Cooking and Cooking Procedures PDF

Cooking and Cooking Procedures Cooking is the act of preparing food for eating/consumption with the use of heat or ways in which food is transformed by applying heat to it It is an important step in meeting the nutritional needs of the family. Foods are enjoyed only when cooked in different...

Cooking and Cooking Procedures Cooking is the act of preparing food for eating/consumption with the use of heat or ways in which food is transformed by applying heat to it It is an important step in meeting the nutritional needs of the family. Foods are enjoyed only when cooked in different ways by subjecting it to various heat treatment. It is not enough that food be nutritious, it has to be pleasing in appearance and taste for it to be eaten. Good food preparation is a prerequisite for food acceptance. Therefore it is important to prepare and serve food which is nutritious and acceptable to the family. Cooking can be defined as the preparation of food to bring about both physical and chemical changes such as breaking down of connective tissue in meat and softening of the cellulose in plants. Cooking and Cooking Procedures Most foods are only acceptable when they are cooked except for some fruits and vegetables that can be eaten raw. A food item goes through various stages of preparation before it is cooked. The art and science of food preparation is based on the understanding of physical and chemical changes that occur during food preparation. Hence, cooking is the process of subjecting foods to the actions of heat. The methods of heat transfer during cooking are: i. Radiation: transfer of heat in air medium e.g. baking and grilling. ii. Convection: transfer of heat in liquid medium e.g. steaming and boiling. iii. Conduction: transfer of heat in solid medium e.g. transfer of heat from source to the cooking pots and pans; Purposes of Cooking Foods are cooked for the following reasons: To destroy or inactivate pathogenic (harmful) microorganisms present in the food, thereby making it safe for consumption. Preserve the food from natural and microbiological decay. Microorganisms that cause food deterioration are destroyed. To destroy natural toxins in foods. Cooking improves the digestibility of foods To reduce bulk e.g. green leafy vegetables reduces considerably when cooked so that more of it can be eaten. Cooking helps to enhance the taste and flavour of food making it more appetizing and palatable. New flavors are developed which stimulate the appetite and flow of digestive juices. It gives variety to the diet and make meals more interesting e.g. yam can be boiled, fried or roasted etc. It makes food easier to eat/making it soft, easy to swallow e.g. cooking tenderizes meat and makes it easier to chew and swallow. Cooking enhances general acceptability of food. To preserve food for later use thereby preventing wastage. Cooking Procedures Choice of Cooking Method The preparation of many foods involves the application of heat in a certain way. Various methods of cooking can be employed in the preparation of a particular meal. However, lot of factors must be considered before choosing a cooking method. These are i. The food to be cooked ii. The facilities available: fuel, equipment, storage etc. iii. The needs of the individuals such as the food being prepared, state of health, age, preference etc. iv. The time available v. The amount of preparation required vi. Individual preference Methods of Cooking Food must be cooked properly before they are eaten. Different foods require different cooking methods. Methods of cooking can be classified into four and each has its own advantages and disadvantage according to how heat is applied; i. Moist Methods where heat is applied through the medium of a liquid e.g. boiling, steaming, simmering, stewing, poaching, braising etc. ii. Dry methods: heat is applied directly to food e.g. baking, roasting, grilling, barbecuing etc. iii. Frying methods: heat is applied through the medium of fats or oils e.g. deep frying and shallow frying. iv. Microwave method: this uses the heat generated by electric magnetic waves. Cooking Methods Moist method of cooking a. Boiling: Is the cooking of foods in a liquid at boiling point (1000). The liquid could be water, milk, broth etc. It is a common method of cooking. Foods cooked by boiling include yam, rice, eggs, potatoes, meat, fish etc. The various method of boiling are: i. Add water to the food and boil the food so that the stock is strained from the food e.g. yam, plantain ii. Allow the food to absorb the water used in cooking e.g. beans, porrigdes iii. Mix the food with water before cooking as in the preparation of Ogi, yam flour, semovita Advantages of boiling 1. It is suitable for preparing different types of food. 2. This method is appropriate for large scale catering 3. It is a simple, quick and easy method of cooking 4. Boiled foods are easy to digest 5. It does not require constant attention 6. Boiled foods are suitable for all health conditions Disadvantages of boiling 1. The loss of heat-labile nutrient is increased e.g. the water soluble vitamins and some minerals may leach into the boiling water. 