Transcript Food Technology

Food Technology’s
Top 30
Revision Slides
2011
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Slides content
3 – Food choices
4 – Dietary goals
5 – Individual needs
6/7 – Hygiene and safety in the food
industry
8/9 – Quality
10 – Properties and functions of food
ingredients
11 – Heating and nutrition changes
12 – Cereals
13 – Fruit and vegetables
14 – Meat, poultry, fish
15 – Fats and oils
16- Milk, cheese and dairy
17 – Eggs
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18 – Sugar
19 – Methods of cooking and transfer
of heat
20 – Raising agents
21 – Setting ingredients
22 – Additives
23 – Components of foods
24/25 – Preservation
26 – Smart foods
27 – Systems and control
28 – HACCP
29 – Jobs in the food industry
30 – Product analysis
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Nutritional needs and Food Choices
Food Choices
• Food provides us with a variety of nutrients to keep us healthy
• We need to eat a balanced diet. The nutrients we need are:
 Proteins – body building, growth and repair
 Carbohydrates and fats – supply the body with energy
 Vitamins and minerals – protective, keep us healthy
• Food labels provide nutritional information – this is important:
 Comparisons of the nutritional content of different products
 People may be on special diets e.g. low fat
 Allows informed choices and that they have a variety of nutrients
• What affects our food choice?
Cost; Availability of food; Regional variations or where people live;
Personal preferences; Lifestyle; Moral beliefs; Storage and cooking
facilities; Religious beliefs; Health; Peer pressure; Recent food scares;
Food trends; Cultural preferences.
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Nutritional needs and Food choices
Dietary goals
• DRV – Dietary Reference Values – show the amount of food energy or
other nutrients needed by people of different ages
• RNI – Reference Nutrient Intake – the amount of nutrient sufficient for
nearly everyone (about 97% of the population)
• EAR – Estimated Average Requirement – is the amount of the average
need for food energy or a nutrient – this is an average for a group
• Dietary changes:
Reduce fat – in cooking, choose lower-fat versions of food ingredients,
remove visible fat from meat, bacon and poultry
Reduce sugar – used in recipes, avoid very sugary foods
Reduce salt – add less salt to recipes and avoid ingredients that contain a lot
of sodium
Increase fibre – eat more wholegrain foods – bread and cereals, more fruit,
vegetables, pulses and nuts
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Nutritional Needs and Food Choices
Individual Needs
• People have different nutritional needs, which change with age and
activity
• Food products are designed to appeal to different people
• Groups of people with special dietary needs:
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Vegetarians – vegan, lacto
Obesity – low fat products
Diabetics – too much
glucose in their body
Food allergies – milk, nuts,
eggs, fish and seafood,
colourings
Coeliacs – allergy to gluten
the protein in wheat
Babies – no salt, sugar,
smooth texture
Religion – Muslim, Jewish
Children – portion size ,
nutrients and additives
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Hygiene and Safety in the food industry
Part 1
• Good hygiene is essential throughout the food preparation chain –
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Choosing and buying food; Transporting the ingredients; Storing food;
Preparing food; Cooking food; Keeping food warm or storing it
Rules and regulations support the preparation of food so that it is safe
to eat.
Health and Safety is an important issue for the manufacturer, retailer
and consumer
The consumer is protected by:
Food acts and regulations
Trading standards officers
Environmental health officers
Food factories have strict rules for hygiene and food preparation
Environmental issues that should be considered by the manufacturer,
retailer and consumer – packaging, use of chemicals in the manufacturing
process, disposal of waste products
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Hygiene and Safety in the food industry
Part 2
• Bacteria need warmth, moisture, food and time to grow and multiply
• Cases of food poisoning are increasing
• Cross-contamination – raw food touching cooked food
• Microbial contamination – occurs when food has been infected by
bacteria, moulds and yeasts
• Examples of bacteria – Salmonella, Staphylococcus aureus
• Food retail is the point at which food is sold. Includes shops, restaurants,
fast food outlets, cafes, snack bars and vending machines
• Temperature control is an effective way to control bacteria
• Refrigerators – food stored at 5°C
• Freezers – domestic at -18°C, supermarket at -29°C
• The food industry monitors temperature during production and
distribution
• Harmful bacteria – destroyed at 70°C for 2 minutes
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Hygiene and Safety in the food industry
Part 3 - Quality
• Quality assurance and quality control systems ensure that quality
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food products are available to consumers
Quality assurance – relates to the specification, hygiene procedures,
monitoring waste and sensory analysis
Quality control – checks might include – weight, measurement,
temperature, checks for foreign bodies and bacteria
The shelf life of a product is the length of time a product will last
without deteriorating
‘Use by’ and ‘best before’ dates inform the consumer if the food
product is safe to eat and is of good quality
To maintain a good quality - food products must be stored correctly.
