Successfully reported this slideshow.
Your SlideShare is downloading. ×

Food preservation by refrigeration and air conditioning

Ad
Ad
Ad
Ad
Ad
Ad
Ad
Ad
Ad
Ad
Upcoming SlideShare
food preservation
food preservation
Loading in …3
×

Check these out next

1 of 17 Ad
Advertisement

More Related Content

Slideshows for you (20)

Advertisement

Similar to Food preservation by refrigeration and air conditioning (20)

Recently uploaded (20)

Advertisement

Food preservation by refrigeration and air conditioning

  1. 1. Refrigeration and Air Conditioning Systems in Food Preservation BY: AKSHAY PATHANIA ASSISTANT PROFESSOR MECHANICAL ENGINEERING DEPARTMENT
  2. 2. Food Preservation THE FOOD PRESERVATION MAY BE DEFINED AS THE STATE IN WHICH FOOD MAY BE RETAINED OVER A PERIOD OF TIME WITHOUT BEING CONTAMINATED BY PATHOGENIC ORGANISMS OR CHEMICALS AND WITHOUT LOSING ITS COLOUR, TEXTURE, FLAVOR AND NUTRITION VALUE.
  3. 3. Food Preservation By R & AC Applications of Food Preservation  It adds variety to the food.  It increases the shelf life of food.  It increases the food supply It decreases the wastage of food.
  4. 4. Causes of Food Spoilage 1. Spoilage due to physical changes. 2. Spoilage due to chemical changes.  Enzymes  Micro-organisms  Bacteria  Yeast  Moulds (fungus) Food Preservation By R & AC
  5. 5. Methods of Food Preservation 1. Heat Processing 2. Dehydration 3. Chemical Preservation 4. Oils and spices 5. Canning 6. Pasteurization Food Preservation By R & AC
  6. 6. Food Preservation by Refrigeration  The Refrigeration is the only means of preserving food in its original position.  The preservation of perishable foods by refrigeration involves the use of low temperature as a means of eliminating the activity of spoilage agents.  It has been found that the growth of food destroying microorganisms is much faster (about 100 times) at a temperature of 10°C than at 4°C.  This is enough to emphasize the use of refrigerators for preserving fruits, vegetables, fish, meat, milk etc. Food Preservation By R & AC
  7. 7. Domestic Refrigeration for Food Preservation  The main purpose of a domestic refrigerator is to provide a low temperature for storage and distribution of foods and drinks.  The storage in domestic refrigerators is generally short term or temporary storage.  These are small in size and vary in capacity from 0.1𝑚3 to 0.25𝑚3 .  The refrigerant used should preferably be non-toxic. Generally, methyl chloride, R-12 and R-11 are used as refrigerants. Food Preservation By R & AC
  8. 8. Commercial Refrigerators for Food Preservation  Reach-in Refrigerators These refrigerators are the most versatile and the most widely used of all commercial fixtures. These refrigerators may be used for both storage and display of the product. When used for storage only, they have solid doors, while for display of product, glazed doors are provided. These refrigerators are commonly used in grocery stores, meat markets, bakeries, lunch counters, restaurants and hotels. Food Preservation By R & AC
  9. 9. Commercial Refrigerators for Food Preservation  Walk-in Cooler The walk in coolers are mainly used as storage fixtures. They are available in a wide variety of sizes. These are used by nearly all retail stores, markets, hotels, restaurants etc. for the storage of perishable foods. Some walk-in coolers are provided with glazed reach-in doors for storing, displaying and dispensing of dairy products, eggs and beverages. Food Preservation By R & AC
  10. 10. Commercial Refrigerators for Food Preservation  Display Cases The principal function of display cases is to display the product or commodity in a most attractive manner in order to simulate sales. Thus, in the design of a refrigerated display fixture, the first consideration is given to the product being displayed. a. Self service case b. Service case Food Preservation By R & AC
  11. 11. Cold Storage for Food Preservation Many food products may be stored at some temperature above freezing point. The storage may be short term storage or long term storage. The storages which are used for short term storage purposes are known as cold storages. The period for short term storage ranges from one to two days or to a week or more in some cases, but not more than 15 days under any circumstances. When perishable foods are to be stored for a longer period, they should be frozen and stored in frozen stores. Food Preservation By R & AC
  12. 12. Considerations should be kept in mind while storing the foods in cold storages 1. Storage Temperature 2. Relative humidity and air motion 3. Mixed Storage 4. Product chilling Food Preservation By R & AC
  13. 13. Frozen storages for Food Preservation • When the food products are to be preserved in its original fresh state for longer periods, then they are usually frozen and stored approximately at -15°C or below. • They differ from cold storages in their size and the temperature range. • The high quality products in good condition should only be frozen. • The meet products do not require any special processing before freezing. They are directly freezed taking them into frozen storages after washing. Food Preservation By R & AC
  14. 14. Methods of Food Freezing I. Slow or Sharp Freezing (-17°C to -40°C, used for boxed poultry, fish, eggs in cans etc.) II. Quick Freezing a. Immersion freezing (for liquid products) b. Indirect contact freezing c. Air blast freezing (-17°C to -40°C, used for shrimp, fish fillets, pre-cooled products packed in small packages) Food Preservation By R & AC
  15. 15. Cold Storage Temperatures
  16. 16. Cold Storage Temperatures
  17. 17. Cold Storage Temperatures

×