Food Preparation & Nutrition

AQAWalton High School

Section A –Multiple Choice Questions

Section B – Core knowledge • This section will test your core knowledge and

may include questions on:

Food, Nutrition and healthFood ScienceFood SafetyFood ChoiceFood ProvenanceFood preparation and cooking techniques

Nutrition Macro nutrients – FAT, PROTEIN, CARBOHYDRATE. All need in large amounts and measured in grams. Micro nutrients – Vitamins & minerals. Needed in very small amounts and measured in in mg (milligrams).

Key things to remember: Protein – For growth, repair, maintenance of body cells. Made from amino acid chains found in animal and vegetable sources. Animals sources are HBV (High Biological Value), Vegetable are LBV (low biological value).Fat – For Insulation, body warmth, protecting vital organs, act as a carrier for fat soluble vitamins (A,D,E & K), hormone production, supplying essential fatty acids. Saturated fats – mainly found in animals fats are or can be linked to CHD. Examples of saturated fats are butter, ghee, cheese and meat fat. Unsaturated fat (monounsaturated or polyunsaturated) found in vegetable based products – olive oil, avocado etc. This fat helps to reduce bad blood cholesterol and CHD. All diets must contain fat. A fat deficiency can mean a lack of vitamin A,D,E & K as these can not be absorbed. Carbohydrate – two types - Complex/starch (pasta, bread, potatoes etc), these give slower releasing energy , help us feel fuller for longer. Simple/sugar ( fruit, veg, honey, sugary drinks ) release glucose very fast , giving us short bursts of energy. Dietary Fibre (NSP) – 2 types. Soluble – found in oats, peas, beans, carrots and apples IS digested, helping lower blood cholesterol. Insoluble – found in wholegrains, nuts, many fruit & veg. Travels through the digestive system WITHOUT being digested. It is needed absorb water and bulk out poo making it softer and easier to pass. Keeps the colon and bowel healthy by preventing disease. A diet high in fibre keeps us feeling fuller for longer, which stops people fro snacking and helps maintain a healthy weight. Fibre also helps control blood sugar levels.

Vitamins & Minerals • Vitamins – 2 types.

• Fat soluble (Vit A, D, E & K). These are found in fats and foods naturally containing fats. These vitamins can be stored in the liver and fat reserves for later use- when the body needs it.

• Water soluble (Vit C and B group). These CANNOT be stored in the body so must be eaten daily. Too much of these are flushed away in urine. These Vitamins are the ones that are easily destroyed by heat & water. Best way to get these is by eating fruit & veg raw!

• Minerals• Calcium – Needed to form, strengthen and maintain bones and teeth, blood clotting and for

muscles and nerves of the heart. Found in dairy produce, dark green leafy veg. Not enough –rickets and osteoporosis – weak bones!

• Iron – Makes haemoglobin, which carries oxygen to cells. Found in red meat, liver, wholegrain cereals, beans, nuts, dark green leafy veg. Not enough? – Anaemia (tired, lethargic etc).

• Sodium – Helps maintain water levels in all cells. Controls nerves and muscles. Can often be ‘hidden’ in many processed foods. Too can contribute to high blood pressure and strokes.

Nutrients working together. • Don’t forget some nutrients work hand in

hand.• Vitamin C & Iron – Vitamin C HELPS with the

absorption of Iron into the body. • Vitamin D & Calcium – Vitamin D is essential

for you to absorb calcium into the body –without Vit D it can’t be absorbed.

Water Is not a nutrient but is essential for life because it: Regulates body temperature Transports nutrients in the blood Removes waste from cells Aids digestion

Can be obtained from all the food and drink we consume. A lack of water caused dehydration resulting in headaches, thirst, dizziness andpoor concentration.

Fortification –means when a nutrients such

as Iron is added to a food to make it more

nutritious. For example ,

calcium is addedto white bread.

The word ‘diet’ refers to the food we eat. To have and maintain a healthy diet it must have a good balance of all the necessary nutrients.

Research suggests that following the EATWELL GUIDE will help us to eat healthily.

Nutritional needsRemember our nutritional needs change according to our age, gender, activity levels and overall health.

For example, a teenage boy’s dietary needs are different from an adult male builder; a middle-aged woman’s dietary needs are different to a pregnant woman’s; and a ‘couch potato’ hasdifferent dietary needs to a Athlete.

