🍶 Preservation

• Highest food processing industries is in Andhra Pradesh.

Fruit preservation

• The art and science of keeping fruits for longer time without detonation in quality.

Principle of preservation

Canning

• It is method of food preservation in which food is processed and sealed in an airtight container (jars like mason jars and steel and tin cans).
• Packed in vacuum.
• Fruits can be processed at a temperature of 100 °C.
• Vegetable can be processed at temperature of 115-121 °C.
• Lidding or Clinching
  • Cans after being filled, are covered loosely with lid and passed through the exhaust box.
  • Lidding is now replaced by clinching in which the lid is partially seamed to the can by a single first roller action of double seamer.

Pasteurization

• Heating of fruits and vegetable juice at 85-90 °C for 30 minutes.
• It kills only harmful microbes.

Sterilization

• Heating of fruits and vegetables above 100 °C
• It kills both beneficial and harmful bacteria.

Freezing

• Cooler storage: 15 °C
• Refrigeration or chilling: 0 - 5 °C

Cry preservation

• Preserve in liquid nitrogen at -196 °C.

Lyophilization or Cryodesiccation

• Freeze drying, also known as lyophilization or cryodesiccation, is a low temperature dehydration process that involves freezing the product, lowering pressure, then removing the ice by sublimation.
• This contrasts with dehydration by most conventional methods that evaporate water using heat.

Drying

• Removal of moisture by applying heat is called drying.
• E.g. Raisins (Kismis).

Preservation through osmosis

• High concentration of sugar.
• E.g. Jam (68 % sugar), Agari ka petha.

Salt preservation:

• Salt conc. 10-25 % is sufficient (in pickles: 15%).

Preservation by chemicals

• KMS (Potassium Meta bi Sulphite): @ 500 ppm/0.05%.
  • Sulphur di oxide is responsible for preservation.
  • It used against colour less fruit Juices/pulp.
• Sodium benzoate: @ 700 ppm/0.07%.
  • Benzoic acid is responsible for preservation.
  • Used in colored fruit (only in non-acid fruits).

Fermentation

• Grape wine (alcohol 7-20%) is oldest example of fermented beverage.

Asepsis

• Prevent entry of microbes.

Oxidation

• Oxidation can be checked by antioxidants (Ascorbic acid /vit. C)

Enzymes

• Checking of enzymatic spoiling: Blanching in cauliflower
• Clostridium pasteurianum is a beneficial bacteria for fruit preservation industry. ^{UPPSC 2021}

Waxing

• Wax coating treatment enhance the shelf life of fruit by inhibiting respiration.

Maturity Indices of Fruits

👉🏻 Symptoms which indicate that fruits are ready to harvest:

Post Harvest Handling

Degreening of fruit is a post-harvest process by which the green color is removed from the peel by treating the fruit with ethylene gas to degrade chlorophyll and reveal yellow and orange colors for commercial and marketing purposes.

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