food tech

Protein is made up of amino acids- the body can make some amino acids itself (non-essential) but the rest we need to eat (essential)

Sources- meat, fish, dairy products, eggs, soya beans, quinoa- HBV (high biological value) contain all essential amino acids. 

LBV (low biological value) are missing amino acids- plant sources peas, lentils, nuts, seeds, spinach, nuts , seeds and beans

protein complementation- combining different foods to get a complete suply of amino acids

Amounts- 55g average male  45g average female each day 

Growth-childhood to adulthood-hair, nails, muscle mass. Repair- muscles, tissues and organs after illness or injury, maintenance-enzymes for digestion and for antibodies

more protein is needed when you are a growing child for size, body mass, physically active people for muscle growth and repair and pregnant and breast feeding women

Deficiency- growth is slowed down, hair, nails and skin poor condition. Immune system suffers-so wounds heal slowly and more likely to infection. Can also get OEDEMA- swelling of feet. 

Severe deficiency-disease called KWASHIORKOR in severly malnourished children-swollen stomachs

Alternative proteins- soya is a plant based HBV protein source, used to make soya milk and processed to make Tofu or TVP (texturised veg protein). Mycoprotein made from mushroom like fungus and egg white. 

Fats- give twice as much energy per gram than protein or carbs, source of fat soluble vitamins A, D, E, K. They form an insulating layer under the skin which keeps us warm and this layer of fat protects bones and organs.

Made up of 3 fatty acids and connected by glycerol-this is a TRIGLYCERIDE

Saturated fats- bad for health. usually solid at room temp, usually from animal sources- meat, processed meat, butter, lard, suet, cheese or plant sources coconut oil, coconut milk

Unsaturated fat-usually healthier, soft or liquid at room temp, veg sources eg peanuts, seeds, sunflower oil, olive oil. They can be monounsaturated or polyunsaturated

Fats 35% or less of daily food energy and only 11% of this from saturated fats. AMOUNTS adult 70g a day of which only 20g of this being saturated. 

TOO MUCH-weight gain, obesity, type 2 diabetes. Increase blood cholestrol -cholestrol builds up in arteries and restricts blood flow leading to high blood pressure, strokes, heart attacks, CHD

TOO LITTLE- vitamin deficiency as less fat soluble vitamins can be absorbed, less insulation, thinner layer of fat for protection so more bumos, bruises

2 main types- STARCH & SUGAR

SUGAR- Glucose , fructose found in food naturally or can be added during manufacturing, added sugars can be called empty calories as have no nutritional benefit other than energy

STARCH- Potatoes, bread, pasta, rice cereals, veg and fruit- contains B Vitamins, iron and calcium, wholgrain starchy foods have high fibre content

Simple carbs eg sugar digested quickly, blood levels rise quickly which give short burst of energy Complex carbs eg starch slower to digest, gradually increase blood sugar levels so slow, steady release of energy

The Glycaemic index shows how carbs affect blood sugar levels, high GI foods digested quickly, low GI digested slowly. GI index good for diabetes sufferers as can check blood sugar levels.

50% of energy from carbs- should be mostly from starchy foods, no more than 5% from free sugars

TOO MUCH- Any extra carbs converted into fat, sugary foods-tooth decay, surges in blood sugar can lead to type 3 diabetes TOO LITTLE- blood sugar levels drop-cause hunger, tiredness, dizziness, if not enough carbs for energy will use up the fat and if lack of fat body will use protein so leads to lose muscle causing weakness

VIT A-  daily 0.7mg men, 0.6mg women. good eyesight, growth, healthy immune system, skin, also an antioxidant. SOURCE-retinol which is found in liver, butter, oily fish, eggs.

TOO MUCH- weaken bones, TOO LITTLE- night blindness, weak immune system, stunted growth

VIT D- daily 0.01mg. Helps absorption of minerals eg calcium. SOURCE- oily fish, egg yolks, also produced when skin exposed to sunshine. TOO MUCH- makes you absorb too much calcium which leads to kidney damage. TOO LITTLE- bone disease (osteomalacia-soft bones, rickets or osteoporosis-brittle bones)

VIT E- daily 4mg men, 3 mg women. Keeps skin and eyes healthy, improves immune system, also as an antioxidant helps protects from free radicals. SOURCE- leafy greens, broccoli, nuts, veg oils, wheat germ. TOO MUCH- nausea, blurred vision, interferes with blood clotting TOO LITTLE-weak muscles, problems with sight 

