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Ingredient Contribution in Extruded Product - Carbohydrate Sources

Ingredients Contribution in Extruded Products - Carbohydrate Sources

In extrusion, the primary form of carbohydrate that has a prominent effect on the texture of the extrudate is the starch. This starch exists in many of the cereal grains or tuber's roots. Starch exists in two forms, amylose and amylopectin. Starch from every source will differ in the percentages of amylose vs amylopectin and the granule size. The other form of carbohydrate is cellulose, which has less effect during extrusion.

During extrusion, the combination of moisture, heat, pressure, and mechanical shear will change the physicochemical properties of the starch and therefore generate cooking, changes in viscosity, expansion, breakdown of starch molecules, and the formation of bubbles in the extrudates.

In the table below, I have listed some carbohydrate-source ingredients and their effect on the extrusion process.

  • Ingredient
  • General Information
  • Effect in Extrusion
  • Citation


  • Crop from subtropical countries
  • Cause stickiness at levels above 40%
  • Need to fine grind
  • A good starch source
  • Gives expansion up to 1.12 times during 100°C extrusion
  • The big particle may reduce starch cooking
  • Al-Rabadi et al., 2011
  • Awan et al., 2010
  • Forte and Young, 2016
Beet Pulp
Beet pulp
  • A by-product of the sugar extraction process
  • Mainly used for food application (for sweetener and food coloring)
  • Source of soluble and insoluble fiber
  • Good water retention capacity as finely ground fiber
  • Causes increased wear of extruder parts
  • Cho and Samuel, 2009
  • Forte and Young, 2016
  • Simić et al. 2021
  • Starchy root vegetable or tuber was native to South America.
  • Moderate expansion may occur (compared to corn starch)
  • Great expansion occurs at 170°C
  • Fallahi et al., 2015)
  • Forte and Young, 2016
  • Grossman et al., 1989
  • Kannadhason and Muthukumarappan (2010)
Coconut meal
coconut meal
  • By-products from coconut oil extraction
  • High in fiber and requires fine grinding
  • Reduces expansion
  • Requires more water during processing
  • Dumchaiyapoom et al., 2019
  • Forte and Young, 2016
  • The main food source for humans in the world
  • Yellow corn has a bigger benefit than white corn
  • Starch source for good expansion and binding
  • May become sticky during the extrusion process
  • Shahmohammadi et al, 2016
  • van der Sman et al, 2018
  • A viscous liquid from the sugar refining process
  • Usually in syrup form (20% moisture)
  • Good binder but sticky at a high level
  • Can reduce expansion and lower water activity
  • Forte and Young, 2016
Potato Starch or Flour
Potato starch or flour
  • Starchy material extracted from the root of potato plant tuber
  • Excellent starch source for binding and expansion
  • High water absorption capacity
  • Has higher viscosity (due to higher molecule weights of amylose and amylopectin)
  • Forte and Young, 2016
  • Valle et al, 1995
  • Important source of energy
  • High content in starch
  • Short grain variety will have more stickiness
  • Hydrate slowly, good expansion property
  • Use less steam in pre-conditioning
  • increase in feed moisture (up to 31%) reduces the expansion ratio
  • Forte and Young, 2016
  • Walter et al., 2005
  • Zambrano et al., 2021
Rice bran
Rice bran
  • High in fiber
  • Starch, protein and fat content may vary
  • Required fine grinding for adequate processing
  • Reduce expansion and binding
  • Forte and Young, 2016
  • Rafe et al., 2016
  • Staple food crop
  • Mainly contain starch
  • Has high viscosity due to high starch content
  • Al-Rabadi et al., 2011
  • Dicko et al, 2006
  • Wang, 2018
Wheat Bran
Wheat bran
  • Fiber source with some protein and starch
  • starch will vary greatly as will expansion effects
  • Require fine grinding
  • Forte and Young, 2016
Wheat flour
Wheat flour
  • Grinded wheat, divided to hard and soft based on gluten content
  • Excellent starch source for binding and expansion (dependent upon gluten content)
  • Forte and Young, 2016

Graduated from National Taiwan Ocean University Food Science Department earning the title of Master of Science (MSc.) Albert has a strong background in science and used this science-based approach to deliver knowledge to Customers. Yearly experience in sales, technical, and marketing departments, added with continuous communication with the Customer gives him the knowledge in feed machinery and its operations.

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