2. The flavor and color of the food can be affected by boiling unless garnished or served with some soup/stew 3. Food may break into pieces during cooking Cooking Methods b. Simmering: This is the cooking of food in a liquid at a temperature just below the boiling point (820). Examples of foods that can be simmered include fish, poultry, potatoes, vegetables. Simmering is preferred over boiling because it is more gentle and will usually not physically damage the food and foods will cook as quickly as they do when boiled. c. Poaching: Poaching is cooking of food in water at just below the temperature used for simmering. It is a very gentle method of cooking. In poaching, the right quantity of water should be added to the food and the heat applied slowly until the food is cooked. Foods prepared by this method includes fish, egg, chicken etc. Poaching is used to prepare delicate foods like fish and eggs which could break apart under the more vigorous action of boiling. Advantages i. Poached foods are easy to digest hence suitable for infants and people with weak digestive system. ii. Maintains the maximum food value. Disadvantages i. It needs constant attention. ii. Suitable for only few types of food. Cooking Methods d. Steaming: This is the method of cooking with water vapor i.e. steam from boiling water. Food that is steamed does not come into direct contact with the water but is cooked in the steam rising from the boiling water. Cooked vegetables are at their best when steamed because texture, color, taste and nutrient are retained. E.g. beans/corn puddings, egg custard. Advantages i. Loss of nutrients by leaching is reduced as the food does not come into direct contact with the water. It is a healthy cooking method as nutrients are conserved. ii. There is less risk of over cooking. iii. Steamed foods are lighter and easy to digest hence suitable for preparing food for infants, invalids, convalescents, elderly and people with weak digestive systems. iv. It is an economical way of cooking as more than one food may be cooked in one pot. Disadvantages i. Food takes long time to cook and so consume more fuel. In addition to the lengthy process involved. ii. The heat destruction of Vitamin C is likely to occur due to long cooking time. iii. Limited number of foods/not many types of food can be cooked by this method. Cooking Methods e. Stewing: Is a long and slow method of cooking food in a small quantity of liquid at a temperature below boiling point. The temperature for stewing is the same as that of simmering. The liquid in which the food is cooked is normally served with the food. Stewing refers to simmering ingredients in a small to moderate amount of liquid which often becomes a sauce as the food cooks. Stews often taste better the day after the initial preparations because the overnight rest deepens the flavor. Advantages i. Nutrient losses are reduced, flavor retained as the liquid is served with the meal. ii. It tenderizes tough foods such as meat/poultry and makes it easy to digest. iii. Large variety of stews can be prepared. Disadvantages i. It is a long and slow cooking method ii. Requires constant attention to ensure food does not get burnt. iii. Sometimes the Vitamin C in food are destroyed due to prolonged cooking time. Cooking Methods f. Braising: Braising is similar to stewing in that food is simmered in a small amount of liquid in a covered pot or casserole. It is a combination of stewing and roasting. Braised food can be greasy if excess fat is used. It is a method suitable for tougher cuts of meat e.g. meat, poultry etc. Braising helps in the retention of flavor and nutritional value of foods. Dry Methods of Cooking a) Baking: This is heating of food by hot air dry heat in an oven. It is cooking quickly in a closed pre-heated oven or an enclosed space by direct radiation. The average baking temperature is 1770C although temperature may range from 1490C to 2190C. Dry heat is applied and the food is surrounded by a current of hot air either in an enclosed space or an oven (gas or electric), kerosene tin, drum oven, cupboard oven or in a heavy pot with lid. The heated air then cooks the food. It should be noted that the source of heat in an oven will affect the way in which baking tins should be placed and the evenness of baked products. Advantages: i. Baked foods are usually attractive and appetizing. ii. There is no loss of soluble nutrients. iii. Large variety of sweet foods can be produced. iv. It is economical on fuel many foods can be baked at once. Disadvantages i. It requires constant attention otherwise the food may be burnt. ii. Oven must always be heated to the required temperature before the food is placed. iii. It requires careful temperature control and skill iv. It is expensive to heat the oven as it waste fuel to bake only one food. Dry Methods of Cooking b. Roasting: This is cooking by radiated heat on a spit or oven on a low temperature. It is cooking in dry heat in an oven. Roasting is similar baking in that dry heat is applied in each case. The food is surrounded by a current of hot air. When roasting, little amount of