Question

Food processing technique that combines multiple unit operations such as mixing, kneading, shearing, heating, cooling, shaping and forming -

• A. Extrusion
• B. Cold sterilization
• C. Irradiation
• D. Sous vide technique

Hint:

Extrusion is a highly efficient continuous bioreactor process.
It performs raw ingredient mixing, starch gelatinization, protein texturization, and final product shaping in one compact machine.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Food processing often uses systems that combine multiple thermodynamic and mechanical unit operations into a single continuous process to increase production efficiency and improve product texture.

Step 2: Detailed Explanation:
Let us analyze each of the listed techniques:
- Extrusion (specifically HTST - High Temperature Short Time extrusion cooking) is a versatile food processing method.
Raw materials are fed into a tight barrel containing one or two rotating screws.
As the material moves along the barrel, it undergoes: mixing of ingredients, kneading into a dough, mechanical shearing, heating from friction and external heaters, and cooling towards the end of the barrel.
Finally, the pressurized plasticized material is forced through a shaped die, expanding and shaping it into products like breakfast cereals, pasta, and pet foods.
- Cold sterilization refers to preservation methods (like filtration or chemical treatment) that do not use heat to destroy microorganisms.
- Irradiation exposes food to ionizing radiation (gamma rays or electron beams) to eliminate pathogens and extend shelf life.
- Sous vide is a cooking method where food is vacuum-sealed in a plastic pouch and cooked in a water bath at precisely controlled low temperatures.
Therefore, extrusion is the only process that combines mixing, kneading, shearing, heating, cooling, and shaping into a single operation.

Step 3: Final Answer:
The food processing technique that combines these operations is extrusion.