Section Two - Properties Of Food Flashcards
What are the three types of carbohydrates
Sugar, starch and fibre
Properties of Sugar
Includes simple sugars like glucose and fructose as well as double sugars like lactose and sucrose. Easier to digest than start
Properties of starch
It is a complex sugar. It needs to be broken down by digestion before the energy can be used which is why it’s good to each starchy foods like pasta and rice a few hours before playing sport.
Examples of fibre
Bran, fruit, beans and brown bread
What are simple sugars science name
Monosaccharides
What is the science name for double sugars
Disaccharides
What is the science name for complex sugars
Polysaccharides (longs chains of monosaccharides)
What is the science name for fibre
Non-starch polysaccharides (NSPs) (long chain monosaccharides)
What is energy that is not used stored as
Fat so it’s often carbohydrates not fats that make people overweight
What is granulated sugar used for
General kitchen use e.g sweetening tea or breakfast cereal
What is caster sugar used for
It has finer crystals than granulated sugar so is used for baking like cakes and biscuits which need a fine texture
What is brown sugar used for
Demerara and muscovado have strong distinctive flavours so are used in rich fruit cakes, and gingerbreads.
What Is icing sugar used for
It is white and powdery used for icing and sweets
Where do sugars originally come from
Sugar cane and some sugars also naturally occur in things like fruit and honey
What are some names of sugars
Fructose, dextrose, sucrose, inverted sugar, malt rose, lactose and glucose
What are the six functions of sugar
- Makes things sweet or softens sharp flavours
- Acts a preservative e.g in jam
- In creamed mixtures sugar is beaten with fat which aerated the mixture and helps lighten it
- Speeds up fermentation e.g in bread
5 sugar adds colour e.g in pastries - Sugar can be heated until it becomes sweet-tasting brownish liquid (caramelisation)
What is caramelisation
When sugar is heated to become sweet tasting and brownish and is used to top off deserts
What can sugar substitutes be used for
To sweeten drinks and foods
Why are sugar substitutes good
They are better for your teeth and contain fewer calories so good for people on a slimming diet. They are also good for diabetics who have to control their sugar intake
Why shouldn’t sugar substitutes be used for home baking
Because they don’t have the same properties as cane sugar
What are the four things starch is used as
Bulking agent
Gelling agent
Thickening agent
Manufactured products
Why can starch be used as a bulking agent
Starch granules swell when a liquid is added and so can provide the bulk of a product e.g the starch in flour makes up most of the volume of flour
How is starch used as a gelling agent
When moisture is added to starch granules and heat is applied:
- Granules begin to absorb the liquid and swell
- At 80*c the particles break open making the mixture thick and viscous this is gelatinisation
- Gelatinisation is completed when liquid reaches 100*c
- Thickened liquid forms a gel
- On cooling the gel solidifies and takes the form of the container its in
How is starch used as a thickening agent
- Starch and liquid mixed together (thickness depends on their proportions)
2: the starch particles form a suspension - they don’t dissolve - The mixture is stirred to keep particles suspended
- Heat is applied and gelatinisation occurs
What are two examples of food using starch as a thickening agent
Sauces and gravies
How is starch used in manufactured products
Modified starch is used to thicken things like instant desserts, whipped cream, Yogurts and packet soups. Usually a liquid is added and it is stirred or whisked.
