COOKING RULES AND PRESERVATION OF NUTRIENTS.





COOKING RULES AND PRESERVATION OF NUTRIENTS.
Principles of healthy cooking :-
 To begin cooking for good health,we have to revise the way we think of meals.
  THE BASIC PRINCIPLES OF HEALTHY COOKING ARE:-
1.       Select ingridents with care :-
v  Select to include a large variety of ingridents.
v  Select high quality ingredents .
v  Use fresh seasonal produce in menu planning when seasonable.
2.       Store and prepare all food with the aim of preserving their best possible:-
v  Control temperature carefully in receiving storage preparation and service.
v  Select fundamental cooking techniques properly to ensure quality finished products.
3.       Manage the amount of fat used both as an ingredient of as part of a cooking technique:-
v  Use vegetables oil whenever possible and reduce the use of animal fats.
v  Select lean animal products.
v  Explore non traditional low fat ingredients and methods.
4.       Serve appropriate portions of foods:-
v  Monitor overall menu balance.
v  Size portions to reflect the recommendations of the good guide pyramids.
5.       Offers a variety of beverages both alcoholic and non alcoholic that complemen the good food menu :
6.       Use salt with care and purpose :
v  Explore a variety of seasonings,preparation methods and cooking techniques to reduce reliance on salt.
v  Emphasize clean,distinct assertive flavours.
v  Use higher sodium ingredients sparingly to add flavor
v  Incorporate contrmporary saucs such as juice to increase flavor.

METHODS OF COOKING :-
  Heat is transferred to the food during cooking by conduction,convection,radiation or microwave energy.
Cooking methods :
1.       Moist
v  Boiling
v  Stewing
v  Pressure cooking
v  Poaching
v  Staming
v  Blanching
2.       Dry method
v  Roasting
v  Toasting
v  Grilling
v  Baking
v  Sauteing
v  Frying
3.       Combination of moist and dry :
v  Braising
v  Microwave cooking
v  Solar cooking
MOIST HEAT METHODS
1.       BOILING :
Boiling is a method of cooking foods by just immersing then in water at 100 degree and maintaining the water at that temperature till the food is tender . rice ,egg,dhal,meal,roots and tubers are cooked boiling.
Merits :-
v  Simple method does not require special skill and equipment
v  Uniform cooking can be achieved.
             Demerits  :-
v  Continuous excessive boiling leads to damage in the structure and texture of food.
v  Loss of heat labil nutrients such as B and C vitamins if the water is disordered.
v  Time consuming boiling takes more time to cook food and fuel may be wasted.
v  Loss of colour-waste soluble pigments may be lost.
2.       STEWING :-
It refers to the simmering of food in a pan of with a tight fitting lid using small quantities of liquid to cover only half the food . this is a slow method of cooking. The liquid is brought to boiling point and the heat is reduced tobmaintain simmering temperatures.the foodbabove the liquid is cooked by the steam generated within the pan.apple,meat along with roots, veg and legumes are usually stewed.
Merits :-
1.       Loss of nutrient is avoided as water used for cooking is not discarded
2.       Flavor is retained
          Demerits : -
           The process is time consuming and there is wastage of fuel.
3.       STEAMING :-
It is a method of cooking food in steam generated from vigoursly boiling water in a pan .the food to be steamed is placed in a container and is not in direct contact with the water or liquid.idly custard and idiappam are made by steaming vegetables can also be steamed.
Merits :
1.       Less chance of burning and scorching .
2.       Texture of food is better as it becomes light and fluffy.e.g:- idli .
3.       Cooking time is less and fuel wastage is less.
4.       Steamed foods like idli and idiappam contain less fat and are easily digested and are good for children,aged and for therapeutic diets.
5.       Nutrients loss is minimized.
                       Demerits  :-
v  Steaming equipments is required.
v  This method is limited to the preparation of selected foods.
4.       PRESSURE COOKING :-
When steam under pressure is used the method is known as pressure cooking and the equipment used is the pressure cooker. In this method the temperature of boiling water can be raised above 100 degree C. rice ,dhal,meat roots, and tubes are usually pressure cooked.
Merits :-
v  Cooking time is less composed to other methods.
v  Nutrients and flavor loss is minimized
v  Conserves fuel and time as different items can be cooked at the same time.
v  Less chance for burning and scorching
v  Constant attention is not necessary .
Demerits :-
v  The initial investment may not be affordable to everyone.
v  Knowledge of the usage ,care and maintance of cooker is required to prevent accidents.
v  Careful watch on the cooking time is required to prevent over cooking.
5.       POACHING :-
This involves cooking in the minimum amount of liquid at temperatures 80 -85 degree Celsius that is below the boiling point. Egg and fish can be poached.
Merits :-
v  No special equipments is needed.
v  Quick method of cooking and therefore saves fuel
v  Poached foods are easily digested since no fat is added.
Demerits :
v  Poached foods may not appeal to everybody as they are bland in taste.
v  Food can be scorched if water evaporates due to careless monitoring.
v  Water soluble nutrients may be leached into the water.
BLANCHING :-
In meal preparation , it is often necessary only to peel of the skin of fruits and vegetables without making them tender. This can be achieved by blanching.in this method,food is dipped in boiling water for 5 seconds to 2 minutes depending on the texture of food.this helps to remove the skin and peel without softening of food.blanching can also be done by pouring enough boiling them for short periods and then immediately immersing in cold water.the process cause the skin to become loose and can be peeled off easily.
Merits :-
·         Peels can easily be removed to improve digestibility.
·         Destroys enzymes that bring about spoilage.
·         Texture can be maintained while improving the colour and flavor of food.
Demerits :-
·         Loss of nutrients if cooking water is discarded.
II) DRY HEAT METHODS:-
1.       ROASTING:
In this method food is cooked in a heated mental or frying pan without covering it.
 e.g- groundnut.