Food spoilage will occur if food is not stored correctly or if it has
reached the end of its shelf life
ISO 9000 – series of international standards – for quality assurance. Gives
greater efficiency in quality control systems
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Hygiene and Safety in the food industry
Part 4 - Quality
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High risk foods – spoil in a short amount of time e.g. meat and fish
Perishable foods – go off or spoil quickly
Low risk foods – have a long shelf life
Dehydrated foods – had the moisture removed
Ambient temperature – normal room temperature - 20°C and 25°C
• To avoid cross contamination – use coloured chopping boards and
knives: raw fish – blue; raw meat – red; fruit and vegetables – green;
cooked meat – yellow
• Food is processed in a variety of ways in the food industry – assembling
food products, application of heat and cold, food preservation and
finishing techniques
• Food preservation is used to prolong the shelf life of products
• Food preservation – freezing, canning, irradiation, AFD, MAP and
dehydration
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Food Ingredients
Properties and functions
Food ingredients have a function within a recipe, some may have several
• Coating – chocolate on biscuits
• Glazing – egg on top of bread
• Emulsifying – egg yolks added to
• Aerating – eggs used in a
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whisked sponge (cake made
lighter by adding air)
Binding ingredients – milk in
scone mixture
Bulking – flour used in pastry
Setting – gelatine used in jelly
Thickening – flour used to
thicken a sauce
Adding flavour – herbs and
spices – to a variety of products
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mayonnaise (stops ingredients
separating out)
Preserving – vinegar used to
preserve onions (last longer)
Shortening – lard or vegetable
fat will give a crumbly texture
Sweetening - honey in cakes
Adding moisture – milk is
added to a batter
Adding texture – nuts in cakes
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Food Ingredients
Heating and nutrition changes
• Starch
• Protein
Dry heat – starch turns to dextrin
Moist heat – starch granules soften
and swell and absorb water and
thicken liquids (gelatinisation)
Denatures (changes) on heating,
then coagulates and sets
• Vitamins A & D (fat soluble)
Not affected by the cooking process
as they are not soluble in water
• Vitamins B & C (water soluble)
Are soluble in water and are
destroyed by heat
• Sugar
When heated sugar dissolves, it
changes from white to golden
(caramelises)
• NSP
• Fats – solid
Melt to a liquid, bubble and can
decompose at high temperatures
when fats give off smoke and
burn
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Softens when it is heated with liquid
• Minerals
Heating has little affect
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Food Ingredients
Cereals
• Cereals are important foods in our diet
• Cereals are used in a variety of products
• The main nutrients – starch, some protein, NSP and some calcium, iron
and B vitamins
Types of cereals and products made from them
Wheat – bread, pasta, pastry, biscuits, pies, cakes
Oats – biscuits, porridge, oatcakes, bread, muesli
Maize – bread, popcorn, sweetcorn, cornflour, polenta
Rye – rye bread, rye crispbread, muesli
Rice – noodles, rice cakes, puddings, ready-meals with rice
Barley – soft drinks, beer, scones
• Some cereals contain gluten which forms the structure of products such as
bread
• Types of flour – wheat, cornflour, potato, rice, arrowroot (tropical root)
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Food Ingredients
Fruit and Vegetables
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We should eat five portions of fruit and vegetables a day
Fruit and vegetables provide us with vitamin C, betacarotenes,
carbohydrates and NSP (dietary fibre)
Vegetables and fruit need careful preparation to avoid loss of
vitamins and minerals
Saving vitamins and minerals:
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Buy good quality and store in a cool, dark place for a short time
The nutrients are found under the surface of the skin, so either peel
thinly or eat with the skin on.
