Extrusion is a process that forces food ingredients through a die under pressure, heat, and shear. This continuous process cooks and shapes moistened materials using temperature, pressure, and mechanical shear. An extruder can alter texture, grind, thermally treat, hydrate, partially dehydrate, expand, homogenize, denature proteins, mix, gelatinize, destroy microorganisms, and shape ingredients. Common extruded foods include cereal snacks, soups, pastas, chewing gum, pet foods, and processed meats. Single-screw and twin-screw extruders are the main types used. Extrusion cooking has advantages like producing various textures at lower cost while minimizing nutrient degradation.

1. EXTRUSION
(Teacher Incharge:Dr.SHANOOBA.)
PRESENTED BY:VIHAR.R.PATIL.

2. What is Extrusion:
 Food extrusion is a process in which food
ingredients are forced to flow under one or
several conditions of mixing,heating and
shear,through a die that forms or puff dries the
ingredients.
 Basically extrusion is the process of cooking
under pressure,moisture and elevated
temperature.

3. DEFINATION OF EXTRUSION COOKING:
 A continuous process by which moistened,
expansile, starchy,and a proteinaceous materials
are plasticized and cooked by combination of
moisture, pressure and temperature,and
mechanical shear.
 Extrusion process is done by using EXTRUDER.

4. FUNCTIONS THAT AN EXTRUDER CAN PROVIDE:
*Texture Alteration *Grinding
*ThermalTreatment *Hydration
*Partial Dehydration *Expansion
*Homogenization *Shearing
*Protein Denaturing *Mixing
*Gelatinization *Shaping
*Destruction of some micro-organisms and some
*toxic compounds.

5. EXAMPLES OF EXTRUDED FOOD:
Types of products Example
1)Cereal based products Expanded snackfood
Soup and beverages bases,instant drink
Pasta products
2) Sugar based products Chewing gum
Toffee,Caramel,Peanut brittle
Fruit gums
3)Protein based products Petfoods and animal feed and protein
supplement
Sausage,Hot dogs
Processed cheese.

6. TYPES OF EXTRUDERS:
 1)SINGLE-SCREW EXTRUDERS:
 Single screw extruder contains a single rotating screw in
a metal barrel,and come in varying pattern.Single screw
usualy consists of three section (1)feed (2)transion or
compresion (3)metering.The raw material are fed in a
granular form at the hopper located in the feed section.In
the transition section the screw channel become
shallower and the material is compacted.

7.  A major portion of mechanical energy is dissipated in this
section,which result in rise in temperature of the
material.starch become gelatinized,and material
becomes more cohesive.It is transported further by the
metering section and pushed through the die opening
.The barrels of single screw extruder usually have helical
or axial grooves on the inner surface.This helps to convey
and mix the material more effectively.
 Single screw extruders are usually characterized by ther
length to diameter ratio and their compression
ratio,which is the ratio of the maximum channel depth to
the minimum chanel depth.The most commonly used
compresion ratio is 3:1.The throughput capacity of a
single screw extruder is linked to screw speed,screw
geometries,and material characteristics.

8. TYPES OF EXTRUDERS:
 2)TWIN SCREW EXTRUDER:
 Generally one and half time more expensive than SSE for the same
capacity
 Yet the degree of quality control and processing flexibity they offer
can make them attractive in food appliances.
 They can handle viscous, oily, sticky and very wet material and some
other products which will slip in SSE.
 TSE produce a more uniform flow of products through the barrel due
to the positive pumping action of the screw flights.

9. ADVANTAGES OF EXTRUSION :
i. A variety of shapes, texture, colour and apperance can
be produced, which is not easily formed using other
production method.
ii. Extrusion has lower processing cost than other cooking
and forming processes, we can save 19% raw
material,14%labor,and 44%capital investment.
iii. Extrusion processing also need less space per unit of
operation than other cooking system.
iv. Since extrusion is HTST heating process,it minimizes
degradtion of food nutrients, while improving the
digestibility of proteins.

10. 
THANK YOU !!!!!