Raw Material Formula: Potato Starch.
Production Process: Starch → Starch Slurry → Gelatinization → Drying → Pulverizing → Packaging
Key Operational Points: The production of this starch can be achieved using the following three methods:
Drum Drying Method
This method comprises two variations: the double-drum type and the single-drum type. In the double-drum dryer, the two drums rotate in opposite directions. Starch slurry is fed into the gap between the two drums, which are heated to approximately 150°C; the slurry gelatinizes instantly and dries on the drum surfaces to form a thin film. This film is then scraped off using a scraper blade and pulverized to yield the final product. The quality of the product depends on the degree of gelatinization achieved. By adjusting parameters such as the starch slurry concentration, drum temperature, and rotational speed, it is possible to control product properties such as shear resistance, retrogradation during drying, and viscosity. The single-drum method involves directly conveying the starch slurry onto the surface of a drum heated to approximately 150°C to induce gelatinization. However, the single-drum system suffers from lower thermal efficiency and limited production capacity.
The drum drying method is characterized by continuous production, simple operation, low energy consumption, stable product quality, and broad applicability. However, this processing method causes the starch granules to expand rapidly-reaching several hundred times their original volume-while simultaneously subjecting them to intense shear forces that cause the granules to rupture. Consequently, the resulting product suffers from significant defects, including a narrow peak viscosity range, structural non-integrity (fragmented granules), and an inability to withstand the shear forces, as well as acidic or alkaline conditions, encountered during application. Furthermore, the product exhibits poor elasticity and flowability. Under this method, the starch slurry typically achieves a gelatinization rate of only about 80%.
Spray Drying Method
In this method, a continuous jet cooker is utilized to mix starch slurry with high-pressure steam, thereby inducing gelatinization. The gelatinized slurry is then rapidly dried via atomization (spraying) to produce pre-gelatinized starch.
A key feature of the spray drying method is that it eliminates the need for a separate pulverizing step, yielding a finished product consisting of hollow, spherical granules directly. However, the viscosity of the starch slurry increases dramatically following gelatinization, which renders the subsequent spraying process complex and technically challenging. Additionally, this method typically requires the use of low-concentration starch slurries; consequently, a large volume of water must be removed during drying, resulting in high exhaust gas temperatures, substantial energy consumption, and elevated production costs.
Extrusion Method
This method involves the use of a screw extruder (expansion machine) to produce pre-gelatinized starch, based on the principles of extrusion and expansion processing. Pre-mixed wet starch, with a moisture content of 15–20%, is fed into an extrusion puffing machine. Inside the machine, friction and compression generated by a screw shaft cause the starch to heat up and gelatinize. The material is then extruded under high pressure through small orifices ranging from 1 to 10 millimeters in diameter; upon entering the atmosphere, it undergoes instantaneous expansion and drying. Following subsequent pulverization and screening, pre-gelatinized starch is obtained. Due to the application of high-intensity shear forces during this process, the product's viscosity is reduced, and its solubility is significantly higher than that of products produced via the drum-drying method. Furthermore, since the manufacturing process requires virtually no additional water-relying instead on internal frictional heat to maintain a temperature of 120–160°C-no external heat source is required for drying.
This process is characterized by low equipment investment and minimal power consumption; however, the resulting pre-gelatinized starch-having been subjected to high-intensity shear forces-exhibits low viscosity and possesses almost no elasticity.
