17E-9 |
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J.-Y. Imm and K.-H. NOH. Food and Nutrition, Kookmin University, 861-1, Chongnung-dong, Songbuk-gu, Seoul, 136-702, South Korea Lactoferrin (LF) is an iron-binding protein present in mammalian milk and its antimicrobial activity is of special interest. Generally, chromatographic methods have been used for the separation of LF from mammalian milk but they are time consuming and not well suited for scale up. Based on the principles of reversed micellar (RM) extraction, selective transfer of solubilized proteins from water pool to the organic phase can be achieved by manipulation of some physical parameters. Our objective was to suggest an optimum RM extraction procedure for the separation of LF from LF fortified whey protein isolate (WPI) solution. WPI containing 20% LF were solubilized in the buffers of various pH and the protein solutions (0.1%, w/v) were mixed with the same volume of organic solvent (hexanol/isooctane) containing cationic surfactant, cetyldimethylethyl ammonium bromide (CDAB). After stirring of certain period of time, the aqueous phases were collected by centrifugation. The concentration and profiles of proteins remained in the aqueous phases were examined by SDS-PAGE and densitometry. The effects of surfactant concentration, pH, ionic strength and reaction times on the separation of LF were demonstrated. To verify biological activity of Lf, bacteriostatic activity of recovered LF was tested using E. coli ATCC 25922. LF was successfully separated from WPI solution using RM system. The best separation was done by aqueous pH of 9 containing 50 mM KCl. The separation efficiency was not critically changed more than 100 mM CDAB and reaction time of 10 min. At optimal separation condition, more than 95% of Lf was recovered. The recovered LF fully maintained bacterostatic activity. The separation of LF using RM extraction was simple, highly efficient and easy to scale up. Although this study was performed in a model system, similar extraction procedure can be applied for the separation of Lf from colostrum.
Session 17E, Food Chemistry: Proteins
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