Cook vegetables very quickly in a small amount of water
Leave in large pieces to avoid too much nutrient loss from the
surface of the fruit or vegetable
Try to eat raw fruit and vegetables
Don’t leave them to stand in water – vitamin C & B are dissolved
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Food Ingredients
Meat, poultry and fish
• Meat, poultry and fish are important sources of protein
• Also contain – iron, B group vitamins especially B12
• They are made into a wide variety of products and ready-meals
• Meat is cooked – to kill bacteria, make it tender to eat and improve its
flavour
• Cooking methods – dry – grilling, roasting, baking, frying
• Cooking methods – moist – stewing, boiling, pressure cooking, casseroling
• Cooked meat and raw meat should be stored separately – to avoid crosscontamination
• Poultry – protein, lower in fat and more tender than meat
• Chicken – thoroughly cook to kill off any Salmonella bacteria
• Fish – white, oily and shell
• Fish – good source of protein, B group vitamins, iodine and fluoride
• White fish – low fat. Canned salmon and tuna – good source of calcium
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Food Ingredients
Fats and oils
• Fats and oils contain mainly fat, some contain vitamins and essential fatty
acids
• F at should provide no more than 35% of food energy
• Butter and margarine – 80-82% fat. Used for spreading, baking, shallow
frying, pastry, sauces
• Reduced fat margarine/spread – 60-62% fat. Used for spreading, allin-one cakes, sautéing, short crust pastry, sauces, scones
• Half-fat butter/margarine/spread – 39-41% - Used for spreading,
sautéing, sauces, scones, choux pastry
• Low fat/light spread – less than 40% - spreading
• Other fats used in cooking – lard, suet, dripping
• Margarine is fortified with vitamins A and D
• Genetic modification of oils – used for Soya, maize and oilseed rape
• Use of fats – shortening, flavour, trapping air
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Food Ingredients
Milk, cheese and dairy products
• Milk and dairy products are good sources of calcium, protein, vitamin
B12 and vitamins A and D
• To reduce fat content choose lower fat versions e.g. semi-skimmed and
skimmed milk, low fat yogurts or fromage frais and lower fat cheese
• Soya milk is used by vegans
• Yogurt – milk is heated, cooled and mixed with a culture of bacteria.
Kept at 40-45°C for 3-6 hours. Protein coagulates, the yogurt thickens
• Cheese – coagulating the protein in milk making curds and whey. The
curd is pressed to make hard cheese like Cheddar
• Storage – should be kept in the fridge until the ‘use by date’
• UHT – can be kept at room temperature until opened
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Food Ingredients
Eggs
• Nutritional value – good quality protein, fat, cholesterol, vitamin A,
minerals: iron, phosphorus and calcium
Uses of eggs
• Thickening – coagulation of the protein thickens sauces and custards
• Binding – egg coagulates and sticks the dry ingredients together as they
cook e.g. bean burgers
• Coating – egg and breadcrumbs – the egg coagulates and provides a strong
coating round fish
• Forms a foam – egg white can entrap air when its beaten – meringues
• Emulsifier – will stabilise – fat and sugar in a cake, oil and vinegar in
mayonnaise
• Glaze – during baking – egg turns golden brown
• Salmonella – raw egg may contain this. Many companies use pasteurised
egg. The Lion Quality mark shows that the hens have been vaccinated
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Food Ingredients
Sugar
• Sugar provides energy. Sucrose is made from sugar cane or beet
Types of sugar
• Granulated – used to sweeten drinks, adding to breakfast cereals
• Caster – finer – cakes and biscuits
• Icing – very fine - icings and sweets
• Brown (soft) – gingerbreads and biscuits; Demerara – in coffee
Functions: Sweetness, preservative, changes flavour, adds colour, bulking
agent, speeds up fermentation process e.g. yeast in bread, aids lightness
in cakes
Sugar comes in many forms
Sucrose – also known as hydrolyzed starch, honey, glucose syrup
Maltose – also golden syrup, lactose, brown sugar
Maple syrup – glucose, fructose, fruit juices
Invert sugar – dextrose, treacle
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Cooking Choices
Methods of cooking and transfer of heat
• There is a variety of cooking methods used in food preparation
• Large-scale manufacturers use the same processes but on a large scale.