What can modified starch from barley do and why
Make low fat cakes and biscuits because it has similar properties to fat
What are modified starches sometimes called
Smart starches
What is a modified starch
Starches that have been treated so they react in a particular way in certain conditions
What does pre-gelatinised starch do
Thickens instantly when mixed with hot water e.g instant noodles
What happens when protein is added to starch
It coagulates and squeezes out the fat and water which is known as syneresis
What do some starches allow without syneresis
Products to be reheated which is handy with frozen foods so they can keep their moisture and nutrients when they’re cooked
If a normal starch reacts with an acid what happens
It no longer works properly
If a modified starch reacts with an acid what would happen
Nothing some are immune to it so they can be used to thicken acidic products like salad cream
Why do you need bread dough to be elastic
So it doesn’t turn out heavy and dense
What happens when a dough made with flour is kneaded
A protein called gluten is formed
How do you get a well-risen loaf of bread
Use strong bread flour because it will form more gluten than other types of flour
What does gluten do to bread
Gives dough its elasticity and helps bread rise
What does the dough mixture contain besides starch and what happens
Yeast and ferments the sugar to product carbon dioxide
How does a bread rise
The gluten stretches to hold the carbon dioxide that is produced by the yeast fermenting the sugar
How do you obtain the light, airy texture of well-risen bread
When gluten reaches a high temperature it coagulates (changes into s more solid state) and the dough stays stretched to give it this texture
What is gelatinisation
When a mixture becomes thick and viscous
What does protein do
Helps our bodies build and repair muscles, tissues and organs and helps children grow
What is protein made of
Amino acids
Why do you have to eat essential amino acids
Because your body can’t make these amino acids like it can make others
Examples of some foods with high biological value
Meat,fish, eggs, milk and soya beans and tofu
Examples of food with low biological value
Peas, lentils, nuts and most beans
How does your body make muscle
When you eat protein your body breaks it down into amino acids and use them to build new proteins
What are the three main types of meat in the Uk
Beef
Lamb
Pork
What do beef and lamb contain
Loads of B vitamins and minerals like iron and zinc
Livers have loads of vitamins
What does pork contain
Lots of thiamin (vitamin B1) and niacin (B3)
What are beef, lamb and pork usually called
Red meats (but pork is sometimes white meat)
What can too much meat cause
Problems like heart disease
How do you tenderise meat
You have to partly break down the fibres in the meat.
You can do this by bashing it with a mallet, marinating it in something acidic or cooking it really slowly.
How do you prevent meat from drying out during cooking
Sealing the outside of the meat (by cooking at a high temperature for the first couple of minutes) this keeps the juices in
What are the three main types of poultry
Chicken
Turkey
Duck
What kind of meant is poultry
White meats (duck is sometimes red meat)
Why is poultry good
It’s a good source of protein and B vitamins and is fairly low in saturated fat
Why is poultry bad
It can be contaminated with salmonella bacteria which can make you seriously ill
What are the three types of fish
Oily fish e.g salmon, tuna and mackerel
White fish e.g cod, haddock , plaice
Shellfish e.g crab, lobster, mussels
Why is fish nutritious
It contains loads of vitamins plus omega 3 oils
What are some examples of alternative protein
Tofu - sofa beans (stir fry sometimes in deserts)
TVP - sofa beans (sausages, burgers and ready meals)
Quorn - mushroom like fungus and egg white (chicken substitute available in chunks, mince or fillets
How do you add flavour to meat replacements
Marinating them in a mixture of things like oil, wine, vinegar and herbs before cooking
What is the nutritional value of an egg
Protein - about 13%
Fat (mainly saturated) - about 10%
Vitamins A, B2 and D
Minerals, including iodine
How are eggs used in binding
Coagulation sticks the ingredients together as they cook e.g in burgers
How are eggs used in coating and enrobing
Eggs help dry ingredients like breadcrumbs stick to food
How are eggs used in glazing
Brushing egg over bread gives it a glossy finish when it’s cooked e.g bagels
How are eggs used in thickening
Egg whites coagulate at 60c and yolk at 70c and when it reaches these temperatures it sets and stays thickened e.g in quiche
How are eggs used in aeration
Egg white traps air when it’s beaten because the protein stretches e.g in cakes
How are eggs used in emulsification
Oil and water mix together form an emulsion but the emulsion usually seperates. So lecithin found in egg yolks keep the emulsion stable (stops seperating) e.g in mayonaise
What may raw eggs contain
Salmonella which can cause severe food poisoning
Why must eggs be cooked thoroughly
So all the bacteria are destroyed
Who should you be extra careful when cooking eggs for
Pregnant women, babies, elderly or frail people
What do manufacturers often use to be on the safe side instead of fresh egg
Dried or pasteurised egg
What are three ways to cook eggs
Boiled and poached eggs - healthy because no fat used to cook
Scrambled eggs - do in microwave and need no fat
Fried eggs- absorb fat from oil, best to use unsaturated fat and drain off as much oil before eating them
What are the six types of fats and oils
- Butter from churning cream
- Margarine from vegetable oils blended with stuff like water
- Lard from pig animal fat
- Suet from the fat which protects animals organs
- Oils from pressed seeds e.g sunflower
- Low fat spreads are emulsions of vegetable oils usually hydrogenated and water
Why are fats used in pastries and biscuits
- Add flavour
- Add colour to make it golden yellow
- Shortening - rubbing fat into flour to prevent gluten being produced to make pastry and biscuits short so they are crumbly
What are some ways besides cakes that fats and oils are used in food
Cooking e.g deep frying or shallow frying
Enriching adding butter or cream to a sauce to thicken it and improve the taste
Emulsions mixing together oil and water makes a thickish liquid
What are the nutritional values of fat
- Concentrated source of energy
- Source of vitamin A,D,E and K
- Provide fatty acids which are essential to the structure and function of body cells
- Keep us warm
Characteristics of saturated fats
Come mainly from animal sources e.g meat, butter and are solid or semi solid at room temperature. The often have high amounts of cholesterol.
