• Cryoconcentration;
  • gravitational thawing;
  • microwave-assisted thawing;
  • phase separation;
  • process efficiency;
  • skim milk


In the present study, skim milk was successfully cryoconcentrated up to 43.72 ± 0.69% (w/w) total dry matter after four cryoconcentration cycles. Total proteins were concentrated up to 22.49 ± 0.31% (w/w). It was found that the cryoconcentrated skim milk fraction was rich in potassium ions. The effect of the cryoconcentration cycle and thawing mode on process efficiency was studied. The obtained data showed that the cryoconcentration cycle effect was significant (P < 0.001). The thawing mode (gravitational and microwave assisted thawing) had no effect on process efficiency. However, the microwave assisted thawing mode was more efficient regarding to the time needed to obtain the desired thawed fraction. To achieve high process efficiency, three cryoconcentration cycles were sufficient since the process efficiency drastically decreased after this cycle. The concentration of the dry mater entrapped in the ice fraction was the highest at the fourth cryoconcentration cycle.