Physical properties of sodium alginate solutions and edible wet calcium alginate coatings

- Sodium alginate viscosity provided information about the wet film strength.
- A simple method allowed the determination of the alginate gelation time.
- Colour, moisture, aw and permeance of the different wet films were similar.
- Alginate films could substitute natural casings in fermented sausages.

Calcium alginate structures are of interest to the meat industry as replacers for natural casings. This paper focuses on the study of the physical properties of sodium alginate solutions and wet calcium alginate films at 12 °C for their assessment as fermented sausage coatings. Six different commercial sodium alginates were dissolved at different concentrations (0.02, 0.03 and 0.04 kg/kg solution). The viscosity of the sodium alginate solution provided information about the maximum force and tensile strength of the calcium alginate films, depending on the alginate type and concentration of the solution. The required time for the conversion of sodium alginate solution to calcium alginate gel was higher at a higher alginate concentration, and the method used for its determination was appropriate and simple. No significant differences in colour, moisture, water activity and permeance of the wet films made from the different sodium alginate types were found. The results of the mechanical properties and permeance indicate that alginate coatings could be appropriate as a substitute for natural casings.