EFFECTS OF FREEZING AND THAWING METHODS AND STORAGE TIME ON THERMAL-PROPERTIES OF FRESH-WATER PRAWNS (MACROBRACHIUM-ROSENBERGII)

Thermal stability of proteins in frozen and thawed freshwater prawns w as measured by differential scanning calorimetry. The onset and peak m elting temperatures corresponding to myosin denaturation, as well as t otal enthalpy of denaturation of prawn muscle, decreased after freezin g-thawing treatments. There were no significant differences in the the rmal properties of prawns with changes in the rate of freezing, ie bla st (fast) vs still (slow) freezing. However, the thermal properties we re influenced by the rate of thawing. Rapid thawing using a combinatio n of microwave and tap water resulted in a lower (P less than or equal to 0.05) thermal stability of prawn proteins compared to slow (refrig eration) or moderately fast (tap water) thawing methods. Keeping prawn shells intact or not intact during freezing-thawing did not alter the thermal properties of the prawn proteins.