Residual sulphur dioxide (SO₂) is one of the most important parameters on a tapioca starch specification, because it is what usually distinguishes a food grade from an industrial grade. If you’re sourcing starch, knowing which SO₂ level your application needs avoids both over-paying and non-compliance.
Why SO₂ is present
Small amounts of sulphur dioxide are used during starch processing to control microbial growth and protect whiteness while the starch is wet. The finished starch retains a residual level, measured in parts per million (ppm). Lower residuals are required for sensitive food uses; higher residuals are acceptable for industrial uses where the starch never enters food.
The three grades
TQ Industry Starch supplies native tapioca starch in three SO₂ grades:
- ≤10 ppm — food grade. The lowest residual, for food applications with the strictest limits and for buyers who want maximum headroom under their market’s regulations.
- ≤30 ppm — food grade. A standard food grade suitable for most food manufacturing.
- ≤100 ppm — industrial grade. For paper, textile, adhesive, and other non-food uses where a higher residual is acceptable.
How to specify the right grade
- Confirm your market’s regulatory limit. Maximum permitted SO₂ in food varies by country and by food category — specify a grade comfortably below your limit.
- Match the grade to the end use. Don’t pay for ≤10 ppm if your industrial process accepts ≤100 ppm; equally, never use an industrial grade in food.
- Ask for the full specification. SO₂ is one parameter among several. Moisture, starch content, whiteness, pH, viscosity, ash, and fineness are all controlled — our guaranteed limits are published on the native tapioca starch product page, and every lot ships with a Certificate of Analysis. New to spec sheets? See how to read a tapioca starch specification.
See the food applications and industrial applications pages for where each grade is typically used.
We manufacture all three grades at our factory in Sa Kaeo, Thailand — see how ordering works as a manufacturer-direct buyer. To get the right grade for your process, tell us your application and destination and we’ll confirm the grade and send a sample on request.