Controlling heat induced aggregation of whey proteins by casein inclusion in concentrated protein dispersions

Isolation and characterisation of κ-casein/whey protein particles from heated milk protein concentrate and role of κ-casein in whey protein aggregation

“…The size of the aggregates decreased with the concentration of caseins. Thus, the ratio of whey proteins to caseins positively affected the size of the aggregates, as observed in previous studies (Guyomarc 'h et al, 2009;Liyanaarachchi et al, 2015). The chaperone activity of caseins has been reported to reduce whey protein aggregation (Kehoe & Foegeding, 2010;Mounsey & O'Kennedy, 2010); the chaperone activity of a biomolecule refers to its ability to protect another biomolecule against unfolding, aggregation and precipitation.…”

“…In the serum phase of skim milk heated at 90°C for 10 min (pH 6.7), the ratio of whey protein to κ-casein in the aggregates is in the range 1:0.2 to 1:0.7 (Donato & Dalgleish, 2006). The whey protein and casein aggregates appear to be roughly spherical with a size ranging from 50 to 70 nm, which increases with the whey protein content of the solution (Beaulieu, Pouliot, & Pouliot, 1999;Liyanaarachchi, Ramchandran, & Vasiljevic, 2015). The molecular weight of the aggregates was estimated to be 2×10 7 Da, the apparent isoelectric point of the aggregates was 4.5 in milk permeate, and the surface charge at pH 7.0 was 17 mV (Jean, Renan, Famelart, & Guyomarc'h, 2006).…”

Coaggregation of κ‐Casein and β‐Lactoglobulin Produces Morphologically Distinct Amyloid Fibrils

“…Our results provide compelling experimental evidence that not only do β‐Lg and κ‐CN individually form amyloid fibrils, but that UHT milk gelation could also arise from the coaggregation of β‐Lg and κ‐CN since they can form heteropolymeric amyloid fibrils under high temperature heating. During UHT of milk, the whey proteins (in particular, the major protein β‐Lg) start to unfold and potentially form amyloid structures, whereby the chaperone activity of κ‐CN is activated causing the two proteins to interact . As κ‐CN is located on the surface of the casein micelle, it is the casein that is in the closest proximity to β‐Lg.…”

Conformational changes of β-lactoglobulin induced by shear, heat, and pH—Effects on antigenicity

“…Each prepared sample of β-LG was subjected to different shear rates (100, 500, or 1,000 s −1 ) and temperatures (80, 100, or 120°C) in a pressure cell (CC25/PR-150) of a rheometer (Physica MCR 301 series; Anton Paar GmbH, Ostfildern-Scharnhausen, Germany) with constant pressure of 250 kPa following the method of Liyanaarachchi et al (2015). Samples at control pH (7.6) not subjected to shear were the controls under each condition of sample preparation.…”