VIT K- Daily 0.001mg, helps blood clot, heals wounds, maintains immune system and bones. SOURCE- Leafy greens, cereals, veg oilsplus some meats and dairy. It is very rare to have to little but could cause uncontrolled bleeding in newborns

Minerals are chemical elements that are bodies need in small amounts

CALCIUM- needed for strong bones, teeth, healthy nerves and musclesand blood clotting- SOURCE-milk, cheese, tofu, green veg, hard water, sesame seeds TOO MUCH-rare but can cause kidney stones, TOO LITTLE- rickets, osteoporosis, slow downs blood clotting

IRON- needed to form part of haemoglobin which gives blood cells their red colour SOURCE-spinach, meat eg liver, kidney TOO MUCH- is poisonous, can cause stomach pains, nausea, constipation TOO LITTLE- anaemia

SODIUM-sodium chloride (salt )controls the bodies water content, helps nerves and muscles to function. Source-found in most foods. TOO much -high blood pressure, heart disease. TOO LITTLE-nausea and muscle cramps

PHOSPHORUS-needed for healthy bones and teeth SOURCE-protein rich foods-meat, fish, dairy, nuts, beans, cereals. TOO MUCH harder to absorb calcium TOO LITTLE- weak muscles, painful bones

Trace elements- Flouride- strengthens teeth, hardens tooth enamel, prevents tooth decay-SOURCE- fish, tea. TOO MUCH- is toxic, TOO LITTLE-weak teeth, enamel leading to tooth decay       

Iodine-used to make some hormones SOURCE-Seafood,dairy foods, veg.TOO LITTLE-causes goitre (neck swelling)

Fibre or NSP (non starch polysaccharide) or roughage- Daily 30g adult, fibre is a type of carbohydrate which helps digestion as keeps food moving through it. Source-veg, fruit and fruit juice, brown bread, wholemeal or wholegrain foods, lentils, beans, seeds and nuts TOO LITTLE- bowel cancer, constipation, high blood pressure

WATER- 60 % of the body is water, we need water to eliminate waste from the body, control body temp, help digestion. 

TOO LITTLE- dehydration, slower reactions as brain needs water to function, blood to thicken making it harder for the heart to pump the blood around the body, increase in body temp

TOO MUCH-drinking too much water in a short time leading to headaches, nausea and confusion

Need 2 litres a day more if hot or exercising

Eatwell plate-Food groups                      women- 2000 kcal, men 2500 kcal

1. Fruit and veg- 1/3 of daily intake, aim to eat 5 portions a day

2. Starchy carbs- 1/3 of daily food intake,

 3. Oils  and spreads use unsaturated

4. Dairy products and alternatives

5. Beans, pulses, fish, meat and other protein- aim for 2 portions of fish a week, one oily. Choose lean cuts of meat, less processed meat

Drink 6-8 glasses of fluid and eat less sugary, salty and fatty foods 

YOUNG CHILDREN (2-5 yr olds)- eat small frequent meals as dont have large stomachs, need 300ml of milk daily for calcium and good source of vit A . Try to encourage that they eat a variety of foods

CHILDREN (5-12 yr olds)- they grow quickly and are active so extra demand for energy and nutrients. Protein for growth and repair, carbs for energy and some fats provide energy. Calcium and Vit D for healthy teeth and bone development. Avoid foods high in sugar

Teenagers- aim for a balanced diet, rapid growth spurts at this age so need protein, boys more protein as more muscular development. Iron -girls lose iron during periods which can lead to anaemia , vitamin C helps the body absorb iron. Calcium and Vit D as skeleton grows quickly and bone strength.

Also consider time of stress due to exams which can affect eating habits  eg anorexia, also overeating can lead to obesity

ADULTS- growth stopped so focus on healthy lifestyle-follow eatwell guide. 

ELDERLY ADULTS- muscle turns to fat so less energy needed, cut down saturated fats to avoid CHD. Ensure enough calcium, Vit D to stop bones weakening, VIT B12 to keep brain healthy, fibre to prevent constipation as digestive system weakens, Vit A for eyesight

Obesity is when the body has too much fat- affects 1 in 4 adults in the UK- BMI (body mass index) used to check levels between 18.5-25 is classed as a healthy weight 25-30 overweight, 30-35 obese , 35 morbidly obese.

