Principles Of Food Preservation

In this post, we are going to learn about the Objectives, Methods and principles of food Preservation

Meaning: Food preservation is the act of treating food so as to prevent or greatly reduce spoilage, foodborne illness and preserve its nutritional value, texture, and flavour.

PRINCIPLES OF FOOD PRESERVATION

Food preservation is based on the following principles: 

  • Preservation or delay in microbial degradation: This is archived by:
  • Assisting microorganisms (asepsis).
  • Filtration is used to remove microorganisms.
  • Low temperature, drying, and anaerobic conditions can inhibit the growth of microorganisms.
  • Radiation or heat can kill microorganisms.
  • Preservation or delay of food’s decomposition by oneself This can be caused by:
  • Blanching or other methods that destroy or inactivate food enzymes
  • Preservation or delay in chemical reactions, i.e. preservation of oxidation with an antioxidant
  • Preservation of damage from insects, animals and mechanical causes

Objectives Of Food Preservation

Food processing at home, in institutions, and in the food industry has similar goals. These include:

  • Food contaminant Removal-Unwanted matter can be harmful, inedible or indigestible.
  • Food safety –Natural toxins can be found in food, such as the trypsin inhibitor (soya bean), fungal toxin (groundnut & grains), infected food materials, and green portions of potatoes. Chemical toxin & poison should be removed. You can ensure food safety by heating to create microorganisms & their toxins. Contamination is prevented by safe processing.
  • Digestibility increases –Most foods are difficult to digest without being cooked. Cooking reduces the fiber and gelatinized starch in food, makes it easier to digest, and denatures proteins. Special processing is required for food preservation.
  • You can enhance the flavor and taste of your food.Food’s organoleptic properties determine its acceptability. Many processing techniques improve the appearance of food and make it more flavorful. Miller reaction is responsible for the browning crust that gives baked goods their baked aroma and taste. Foods get a unique flavor through processing such as fermentation and caramelization.
  • Improve texture and consistency Emulsification, gel formation and increase in viscosity all aim to improve the texture and consistency of ready-to-eat foods.
  • Reduced loss of nutrients –Controlled processing conditions like freeze drying, autoclaving and controlled heat are better for nutrition retention. Adding vitamins to your food can help reduce the loss of nutrients due to processing. Vitamins are added to processed butter, margarine, and other foods. Many other processed foods are also enriched with vitamins, minerals and lysine.

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  • Expanding your self-life The self-life extension of processing is possible because aside from the removal of unwanted, spoilt, and harmful matter and subjecting the food temperature to temperatures outside of the danger zone, all processes like dehydration, cold preservation, canning, and pasteurization are designed to preserve the food.
  • Fake foods have a higher acceptance rateMarket has seen new products in uniform sizes and shapes. These products are made from low-grade commodities that are either plentiful or healthy.

Methods of food preservation

Principles Of Food Preservation
  1. Pickling
    1. Food preserved in vinegar
    2. Preserves meat, vegetables due to the action of acetic acid which prevents microbial growth
  2. Salting
    1. Food preserved in salt such as fish, meat
    2. Salt prevent microbial growth
  3. Smoking
    1. Smoking of fish and meat prevent spoilage by dehydration
    2. The wood smoke contains large number of compounds, which are anti microbial and slow rancidication of animal fats
  4. Canning
    1. It is a method of preserving food in which the food contents are processed and sealed in an airtight container at high temperature.
    2. Nicholas Appert-father of canning
    3. Food products such as meat, fish, fruits, vegetables
  1. Bottling
    1. It is a method of preserving food in which the food contents are processed and sealed in airtight bottles at high temperature
  2. Pasteurization
    1. It is the process of heating milk below boiling point (or any liquid or a food) to kill pathogenic bacteria to make the food safe to eat. Stops fermentation
  1. Refrigeration
    1. Keeping food at low temperatures or cold

Methods of food preservation on the basis of food preservation principles

Physical method

Method

a)By removal of heat (Preservation by low temperature)

Refrigeration, Freezing preservation, dehydro-freezing, carbonation

b. By addition of heat (preservation by high temperature

Pasteurization (LTLT, HTST), sterilization, UHT Processing, microwave.

c. By removal of water

Drying (open sun, solar/poly tunnel solar), Dehydration (mechanical drying), Evaporation/concentration, Freeze concentration, reverse osmosis, freeze drying, foam mat drying and puff drying

d. By Irradiation

UV rays and gamma radiations

e. By non-thermal methods

High pressure processing, pulsed electric fields

Chemical methods

 

a. By addition of acid (acetic or lactic)

Pickling (vegetable, olive, cucumber, fish, meat)

b. By addition of salt/brine

Salted mango/vegetable slices, salted and cured fish and meat

i. Dry salting

ii. Brining

c. By addition of sugar along with heating

Confectionary products like jams, jellies, preserves, candies, marmalades etc.

d. By addition of chemical preservatives.

i) Use of class II preservatives like Potassium meta-bi- sulphite, sodium benzoate, sorbic acid in food products.

ii) Use of permitted and harmless substances of microbial origin like tyrosine, resin, niacin as in dairy products.

iii. By fermentation

i. Alcoholic fermentation (wine, beer)

ii. Acetic acid fermentation (vinegar)

iii. Lactic acid fermentation (curd, cheese, pickling of vegetables).

iv. By combination method

i. Combination of one or more methods for synergistic preservation.

ii. Pasteurization combined with low temperature preservation.

iii. Canning: heating combined with packing in sealed container.

iv. Hurdle technology like low pH, salting, addition of acid, use of sugar, humectant and heating.

Importance Food Preservation

The supply and demand for food do not always match. Some places have surplus production while others have inadequate supply. Even perishable foods, such as tomatoes, mangoes and papaya, can quickly spoil. It is important to increase and improve storage and preservation facilities. Food preservation is important for:

1. Increase the shelf life of food and increase the supply. Many perishable foods can last for a very long time.

2. The availability of seasonal food throughout the year.

3. Variety is key to a healthy diet

4. You can save time as the food is already partially processed, which allows you to reduce preparation time and energy.

5. Stabilizing food prices, since there is less chance of a shortage.

6. Reduce wastage by preventing food spoilage or decay.

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