Protein

Post on 02-Nov-2014

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GCSE food technology

Transcript of Protein

Why do we need Protein?Why do we need Protein?

Protein is used by our bodies for growth and repair.

Our bodies will use protein as an energy source if there is nothing else to use.

What’s in a Protein?What’s in a Protein?

Protein molecules are long chains of

AMINO ACIDS

There are two different types of

amino acids.

Essential Amino AcidsWe can only get these by eating them in our food. We cannot make them in our bodies. There are eight essential amino acids.Non - Essential Amino AcidsThese can be made in the body.

Meat and Fish have a High biologicalvalue

This means that they contain all

the amino acids your bodyneeds to make the proteins

itrequires.

Who may have to choose Who may have to choose their foods carefully to get their foods carefully to get all their high biological all their high biological value proteins?value proteins?Vegetables do not usually contain all the necessary amino acids (low biological value). Vegetarians and Vegans must eat a wide variety of foods (e.g. plant proteins, beans and pulses) to make sure they are getting all the amino acids.

How much is enough?How much is enough?

Estimated Average Requirement

EAR (protein) = 0.6 X Body Mass (kg)

Eg A woman who weighs 60kg would need

0.6 x 60 = 36g of Protein a day.

Serving Size You should eat two to three servings of

protein every day from both plant and animal sources. Here are some examples of one serving (about the size of a standard pack of playing cards):

1. 100g boneless meat (eg lean beef, lamb or pork)

2. 100g boneless poultry (eg chicken or turkey breast)

3. 100g fish (eg salmon, sardines or tuna) 4. 2 medium eggs 5. 3 tablespoons of seeds (eg sunflower or

pumpkin seeds) 6. 3 tablespoons of nuts (eg almonds or walnuts)

Meat AnalogueSome people choose not to eat

meat for a variety of reasons and obtain all their protein from other sources. In recent years manufacturers have produced many meat-like products, called ‘meat analogues’, which mimic the sensory properties of meat and can be used to replace meat.

Why might people choose not to have meat??!

Examples TVP – textured vegetable protein

made from soya bean Quorn – mycoprotein which is related

to the mushroom Tivall – wheat and vegetable protein,

it has a texture similar to meat Tofu and bean curd – soya bean Meat analogues are often:1. Enriched with vitamins and minerals2. Low in fat3. Have a similar nutritional value to

meat

Advantages vs DisadvantagesAdvantages:

they are versatile they are easy to store they are cheap

Disadvantages: they can be bland they can be colourless they can be quite dry

Types of non meat eaters

Will not eat: Will eat:

Lacto vegetarian

Meat, fish, poultry, eggs

Milk, cheese, butter, cream, yoghurt

Lacto-ovo vegetarian

Meat, fish, poultry,

Eggs, milk, cheese, butter, cream, yoghurt

Vegan Any animal product

Plant based products

Key terms Amino acids: smallest unit of a

protein Essential amino acids: can not be

made by the body HBV: contain essential amino acids LBV: do not contain essential amino

acids Alternative protein foods: foods

used instead of meat Meat analogues: foods that are used

in a similar way as meat

Homework for 1. What are the differences between meat and meat

analogues? (5 marks) -nutritional info -taste, texture, aroma, appearance (discuss what you did in the

lesson) -cost -ease of purchase, availability2. How can you recognise a meat analogue product? (2 marks) -symbols –look them up on the internet or on packaging3. What meat analogue products are available? (3 marks) -list of products, cost, where available 4. Why might someone chose to become vegetarian or use

meat analogueproducts? (5 marks) -religious reasons -meat scares -health reasons -cost

Complete your own research using the internet or in a supermarkets to answer the majority of these questions