Health problems of obesity- high blood pressure, high cholesterol, CHD, strokes, cancer , type 2 diabetes- breathing difficulties, tiredness and low self esteem 

CHD caused by clogged arteries as they are narrowed due to fatty deposits

Causes - too much saturated fat, inactive, smoking reduces oxygen in blood, high blood pressure

ANAEMIA- caused by Iron deficiency 

DIABETES-type 2 diabetes is a disorder where blood glucose levels stay too high -causes being overweight or obese, excessive sugar in the diet

other health problems- rickets, osteoporosis, tooth decay 

BMR- Basal metabolic rate- minimum energy needed to function eg breathing, heart beating, these basic life processes can use up to 75% of energy we use each day, other things like digestion and physical activity make up the rest. 

BMR- decreases as we get older due to reduction of muscle mass, women have generally lower BMR, weight and height affect BMR as larger bodies need more calories so higher BMR, Exercise increase muscle which raises BMR

PAL- Physical activity levels- higher PAL if you are more active. BMR and PAL multipled give you your daily energy requirement

If you consume more energy than you use you will gain weight, consume less energy than you use you will start to lose weight

Macro nutrients have different energy values

Energy expressed in Kilojoules (kj) or called kilocalories (kcal)

1 gram of each macro nutrient- FAT =9 kcal , PROTEIN= 4 kcal, CARBOHYDRATE=4 kcal  so 1 boiled egg contains 7g fat, 9 g protein, 0.6g carbs = 101.4 kcal

Packaged foods have to include nutritional labels by law

Modifying meals to follow healthy eating guidelines eg for a crumble switching to wholemeal flour, lowering sugar content, substituting oats for some of the flour to add fibre

Reducing sugar- check labels as sometimes sugar is disguised as sucrose, corn syrup. Use fewer sugary condiments eg ketchup, use less sugar when baking

Reducing salt- use less foods that have salt added to preserve or flavour them, create own sauces as lower in salt, use other seasonings other than salt

Reducing saturated fats- use low fat spreads, eat lean cuts of meat, grill , bake or steam instead of frying/roasting, allow fat to drain away when cooking

Increasing Fibre- keep skin on veg eg potatoes, carrots.Use Wholemeal bread , flour, pasta and add more lentils, beans and veg

LACTOSE INTOLERANT- need to avoid food containing a type of sugar called lactose, lactose is found in milk- could use soya or almond milk,

NUT ALLERGY- Avoid nuts or products with nuts in them- allergic reactions can be fatal

COELIAC DISEASE - cannot eat food containing gluten, avoid wheat, barley, and rye, use alternative flours eg coconut, tapioca or rice flours

VEGETARIANS- chooses not to eat meat. #

PESCATARIANS- dont eat meat but will eat fish and animal products.

 LACTO-OVO will not eat any meat or fish but will eat milk, eggs and other animal products. LACTO will not eat meat, fish or eggs but will consume milk and other dairy products.

Vegans will not eat any meat, fish or animal products

Different cooking methods change our food in different ways- changes to appearance, texture, flavour, smell and nutritive value

We cook to make food safe to eat, some foods contain harmful bacteria, bacteria can be killed if food cooked for long enough at a high temperature or to remove harmful toxins- red kidney beans

To improve shelf life- when foods are cooked at high temp bacteria and moulds are destroyed, this way food can be preserved during the manufacturing process eg milk is pasteurised-heated to a higher temp so it stays fresher for longer

To develop flavours-chemical reactions take place during cooking that change flavour of food eg caramelisation. Roasting meats and veg create more intense flavours-food becomes browner as more fat added and water evaporates

To improve texture- cooking makes food easier to chew, swallow and digest. Pasta, rice will swell due to starch softening. Meats more tender as solid fats in the food melt and proteins soften. Egg whites become firm when cooked-coagulate

To give variety in the diet as food can be cooked in different ways

Transferring heat energy- moving it from one place to another

Conduction-transfer of heat energy through the vibration of particles- pan on the hob, heat energy from the hob causes particles in the pan to vibrate- particles collide and pass on heat energy and when food is added to the pan heat energy moves to the particles in the food. 

