Inhibition of Streptococcus mutans binding to hydroxylapatite using partially digested whey protein concentrate and individual whey proteins

The effect of a bovine whey protein concentrate partially digested with lipase to release free fatty acids (WPD) on growth and viability of Streptococcus mutans, and its adherence to hydroxylapatite (HA) in phosphate-buffered saline were examined. The effects of other whey mixtures and individual whey proteins, β-lactoglobulin (BLG), lactoferrin (LF), caseinoglycomacropeptide (CGMP) and α-lactalbumin were also investigated. Bacterial viability was assessed by incubation with whey protein and measuring colony-forming units. S. mutans binding was quantified using Syto-13 nucleic-acid binding dye and Alamar Blue, which measures cellular metabolic activity. WPD was bactericidal, and inhibited S. mutans growth and adhesion to HA. Other wheys inhibited S. mutans adhesion, particularly acid whey, as well as the parent compound for WPD, Carbelac 80, and a whey protein isolate. BLG, CGMP and LF inhibited S. mutans adhesion. A mixture containing 56% BLG and 20% CGMP was as effective an inhibitor of bacterial adhesion as WPD.