2FACTORS TO BE CONSIDERED WHEN PLANNING A MEAL Nutrition- balanced meal.Follow healthy eating guidelines.Requirements of age-group being served.Special diets e.g. coeliac.Variety- tastes, colour, texture, cooking methods.Time available.Knowledge & skill.Budget.Availability of ingredients.Availability of equipment.
3CHANGES THAT HAPPEN DURING FOOD PREPARATION Physical ChangesIncrease in size e.g. soaking dried food.Thickening e.g. whipping cream.Loss of nutritive value e.g. water - soluble vitamins dissolve into water.Tenderising e.g. meat is tenderised by beating, mincing.Chemical changesColour change e.g. enzymatic browning.Nutrient loss e.g. enzyme oxidase destroys vitamin C.Tenderising e.g. proteolytic enzymes tenderise meat fibres.Increase in size e.g. yeast dough expands as enzymes make CO2 .
4CHANGES THAT HAPPEN DURING COOKING OF FOOD Physical ChangesTexture changes e.g. cell walls soften in vegetables.Bacteria killed.Nutrient loss e.g. vitamins & minerals dissolve into cooking liquid.Food solidifies e.g. egg protein coagulates.Food thickens e.g. gelatinisation of starch.Shrinkage - protein coagulates & shrinks e.g. meat.Chemical ChangesMaillard reaction – when amino acids & carbohydrates are heated together, the food turns brown.Caramelisation - sugar heated above dissolving point turns brown e.g. toffee.Dextrinisation - long starch chains break into shorter chains called dextrins & a brown colour develops e.g. toasting bread.
5REASONS FOR COOKING FOOD To destroy pathogenic bacteria making food safer.To destroy enzymes and prevent food spoilage.To make food palatable & digestible e.g. starchy foods like potatoes.To improve appearance e.g. meat.To develop flavour e.g. meat extractives released.To stimulate digestive juices - sight & smells of cooked food.To destroy natural toxins e.g. red kidney beans.To combine ingredients and create new flavours.
6UNDERLYING PRINCIPLES OF COOKING FOOD Conduction - Transfer of heat from one molecule to another by vibration of molecules. E.g. heat passing from the cooker hob through the base of the saucepan.Convection - Molecules near heat source become hot, less dense and rise up. This allows cold molecules to take their place. This sets up convection currents and heat is spread e.g. simmering stews.Radiation - Heat passes in straight rays, from the source, to the first solid object they reach, without heating air in between e.g. grilling burgers.Most cooking methods involve one or more of these principles.
9CHOOSING A COOKING METHOD Ingredients available e.g. stewing beef or sirloin steak.Experience of cook.Time available.Equipment available.Desired result e.g. crispy, brown, moist.Fuel economy.Retention of nutrients.
10Advantages & Disadvantages BOILING / SIMMERINGDefinitionGuidelinesSuitable foodsAdvantages & DisadvantagesCooking by convection & conduction in 100ºC in covered saucepan on the hob.Simmering - 90 ºC100 all times.Vegetables - small amount of liquid.Use cooking liquid – soups, sauces.Cook food for shortest possible time.Meat - bacon, mutton.Eggs.Pasta.Rice.Veg.Needs little attention.Clean.Food stays moist.Digestible.Less greasy.Little preparation.Little flavour added.Loss of nutrients.Lacks texture.
11Advantages & Disadvantages POACHINGDefinitionGuidelinesSuitable foodsAdvantages & DisadvantagesCooking by convection & conduction in 85ºC in covered container on hob or in oven.85 all times.Water barely moving, not bubbling.Use for delicate foods that need gentle cooking.Fish.De-shelled eggs.Fruit.Clean.Food stays moist.Digestible.Less greasy.Little flavour added.Loss of nutrients.Lacks texture.Slow.Needs attention.
12Advantages & Disadvantages BRAISINGDefinitionGuidelinesSuitable foodsAdvantages & DisadvantagesCooking meat in a small amount of stock, on a layer of vegetables (mirepoix). Meat is in a covered saucepan on the hob.Combination of steaming and stewing.Use only enough stock to cover vegetables.Food can be browned under grill before serving.Root vegetablesChicken.Offal.Tougher cuts of meat.Little attention needed.Food stays moist.Complete meal in one pot – saves fuel & wash-up.Less nutrient loss.Digestible.A lot of prep.Slow.Lacks texture.
13Advantages & Disadvantages STEWINGDefinitionGuidelinesSuitable foodsAdvantages & DisadvantagesSlowly cooking food in a little liquid, by conduction & convection, using gentle heat (80 ºC - 90 ºC), in a covered container, on hob or in oven.Bring to boil & then reduce heat.Temperature of 80 ºC -90 ºC.Keep covered.Use pressure cooker to reduce time.Tough cuts of meat/fish.Veg.FruitLittle attention needed.Food stays moist.Complete meal in one pot – saves fuel & wash-up.Less nutrient loss.Digestible.A lot of prep.Slow.Lacks texture
14Advantages & Disadvantages STEAMINGDefinitionGuidelinesSuitable foodsAdvantages & DisadvantagesCooking food slowly in steam rising from boiling water.Food can be steamed:a. Between two plates.b. In a covered bowl in a saucepan of boiling water.c. In a steamer over boiling water.d. On a trivet in a pressure cooker.A tightly fitting lid prevents evaporation.Water boiling before & during cooking.Food must not touch liquid.Thin pieces of chicken and fish.Steamed puddings, e.g. canary, Christmas, chocolate.Vegetables.No loss of nutrients.Clean.Food stays moist.Digestible.Not greasy.Little flavour added.Lacks texture.Slow.Not suitable for large pieces of food.
