Coagulation properties of ultrafiltered milk retentates measured using rheology and diffusing wave spectroscopy

Gelation properties of casein micelles during combined renneting and bacterial fermentation: Effect of concentration by ultrafiltration

“…The decrease may be due to changes in the environmental conditions (serum viscosity) and to the increased electrostatic and steric interactions, due to the close proximity of the particles. These results are in full agreement with other data on milk concentrated by UF (Sandra, Cooper, Alexander, & Corredig, 2011). The stages preceding the aggregation of the casein micelles were observed by DWS immediately after culture and rennet addition, as shown in Fig.…”

“…The pH at maximum and the corresponding G 0 were significantly different amongst treatments (p < 0.05, Table 2). Up to these pH values, the increased curd-firming rate with concentration was consistent with previous reports on stiffer gels made with UF concentrated milk during renneting, because of the higher number of bonds/bridges between the renneted particles (Karlsson et al, 2007;Sandra et al, 2011;Waungana et al, 1998). At this point, a progressive demineralization of the casein micelles and a clear weakening of the network occurred (Fig.…”

“…In this study, there were no differences between the treatments up to the point of rennetinduced coagulation, as measured by CMP release, DWS and also rheology (see below). This is also consistent with other data on renneting of UF milk at neutral pH (Sandra et al, 2011;Waungana et al, 1998). It is important to point out that the differences found in the literature on the gelation time of single strength and UF milk can be attributed to variations in the experimental procedures and samples processing history.…”

“…At this point, the error for 1/l* rapidly increased because of gel formation. This behaviour, typical of rennet-induced aggregation of casein micelles has been previously described in great detail for unconcentrated as well as milk concentrated by UF (Sandra, Alexander, & Dalgleish, 2007;Sandra et al, 2011). Similarly, Fig.…”

Rennet coagulation of sheep milk processed by ultrafiltration at low concentration factors

“…However, during the UF milk concentration process the micelle size decreases and possibly there is rearrangement via hydrophobic bonds to a more compact structure. That may lead to physicochemical changes during the renneting, resulting in an increase in curd firmness (Erdem, 2005;Sandra et al, 2011).…”