EATWELL GUIDE

Special Dietary needs Coeliac Disease – The body cannot absorb the protein found in wheat, rye, barley and some oats. The protein is called gluten. People with this will need to avoid ALL food and drink with this in it. Anaemia – The body lacks iron which is needed for red blood cell production. Red meat and green leafy veg are good sources and will help increase iron levels and so can be easily fixed. Diabetes Type 2 – The body has become insulin resistant and cannot utilise the glucose produced by carbohydrates. To help prevent this condition people should follow the healthy eating guidelines, exercise and keep and eye on weight. This can often be because of poor diet & health and obesity. Cardio vascular disease – The body develops raised blood pressure, high cholesterol and blocked arteries leading to heart disease. To help prevent this people should take more exercise, follow healthy eating guidelines and stop smoking. Osteoporosis - Once bones reach peek bone mass at 30 years old very gradually over the years minerals are removed from them and not replaced. Eventually the bones become porous and therefore weak, and are more likely to break away. In some cases can become painful and weak and result in a bent spine. blood pressure, cancer, arthritis.

Special Dietary needs

Obesity – the body takes in more energy than what is being used. The spare energy is then stored under the skin and around the organs in a fatty layer. Allergies – can be serious – might cause death (nuts, cheese, shellfish etc).Intolerances – are not life threatening but can cause unpleasant symptoms (I.e lactose intolerant) Vegetarianism :• Lacto-ovo – eat dairy food and eggs BUT

NOT meat and fish• Lacto vegetarians – eat dairy foods but not

eggs, milk or fish• Vegans – do not eat any animal produce

(including honey) Religious beliefs – Some religions exclude foods. For example Hindu do not eat meat from a cow as it is a sacred animal.

The science of cooking Food

• Heat Transference

Why do we cook food:

• To make food safe to eat _heat kills pathogenic bacteria

• To soften the food, making it easier to chew, swallow and digest

• To make it look appetising and improve the flavour

• To warm us up – hot food in cold weather.

ProteinsProteins denature and coagulate when: They are heated They come into contact with

acidic/alkaline ingredients They are whisked, beaten or kneaded

(foams and gluten development) The proteins unravel becoming firm

when heated.

Dry heat on meat protein cause the Maillard reaction. This occurs when there is a chemical reaction between the protein and the naturally occurring sugars in the meat AND can only begin to happen when the temperatureis above 140C.

Heat Transference – 3 basic methods

Conduction –boiling, baking, frying, microwaving, roasting –heat is transferred by contact with heat

Convection –baking, boiling, frying, roasting, steaming – heat moves through the convection currents. The hot air rises and cool air falls.

Radiation –grilling, BBQ, microwaving – direct rays pass from the heat source to the food

Conduction

Watch the video in the AQA text book on page 85 to help

complete your worksheet

Convection

Watch the video in the AQA text book on page 86 to help

complete your worksheet

RadiationWatch the video in the AQA text book on page 87 to help

complete your worksheet

Fats • At room temp fats can be easily spread and mixed with

other ingredients. This property is called plasticity. • Fats melt and become liquid when heated.• They add flavour and texture to cooked food, and some

fat can ‘melt out’ from the ingredient. • Fats ‘SHORTEN’ gluten strands in shortcrust pastry and

biscuits creating a crumbly texture. (Remember NEA 1 ? – The fat coat the flour particles making them water proof and thus preventing the formation of gluten).

Carbohydrates Starch carbohydrates such as flour, when mixed with liquid

and heated will GELATINISE (Starch granules soften under heat, they then swell and absorb the liquid)

Sugary Carbohydrates such as the natural sugars in fried onions will CARAMELISE when heated – this also happens in cakes .

Starchy carbohydrates when exposed to DRY heat create dextrins – and this known as DEXTRINISATION. (I.ewhen bread is toasted)

Oxygen • Oxygen can have a negative effect on many foods.• Fruit and vegetables – cut surfaces go brown due to

oxidising of enzymes – Enzymatic browning • Meat – the red surface becomes brown/grey due to

oxygen affecting the myoglobin. • Fish – oxygen works with fish enzymes

making it spoil rapidly and smell very fishy. • Fats and oils – oxygen turns fats and oils rancid.

ENZYMIC BROWNING - facts

What causes enzymic

browning?

Plant cells contain storage vacuoles (spaces) in the centre, which may contain a variety of natural substances. Around the outside of the vacuole is cytoplasm which contains substances called enzymes.

When the cell in broken up, the enzymes in the cytoplasm and oxygenfrom the air mix with the substances in the vacuole. When substances combine with (pick up) oxygen it is called oxidation. This makes the substances join together and change colour.

