Fish Silage Preservation

Fish Silage Preservation

By-products from farmed species and wild fish are raw materials for fish silage production. Borregaard LignoTech has developed a combination of formic acid and lignosulphonic acid, which controls the pH and reduces corrosion.

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


  • SoftAcid Aqua M / SoftAcid Aqua MA+


  • Increased antioxidant effect
  • Stable fish silage/refined products
  • Reduced corrosion 

Degradation of propyl gallate with and without lignosulphonic acid (LS) in Formic acid:

Improved antioxidant effect with SoftAcid Aqua MA+

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 lignosulphonic acid shows a stabilizing effect upon propyl gallate, ref. Borregaard`s patented technology: ”Sacrificial agent”, EP2209388B1

Significantly less corrosion with SoftAcid on carbon steel:

Significantly less corrosion with SoftAcid on carbon steel

The photos above show nuts which has been one week in different solutions: 80% Formic acid (2), SoftAcid Aqua MA+ (3) and water (4). The reference to the left (1) shows how the nut looks like before exposure/treatment.