Desalting and water restoration of salted jellyfish Rhizostomeae during immersion in water

The physical properties of salted jellyfish were studied by X-ray fluorescence (XRF), energy dispersive X-ray analysis (EDX), and thermogravimetric analysis (TGA). The jellyfish were cut into two parts (Middle and Edge) and immersed in water for up to 9 days. XRF and EDX analysis results indicated that NaCl was removed from the salted jellyfish on immersion, and that no further NaCl was lost after 3 h. Water contents of unheated and heated (60 degrees C), Middle and Edge parts after immersion were analyzed by TGA. For each sample, water content increased to an equilibrium level. For both unheated samples, water restoration took about 1 h, so the desalting and water restoring times were different. This implied that the mechanism of rehydration involved both displacement of NaCl by H2O and also swelling. Although the heated samples did shrink, the equilibrium water contents (after water restoration) were very similar to the unheated samples. This indicated that the water retaining structure of the salted jellyfish was not damaged under those conditions (60 degrees C for 15 min).