Download
1 / 36
22.56k likes | 68.41k Vues
FOOD PRESERVATION. Food preservation frees people from total dependence on geography and climate in providing for their nutritional needs and wants . . Through food preservation, wastage of food can be reduced. As the old saying goes “Waste not, want not”.
E N D
Food preservation frees people from total dependence on geography and climate in providing for their nutritional needs and wants.
Through food preservation, wastage of food can be reduced. As the old saying goes “Waste not, want not”
Ultimately, all natural foods will spoil and even those which have been preserved in one form or another lose their color, flavor, texture, and nutritive value.
Based on theirperish ability, foods may be classified as follow:
Perishable foods Those that spoil readily like milk, fish, meat, poultry, ripe succulent fruits, and leafy vegetables.
Semi-perishable foods Those that can keep for a limited period of time like onions, garlic, eggs, and roots crops.
Relatively nonperishable foods Those that keep for almost an unlimited period of time like rice, dried mature beans, mature corns, and many mature nuts and dry legumes or pulses.
SIGNIFICANCE OF FOOD PRESERVATION Food preservation is also essential from the hygienic stand point. Unless perishable and semi perishable foods are adequately preserved, they form products harmful to the body and are hazard to health.
Food preservation is important from the standpoint of convenience also. The family is greatly helped by the availability of well-preserved foods in convenient forms easily and compactly stored.
SALT - is the primary ingredients used in meat curing. It makes up the bulk of the curing mixture because it is not only a good preservative but if provides the most desirable flavor.
Sugar - is a secondary ingredients in the curing formula which counteracts the astringent quality of salt. It enhances the flavor of the product.
Nitrates - are color fixation agents or substances responsible for the development of the proper color in cured meat products.
Ascorbic acid - these substances speed up curing reaction Phosphates- are used to increase the water holding and binding Capacity of cured products.
Vinegar - is added to flavor but it also has some antiseptic value. Therefore aids in prolonging the shelf life of the finished products.
Spices - although the flavoring materials are naturally prescribed in many foodstuff, palatability is further enhanced by the addition of various substances, though lacking in nutritional value, stimulate the flow of digestive secretion thereby materially digestion.
Binders, fillers, emulsifiers - do not cause any radical change in the quality of the product and in some causes actually improved its characteristics.
DETERIORATION AND SPOILAGE OF FOODS To preserve foods, we must cope with their spoilage, and to cope with spoilage, we must know what causes it and how it is brought about.
Drying - is the first known methods of preserving foods. The principle involved is the reduction of the water content in a food to such a degree as to prevent it from spoiling.
The general methods used in draying are: By sunshine- food is usually sliced and spread to dry under the heat of the sun. By artificial heat- food is dried by exposing it to hot air, as in the oven. By air blast- food is dried by means of a fan driven by electricity, alcohol or kerosene.
Smoking This process of preserving is usually used with fish and meat. The material is first salted and exposed to smoke produced by slow-burning sawdust or shavings of one of the Philippine woods, like camachile, guava, or tamarind.
Salting This method is one of the first known and practice here. It is used both with animal and vegetable foods. The salt draws out the water content of the food and enters the tissues, thus making the food firmer and preventing decay.
The two most important methods of salting are: Dry salting- the food is first mixed with salt to remove a large amount of its moisture and then dried. Brining- the food is packed in a container and covered with a solution of salt (brine) until used.
Pickling - is applicable to foods that do not have much taste. Vinegar and condiments serve as preserving materials and give delicious flavor and odor to the food.
The methods of pickling generally used are: Simple pickling- food is prepared, salt and preserved with vinegar and other condiments. These ingredients give the food a better taste and preserve it. Sugar is added to the vinegar when sweet-sour pickle is desired.
Fermented pickling- this is accomplished by curing the food with salt and allowing the latic acid fermentation to develop for a few weeks. The following spices are used in this method- vinegar, pepper, cinnamon, clove, allspice, nutmeg, celery seed, caraway, coriander, turmeric and bay leaves.
Sugar as a preservative - Syrup in a concentrated form acts as a preservatives and food products can be preserved either in dry sugar or syrup which is made by dissolving the sugar in water.
canning - Is a method of heating the food and sealing it in an air-tight container.
The preservation is affected because: • a. The heat destroys chemical agents (enzymes) in the food which are beneficial in causing fruits and vegetables to ripen and meat to become tender, but its continuous action causes over-ripening. • b. Canning destroys microscopic organisms which cause food spoil. • c. Canning prevents organism from getting into the food after it is heated.
Canning is a method that can be used with success with the widest variety of foods. The advantages of canning is that the food can keep long and is always ready to use.
Methods of Canning Boiling water bath method Open kettle method Steamer or oven method Pressure-canner method
Freezing - Is the simplest way to preserve food and the most natural although not the cheapest.
Methods of Food preservation in Freezing • a. Flavor and appearance are unchanged • b. The method is very easy to learn. • c. It is safe. Food spoiling organism present are unable to multiply at freezer temperature.
d. If freezer is done in a regular freezer unit, “it provides you a market in your kitchen, stores whole meals ready to heat, banishes leftovers, and makes a “bank” for pies and cakes”- or what have you. • e. It is a permanent larder of perishables.