Watch the video in the AQA text book on

page 162 on enzymicbrowning and prevention

Dextrinisation

Caramilisation

Denaturation

Mechanical and Acid Denaturation

Watch the video in the AQA text book

on page 106.

Emulsification

• An EMULSION is where oil and water join together in suspension (where they don’t separate out).

• To bring a mixture of oil and water together – like in mayonnaise an emulsifier is needed. For example in mayonnaise and egg yolk is used.

• An emulsifying ingredient has a hydrophilic head (loves water) and hydrophobic tail (hates water).

• So by using this ingredients the head end gravitates towards the water and the tail end gravitates towards the oil thus bringing them together.

Raising agents • Mechanical – where an action helps the rise.

These ‘actions’ cause ‘aeration’ which is the addition of air to food because air particles expand when heated. Mechanical actions which cause aeration include Whisking, Sieving, Beating, Creaming and Laminating.

• Steam – Steam is produced in oven baked products creating a puffed up risen effect. Mixture must have a high volume of liquid which turn into steam from the heat, e.g Choux pastry.

• Chemical – substances added to food to help the rise. Carbon dioxide is produced when self-raising flour, baking powder or bicarb of soda are mixed with a liquid and heated. The CO2 gas produced bubbles, which ‘push up’ the food giving a light risen texture.

• Yeast – needs food, moisture and time to grow and will then give off CO2 bubbles creating the light, airy, risen texture of bread.

Food Spoilage Causes of Food spoilage – bacteria, moulds, yeasts, fungi, chemical reactions (oxygen) Environmental factors, time, insects & rodents, enzymes. If all of the above is controlled food spoilage can be slowed down. For example storing food in a fridge or in an air tight container will do this. GOOD HYGIENE is critical when storing and preparing food because unhygienic practise such as coughing and sneezing on the food, not washing hands, unclean equipment or surfaces will introduce harmful PATHOGENIC BACTERIAto food. This bacteria CANNOT move on its own. It needs a vehicle – and that vehicle could be someone’s hands, cut, it could be brought by an insect or something like hair dropping in the food. Moving bacteria from one place to another is called CROSS CONTAMINATON making the food unsafe to eat. If this food is eaten it can cause FOOD POISONING.

Storage and cooking of food –key temps • Foods MUST be stored in the correct

temperature conditions to slow down bacterial growth and food spoilage.

• Chilled foods – fridge between 0-5C• Frozen foods – freezer at -18C or colder• Ambient foods – stored on a shelf in a

cupboard at room temp• Hot-held foods - (Those that are kept

warm) – must be kept at 63C or above on hot food counters.

• Core of all food cooking to 75C to ensure that most pathogenic bacteria are killed.

• If not being eaten immediately it should be chilled to 5C within 90 minutes of cooking

Preparing foods safely• Use of colour coded boards to ensure no

cross contamination• Clean equipment/surfaces/utensils• Excellent personal hygiene (clothing, wash

hands, hair up/hair net etc)If you are asked an

anything about preparing cooking and

storing food safely and correctly

remember the 4 C’s ….. And then EXPAND.

Food Provenance

• This simply means where the food is grown or livestock is reared. Knowing where the origin of the food is allows consumers to make informed choices.

• Food miles – Mean the distance a food has had to travel to reach our kitchens. Locally grown runner beans may have travelled 6 miles, whereas runner beans from Zimbabwe have travelled 7600 miles.

• The CARBON FOOTPRINT of food is calculated from the amount of fuel used during growing and production, transportation and the miles consumers have to travel to buy their shopping.

• The fewer miles the food has travelled the better it is for the environment because less CO2 has been produced.

8 ways to reduce food miles • Buy local • Learn to cook from scratch (convenience foods are

often not locally made)• Shop at farmers markets (seasonal food, fresh, local)• Eat seasonally (foods produced will be local to your

areas, i.e swedes in winter. Plan meals around what is being harvested at that time)

• Walk or cycle to the shop • Grow your own!• Pick your own! (Many local farms are now encouraging

this)• Shop less frequently (Use stockpiling techniques)

Further environmental issuesFood wasteMany families was £400-

£700 worth of food yearly. (Buying too much for what they need).

Most waster food ends up in landfill producing greenhouse gases which effect the Environment.

To prevent food waste families could plan meals, use a shopping list and stick to it, freeze leftovers and ensure all food is used before it goes out of date.

Understand the difference between ‘best before’ and ‘use by’.

Food packaging waste Much food packaging ends up in

landfill. It takes decades to degrade and produces greenhouse gases that negatively effect the environment.

