, roots and seeds of plants.
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Animals can also be a source of food colourings. Cochineal, or
carminic acid, is a red colour that is obtained from the bodies of
certain scale insects.
Beet
Carmine
Grape
NATURE IDENTICAL COLORS
The colors are exactly the same molecules found in natural sources but
they are made synthetically.
Alchoholic Beverages
Diary and Ice Cream
Bakery Products
SYNTHETIC COLORS
These are colors that do not occur in nature and have been made in a
factory. They have been carefully tested to make sure that they are safe
EMULSIFIERS
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There are two types of emulsions. An oil-in-water emulsion contains
small droplets of oil that are dispersed in water. Alternatively, a water-inoil emulsion has small droplets of water that are dispersed in an oil.
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They are used to aid in the processing of foods and also to help
maintain quality and freshness. In low fat spreads, emulsifiers can help
to prevent the growth of moulds which would happen if the oil and fat
separated.
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The emulsifier keeps oil and water mixed. With
out an emulsifier water and oil would be
separate.
Soy Based
Emulsifier
FLAVORINGS
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The brain interprets signals from taste, smell and even vision before
turning them into an impression of the food's taste. Different people will
find different tastes nice or unpleasant.
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Flavorings are added to food products to give, enhance or intensify
flavor.
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Foods may contain more than a thousand chemical compounds that
contribute to their flavor.
GELLING AGENTS
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Gives shape and structure.
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Thickeners or thickening agents make foods thicker.
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Stabilizers help to maintain the physical and textural properties of
foodstuffs through their production, transport, storage and cooking.
GELLING AGENTS
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The substances belonging to this
group are high molecular weight
compounds. They are usually
proteins, such as gelatin, or complex
carbohydrates like pectins , starches,
alginates and gums.
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Most are long chain molecules
(polymers) that are made up of
hundreds of linked units called
monomers.
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They can be divided into a number of
categories depending on their source
of origin.
PRESERVATIVES
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Food preservation is the procedure of treating and handling food to
prevent or greatly slow spoilage (lack of quality, edibility or nutritive
value) caused or accelerated by micro-organisms.
Most preservatives today are actually fungistatic in their action. That
means they prevent the growth of fungi, molds and yeast.
They have little effect on bacteria but using a combination of
preservatives, with antibacterial properties, can give food all round
protection.
Food preservatives help to control the spread of bacteria which can
cause life threatening illnesses such as salmonellosis or botulism.
There are mainly 3 types of preservatives:
 Natural Preservatives
 Artificial Preservatives
 Chemical Preservatives
NATURAL PRESERVATIVES
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Natural preservatives are considered safer by many because they have
always existed in nature and our immune systems are used to them. Most
of the preservatives that come from a plant source are safe for humans.
Popular Natural Preservatives
 Neem Oil
 Salt
 Sugar
 Lemon
 Honey
 Citric Acid
 Bee Propolis
 Rosemary Extract
 Grapefruit See Extract
 Potassium Sorbate
 Alpha tocopherol (also known as vitamin E)
ARTIFICIAL PRESERVATIVES
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Artificial preservatives are a group of chemical substances added to
food, sprayed on the outside of food, or added to certain medications to
retard spoilage, discoloration, or contamination by bacteria and other
disease organisms.
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Artificial food preservatives can be divided into three major groups,
antimicrobial agents, antioxidants and chelating agents.
CHEMICAL PRESERVATIVES
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Chemical preservatives are added to food to keep them fresh and
unspoiled during storage.
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There are three classes of chemical preservatives commonly used in
foods:
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Benzoates (such as sodium benzoate)
Nitrites (such as sodium nitrite)
Sulphites (such as sulphur dioxide)
METHODS OF FOOD PRESERVATION
Preservation
How it Works
Canning
Foods are sealed into cans and then heated to a high temperature (above 100°C). This kills
any microbes in the food and the sealed can prevents fresh contamination.
Freezing / chilling
Lowering the temperature slows enzyme activity in the food spoiling microbes. This slows
cellular respiration and therefore growth. The colder the temperature, the slower the growth.
However, microbes are not killed when they are chilled. Foods heated up may still contain
microbes that are alive and need to be thoroughly cooked before being eaten.
Drying
Removes water from the food and so dehydrates the microbes. This prevents their growth but
does not remove any toxins that may already be present.
Pickling
Vinegar is acidic and lowering the pH of the food can prevent the growth of microbes. The
acidic environment reduces the enzyme-activity of the food-spoiling microbes.
Jam-making
Jams contain high concentrations of sugar. This effectively draws water out of any microbes in
the food and dehydrates them. This method of preservation is traditionally used to make jams.
Smoking
Possibly the oldest known method of food preservation. Foods are hung in wood smoke and
chemicals in the smoke act to kill microbes in the food and also give it a distinctive flavour. This
ancient method survives into our modern times. Some meat, particularly bacon, and fish, such
as haddock and salmon, are smoked.
Preservatives
Some methods of preserving food depend on the use of additives. These substances reduce
the growth of microbes but must not be seen as an alternative to proper food hygiene and
cooking. Preservatives play their part in clean and hygienic methods of food production.
http://www.understandingfoodadditives.org/pages/Ch2p5-2.htm
SWEETENERS
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Provide texture in baked goods it stops them from drying out.
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Lowers the freezing point in ice creams
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Acts as a preservative in jams
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Strengthens "mouthfeel" in soft drinks
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Adds bulk to baked goods
ANTI-CAKING AGENTS
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Processed foods often contain ingredients that are mixed as powders.