Convection- transfer of heat energy through gases e.g air or liquids, convection also occurs in ovens- hot air rises and cooler air falls

Radiation- Grills, toaster,transfer of heat energy through waves of radiation- with radiation there is no direct contact between the heat source and the food . Waves of radiation when they reach the food they are absorbed and heat the food up . Microwaves use radiation to heat up the fat, sugar and water molecules in our food

Boiling- not used for delicate foods, healthy way to cook as no fat is added but can lose nutrientts if bolied for too long -eg water soluble vitamins. SIMMERING lower boiling point- soups and curries

Steaming- foods to steam-fish, rice and veg. No fat is added, because of no direct contact with water the veg keeps more taste, texture, colour and nutrients

Blanching-part cooking food in boiling water and then in cold water- keeps nutrients

Poaching- cooking food in a pan of liquid below boiling point- types of food eggs, fruit, fish- keeps food tender

Braising- slowly cooking food in a pot with a lid that contains liquid. Good for tough cuts of meat as helps to tenderise it

Stir frying- in a wok, small amount of oil, foods cook quickly so need to be moved about, keep more of the nutrients

Shallow frying- medium amount of oil, foods include meat, fish, eggs, pancakes-gives crispier texture- sweating is shallow frying on low heat making food tender and sweet

Baking uses dry heat- because heat rises the top of the oven is hotter. Most ovens are usually fan assisted which circulates hot air around oven so food bakes more evenly. Wide variety of food can be baked, quite healthy because no extra fat is added but baking can take a long time and food can dry out , also uses a lot of energy.

Grilling- uses radiation- foods cook quickly at high temp, fairly healthy as fat drips off but difficult to cook evenly as high heat and easy to burn the food. Outside might be cooked but inside raw which could lead to food poisoning

Roasting- can often add fat e.g potatoes, veg to help it brown, stay moist, fat can be put back on top this is called basting

Dry Frying- means cooking food in a pan without fat or oil- some foods contain natural fat eg minced meat, bacon

Proteins denature during preparation and cooking - this means the chemical bonds holding the structure together break down. The proteins unravel and their shape changes. Proteins can be denatured by physical agitation- eg whisking, beating, kneading or through changes in temperature or in marinades eg lemon juice - makes meat more tender. 

After denaturing protein molecules collide with other protein molecules and coagulate (join together). Coagulation changes appearance and texture of food eg fried egg -changes from see through liquid to a white solid

Foams are formed when air is trapped- when liquids containing protein are agitated eg egg whites whisked the proteins inside the liquid denature and air becomes trapped in the liquid. When the proteins coagulate the air becomes trapped creating a foam. HOWEVER over whisking causes protein bonds to break, air escapes and foam collapses

Gluten allows doughs to stretch and rise- gluten is a protein found in wheat flours, molecules of gluten are coiled which means they can stretch and bend which gives elasticity. Knead doughs to stretch gluten strands, when cooked gluten coagulates which gives bread a light , airy texture

Starch- gelatinisation thickens liquids- when starch granules are mixed with liquid they become suspended in it. When heated the bonds between starch molecules start to break allowing water molecules to enter, as water is absorbed the starch granules swell and soften

At 62-80 c the starch granules burst open, release starch and mixture thickens. When cooled the liquid solidifies. 

Dextrinisation- this occurs when starch is exposed to dry heat eg toasting or baking. When toasted the starch molecules break down into smaller molecules called dextrins

Sugar caramelises when its heated- sugar molecules break down when they reach a high temp, the sugar then turns brown and change flavour. This process is called caramelisation

Aeration-when fats such as butter are beaten with sugar air becomes trapped in the mixture., this gives spongyand light texture

Shortening- rub fat into flour, the flour gives a waterproof coating and means dough cannot become stretchy

Plasticity-meaning able to spread fats and manipulate them. The more unsaturated fat  the more plasticity the fat or oil will have-helps to decorate cake, rubbing fat , spreading butter

Emulsions are formed when oil and water are shaken- milk, marg and mayonnaise are emulsions

Usually oil and water don't mix together and so emulsions separate unless you keep shaking or use an emulsifier

Emulsifiers have 2 ends - 1 attracted to water- HYDROPHILIC and the other end repulsed by water- HYDROPHOBIC. Adding an emulsifier means the water molecules bond to the HYDROPHILIC side and the oil molecules bond to the HYDROPHOBIC creating an emulsion.