Merits :
·         Quick method of cooking
·         It improves the appearance,flavor and texture of the method.
·         Spices are easily powered if they are first roasted.
Demerits :-
·         Food can be scorched due to carelessness.
·         Roasting denatures proteins reducing their availability.
2.       GRILLING :-
Grilling or boiling refers to the cooking of food by exposing it to direct heat. In this method food is placed above or in between a red hot surface. Papads,corn,phulkas chicken can be prepared by this method.
Merits :-
·         Enhances flavor,appearance and taste of the product.
·         It requires less time to cook
·         Minimum fat is used.
Demerits:-
·         Constant attention is required to prevent charring.
3.       TOASTING :-
This is a method where food is kept between to heated elements to facilitate growing on both sides.bread slices are cooked by toasting.
Merits :-
·         Easy and quick method.
·         Flavor improved.
Demerits :-
·         Special equipment required.
·         Careful monitoring is needed to prevent charring.
4.       BAKING :-
In this method , the food gets cooked in an oven or ovenlike appliance by dry heat. The temperature range maintained in an oven is 120-260 degree celcius. The food is usually kept uncovered in a container greased with a fat coated paper. Bread,cake,biscuits,pestries ,and meat at prepared by this method.
Merits :
·         Baking lends a unique baked flavor to foods.
·         Foods become light and fluffy cakes,custards,bread.
·         Certain foods can be prepared only by this method – bread,cakes.
·         Uniform and bulk cooking can be achieved . e.g. – bun, bread.
·         Flavor and texture are improved.
·         Variety of dishes can be made.
Demerits :-
·         Special equipment like oven is required.
·         Baking skills are necessary to obtain a product with ideal texture,flavor and colour characteristics.
·         Careful monitoring needed to prevent scorthing.
5.       SAUTÉING :-
Sauting is a method in which food is lighly tossed in little oil just enough to cover the base of the pan. The pan is covered with a lid and the flame or intensity of heat is reduced. The food is allowed to cook till tender in its own steam. The food is tossed occasionally or turned with a spatula to enable all the pieces to come in contact with the oil and cooked evenly. The product obtained by this method is slightly moist and tender but without any liquid or gravy. Foods cooked by cauteing are generally vegetables which are used as side dishes in a menu. Sautéing can be combined with other methods to produce variety in meals.
Merits :-
·         Takes less time
·         Simple technique
·         Minimum oil is used.
Demerits :-
·         Constant attention is needed as there is chance of scorching or burning.
6.       FRYING :-
In this method , the food to be cooked is brought into contact with larger amount of hot fat.when food is totally immersed in hot oil,it is called deep fat frying. Samosa,chips,pakoda are examples of deep fat fried foods.
In shallow fat frying only a little fat is used and the foot is turned inorder that both side are browned. E.g- omlete cutlets,parotas.
Merits :-
·         Very quick method of cooking
·         The calorific values of food is increase since fat is used as the cooking media.
·         Frying lends a delicious flavor and attractive appearance to foods.
·         Taste and texture are improved.
Demerits :-
·         Careful monitoring is required as food easily gets charred when the smoking temperature is not properly maintained.
·         The food may become soggy due to too muchoil absorption.
·         Fried food are not easily digested.
·         Repeated use of heated oils will have ill effects on health.
 III.COMBINATION OF COOKING METHODS:-
1.       BRAISING :-
Braising is a combined method of roasting and stewing in a pan with a tight fitting lid. Flavourings and seasonings are added and food is allowed to cook gently. Food preparations prepared by combination methods are:
Uppuma – roasting and boiling
Cutlet – boiling and deep frying , vermicelli payasam- roasting and simmering.
2.       MICROWAVE COOKING :-
Microwaves are electromagnetic waves of radiant energy wave lengths in the range of 250X106 to 7.5X109 Armstrong . the most common only used type of microwave generator is an electronic device called a magnetron which generates radian energy of high frequency .
A simple microwave oven consists of a metal cabinet into which the magnetron is inserted.
The cabinet is equipped with a metal fan that distributes the microwave throughout the cabinet. Food placed in the overs is heated by microwaves from all directions- moist food and liquid foods can be rapidly heated in such ovens. Food should be kept in containers made of plastic glass or chainware which do not contain metallic substances. These container are used because they transmit the micro waves but don’t absorb or reflect them.
Merits :-
v  Quick method :- 10 minutes faster than conventional method so loss of nutrient can be minimized.
v  Only the food gets heated and the oven does not get heated.
v  Foods gets cooked uniformily
v  Left overs can be reheated without changing the flavor and texture of the product.
v  Microwave cooking enhances the flavor of food because it cooks quickly with little or no water.
Demerits :-
v  Baked products do not get a brown surface.
v  Microwave cooking cannot be used for simmering stewing or deep frying with little or no water.
3.       SOLAR COOKING :-
Solar cooking is a very simple technique that makes use of sunlight or solar energy which is a non conventional source of energy.solar cooker consists of a well insulated box which is painted black on the inside and covered with one of more trtransparent covers.these covers allow the radiation from the sun to come out of the box.because of this temperature upto 1400 c can be obtained which is adequate for cooking.
                Merits :
v  Simple technique , requires no special skill.
v  Cost effective as natural sunlight is the form of energy.
v  Original flavor of food is retained.
v  There is no danger of scorching or warming
v  Loss of nutrients is minimum as only little amounts of water is used in cooking.
Demerits :
v  Special equipment is needed
v  Slow cooking process
v  Cannot be used in the absence of sunlight , rainy season,late evening and night.
PRESERVATION OF NUTRIENTS :-
1.       Foods cooked by steam for e.g: idlis are very easily digestable and are suitable for small children and even the aged. Food stuffs like vegetables and rice can be cooked with the help of steam in a single vessel.
2.       It is very nutritious to include vegetables which can be eaten row like carrots,tomatoes ,cucumber,onions,cabbage and beans in preparations like vegetable salads.
3.       There are certain tips to be remembered when cooking rice,vegetables and pulses.washing rice several times before cooking results in the loss of many water soluble nutrients like B-complex vitamins.
4.       In many homes,when rice is cooked the canjee or starch water is drained off and wasted.this is not a good practices as canjee contains many nutrients like B-complex vitamins.
5.       Vegetables contain vitamins and minerals which are dissolved in water during the process of cooking.all vegetables should be washed well and then cut into big cubes and later cooked.
6.       The water used for cooking vegetables should not be drained.it drained this should be added to some other preparation like sambar or rasam.
7.       Root vegetables like potato and sweet potato should be cooked in their skins to retain the nutrients.
8.       Adding baking soda to pulses during hastens cooking.though baking soda shortens the cooking time the B-complex vitamins present in them are destroyed.this practice should be discouraged.
9.       Green leafy vegetable should first be washed thoroughly in running water and then cut into pieces and cooked.
10.   It should be remembered that over cooking vegetable increases the loss of nutrients.
11.   Fresh vegetables that brought should be cooked soon and not stored for long as exposure to sunlight and air also results in certain losses of nutrients.
12.   Fried foods are difficult to digest and therefore small amounts should be given to children.
13.   Using the same heated oil by adding some more fresh oil is not good as the continuous reheating of oil can sometimes result in the formation of harmful products.
14.   It is always better to serve food hot as it tastes better and also reheating may destroy some of the nutrients.
 STAFF FOOD HANDLING :-
a.       Personal hygiene :-
v  Do not permit individuals with cold,sore throat or diarrhoea to handle food until they have recovered.
v  Do not permit anyone with boils, pimples or carbuncles on hands or face to handle food  or table ware.
v  Avoid sneezing or coughing never foods.
v  Always wash hands after using the toilet,scratching the head or other part of the body or blowing the nose.
v  Avoid indiscriminate handling of food with fingers.
v  Do not return tasting spoon to food without washing it.