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Anti-caking agents are added to allow them to flow and mix evenly
during the food production process.
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They rarely have nutritional value and only a small proportion of the
additives find their way into the food.
ANTIOXIDANTS
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Antioxidants are added to food to slow the rate of oxidation and, if used
properly, they can extend the shelf life of the food in which they have
been used.
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Spoilage of fat is called rancidity. All fat containing foodstuffs like nuts,
breakfast cereals or potato chips have a tendency to become rancid.
Antioxidants are added to these products to prevent rancidity.
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There may be health benefits from the use of antioxidants.
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Oxidation reactions in the body could be linked to the build-up of fatty
deposits that cause blockages in arteries that can cause heart attacks.
Antioxidants may be important in preventing this and there could also be
a link with the prevention of certain cancers, arthritis and other
conditions.
RANGE OF ANTIOXIDANTS
Antioxidant
Typical foods
Ascorbic acid
(vitamin C)
Beers, cut fruits, jams, dried potato. Helps to prevent cut and pulped
foods from going brown by preventing oxidation reactions that cause
the discolouration. Can be added to foods, such as potato, to replace
vitamin C lost in processing.
Tocopherols
Oils, meat pies. Obtained from soya beans and maize. Reduces
oxidation of fatty acids and some vitamins.
Butylated
hydroxyanisole
(BHA)
Oils, margarine, cheese, crisps. Helps to prevent the reactions that
break down fats and cause the food to go rancid .
Citric acid
Jam, tinned fruit, biscuits, alcoholic drinks, cheese, dried soup.
Naturally-occuring in citrus fruits like lemons. Helps to increase the antioxidant effects of other substances. Helps to reduce the reactions that
can discolour fruits. May also be used to regulate pH in jams and
jellies.
ACIDULATES
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Acidulants are additives that give a sharp taste to foods. They also
assist in the setting of gels and to act as preservatives.
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Common acidulates; acetic acid, citric acid, fumaric acid, lactic acid,
malic acid, phosphoric acid, tartaric acid.
TWELVE MOST DANGEROUS FOOD ADDITIVES
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Sodium Nitrate, Sodium Nitrite
BHA and BHT
Propyl Gallate
Monosodium Glutamate
Hydrogenated Vegetable Oil
Aspartame
Acesulfame-k
Food colorings: blue 1,2; Red 3;Green 3;yellow 6
Olestra
Potassium Bromate
White Sugar
Sodium Chloride
ARE PRESERVATIVES SAFE?
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Food preservatives have to be safe for human consumption.
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They can stop the food-decay microbes from growing but must not harm the
cells of the human body.
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There are also maximum levels of preservatives allowed, so that high
concentrations of preservatives in food are not permitted.
HEALTH RISKS OF PRESERVATIVES (I)
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Usage of preservatives have to be regulated as excessive consumption pose
health risks.
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Sulfur dioxide and sulphites are used in fruits, wines and dried fruits and
vegetable, in order for these products to avoid turning to brown. But sulphites
are linked with hyperactivity and it is not recommended for people who are
suffering from asthma.
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Many food products use Butylated hydroxyanisole (BHA) and
hydroxytoluene (BHT) as preservatives. But with these preservatives, it can
cause tumors and cancer for their carcinogenic characteristics. Cholesterol
imbalance, hyperactivity, asthma attack, and some other disorders are linked to
products that use BHT as preservative. These are considered the two most
dangerous preservatives. BHT is banned to several countries across the globe.
HEALTH RISKS OF PRESERVATIVES (II)
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Benzoic acid which is added to sauces in food is linked to hyperactivity and also skin and
eye irritations. Asthmatic people can not consume products with benzoic acid. It also can
cause neurological problems.
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Sodium Citrate is used in meat and baby food but also in personal care products. Large
amounts can cause bladder tumors. However, Sodium Citrate is related to Citric Acid and
is much safer than other synthesized food preservatives.
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Tertiary butylhydroquinone (TBHQ) are added to fats, oils and margarine, so they are
often found in snacks like chips. It can cause nausea and delirium. It is petroleum based.
Not much information is available about this preservative and it has been referred to as the
"mystery preservative“ and one which should be wary of.
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Nitrates are used to bring up the flavor to a higher notch. Large use of nitrates is already
fatal to one’s health. Nitrate is bad for the blood because it will be converted in the blood to
form a harder substance that makes it really difficult for the blood to transport oxygen.
COMPARING BLACKCURRANT JAMS
Brands
Ingredients
Nutritional Information
Cost
All natural ingredients:
- Blackcurrant Cassis
- Unsweetened Grape Juice
Concentrate
- Fruit Pectin
Per 100g:
- Energy 905 kJ., 213 kcals
- Protein <0.6 g
- Carbohydrate 52 g
Sugars 52 g
- Fat 0.3 g
Saturates 0.1 g
- Fibre 2.5 g
284g for $5.40
-
Per 100g:
- Energy 775kJ / 183kcal
- Protein 0.8 g
- Carbohydrate 42 g
Sugars 38 g
- Fat 0.7 g
Saturates 0.1 g
- Fibre 2.9 g
- Sodium 3.5mg
454g for $4.10
Blackcurrant
Sugar
Glucose Syrup
Geling Agent: Pectin
Acidity Regulator: Citric Acid
Preservative: Potassium
Sorbate