Abstract

The ability of alphas1/beta-casein and micellar casein to protect whey proteins from heat-induced aggregation/precipitation reactions and therefore control their functional behavior was examined. Complete suppression (>99%) of heat-induced aggregation of 0.5% (w/w) whey protein isolate (pH 6.0, 85 degrees C, 10 min) was achieved at a ratio of 1:0.1 (w/w) of whey protein isolate (WPI) to alphas1/beta-casein, giving an effective molar ratio of 1:0.15, at 50% whey protein denaturation. However, in the presence of 100 mM NaCl, heating of the WPI/alphas1/beta-casein dispersions to 85 degrees C for 10 min resulted in precipitation between pH 6 and 5.35. WPI heated with micellar casein in simulated milk ultrafiltrate was stable to precipitation at pH>5.4. Protein particle size and turbidity significantly (P<or=0.05) increased from an initial diameter of 165.5 nm in the unheated mixture to 272 nm following heating at 85 degrees C for 10 min at pH 6. Whey protein denaturation was significantly (P<or=0.05) promoted when heated in the presence of micellar casein, but whey protein aggregation was controlled down to pH 5.4. The protective behavior of alphas1/beta-casein and micellar casein differed in that the former inhibited denatured whey protein aggregation, whereas the latter system promoted denaturation but controlled aggregation.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call