Dextrin (Modified Starch): Types, Production Process, and Wide Industrial Applications

Release date：26-04-23 13:52
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Dextrin (Modified Starch): Types, Production Process, and Wide Industrial Applications

Dextrin is one of the earliest modified starch products ever discovered. In 1821, a fire in a Dublin textile factory accidentally produced a substance that dissolved in cold water and had strong adhesive properties. Since then, dextrin has become a vital industrial raw material.

Today, dextrin is produced by controlled chemical or enzymatic degradation of starch. It offers cold‑water solubility, low viscosity, high adhesive strength, and excellent film‑forming ability. Depending on the production conditions, three main types of dextrin are produced: white dextrin, yellow dextrin, and British gum.

What Happens During Dextrin Production? The Reaction Mechanism

The production of dextrin involves two main reaction types:
1. Hydrolysis – breaks the α‑1,4 glycosidic bonds, reducing molecular weight and increasing solubility.
2. Repolymerization – includes transglycosidation and reversion reactions, forming new α‑1,6 and α‑1,3 branches.

The balance between hydrolysis and repolymerization depends on temperature, moisture content, and catalyst (acid). This balance determines the final product properties.

Dextrin Type	Temperature	Solubility	Main Reaction
White dextrin	100–120°C	50–70%	Hydrolysis
Yellow dextrin	120–200°C	70–100%	Hydrolysis + repolymerization
British gum	180–200°C (longer time)	High	Minimal hydrolysis, mainly repolymerization

White dextrin is primarily a degradation product.
Yellow dextrin results from both hydrolysis and branching (transglycosidation), giving higher solubility and stability.
British gum is produced by heating starch at 180–200°C for up to 20 hours, often with a mild alkaline buffer (e.g., borax, trisodium phosphate). It forms a gel that shows a rapid viscosity drop upon cooling – ideal for certain adhesive applications.

Industrial Production Process of Dextrin

Modern dextrin production follows five key steps:
1. Acidification – Acid (gaseous or mist) is mixed evenly with starch.
2. Pre‑drying – The acidified starch is dried at relatively low temperatures to minimize hydrolysis. This step strongly influences the final reducing sugar content, which affects hygroscopicity, adhesion, color, and flow properties.
3. Heating (roasting) – Performed in open or vacuum roasters. Vacuum roasters improve water removal and material flow.
4. Cooling – Rapid cooling stops the reaction.
5. Re‑humidification – Final moisture is adjusted to 0.5–3% for product stability during storage.

A fluidized bed roaster is ideal for uniform heating, acid distribution, and volatile removal – ensuring consistent product quality.

Key Properties of Dextrin by Type

Property	White Dextrin	Yellow Dextrin	British Gum
Cold‑water solubility	50–70%	Up to 100%	High
Solution behavior	Non‑Newtonian, prone to retrogradation	Near‑Newtonian, low viscosity, stable	Viscosity drops quickly on cooling
Adhesive strength	Moderate	Strong	Good gel properties

Yellow dextrin exhibits strong adhesion to cellulose fibers and inorganic materials, making it the most versatile type for industrial binders.

Wide Industrial Applications of Dextrin

1. Adhesives & Binders
- Re‑moistening adhesives – postage stamps, gummed tape, wallpaper, paper bags.
- Foundry cores – binding sand for metal casting molds.
- Briquettes & cement plaster – as a binder for coal briquettes and gypsum plasters.

2. Paper Industry
- Surface sizing and coating – improves printability and surface strength.
- Paper tube and core adhesives.

3. Textile Industry
- Printing thickener for pigments and dyes.
- Fiber processing and finishing.

4. Paints & Coatings
- Water‑based paints, adhesives for wallpaper, and specialty coatings.

5. Pharmaceuticals & Food
- Microencapsulation of drugs.
- Fermentation substrate for industrial microbiology.

### 6. Other Uses
- Cement **setting retarder**.
- Flotation agents in mining.
- Sensitizers for photographic materials.
- Mixed with latex to produce modified plastics (partial PVC replacement).

Formulation Synergies

Dextrin’s performance can be enhanced with additives:
- Boric acid or caustic alkali → increases viscosity.
- Urea, thiocyanates, formalin, sodium nitrate → improves solution stability and film formation.
- Glycerol, ethylene glycol, sugar alcohols → plasticizers.

Why Choose Huimei Starch for Your Dextrin Needs?

At Guangdong Huimei Starch Technology Co., Ltd., we produce high‑quality white dextrin, yellow dextrin, and British gum from cassava and corn starch. Our advantages:
- Strict control of hydrolysis and repolymerization parameters.
- Customizable solubility (50–100%) and viscosity profiles.
- Consistent quality – produced in modern fluidized bed roasters.
- Suitable for adhesives, paper, textile, foundry, paints, and pharmaceuticals.

Contact us for technical data sheets, samples, or formulation support.

References
- Zhou Zhongkai. Modified Starch – Dextrin. Resource Utilization, Wuxi University of Light Industry (original Chinese publication).
- Additional technical literature on starch chemistry.

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