Location: Warmwater Aquaculture Research UnitTitle: Influence of Whey Peptides on the Surface Activity of k-casein and ß-lactoglobulin Author
Submitted to: International Journal of Dairy Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/18/2009
Publication Date: 5/1/2010
Citation: Haque, Z.U., Williams, J.B., Mikel, W.B. 2010. Influence of Whey Peptides on the Surface Activity of k-casein and ß-lactoglobulin. International Journal of Dairy Technology. 63(2)190-196. Interpretive Summary: Different hydrolytic levels and blends of whey hydrolyzates (WPH) are used in a spectrum of food industry applications where the primary physicochemical function of WPH is that of an emulsifier in oil-water emulsion systems. Hence, the stability of all these systems is dependent on the amphipathicity, and consequent surface activity (SA), of the WPH. We have recently reported enhanced emulsifying activity (EA) and thermostability of whey-based antioxidative and antimicrobial edible film forming preparations as a consequence of milk peptide addition. Here, we used a model oil-water interface to understand how peptides affect SA of key functional proteins in whey; the sequence of addition and pre-mixing were critical. Pre-mixing of the hydrolyzate and proteins significantly improved EA regardless to the peptide surface hydrophobicity, whereas the fractionated peptides by themselves were detrimental.
Technical Abstract: Whey protein hydrolysate (WPH) was fractionated by reverse-phase chromatography to obtain fractions of varying surface-hydrophobicities. A model oil–water interface (MI) was pre-coated with the WPH or fractions thereof. Contact angle (') of sessile drops of '-casein ('-CN) or ß-lactoglobulin A (ß-LGA) were measured on the MI. Pre-coating of MI with un-fractionated WPH decreased ', that is, increased surface activity, of both '-CN (35–8.3°) and ß-LGA (38–21.3°). Conversely, pre-coating of MI with the fractions significantly increased ' of both proteins as a function of hydrophobicity. Data provide insight into variability of whey protein functionality in food applications.