Fish Silage Preservation

SoftAcid® is a highly efficient acidifier for fish silage production. It preserves the fish by-products from oxidation and reduces corrosion.

By-products from both farmed species and wild fish are used as raw materials for fish silage preservation. For this application we have developed a combination of formic acid and lignosulfonic acid, which controls the pH and reduces corrosion.

The lignosulfonic acid in SoftAcid acts as an antioxidant, which provides extra protection against degradation of the fish silage. Hence, SoftAcid improves the quality of the fish silage by preserving the fish by-products from oxidation.


  • Increased antioxidant effect 
  • Stable fish silage/refined products 
  • Reduced corrosion 
  • Safer and easier to handle than pure acids 
  • More sustainable than pure acids

Degradation of propyl gallate with and without lignosulfonic acid (LS) in formic acid. (Results from Borregaard's laboratory)

The results are measured as remaining amount of propyl gallate (PG). The amount of PG was measured during a period of 75 days. In the figure above percent remaining PG is compared with the amount of PG the day the samples were made (day 0). The lignosulfonic acid shows a stabilizing effect upon propyl gallate, ref. Borregaard`s patented technology: ”Sacrificial agent”, EP2209388B1

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