15Advantages & Disadvantages BAKINGDefinitionGuidelinesSuitable foodsAdvantages & DisadvantagesDry method of cooking food by convection currents in the oven.Pre-heat oven.Steam made in the oven stops food drying, tinfoil & greaseproof paper also used.Avoid opening oven door.Bread. Cakes. Biscuits. Pastries.Vegetables e.g. potatoes,tomatoes, peppers.Fruit e.g. Apples.Puddings, apple crumble.Attractive appearance.Doesn’t add fat.Little loss of nutrients.Dries food.
16Advantages & Disadvantages GRILLINGDefinitionGuidelinesSuitable foodsAdvantages & DisadvantagesFast method of cooking food by radiant heat under a grill.Pre-heat grill.Seal surface of the food with high heat, preventing nutrient loss.Use tongs to turn food.Thin pieces of food only.Don’t salt food before grilling.Oil grill grid to prevent sticking.Meat - chops, steaks, burgers, rashers.Vegetables - tomatoes.Fish fillets.Fast.Little loss of nutrients.Reduces fat content.Attractive appearance & taste.Constant attention needed.Dries food.Spatters grease.Unsuitable for tough or thick cuts of meat.
17Advantages & Disadvantages BARBECUINGDefinitionGuidelinesSuitable foodsAdvantages & DisadvantagesCooking food by radiant heat on a grid over glowing charcoal.Pre-heat barbecue.Seal surface with high heat, preventing nutrient loss.Use tongs to turn food.Thin pieces of food only.Don’t salt food before barbecuing.Oil barbecue grid to prevent sticking.Meat, chops, steaks, burgers, rashers.Vegetablese.g.tomatoesFish fillets.FastLittle loss of nutrients.Reduces fat content.Attractive appearance & taste.Constant attention.Dries food.Spatters grease.
18Advantages & Disadvantages ROASTINGDefinitionGuidelinesSuitable foodsAdvantages & DisadvantagesCooking food in a little fat in (a) a roasting tin in the oven, (b) a saucepan on the hob (pot roasting), (c) on a spit, under a grill or in an oven (spit roasting).Pre-heat oven.Cooking time depends on weight.Baste every 30 minutes.Use cooking juices for gravy.Quick roasting (tender cuts) ºC for 20 mins, 190 ºC for remainder.Slow Roasting (less tender cuts) ºC for all the cooking time.Meat –beef,lamb,pork.Poultry.Vegetables e.g. potatoesVegetables & meat cooked together.Cooking liquid used as gravy.Attractive appearance & taste.Not much prep.Spatters grease.Not suitable for tough cuts.Greasy.Shrinkage occurs.Adds fat.
19Advantages & Disadvantages FRYINGDefinitionGuidelinesSuitable foodsAdvantages & DisadvantagesDry – cooking food by conduction in frying pan on the hob.Shallow – cooking food in hot fat.Deep – cooking food immersed in hot fat.Pre-heat oil.Use tongs for turning.Drain before serving.Coating food:Protects surface.Texture.Flavour.Appearance.Meat - thin pieces e.g. rashers, chops, burgers, sausages.Fish - thin pieces e.g. steaks, cutlets, fillets.Eggs.Vegetables.Doughnuts.Quick.Attractive taste & appearance.Constant attention.Spatters grease.Not suitable for tough meats or large cuts.Not suitable when cooking for large numbers.Greasy.Indigestible
20Definition & principle PRESSURE COOKINGDefinition & principleStructureGuidelinesSuitable foodsFast moist method of cooking high temps. in a pressure cooker.Used for boiling, stewing & steaming.Water under increased pressure higher temp. Pressure increased inside pressure cooker by not letting steam escape. As a result, water 122ºC. Food cooks in 1/3 of normal time.Heavy gauge saucepan. Locking lid.Rubber gasket seals lid.Trivet.Separator basket.Vent on lid.Safety valve.Follow instructions.Never overfill.Build up steam before applying weight.Time very accurately.Reduce pressure before opening-(a) Stand for 15 room temp.(b) Under cold running water.Stocks & soups.Stews.Vegetables e.g. potatoes.Jam.Christmas pudding.Bottling
21Temperature at the start. MICROWAVEPrincipleGuidelinesSuitable dishesElectro- magnetic waves penetrate the food to a certain depth and cause the molecules to vibrate very rapidly. This causes intense heat. The remainder of the food cooks by conduction.Time carefully.Timing is affected by:Composition.Thickness.Density.Temperature at the start.Amount of food.Cover food, keep moist, cook faster.Turn or stir.Pierce skins.Arrange in circle, thickest bit outward.No metal or foil.Allow standing time.Defrosting.Reheating.Cooking.Melting chocolate.Heating liquid.Unsuitable dishesPastry.Meringue.
22EFFECTS OF COOKING ON FOOD Moist methodsLoss of vitamins and minerals into cooking liquid.Cellulose softens.Collagen changes to gelatine.Flavours mix and develop.Dry MethodsVitamins B & C lost due to high temperatures.Grilling causes loss of fat.Shrinkage - meat juices squeezed out - loss of nutrients.Food becomes crispy.Loss of fat causes loss of flavour.Cooking smells are developed.
23EFFECTS OF COOKING ON FOOD Frying MethodsGenerally adds fat.Coating adds nutrients.Food becomes greasier and harder to digest.Adds flavour.Microwave CookingQuick cooking helps retain nutrients.Food stays soft and moist.Food does not brown unless the microwave has a grill also.