To prevent this we could: Buy food which use minimal

packaging (local butcher, loose fruit, buy locally as often food isn’t packaged)

Buy fruit & veg using a local ‘seasonal’ box scheme

Cook from scratch rather than using ready made meals

Recycle all recyclable packaging Reuse jars and plastics where

possible.

Factors influencing different cuisines

Climate This controls what farmers can grow.. If the ground is cold and hard or wet and sodden plants cannot be planted very easily. Most crops need rain and warm weather to germinate and grow. Sun shine is needed to ripen plants and sweeten fruits.

GeographyThe landscape of regions governs which crops and animals are raised for food. Flat lands are needed for crop production whilst livestock can graze on the grass of very hilly land.

Religion/Faith/CulturePeople eat or avoid certain foods according to their religious instructions and beliefs, and culture and traditions. Street food is becoming more popular and embraces many different cuisines.

Migration Immigrants who now live in the UK bring their national foods with them, we now eat a wide variety of dishes that originate from all around the World.

People also travel more nowadays (work, holidays) meaning there is more of a demand for different cuisines.

Technological Developments

There are 11 major factors that push forward changes in food technology:1. Population – the more people there are the more food is needed.

2. Transport –specialist refrigerated and freezing transport have made the transportation of food easier.

3. Preservation – Food preservation has been used for hundreds of years (pickling, canning, salting, freezing). Recently people want more fresh food. New techniques have been developed that rely on heating and drying.

4. TV, Radio, social media –these influence customers about what they need or should buy.

5. Apps and Barcodes –these now make it easy to share info about products and to find out more about products. (Barcodes and QR codes)

6. Environmental awareness –Consumers WANT to be able to reduce, reuse and recycle foods etcand are buying organic and sustainable foods.

7. Science – constantly researching and developing techniques in food processing, preservation and increased shelf life.

8. Economics (money). Controls food companies efficiencies to increase food shelf life, reduce food and packaging waste and compete with other companies.

9. Consumer demand – affect food developments. Changes in ‘food fashions’, population, culture, work/leisure time all change consumer demands.

10. Robots/automation – used in food production. Cheaper and more reliable than humans, can work 24/7 delivering consistent results.

11. Work/leisure time – we now work longer hours, making leisure time precious so don’t want to spend hour preparing meals, preferring to rely on convenience foods.

Food ingredient developments GM foods (Genetically modified or genetically engineered foods) – The

DNA is changed so that the plant becomes resistant to disease and is therefore cheaper to produce.

‘New’ Foods include textured vegetable protein (TVP) and Mycoproteinwhich are good sources of HBV protein and are widely used in vegetarian products.

Seaweed is processed and incorporated into ready made food and dried insects are being considered for us in products because they are so nutrient rich.

Some foods are fortified – with added vitamins or minerals to either increase their nutritional profile, replace the nutrients lost during processing or add nutrients that are not normally in the food, such as adding fibre to yoghurt or calcium to bread.

Government initiatives like the Eatwell Guide, five a day, Change4life andhealthy schools help the consumer learn about diet, health and nutrition. This has led to an increase in food manufacturers creating ‘healthier’ food products such as low fat cheese , sugar free or low calorie drinks and desserts.

What factorsaffect food choice?

Availability and Seasonality

Medical conditions

Cost of food and food poverty

Ethical choices

Sensory analysis

Marketing & advertising

Culture & religion Labelling

Exam tip:This may come up as a longer question. If it does – you need to EXPAND/EXPLAIN these in more depth. Example. One of the factors affecting food choice is ethical reasons. Many people are concerned these days about how their food is produced and so choose foods such as organic produce (which means its has been grown or reared naturally, farm assured , Fairtrade (which means the workers have been given a fair wage) and foods with a low carbon footprint meaning it hasn’t got as many foods miles and therefore impacts lesson on the environment.

Answering longer questions.Remember the CUSTARD technique.

Other tips;

Take your time and apply AT LEAST the circle, underline and scribble of the custard technique

Always be prepared to expand your answer – explain it. Imagine the person reading it has NO IDEA and you need to tell them EVERYTHING about it.

Check how many marks it is worth –make sure you are making valid points with explanations.

Try and write in good English (full sentences, grammar and punctuation).

You will also be asked questions on Commodities – these are the ingredients you have been working with for the past 5 years! (Meat, fish, eggs, cereals, fruit , veg etc). If and when these questions come up, apply common sense and think back to recipes or times you have used them . This may help when answering the question.

And finally ……………………………..