b.      FOOD PROCESSING :-
v  Select foods from plants or markets which maintain high standards of sanitation.
v  Purchase only pasteurized milk buy freshly ground meat and use it within 24 hours after purchase.
v  Protect foods at home or in the market from flies,insects,rodents or contamination by unnecessary handling,sneezing or coughing.
v  Wash all fruits and vegetable before storing in refrigerator.
v  Use a pressure cooker for canning all non acid vegetable,meat and poultry,boil home canned non acid vegetable and meat for 6 to months before use.
v  Carefully label insect powders and other chemicals.
v  Do not keep them near foods.keep them out of the reach of small children.
c.       REFRIGERATION :-
v  Keep the refrigerator temperature at 400 to 450F .
v  Permit adequate circulation of air around foods in the refrigerator.
v  Unwrap foods before putting them in the refrigerator protects meat with loose covering of wax paper and place vegetables and fruits in the hydrator pan.
v  Refrigerator cooked foods as soon as possible after cooking.
v  Keep cream filled bakery products,sandwich and salads under constant refrigeration.
d.      CARE OF EQUIPMENT :-
v  Clean all kitchen equipment thoroughly after each use.
v  When hand washing is used the dishes should remain in rinse water. Detergent or soap powders should be used as directed by the manufacturer and their concentration maintained throughout the wash period.
v  Instruct all food handlers in proper use of all equipment.
STORAGE OF FOOD :-
Proper storage of food is an important part of reducing the risk of food poisoning. Some foods        must be stored  in the fridge and eaten within a short space of time,other foods such as flour,pulses canned foods and many others last much longer and can be stored at room temperature. Select the right place and right temperature for the right time.

