Skim Milk Whey Cryoconcentration and Impact on the Composition of the Concentrated and Ice Fractions

The present work is a continuation of our previous study on the cryoconcentration of whole milk whey. The aim of the present work was to study a cryoconcentration procedure of skim milk whey and to compare the results with those obtained using whole milk whey. In the present study, skim whey was cryoconcentrated at four stages. It was found that by increasing the cryoconcentration stage, total dry matter content of the concentrated fraction increased, while it decreased in the ice fraction only until the third stage. Total dry matter content in the concentrated fraction reached an average value of 35% (w/v) at the fourth stage. The ratio of total protein to total dry matter remained constant in both fractions independently of the cryoconcentration stage. Results showed that the fat matter is an important factor for protein and lactose distribution between the concentrated and the ice fractions. Mathematical equations were developed to help the optimization of the process. Results showed that three cryoconcentration stages are optimal.