Egg yolks contain a natural emulsifier calle LECITHIN , which is used in margarine and mayonnaise. Mayo- stable emulsion of egg yolk, oil, vinegar- add oil gradually. Hollandaise-an emulsion- butter, water, egg yolks and lemon juice (flavour)

CHEMICAL RAISING AGENTS

Some raising agents produce Carbon Dioxide- Bicarbonate of soda when heated breaks down to produce carbon dioxide bubbles that expand to make the mixture rise. 

Baking powder- a mix of bicarbonate of soda and cream of tartar. 

Self raising flour contains a mix of plain flour and baking powder

BIOLOGICAL RAISING AGENTS

yeast is a biological raising agent used in bread dough- a micro-organism that causes fermentation. Fermentation is a process that releases alcohol and carbon dioxide.

ADDING STEAM OR AIR

When mixtures has a lot of liquid eg batters, choux pastry in a hot oven water leaves the mixture as steam. As steam rises it raises the mixture up. 

Air can be folded in through carefully using a spoon in a cake mix or in pastry doughs air folded in between the layers. Also air can be beaten in, whisking, sieving flour, creaming and rubbing fat into flour

MICROORGANISMS are tiny living things found in air, water, soil and on people. eg bacteria, moulds, yeasts. Most are harmless but PATHOGENIC ones can spoil food and cause food poisoning

They need: warm temperature, moisture, food, the right PH, enough time -bacteria split 10-20mins

High risk foods have ideal conditions for bacteria- moist and high in protein- high risk food eg cooked meat, fish, poultry, dairy products, gravies stocks and sauces, shellfish and cooked rice. High risk foods have a short shelf life. 

Enzymes are biological catalysts- they speed up chemical reactions. Enzymes in fruit cause them to ripen eg enzymes in green bananas break down the starch which makes them softer and sweeter.

Enzymic Browning- slicing fruit, the oxygen in the air will turn the fruit brown .You can slow down  browning by- adding an acid, blanching (plunging into boiling water before freezing

MOULDS, YEASTS can spoil food too, in the right conditions can grow and spread quickly, waste products from moulds can cause food poisoning. yeasts can spoil fruit by fermenting the sugars turning them into alcohol and carbon dioxide

To preserve food you need to keep it in conditions were bacteria cannot grow-

Cooking/reheating - above 75 c kills bacteria, reheat for at least 3 minutes . USE TEMPERATURE PROBE 

Danger zone- 5 c to 63 c- at this temperature bacteria grow and multiply quickly- optimum temp is 37c

Chilling 0 -5 c- keeping food between these temperatures slows down the growth of bacteria

Freezing- below -18c - bacteria become dormant-they are not killed , they bacome active when the food defrosts 

Fridges should be 0- 5 c- keep raw meat , poultry and fish on bottom shelf

Freezers are set at around -18c, ideally defrost meat and poultry in a fridge

Some food can be kept at an ambient temperature  eg tinned , sugar, bread, pasta, cereal. ambient foods stored in a cool, dry place. 

Preservation can be used to extend shelf life - eg freeze drying, canning foods, vacuum packing, pickling

Use by date- foods with a short shelf life eg high risk foods

Best before date- longer shelf life products e.g. tinned foods, given as a warning about quality , probably safe eg biscuits might be soft

Bacteria passing from raw food to work surfaces, equipment and hands. Bacteria are then easily transferred to other food which is known as Cross Contamination

Cross contamination- raw meat juices dripping onto cooked food, utensils, equipment and work surfaces, using unclean equipment, dirty cloths on work surfaces, chopping boards. Poor personal hygiene- unclean hands, sneezing or coughing

Pests- flies, rodents contaminate food by walking over them, by laying eggs or droppings on work surfaces

REDUCE RISKS BY: good personal hygiene, use different coloured chopping boards, wash raw veg removing soil. Use clean equipment and an antibacterial spray to sanitise. Defrost food fully in the bottom of the fridge

Cook food at the right temperature and for the correct time, cook food all the way through, test temperature inside food using a temperature probe

temperature probe- sterilise before and after use, insert it into the middle of  thickest part, leave probe until it stabilises, must reach at least 75 c

Serve hot food straight away or keep it above 63 c for no longer than 2 hours. If serving food cold or storing it , cool it down within 90 mins

Bacteria can cause food poisoning- general symptoms sickness, diarrhoea, stomach cramps, fever. In extreme cases it can lead to death. 

You get food poisoning by eating contaminated food containing PATHOGENIC bacteria.