• Heat application used in the food industry –baking, steaming, roasting,
boiling/blanching/simmering, frying – shallow or deep fat, microwave
cooking, grilling
• Heat application is used: to increase shelf life, to destroy enzymes and
micro-organisms, to soften food to make it edible, to produce the desired
consistency, to improve flavour, to increase the variety of food products
Methods of heat transfer
Conduction – heat is conducted from molecule to molecule in solid and liquid
foods
Convection – heat travels around liquids and air by convection currents. Hot
air rises, so ovens are hotter at the top
Radiation – direct rays of heat from the grill heat the food
Microwaves cause the food molecules to vibrate – creates frictional heat
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Food Ingredients
Raising agents
• Bubbles of gas expand when heated and make a food mixture rise
• Three types of raising agent – air, steam, carbon dioxide gas
Air – introduced: sieving flour, beating (batters), whisking egg white
(meringues), creaming (cakes), rubbing in (pastry, scones), rolling and
folding pastry (flaky, puff)
Steam – water when heated turns to steam, this escapes pushing the mixture
up (Yorkshire pudding, éclairs)
Carbon dioxide gas – this expands when heated and pushes up the mixture
Baking powder: made from acid sodium pyrophosphate, rice flour and sodium
bicarbonate. Reacts with the cake mixture > produces carbon dioxide gas
Bicarbonate of soda: same principle – used in gingerbread
Yeast: fungus which needs warmth, food and liquid to ferment producing
carbon dioxide and alcohol. Most types of bread use yeast
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Food Ingredients
Setting ingredients
• Many food products are set to make them firm and attractive to
eat
• Gelling agents create a smooth, set texture and help to suspend
other foods in a jelly
• Gelatine – made by boiling bones and tissues from animal
carcasses. The collagen in the connective tissue turns to gelatine
when heated slowly in liquid. Sold in powder form and in sheets.
Used for jellies and mousses.
• Pectin – found in the cells of fruit. Mixed with the right proportion
of acid and sugar will form a gel. Used in jellies, jams and
marmalades. When the jam is cool, the gelatine forms a network
which sets and suspends the fruit, sugar and liquid
Agar agar – comes from a type of seaweed, used to set milk and
liquids with low acidity (used by vegetarians and certain religious
groups)
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Food Ingredients
Additives
• The food industry uses specialist ingredients and may use additives in
food products – these are added in small amounts
• ‘E’ – the letter ‘E’ sometimes appears before an additive number. This
shows that the additive has been approved by the European Union
• Preservatives – protects against growth of micro-organisms (salt, sugar,
vinegar, sulphur dioxide
• Colours – improve or change the appearance (caramel (E150)
• Flavours and flavour enhancers – improve or replace those lost in the
cooking process (sugar, saccharin, aspartame, monosodium glutamate)
• Emulsifiers and stabilisers – stops food separating (Lecithin)
• Antioxidants – make foods last longer, stops fatty food going rancid
(vitamin C - ascorbic, vitamin E – tocopherol)
• Other additives – raising agents, anti-caking agents, flour improvers,
thickening agents, nutrients, gelling agents
• Are benefits and limitations for the food manufacturer and consumer
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Food Ingredients
Standard Components foods
• Components - used in the food industry to save preparation time and
costs
• Components help to produce a product that looks and tastes the same
every time
• A component is used to describe an individual part of a product
• Pre-manufactured standard components are ready prepared ingredients
or part of a product e.g. pizza bases, frozen pastry, pre-prepared pie
fillings, ready grated cheese, cooked egg, fondant icing
Benefits of using these in the food industry
• Cheaper than producing their own * May not have the equipment to
produce their own * Maintains consistency of the end product * Saves time
by reducing some of the manufacturing process * Reduces costs * Keeps
the assembly process as simple as possible
Limitations – Special storage conditions may be needed * Could be expensive
* Supplier may be produce an inconsistent product * Reliant on supplier to
deliver and to produce product in hygienic conditions
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Food Ingredients
Preservation part 1
Benefits of preserving food
• Prevents micro-organisms (bacteria, moulds, yeasts) from multiplying
• Enzymes – cause deterioration. These must be destroyed to improve the
keeping quality of the food
• Increased shelf life of a product
• Increases the range of foods available
• Convenience – preserved food lasts longer which means fewer trips to the
shops
• Allows the consumer to buy products out of season
• Principle methods of preservation – dehydration, freezing, irradiation and
chemical
