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Made by Esta Finesilver
Biology Revision…read more

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Unit B3 ­ Topic 1 - Biotechnology…read more

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Food and Drink
Functional Foods contain an added ingredient not normally found in food. The
ingredient promotes good health. (which contributes to our wellbeing as well as
keeping us alive)
Normally there is 1kg of bacteria in your gut. Poor diet, stress, food poisoning and
the use of antibiotics can disturb the balance.
Specification Point:- prebiotics are functional foods that are marketed as
providing health benefits.
"Good" bacteria suppress the activities of the "bad" (being troublesome
Prebiotic and Probiotic bacteria boost the number of "Good" bacteria over the
Prebiotics contain added sugars called oligosaccharides. Which cannot be
digested by the body but "good" bacteria in your gut use them as food.
Probiotics contain the "good" bacteria. They replace the lost bacteria and
Encourage growth of the "good" bacteria. Probiotics are produced by…read more

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Specification Point: functional foods are not necessarily produced by
fermentation, including prebiotics such as oligosaccharides found as a food
ingredient on the supermarket shelf, and `spreads' that contain plant stanol esters
that lower cholesterol.
Benecol© is a functional food. It contains stanol ester. It comes from plant
sterols which are fatty substances found naturally in foods like wheat and maize.
Studies show people who include plant stanols in their diet for a year might
expect the cholesterol levels in their blood to fall by up to 10%. Raised
cholesterol increases risk of heart disease.
Manufactures claim the food can prevent, treat or cure disease. However many
scientists have doubts about the value of functional foods as a way of staying
healthy. Because of the uncertainty many scientists think that the foods should
be tested in the same way new drugs are tested before the drugs can be used to
treat diseases.
Present should be cautious, a balanced diet provides many of the ingredients
added to functional foods.…read more

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Making Yoghurt
Specification Point: Bacteria are used in the production of yoghurt from milk
by the conversion of lactose to lactic acid.
Milk turns sour unless kept in a fridge. Even in a fridge will only keep for a few days.
Lactic acid bacteria can be used to preserve milk. The bacteria turned milk into
cheese or yoghurt which keep for much longer than milk itself.
To make yoghurt, milk is heated to sterilise it, killing any bacteria already present.
Then the milk is stirred thoroughly to mix up its ingredients and milk protein is
added. A starter culture of Lactobacillus bacteria is added to the milk while it is still
warm. The Lactobacillus bacteria ferment the sugar lactose in the milk to lactic acid.
Lactose Lactic Acid
The lactic acid lowers the pH of the milk (the milk becomes acid) to the point where
the milk proteins coagulate (solidify). The semi-solid milk is raw yoghurt.
The raw yoghurt is cooled quickly. Different flavourings of fruit may be added to the
yoghurt or it may be put into pots as natural yoghurt. The pots are then sealed and
ready for use.…read more

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Made by Esta Finesilver
1) The equipment is sterilised to kill of any unwanted micro-organisms
2) The milk is pasteurised (heated up to 72oC for 15 seconds) ­ again to kill any harmful micro-
organisms. Then the milk is cooled.
3) A starter culture of bacteria is added and the mixture is incubated ( heated to about 40oC) in
a fermenter.
4) The bacteria ferment the lactose sugar in the milk to form lactic acid. Lactic acid cause the
milk to clot and solidify into yoghurt ( a sample is taken at this stage to ensure the right
5) Finally flavours (e.g. fruit) and colours are sometimes added and the yoghurt is packaged.…read more

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