Bioseparation 9: 385–392, 2001. © 2001 Kluwer Academic Publishers. Printed in the Netherlands. 385 Fractionation of whey proteins with a hexapeptide ligand affinity resin Patrick V. Gurgel 1 , Ruben G. Carbonell 2 & Harold E. Swaisgood 1∗ 1 Department of Food Science, Box 7624, North Carolina State University, Raleigh, NC, 27695-7624, USA 2 Department of Chemical Engineering, Box 7905, North Carolina State University, Raleigh, NC, 27695-7905, USA ∗ Corresponding author Received 14 November 2000. Accepted in revised form 26 February 2001 Key words: α-lactalbumin, bioselective adsorption, peptide ligands, whey protein isolate Abstract The isolation of individual proteins from whey would allow production of more consistent and reliable products by the food industry and possibly would also increase their use in the pharmaceutical industry. α-Lactalbumin is the second most prevalent protein in bovine milk whey and has many uses including serving as an excellent protein source in infant formulas, power drinks and other beverages that require soluble, nutritional protein. In this study, we describe two methods for production of α-lactalbumin from whey protein isolate using bioselective adsorption. The use of a peptide ligand (WHWRKR) attached to a resin allowed production of an α-lactalbumin-rich fraction with a purity of 90.6% and a recovery of 47.9%, while also producing other fractions of commercial interest. The combined use of an amino resin followed by the WHWRKR resin produce a highly purified α-lactalbumin (100%) with a yield of 35.2%. Introduction During the past 10 – 15 years, whey has evolved from waste product to a value-added ingredient for the food industry. Its potential as nutritional protein source has been recognized and its functional proper- ties have become more utilized. It has been proposed that the use of individual whey proteins could be more valuable than their use as a mixture (Huffman and Harper, 1999). The fractionation of whey and isolation of individual proteins would lead to better- controlled products, with fewer variations in composi- tion. Another advantage would be the use of individual proteins with unique or desirable characteristics in specialized products. The most prevalent whey proteins are β -lactoglobu- lin, α-lactalbumin, bovine serum albumin (BSA), ∗ Paper No. FSR 00-23 of the Journal Series of the Depart- ment of Food Science, North Carolina State University, Raleigh, NC 27695-7624. The use of trade names in this publication does not imply endorsement by the North Carolina Agricultural Re- search Service of products named, nor criticism of similar ones not mentioned. immunoglobulins, lactoferrin and lactoperoxidase. β - Lactoglobulin is a good source of essential amino acids, with good gelling properties and potential use in power drinks due to its solubility, BSA and im- munoglobulins have been reported to have anticancer properties and to enhance immunity, lactoferrin is used as an antibacterial agent in infant formulas and lactoperoxidase has demonstrated anticarial activity in toothpaste (Horton, 1996). α-Lactalbumin is the preferred protein source for infant formulas due to its high nutritional value, high digestibility, and lower potential for causing aller- gies, when compared to β -lactoglobulin (Heine et al., 1996). Alternative uses of α-lactalbumin may include its use as a morphinomimetic and antitumor agent (Muller et al., 1999), as well as a contraceptive agent (Maubois and Olivier, 1997). Several methods for whey fractionation have been proposed, including membrane filtration (Zydney, 1998), ion-exchange chromatography (Gerberding and Byers, 1998, Girardet et al.; 1989, Hahn et al., 1998) and thermal (Hill, 1988; Bramaud et al., 1995)