Food Technology GCSE revision

Revision notes on Special dietary needs, functions of different ingredients,  preservation methods, and functions of nutrients

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  • Created by: dominika
  • Created on: 04-03-12 11:53

Protein

Needed for growth and repair of body tissue, needed for the metabolism and hormones.

Proteins make up amino acids, the body needs 20 amino acids -11 are produced in the body and 9 need to be provided from a diet.

HBV (high biological value) proteins - meat, fish, diary products

LBV proteins - peas, pulses, nuts and seeds

Vegans obtain protain from nuts, beans, Quorn, cereal etc.

Protein deficiency - slow or stop of growth in children, enzymes are not produced, muscles become weak, liver doesn't function normally.

Kwashiorkor is a diesease which occurs in less developed countires when a child is taken off breast feeding and has a diet low in protein.

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Functions of vitamins

Vitamin A aids night vision, forms cells on the skin. Vitamin A can be obtained from: carrots, tomatoes, mangoes and other yellow/ orange fruit and veg. Deficiency-  dry skin and impaired vision.

Vitamin D aids the absorbtion of calcium for strong teeth and bones. Vitamin D can be obtained from the sun, fatty fish, eggs and margarine. Deficiency - rickets

Vitamin B  releases engery and can be obtained from cereals, meat, fish, eggs, dairy products, pulses. Deficiency - beri beri, sore lips and pellagra

Vitamin C helps to absorb iron, protects agains infections, forms connective tissue.  Can be obtained from citrus fruit and deficiency can cause scurvey, poor skin condition and slow healing wounds.

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Eggs

Functions of eggs :

Emulsification  - binding oil and water e.g Mayonnaise

Binding - Bining dry ingredients together e.g. cake

Coating  e.g fish cake

Enriches - Makes doughs and sauces more luxurious e.g. Hot cross Buns

Coagulates - Sets pritucts (from a liquid to a solid) e.g quiche

Aerates - adds air to product e.g Swiss rolls

Glazes - adds colour and shine e.g. sausage rolls

Yolk is higher in fat, the white is very low in fat.

You can check if an egg is old by placing in a bowl of water - an old egg would float in water as the chalazae becomes weaker and the air cell increases

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Preservations

High temperative preservation :

Pasteurisation - 72 C for 15 seconds

Sterilisation - 104 C for 40 minutes e.g. Canning

Chilling and freezing methods:

Cook chill - after product is cooked it is chilled to 3 C in 1 and a half hours

Blast freezing - a fan is used to reduce temperatice quickly

Dehydration: Sunlight, spray drying

Chemicals:

Vinegar - bacteria can't servive below 4.5 pH. Used for pickeling

Salt - reducing moisture (osmosis)

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Benefits of preserving

+ Prevents action of enzymes

+ We can buy products out of season

+ prevents micro-organisms from multiplying

+ Increases shelf life

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Allerigies, Coeliac Disease, Lactose intolerance

Nut allergy - throat swells up and you may stop breathing depending on how servere the cindition is, it could be fatal. You cannot eat nuts, pesto, marzipan etc.

Coeliac Disease is when you cannot eat gluten products as it causes stomach pains and sometimes vomitin, you shouldn't eat breat, pasta, cakes etc. as you cannot eat gluten which is protein found in wheat.

Lactose intolerance - You can't have anything that contains milk or dairy as lactose is a sugar found in these products e.g. cheese, carbonara, mousse. Symptoms- stomach cramp, bloating and diarrhoea 

Pregancy - women should consume more energy during last 3 months of pregnancy, should have plenty of Folic Acid as it prevents the baby from developing Spina Bifide. Folic Acid can be found in green vegetables and cereal

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Comments

AJ

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Cheers, this is great!! :)
The only thing I'd say is that quorn is not actually a product vegans eat (as a source of protein) as it contains egg and sometimes milk

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