Comparison of Column and Centrifugal Sephadex Methods for Fractionating Whey and Skimmilk Systems

Abstract

Normal and concentrated whey and skimmilk systems were fractionated into a colloid and a low molecular weight fraction by column and centrifugal procedures using Sephadex G-25 and G-50 Sephadex, and the resulting fractions were analyzed to determine the fractionation efficiency of the process and the composition of the resulting colloid fraction.Sephadex G-50 columns were more effective than Sephadex G-25 columns for removing lactose and mineral constituents from the concentrated skimmilk colloid fraction. The fractionation efficiency of the centrifugal Sephadex method (Sephadex G-25) was intermediate to that of Sephadex G-25 and G-50 columns. Approximately 90–92% of the total proteins of concentrated whey was recovered in the colloid fraction from the Sephadex G-25 column process compared to ∼ 90–95% recovery from concentrated skimmilk. The colloid fractions obtained from concentrated whey and skimmilk samples by the Sephadex G-25 column process exhibited ∼ a six-fold and a two-fold enrichment of the protein content, respectively. Fractionation results were somewhat similar for the Sephadex G-25 centrifugal and column methods; however, the centrifugal method permits larger sample volumes with less dilution of the colloid fraction than does the column method.