Extrusion

Question 1

Extrusion is

Answer 1

The shaping by force through a specially designed opening often after previous heating of the material.
High temp short time process. Works on expansive starchy and/or proteinaceous foods

Question 2

Die

Answer 2

specialised tool use to cut or shape materials like a press.

Question 3

Machine and the mix

Answer 3

The machine which forces the mix through the die is an extruder and the mix is known as the extrudate

Question 4

Expansion ratio

Answer 4

The level to which the extrudate puff and expands

Question 5

Extrusion and protein

Answer 5

increase the digestibility of protein possibly by denaturing the proteins and the inactivation of antinutritional factors that impair protein digests ex: trypsin inhibitors.

Question 6

Extrusion and malliard reaction

Answer 6

Free sugars may be produced from starch hydrolysis during extrusion and react with lysine and other aas with free terminal amines

Question 7

extrusion and carbohydrates

Answer 7

extrusion may result in sugar losses maybe due to reducing sugars in malliard reaction.
extrusion gelatinases starch making it more digestible.

Question 8

Extrusion and lipids

Answer 8

lipid levels over 5-6% impair the extruder.
extrusion minimises lipid oxidation

Question 9

extrusion and vits+minerals

Answer 9

D + K = Stable
A + E = not stable in heat and oxygen
C = sensitive to heat and oxidation
Extrusion increases most minerals as antinutritional factors are reduced