TYPES:

CAMPYLOBACTER- most common cause of food poisoning, found mainly in raw or undercooked poultry or in other raw meat and untreated milk/water. ONset time 2-5 days 

SALMONELLA-found in raw poultry, untreated milk and eggs, onset times 6-72 hours 

E COLI 0157- they live in the intestines of animals, most types are harmless but E coli can cause kidney damage and death. Sources- raw beef, untreated milk/water, unwashed veg and salad. ONSET time 1-3 days

STAPHYLOCOCCUS AUREUS- found on the skin, hair, noses of animals and people. ONSET TIME 1-6 hours

control bacteria by pasteurisation, heating milk to 72 c for 15 secs, vaccination of hens against salmonella

Many Factors influence peoples food choices: Physical activity level PAL- more active consume 20% more calories

Healthy eating- people eating foods based on the nutritional value

Cost of food- cheaper options, deals, buying food in bulk, can be cheaper per portion to make your own food

Income- people on high incomes more likely to buy expensive items, in general people on lower incomes tend to have poorer diets than high income groups

Culinary skills, enjoyment of food

Lifestyle- comfort food, busy lives, different eating habits, bad habits-eating late, skipping breakfast

Seasonality- environmental impact of food miles, buy local foods

Availability- Local shops, on line shopping

Special occasions

Christianity- during lent christians may choose to give up certain foods, celebrations -hot cross buns on good friday, pancakes start of lent

Islam-muslims must eat meat that is Halal as stated in the Quran. Dont eat pork or any product from pork eg gelatn. No alcohol. Fasting during ramadan

Hinduism- many Hindus are vegetarian, any meat eaten slaughtered quickly and painless method- Jhatka. No beef as cows are sacred.

Jewish dietary laws state that food must be kosher- kosher animals are those with split hooves and chew cud, plus fish with fins and scales, so no shellfish. JEWS not allowed to eat pig, rabbit, hare, camel

SIKHS- BAPTISED sikhs prohibited from eatingmeat which is ritually slaughtered. MANY sikhs are vegetarians. 

Buddhists- believe that all living beings are sacred. most are therefore vegetarian or vegan, most avoid alcohol. 

Rastafarians- pork is forbidden, they stick to I-tal (clean and natural) diet, mostly fresh veg. Most dont drink alcohol

Moral and ethical food choices

Animal welfare- free range, avoid meat eg veggie or vegan

Working conditions- Fairtrade products- give fair price to farmers in developing countries for their produce

Environmental impact- people may prefer to buy local or british produce or foods that are in season which support economy, reduce food miles. Sustainable fishing methods to stop damage to the eco-system

Eating naturally-eat organic so no chemicals but natural fertilisers, no GM foods as concerns over unwanted effects on the consumer and environment

Intolerances- eating some foods can lead to illness, eg lactose intolerance, gluten intolerance

Food allergies may cause serious illnesses and can be fatal- common allergens nuts, eggs, dairy, wheat, fish and shellfish. 

Food labels must not be mis leading- EU REGS- clear and easy to read, common allergens must be emphasised in the ingredient listing. Must have nutritional info from dec 2016. FSA- food standards agency must ensure food manufacturers, businesses follow the regs.

EU LAWS ON LABELS- how to store, manufacturer name and address, use by date or best before, where it comes from, weight or volume, product name, any GM ingredients, ingredients which must be listed in descending order of weight, cooking instructions.

NUTRIENTS MUST BE GIVEN PER 100G. 

other label info includes (non compulsory) claims about products, traffic light labelling to show how healthy it is at a glance, also may state whether suitable for a certain group, serving suggestions

Humans taste by using tongue and nose- taste buds detect SALT, SWEET, SOUR, BITTER AND umami (savoury) Taste buds work with olfactory receptors in the nose, this detects smells.Each sense influences food choice - Sight, taste, touch and smell.

Preference tests are used to see which food a person enjoys more, 2 types of preference test are the paired preference test, eg 2 cookies , 1 made with butter, the other marg and the hedonic rating test uses a scale. Discrimination tests check if peole can tell the difference, a type of difference test is a triangle test.