Characteristics of unsaturated fats
Come manly from vegetable sources and are usually liquids at room temperature. Main cooking oils are peanut, sunflower,corn, soya, rapeseed and olive oil
What do our bodies use fat to make
Cholesterol which is essential part of all cell membranes and is also needed to make hormones
What can high cholesterol levels increase the risk of and how would we lower the risk
Heart disease. Most people in the Uk eat more saturated fat than the government recommend so could lower the risk by cutting down.
What are carbohydrates needed for
Energy
Why are vitamins and minerals essential
They help other nutrients to work and can prevent certain diseases
Where do we get most of our vitamin A
From retinol found in liver, butter, fish oil and eggs.
Also from carotene found in orange or yellow fruit and veg and margarine.
What is vitamin A needed for
Good eyesight and growth and function of tissues
Where is the vitamin B group found
In cereals, livers, kidneys, peas, pulses, dairy produce, meat and fish
What does B1 (thiamin) help
The nervous system and the release of energy from carbohydrates
What does B2 (riboflavin) help
The realise of energy and the repaire of tissues
What does B3 (niacin) help with
The realise of energy
What does folic acid help
Growth and important for women planning a pregnancy as low levels of folate at conception increase the risk of s baby having spins bifida
What are the four types of vitamin Bs
Thiamin, riboflavin, niacin, folic acid
What is vitamin C also known as
Ascorbic acid
Where is vitamin C found
In citrus fruits, green vegetables, peppers and potatoes
What is vitamin C good for
Protecting the body from infection and allergies, helps in the absorption of calcium and iron from food and feels blood vessels healthy and heals wounds
What is vitamin D also know ad
Calciferol
Where is vitamin D found
In oily fish and eggs and is produced in the body when the skin is exposed to sunlight
What does vitamin D do
Helps body absorb calcium
What can a lack of vitamin D lead to
Bone diseases like rickets
Where is calcium found
Milk, tofu, salmon, green leafy vegetables, hard water and white bread
What is calcium needed for
Strong bones and teeth especially for growing children and healthy nerves and muscles
What can a lack of calcium lead to
Osteoporosis
Where is iron found
In dark green vegtables and meat especially in liver and kidney
Why is iron need
To form part of the haemoglobin which gives blood cells their red colour,
What does lack of iron cause
A deficiency disease called anaemia
What do fruit and vegetables give you in a normal healthy diet
The majority of your vitamin C (90%) Dietary fibre Vitamin A (from carotene) and B Iron and calcium Not much fat Loads of water Small amounts of protein
How can nutrients and flavours easily be lost or splint
Through over cooking and poor storage.
Microbe in the aim can make fruit and vegtables go rotten.
How should you store fruit and vegtables
In a cool dark place like a fridge
Why should you prepare fruit and vegtables just before you need them
Vitamin c in particular starts to go once the fruit and vegtables are picked, stored, cut or peeled
Why shouldn’t you chop fruit and vegtables into small pieces
It exposed more of the surface and more nutrients are lost when they see cooked
Why should you leave vegtables to stand in water
Vitamins B and C dissolve into water
Why should you peel fruit and veg very thinly or not at all
Most of the nutrients and the fibre are found just below the skin of fruit and vegtables
What are the best ways to cook fruit and vegtables to keep the nutrients
Quickly as possible in a small amount of water. Steaming or microwaving them are the best ways however.
