Some physico-chemical properties of foam-mat salt
Modification of crystal size and form of salt can be achieved by various methods such as freeze drying, vacuum drying, grinding (Kilcast & Den Ridder, 2007), and nano spray drying (Moncada et al., 2015). In this present study, foam-mat drying was chosen to prepare another form of salt. Some basic physico-chemical properties of foam-mat salt compared with regular salt are shown in Table 1. The foam-mat salt had a slightly higher moisture content than commercial salt (0.079% vs. 0.022%) but both had similar water activities (0.657–0.666). The foam-mat salt was whiter than the commercial salt (L*, 94.60 vs. 87.52; whiteness index, 94.33 vs. 87.51). The bulk density of the commercial salt was about two times higher than that of the foam-mat salt (1.29 vs. 0.65 g mL−1). From the scanning electron microscope image, the crystal of foam-mat salt had somewhat irregular shape with flake-type particles. The foam-mat salt had smaller particle size with a range of 34.94–265.07 μm compared to 170.78–529.55 μm (data not shown in Table 1) for the commercial salt.
Table 1. Some physico-chemical properties of commercial salt and foam-mat salt