Presentation on theme: "Food Studies Methods of Cookery and application in the preparation of meals."— Presentation transcript:
Food Studies Methods of Cookery and application in the preparation of meals
Why we cook foods?? Heat affects the food physical and chemical properties. Develops the flavour of food by releasing volatile flavours during the cooking, some intensify and others are spoiled (if food is overcooked) this create the aroma which make us identify ingredients. Aroma stimulates our appetite and make us feel hungry. Heat change the colour of foods and improve the texture of foods but too much heat spoiled the ingredients. Heat softens the fibres of some foods, making tender and easier to eat (cellulose in fruits, connective tissue in meat cuts) Heat make some foods easier to digest because breaks down the structures in the foods. Heat destroy fungi, moulds and bacteria in food making safer to eat. Cooking make food more palatable, by combination new flavours and textures can be created so this increase the variety of foods and any bland ingredient could turn into a more appetising one.
Did you know?? Historical evidence suggest that the cooking of food dates back to approximately years ago. The extinct Homo Erectus “Peking man” may have used the roasting method for meat. Cooking methods and techniques have been adapted but didn’t change much from its origins.
How food is cooked?? Conduction: Heat is conducted from molecule to molecule in liquids or solids. The source of the heat is gas, electric or solid fuel cooker. Metals conduct heat easily and quicker rather than wood or plastic. Food is place on a tool which conduct heat from the source and with constant heat the food is cooked.
How food is cooked?? Convection: Heat moves around in liquids and air by convection, convection currents move the hot air to the top and push the cold air to the bottom continually. When this process is done in liquids uses a combination of conduction, convection heat currents and mixing. As the molecules absorb energy they heat up and raise help by the current, sinking again when they cool off.
How food is cooked?? Radiation: Radiation heat is the transfer of heat by waves, this could be by direct heat or by electromagnetic waves. Heat rays pass directly from the source to any object in their path, this waves vary in length and frequency. When the waves fall on food they cause the molecules in food to vibrate, and the food is heated and subsequently cooked.
How food is cooked?? Radiation types: Visible red: there are short radiant waves emitted from the elements of a griller or BBQ. Food does not come in contact with the heat source and waves are absorb by the food surface and then cooked. Infra-red: there are longer waves, food is placed at a short distance of the heat source (eg. A toaster)
How food is cooked?? Microwave radiation: the longest waves, also the microwaves generates heat and the waves penetrate food. The heart of the microwave is the magnetron which produce the electromagnetic waves which consequently bounce inside the oven and cooked the food. We will discuss this method later.
Activity 1 Individually take a hand note and respond the scenarios.
Methods of Cookery Dry methods: use of high temp. and heat is transferred to the surface by radiation or convection, these include: Roasting Baking Grilling Frying Moist methods: temperatures are lower than dry methods and heat is transferred by convection currents in liquids, the heat from the liquid penetrates the food and cook by conduction, these include: Boiling Poaching Steaming Stewing Braising
Methods of Cookery DRY Roasting: Heat is transferred to the food surface and slowly conduct heat to the centre of the food, thereby cooking it. When ovens have fan (fan forced function) decrease the cooking time of food. Usually used with prime cuts. Baking: Is cooking in an oven, this method mainly uses a convection heat transfer but with new ovens functions you can use the baking method with extra functions. Steam given off during baking prevents food becoming too dry. Some foods require heat for long time and others for short periods. Grilling: is a quick and flavoursome method, the food cooks by radiant heat under or over grill plates. Grill foods can not be re-heated without drying out the food.
Methods of Cookery DRY Frying: is a quick method which uses hot fat or oil to seal food and develop a crisp exterior. Dry frying: uses food with excess fat so to keep the hotplate or pan grease. (sausages, crepes, omelettes, etc). Deep frying: food is submerged totally by oil at a temperature twice of boiling water, is not a healthy method for food preparation. Stir frying: small quantity of oil, food is heated and lifted continuously to seal flavours and cook in a short period of time. Shallow frying: small quantity of oil is use to cover the base of a pan, the oil brings the uneven surface of the food in contact with the heat and food is cooked. Sautéing (brown all sides of the food) Searing (high temp. to brown sides of meat and seal juices) Sweating (slow frying of foods to allow them soften before browning)
Methods of Cookery MOIST Boiling: Is cooking food in liquids at a constant 100 C. This method produce a rapid bubbling all over the surface of the pan and evaporation of the liquids as a steam. All the surface of the foods come into contact with the liquid and heat is transferred to the foods quickly and efficiently. Poaching: Is a fast method of cooking of delicate foods at a low temperature (85-90 C), the amount of liquid needs to be small and foods can be partially or complete covered in the liquids. Steaming : Is cooking food in steam from boiling water, the food must not came into contact with the water but the steam must be able to circulate free around the foods. This method prevent food from drying out.
Methods of Cookery MOIST Stewing: Is a slow, gentle and simmering process to cook foods in a liquid which is reduced or thickened and then served with the cook items. This liquid should be in a small amount. This method is ideal for tougher or cheap meat cuts. Braising: Is a long, slow method for cooking lean meats in the oven. It combines frying (searing) method, which will brown (give colour) the ingredients, and stewing with liquids into the same heat proof container. For this method to work successfully the container or dish needs to be seal with a lid or foil.
Activity 2 Take a Activity 2 worksheet. Find your kitchen station partner, take a laptop computer by each group and respond the questions. You will find all the information in the websites provided. g/mem_food_cooking.htm 0p1.pdf html