Why do bananas needs to be stored away from other fruits and veg
They give off w gas which makes other fruit and vegtables ripen quickly and spoil
What three things can food and ingredients be
Acidic, neutral or alkaline
What do acids and alkalines have a big effect on
The flavour, texture and appearance of foods
Examples of acidic foods
Citrus fruits, lemon juice (citric acid) , vinegar (acetic acid), vitamin C (ascorbic acid). They have a sharp, sour taste
What are the benefits of vinegar
It gives a softer texture. Acids can change the texture of foods by partly breaking down proteins so if you add vinegar to say a meringue it makes a softer, chewie texture. Vinegar is also used in marinade to tenderise meat.
What are the benefits of lemon juice
Inside of fruits tract with oxygen which is called enzymic browning and it turns the fruit brown. But if you add lemon juice it stops enzymic browning so the colour is retained which is good for fruit salads.
How is lactic acid usefully
Lactic acid fermentation produces yogurt. Milk turns sour when the bacteria it contains breaks down sugars in the milk into lactic acid but in yogurt making lactic acid acts on the proteins in milk to thicken it but gives it a slightly sour taste.
Why are acids added to food
Give it a sharp taste and helps preserve food because bacteria can’t grow
What kind of taste do alkalis have
Unpleasant and bitter
How does bicarbonate of soda act as a raising agent
It breaks down to produce carbon dioxide when heated. The carbon dioxide bubbles expand making the mixture rise.
Why is bicarbonate of soda used in things like gingerbread and chocolate cake
Because it needs a strong flavour go make the unpleasant taste it leaves
Why is cornflour used
To give a thicker texture for example you add corn flour to thicken the filling in a pie
What is the eat well plate
Is a government guideline and an easy way of showing how much or little of each food group you should eat
What is on the eat well plate
Lots of fruit and vegtables Some dairy foods Small amounts of fatty and sugary foods Some non dairy sourced protein e.g meat Lots of starchy foods like pasta
What do food labels refer to how much of various nutrients the product contains as
Guideline daily amount (GDA) or recommended daily amount (RDA)
(These are how much of each nutrient and hoe much energy an average adult needs each day)
What do labels usually show
How much protein, carbohydrate, fat and dietary fibre the product contains and is sometimes shown as a percentage of the GDA as well
What are RDAs used for
Vitamins and minerals
How do you cause a nutrient deficiency
Not getting enough vitamins or minerals can lead to health problems.
Not eating enough protein leads to restricted growth in children and muscle wastage
How do you cause a nutrient excess
Eating too much fat can make you overweight which can leave to heart problems and cancer.
Eating too much sugar can lead to obesity, type 2 diabetes and tooth decay.
Too much salt can increase blood pressure meaning a nigger risk of heart disease and stroke.
How can you keep check of how healthy your diet is
Keep a food diary of everything you eat
What are the dietary requirements for vegetarians and vegans
- No meat or fish and for vegans no animal products at all
2. They need protein and vitamins from foods like nuts, beans, lentils and meat replacements
What are the dietary requirements for people with coeliac disease
They can’t eat gluten which is found in wheat, rye or barley.
- Can’t eat breads or pasta
- They have to get starch and fibre from other foods like rice and potatoes or gluten free alternatives
Dietary requirements for lactose intolerant
Can’t digest lactose which is a sugar found in milk
- Need to avoid dairy products and any products lactose is added to
- Will need calcium from foods like green leafy vegtables, salmon and white bread
Dietary requirements for calorie controlled diet
Fat and sugar provide a lot of calories without filling you up but give energy so they should get energy from starchy foods instead and exercise.
Dietary requirements for nut allergies
- Need to avoid products with nuts or have traces of nuts
2. Put warning label on the packet
Dietary requirements for diabetics
- As they can’t control their blood sugar levels they need to avoid sugary foods
- Advised to eat plenty of starchy foods which release energy slowly to avoid having high or low blood sugar levels
What is a new method of producing food all year round
Using huge greenhouses called biodomes
Examples of new ingredients and food
Meat substitutes like TVP, modified starch, genetically modified foods and functional foods.
