In order to characterise the effect of osmotic treatment, physicochemical characteristics (water mass fraction, soluble solid mass fraction and soluble solids in the liquid phase) were analysed. Moisture content was determined by drying to constant weight at 60 C in a vacuum oven at 10 kPa for 72 h (adaptation of method 934.06 AOAC, 2000). Soluble solids were measured in samples, previously homogenised, with a refractometer (Zeiss, ATAGO model NAR-3T, Japan). The calcium concentration of samples was analysed in fresh and processed samples using the atomic absorption spectrometric AOAC method 975.03 (AOAC, 2000). Samples (1.5 g)
were ashed (500 C, 14 h) and dissolved in HNO3 (65%) before analysis
in a Perkin Elmer 3110 atomic absorption spectrometer, under
the following conditions: k = 422.7 nm and air acetylene flame.