Chapter 11 Extrusion

What is the hot extrusion process and how does it work?

• The hot extrusion process involves cooling a material below its recrystallization temperature and forcing it through a die to create a desired shape.

• The hot extrusion process involves heating a material above its recrystallization temperature and forcing it through a die to create a desired shape.

• The hot extrusion process involves heating a material above its recrystallization temperature and pouring it into a mold to create a desired shape.

• The hot extrusion process involves using a material at room temperature and forcing it through a die to create a desired shape.

Describe the cold extrusion process and its applications.

• Product is extruded without cooking or distortion of food

• The cold extrusion process involves heating the material before forcing it through a die.

• The rapid release of pressure as the food emerges from the die cause instantaneous expansion of steam and gas in the material

• The applications of cold extrusion are production of pasta,sausage and some confectionery

What are the differences between hot extrusion and cold extrusion?

• Hot extrusion is done at elevated temperatures, while cold extrusion is done at room temperature or slightly above.

• Hot extrusion uses less force than cold extrusion.

• Hot extrusion and cold extrusion are the same process.

• Hot extrusion is done at room temperature, while cold extrusion is done at elevated temperatures.

What is an extruder and how is it used in the extrusion process?

• An extruder is a machine used to push or pull a material through a shaped opening to create an elongated object with a specific cross-section. It is commonly used in the manufacturing of plastic products, food processing, and metal fabrication.

• An extruder is a musical instrument used to produce sound by blowing air through it.

• An extruder is a tool used for gardening to remove weeds from the soil.

• An extruder is a type of computer software used for graphic design and animation.

Explain the working principle of a food extruder.

• A food extruder works by using heat to cook the food ingredients before shaping them.

• A food extruder works by mixing the food ingredients together to form the final product.

• A food extruder works by forcing food ingredients through a shaped opening in a die to produce a specific shape and size of the product.

• A food extruder works by cutting the food ingredients into the desired shape and size.

How does extrusion affect the nutritional value of food products?

• Extrusion has no impact on the nutritional value of food products

• Extrusion can lead to both positive and negative effects on the nutritional value of food products, depending on the specific process and ingredients used.

• Extrusion always increases the nutritional value of food products

• Extrusion only has negative effects on the nutritional value of food products

Discuss the impact of extrusion on the texture and flavor of food products.

• Extrusion has no impact on the texture and flavor of food products.

• Extrusion only impacts the color of food products.

• Extrusion can impact the texture and flavor of food products.

• Extrusion only impacts the shelf life of food products.

Advantages of extrusion

• Versatility in processing different type of product

• Lower processing costs and higher productivity

• High energy consumption

• Environmental friendly

Factors Influencing The Characteristics of Extruded Products

• Temperature and pressure

• Rheological properties of food

• Diameter of die

• pH value of the food

Effect of Extrusion in Food

• Dough-like material is formed when high temperature and pressure is applied

• Major effect on calour and flavour if HTST is applied

• Starch gelatinization occurs and fading colour due to expansion

• Great loss of nutritional value in cold extrusion or HTST