What does new packaging technology include
Breathable packing for fruits and packaging with more protection against moisture and bacteria
What is a GM food
A genetically modified food that has had its genes altered to give it useful characteristics
How do you genetically modify a plant
Insert a desirable gene from another plant, an animal or bacteria into the plant you want to improve. You plant modified seeds and comes your GM crop e.g pest resistant maize so a bigger yield for farmers
What are the five advantages to GM food
- Crops made to grow quickly
- Producers can Get a higher yield for the same amount of seed and fertiliser
- Makes food cheaper to produce and to buy
- Can have a longer shelf life so less waste
- Can be made to ripen early so fresh food is availed earlier in the year
What are the three disadvantages to GM foods
- Long term health effects aren’t known
- Concerns that modified genes could get into envionment and cause problems e.g weed killer resistant weed
- Can’t sell the food everywhere as the EU restricts the import of some GM foods
Why do some people believe we should mess around with genes
It’s not natural
What are the EU rules about GM food
- All of them must undergo strict safety assessments and they can only be sold if there are no health risks found
2: all foods that are GM or contain more than 1% GM ingredients but be clearly labelled
What is a functional food
One that has been artificially modified to provide a particular health benefit on top of its normal nutritional value
Examples of a functional food
Some fruit juices have calcium added to the,
Eggs containing high levels of fatty acid omega-3 can be produced by feeding hens a diet rich in omega 3
Genetic modification e.g Golden rice is rice that has been GM to contain carotene
What might omega 3 reduce the risk of
Heart disease and cancer
Advantages of functional foods
- Easy way of providing better nutrition
- People who can’t eat certain foods can get the missing nutrients
- Foods like golden rice could help solve some health problems caused by malnutrition
Disadvantages of functional foods
- Still need a varied diet and exercise to be diet - can’t rely on just functional foods
- Don’t provide all the nutrients you’d need e.g difficult to get loads of golden rice everyday to get enough vitamin A
- They don’t tackle the actual cusses of malnutrition in poor countries
Why are some consumers still concerned about what’s in the food
They don’t know whether to believe everyrhing manufacturers tell them
If a manufacturer makes health claims for their food e.g helps maintain a healthy heart what must be labelled
The relevant ingredients clearly and the nutritional information must be on the label
What must health claims do and not do
Be backed up by scientific evidence and mustn’t mislead consumers
What is an additive
Something that is added to a food product to improve its properties
What are the two types of additives
Natural and artificial
What must happen to all additives before they can be used
Pass a safety test if it passes it gets an E number meaning it can be used throughly the European Union
What are the six different types of additive uses
Preservative Colourings Flavourings Emulsifiers Setting agents Raising agents
What do preservative additives do
They prevent bacteria from growing so they can last longer e.g salt is used to cure meats, vinegar is used to pickle foods, sugar in jam preserves it
How do colouring additives work
They make food look more attractive and appealing to eat. Can be used to add colour to something colourless or to return food to its natural colour it may have lost e.g caramel is used to make darkish brown colour and tartrazine used for yellow colour in sweets
How do flavouring additives work
Improve taste or the aroma of a product. E.g herbs and spices, vanilla can be artificial or natural, saccharin to add sweetness to desserts. MSG gives a savoury tastes in things like crisps and its natural.
How do emulsifier additives work
Are used to keep food products stable. Lecithin is a natural one found in egg yolks for things like mayonaise
How do setting agent additives work
Used to thicken products so they set as gel. Gelatin is natural extracted from animals in deserts like jellies
How do raising agent additives work
Used in dough and cake mixtures to aerate them.vthey release bubbles of gas which expand when heated to make the mixture rise. Yeast is a biological raising agent in bread dough and baking powder is a chemical one which breaks down when heated producing co2 making the cake rise.
What are four disadvantages to additives
- Some people especially kids are allergic to them
- Additives like sugar and salt can be bad for health
- Disguise poor quality ingredients
- No one knows the long term health effects yet e.g some say they are linked to behavioural problems
What additive is linked to hyperactivity in children
Sunset yellow