FRIDGES AND FREEZERS :-
To avoid cross contamination to store these foods away from other foods especially cooked foods and ready to eat foods. Store them well covered on the bottom shelf of the fridge so they can drip onto other foods.
v  Eggs should be be kept in their box.
v  Keep prepared cold foods in the fridge until its time to eat them.
v  Many foods now need to go in the fridge.
v  Store foods in separate covered containers don’t reuse foil or film to wrap other foods.
FRIDGE / FREEZER MAINTENANCE :-
v  Make sure your fridge is on
v  Avoid over loading
v  Clean all internal and external surface often especially fridge shelves and door storage compartments. Mop up any spills as soon as they happen.
v  Defrost your fridge/freezer regularly.
STORAGE TIME :-

                 Most prepacked foods carry either a “use by” or “best before” date.
v  Use by dates are for highly perishable foods those that “go off” equite quickly.
v  Best before dates are for foods with a longer life, they indicate how long the food will be at its best quality.
v  Even if a food is within these dates don’t eat if it looks,taste off or smell off.
FREEZER STORAGE TIMES :-
 Check the label on pre-packed food to see if it is suitable home  for freezing. It so freeze as soon as possible after purchase. The star marking penel on food labels will tell you how long you can store your food depending on your type of freezer.

METHODS OF PRESERVATION :-
1.       Refrigeration :-
     vegetable  should be stored in a coolplace or in a refrigerator.storing of fresh fresh vegetable at room temperature especially in hot weather conditions,would result in spoiling and loss of vitamins.
2.       Canning :-
Canned vegetables are easy to store and they have much nutritive value as fresh or frozen products. Canned foods should be stored in a cool and dry place at low humidity.
3.       Deep freezing :-
Al  frozen foods must be stored at 00c if they are to retain a high percentage of their nutrients and good eating quality. Dehydrofreezing relatively a new process consists in evaporating about half the water and then freezing the product.it has been applied particularly to fruits and vegetable. The costs of packaging,shipping and storage are thus reduced water is added to reconstitute the food when it is rehydrated.
4.       Salt treatment :-
Salt act as preservative when used in high concentration i.e. 15-20% as in pickles of mango,lemon etc. at this concentration microorganisms cannot grow and fermentation is prevented. This concentration makes the food too salty for eating and only a few foods are preserved in this manner.
5.       Sun drying and dehydration :-
One of the most popular methods of preserving food is the sun drying and dehydration method. This procedure retards the growth of micro organism and also inactivates enzymeswhich thrive only in the moist conditions.dehydration is the procedure of removing the moisture in the vegetable.
Seasonal vegetable can be sundried and use off season.
6.       Marinating :-
Marinating or treating vegetable with vinegar or lemon juice is a desirable procedure as this will enhance the flavor and act as a preseravative.
7.       Chemical preservation :-
Sodium benzoate is a salt of benzoic acid used in preservation of ketchup and sauces popular items like tomato ketchup and mixed veg sauces are from the same ingredients as chutneys.
8.       Radiation :-
With the radiation technique root vegetables like potatos,onions,carrots etc. can be prevented from germination for long periods radiations also controls metabolic process resulting in delayed ripening of vegetables and fruits through reduced respiration rates.





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