Grading tests used to compare food characteristics - ranking, rating and profiling are grading tests

Ranking- foods put in order from lowest to highest, Rating- as food tasted, testers rate charactersitics eg spice, sweetness, profiling- average rating for each aspect and then average worked out to create a profile          

GM- GENETICALLY MODIFIED have altered genes to give useful characteristic such as improving growth.  eg GM sweetcorn thats pest resistant so bigger yields. Currently no GM crops grown in the UK. 

advantages of GM: grow quicker, higher yields, food is cheaper to produce so cheaper for consumer, longer shelf life so less food is wasted, crops can ripen earlier so fresh foods can be available for consumers earlier in the year, can be modified to contain extra nutrients

Disadvantages- GM have not been around for a long time so there long term health benefits not yet known, concerns that modified genes could get out into the wider environment, cannot be sold everywhere EU restricts the import of some GM foods

In the EU all GM foods must undergo strict safety assessments, any foods containing more than 1% GM ingredients must be labelled

Factory farmed animals and free range.

Red tractor symbol on products lets consumers know that the producer meets the standard of food safety, hygiene, animal welfare and environmental protection set by the assured food standard scheme. RSPCA assured symbol is found on eggs, fish and meat - must meet strict welfare standards

Fortification adds nutrients to a food- improves nutritional value and sometimes used to replace nutrients lost during cooking eg white flour- iron, niacin, calcium are lost during production and by law have to be added back in. 

Breakfast cereals can be fortified with Iron, thiamin and folic acid, butter alternatives can be fortified with A and D. 

Manufacturers may fortify processed foods to help market their products as it makes them appear healthy. 

Addititives change the properties of food- some additives occur naturally and some are made artificially. 

Preservatives are addititives that prevent bacteria from growing- natural preservatives include-vinegar, lemon juice, salt and sugar. Artificial preservatives include nitrates, sulphates. 

Colourings make food look more attractive, add colour to something that is colourless or return food to its natural colour if its lost during processing. Caramel is a natural food colouring, Tartrazine is an artificial food colouring. 

Flavourings improve the taste or the aroma of a product- natural flavourings include herbs and spices, artificial eg aspartame , MSG (mono sodium glutamate) enhances flavour

Emulsifiers/Stabilisers help preserve the shape and texture - emulsifiers help ingredients mix together and stabilisers stop mixed ingredients separating. Lecithin is a natural emulsifier found in egg yolks and soya beans. Pectin is a natural stabiliser found in berries, apples and other fruit

Additives must pass a safety test before they can be used in food- when they passed they are issued with an E number e.g caramel colouring is E150a

Primary food processing prepares raw foods straight from being picked, harvested or slaughtered so they are ready to be eaten or cooked or used as ingredients to make other food products.

Examples: stones removed from fruit eg peaches, fruits are squeezed for juice, grapes sundried to make raisins , veg are washed to remove dirt, insects, chemical sprays, chicken feathers and wings removed

Flour is made by milling wheat grains-grain is made up of bran, endosperm and germ. The grains are harvested, cleaned and stored. Then they are put in a hopper and crushed which crack open the grain. Some B vitamins are lost in white flour so are added back in. EATWELL guide recommends wholemeal products for their nutrional benefit

Milk is heat treated to kill pathogenic bacteria but also non harmful bacteria are lost. Pasterurisation is when milk is heated to 72 c for 15 seconds then rapidly cooled. UHT - MILK is heated to 135c for 1-4 seconds and packed in a sterile container, slightly less nutrional value but can be kept for several months. Sterilisation -steam chamber at 110c for 10-30 minutes- all bacteria are killed. 

Microfiltration MF- bacteria that turn milk sour remain after pasteurisation, MF separates milk from souring bacteria which extends shelf life

Secondary processing uses primary processed foods

eg Flour is made into pasta- colourings can be added eg spinach to make the pasta green , pasta can be sold freash or dried- dried pasta has a longer shelf life

eg Fruit is turned into jam - crushed fruit, sugar and pectin. Pectin is a gelling substance found in fruit and when boiled pectin causes the jam to thicken and set as it cools. The sugar draws water out making it difficult for micr organisms to grow.

However boiling or drying remove important nutrients in food e.g in jam you will lose vitamin C

Milk is turned into cheese- raw milk is pasteurised to kill pathogenic bacteria, friendly bacteria sour and thicken and rennet from calves stomach is added. Rennet makes the milk coagulate into solid cheese curds , the liquid is called whey. Curds pressed into blocks of cheese and bacteria or moulds may be added to change the flavour of the cheese