Methods of preservation
Dehydration – removal of water from a food
AFD, accelerated freeze-drying – food is frozen and dried
Canning – food and liquid in a can, sealed then heated at high temperature
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Food Ingredients
Preservation part 2
MAP, modified atmosphere packaging – adds carbon dioxide, nitrogen or
oxygen
Blast freezing – super quick freezing
Cook-frozen – food is cooked, fast frozen then stored below 0°C
Blast chilling – food is chilled quickly by blasting cold air
Cook-chill – food cooked, fast chilled in 1 ½ hours, then stored at 0°-3°C
Vacuum packaging – air is removed from the product’s packaging
Irradiation – rays are passed from a radioactive beam through the food which
reduces the number of micro-organisms
Other methods – Sodium nitrate (bacon manufacture), Salt (meat, fish),
Sugar (fruits), Vinegar (onions, chutney), Alcohol (fruit), Smoke (fish,
cheese, meats)
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Food Ingredients
Smart foods
• Smart or modern foods - respond to differences in temperature or light
and change in some way. These come about by the invention of new or
improved processes
Examples of smart or modern foods
• Genetically modified foods
• Modified starch
• Meat alternatives e.g. textured vegetable protein (TVP), myco-protein
• Anti-oxidants
• Probiotic yogurts/drinks
• Modified enzymes e.g. chymosin
• Synthetic flavours
Modified starch has been altered to perform additional functions e.g.
pre-gelatinised starch – thickens instant desserts without heat * boiling water
can be added to gravy granules without it going lumpy * prevents ‘drip’
after a product has been defrosted * improves ‘mouth-feel’
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Food production
Systems and control
• A system is a collection of
elements, which work together to
perform a task
• Systems enable products to be
made: safely, hygienically, costeffectively, efficiently,
consistently, to an expected
quality
• Systems are put in place in the
food industry to control the
production of food products
• A system has three main parts:
input, process and output
• A fourth element in a system is
called feedback
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Elements of feedback
• Weight and mix control
• Trading standards regulations
• Environmental health
• Temperature control
• Thermostatic and sensor control
• Microbiological feedback
• Sensory analysis feedback
• Shelf life and storage time
control
• Consumer feedback
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Food production
HACCP (Hazard Analysis Critical Control Points)
• Food premises – where food is prepared, stored or sold
• Hazard – anything that could harm the consumer
Some examples of hazards:
Physical e.g. glass in foods
Microbiological e.g. bacteria in foods
Chemical e.g. cleaning materials entering the product
Potential hazards are identified using a system known as HACCP
• Quality assurance – system set up before product is made – identifies the
procedures for making a safe, quality product
• Quality control – steps in the making process to ensure the product meets
the standards specified. Any faulty products are removed
• Food manufacturers and retailers need to make sure that all necessary
controls are put in place.
Controls – storage & cooking temperatures, weight, size, shape of product,
pests, metal detection, machinery working correctly, food hygiene
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Food production
Jobs in the food industry
• General manager – in charge of everything
• Product development technologist – specification details are correctly
produced and followed
• Production manager – planning the time for production
• Quality control manager – sets up quality assurance procedures
• Health and safety manager – makes sure people are trained, follow
hygienic and safe procedures. Sets up HACCP system. Equipment safety
• Product buyer – finds where to buy ingredients for products, costs and
availability
• Food technologist – equipment needed, the science of the ingredients,
legal implications, responsible for production methods
• Packaging technologist – types of packaging to use
• Nutritionists – examine nutritional content
• Production line supervisor – checks people are working efficiently and
the machinery is operating effectively
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Food Production
Product analysis
• Product analysis is looking at all aspects of a product in detail
• The product development team carry out product analysis on existing
products
• Product analysis is carried out to:
 Investigate how a product is made
 Analyse the types and amounts of ingredients used
 Gain ideas for new product development
 Compare differences between brands
 Check that a product matches its specification
• Considerations when carrying out product analysis
 Target market
 Purpose of the product – how and when would the product be used?
 Ingredients and additives – what are their functions?
 Manufacturing processes used
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