On the Measurement of Sulfate and Viscosity of Carrageenan

Abstract

In order to establish standards and requirements of the natural thickening agent “carrageenan”, sulfate and viscosity tests were studied, to be included in the General Tests of the Japanese Standards of Food Additives, at the same time. Sulfate was determined by the well-known barium sulfate gravimetric method. Sulfate contents of commercial carrageenans, expressed as SO₄, were found to be within the range of 20-40%. Viscosities were measured on 1.5% of carrageenan solution at 75°C by use of either BN type rotation viscosimeter (Wells-Brookfield micro viscosimeter) or Ubbelohde viscosimeter. Standard viscosity solution JS-200 was used for the scale adjustment of rotation viscosimeter. The values obtained by use of the two viscosimeters were found to be in good accordance, the viscosities of commercial carrageenans tested were found to be above 5cps, in accordance with the regulation of FDA.