fat is used to prevent them from drying up. Advantages: i. Roasting tenderizes food ii. Roasted foods are tasty, retains flavor and its food value. iii. Appearance of food is attractive iv. It reduces weight loss Disadvantages: i. It needs constant attention ii. Roasted foods shrinks as a result of moisture loss. iii. High temperature may result in toughening of protein thereby reducing digestibility. iv. Tough foods cannot be cooked properly by roasting. v. It takes longer time at lower temperature Dry Methods of Cooking c. Grilling: Is the cooking of food by radiation using gas or electric grill. It is a fast method of cooking in that food is cooked above an intense heat source. It can be over an open charcoal fire in a coal pot, over a mud stove or heated grill. To prepare food with this method, the grill must be very hot. The food is brushed with fat and grilled for few minutes on both sides to seal in the juices. The surface of the grilled is sealed so that the flavor is well developed. The food should be turned frequently to ensure even cooking. Advantages: i. Is a quick method of cooking in which grilled foods are tasty and easily digested. ii. There is no loss of soluble nutrients as there is maximum retention of nutrient because of speed of cooking. iii. Grilled foods are useful for people on low fat diet hence it is a healthy cooking method. Disadvantages: i. It requires careful timing to prevent over cooking. ii. It needs constant attention. Microwave Method of Cooking Microwave cookery is a method of cooking and reheating food using a high frequency power in a microwave oven powered by electricity. The vibrations of the microwaves activate the water molecules and particles of food and agitate them causing heat by friction which cooks or re-heat the food. Microwave cookery can be used for cooking raw food, re-heating cooked food and de-frosting frozen foods. Advantages i. It is a quick method of cooking. ii. There is less heat destruction of nutrients as cooking time is short. iii. Frozen foods can be defrosted easily. Disadvantages i. It is not suitable for cooking all type of foods. ii. The limited oven space restricts use to small quantities of food at a time. iii. Only microwave safe plates or containers can be used for cooking. iv. Continuous use of microwave could be deleterious to health Frying Method of Cooking Frying is heating foods in fat. It is quick, convenient and popular method of cooking which involves high temperature. Solid fats or oils are used in this method of cooking, transfer heat, act as lubricant to prevent sticking, contribute to flavor, browning and crisp texture. It is a dry heat preparation because pure fat contains no water. There are two types of frying: a) Shallow frying: This is cooking of food in small quantity of preheated fat or oil in a frying pan. Foods are cooked in a heated fat covering the bottom of the pan in which enough fat is used to prevent the food from sticking to the frying pan. The food has to be turned at regular intervals to ensure even cooking and heat penetration. b) Deep frying: In this method, enough oil is used to cover the food completely so that it is immersed in the oil. It involves cooking of food in large quantity of pre-heated oil or fat. Not much turning of the food is required since all sides of the food will cook evenly in the deep oil. Foods may be coated with plain flour, seasoned with salt, eggs or breadcrumbs to protect its shape, seal in nutrients and prevent it from breaking up. These coating make the food crisp and appetizing after frying. Importance of coating in deep frying: i. It protect the surface of the food from intense heat thereby modifying rapid penetration of heat into the food. ii. It protect the shape of the food and prevents it from breaking up into pieces. iii. It seal in the nutrients i.e. it prevents escape of nutrients into the oil. iv. It makes the food crisp and appetizing. v. It can bring about an increase in the shelf life of the fried foods. Frying Method of Cooking Stages in heating oil for deep frying a. Melting Stage: The fat melts from solid to liquid b. Bubbling Stage: The water in the fat boils out giving a bubbling sound. c. Frying Stage: The bubbling sound ceases and a blue haze of smoke begins to rise on top of the oil. Some oils do not give off a blue haze of smoke, therefore a piece of the food may be used to test the temperature. d. Decomposition Stage: If the oil gets heated beyond the frying temperature, dark, acrid fumes are produced which irritate the throat. However, fats have different melting points and temperature at which they decompose. Advantages i. It is a quick method of cooking ii. It enhances the appearance of food making it more appetizing. iii. Frying impacts special flavor and texture to the food making it tender or crunchy. iv. The high temperature used destroys pathogens present on the food. Disadvantages 1. Fried foods are not easily digested. 2. It requires careful and constant attention 3. There is an increase in the energy value of fried food as some of the fat are absorbed by the fried foods thereby increasing the fat content of the food.