What Is Dextrin? Production & Uses in Paper Sizing
SEVAGRAM EXCIPIENTS
Dextrin sits in an unusual middle ground: it starts as native starch, but by the time it reaches a paper mill, heat and acid have transformed it into something with very different flow behaviour. That transformation is the entire reason mills reach for dextrin instead of plain starch in certain surface and coating applications.
What Is Dextrin and How Is It Made?
Dextrin is produced by roasting native starch in the presence of a small amount of acid catalyst, typically under controlled heat. This process partially breaks down the starch’s long molecular chains, a reaction called depolymerization. The result is a starch derivative that dissolves more easily in water and forms a much lower-viscosity solution at the same concentration as the starting native starch.
White dextrin, in particular, is roasted under conditions that limit colour development, keeping the final product light in appearance, which matters for surface applications where colour or visible residue would be a defect.
Why Lower Viscosity Matters
The lower viscosity is the whole point. Native starch, cooked at a high enough concentration to be useful as a binder, becomes too thick to apply smoothly through coating or sizing equipment. Dextrin allows mills to run a higher solids concentration at workable viscosity, which means more binder reaches the sheet per pass without overloading the application equipment.
Uses of Dextrin in Paper and Beyond
- Surface sizing – improves surface strength, reduces dusting, and enhances ink receptivity on the printed sheet.
- Coating adhesive – acts as a low-viscosity binder in coating formulations, allowing higher pigment loading without thickening problems.
- Paperboard and carton coating – improves surface stiffness, ply bonding, and print quality on packaging board.
- General industrial adhesives – used outside paper as a binder in gummed tape, envelope adhesives, and similar low-cost bonding applications.
Frequently Asked Questions
Is dextrin the same as starch?
Dextrin is derived from starch through a roasting process that breaks down its molecular structure, giving it lower viscosity and different solubility than the native starch it came from.
Why is dextrin preferred over native starch for coating?
Dextrin can be used at higher solids concentration without becoming too viscous to apply, allowing more binder to reach the sheet without overloading the coating equipment. See our full comparison of dextrin vs native starch for paper coating.
What is white dextrin specifically?
White dextrin is roasted under controlled conditions that limit colour development, keeping it light in appearance for surface applications where colour matters.