Effect of acidification of whey protein-free precheese retentate on viscosity increase at different concentrations

Power ultrasound as a tool to improve the processability of protein-enriched fermented milk gels for Greek yogurt manufacture

“…In the range from 3.5 to 12.0% (wt/wt) protein, apparent viscosity increased disproportionately from 4.2 to 76.7 mPa•s, and data could be fitted by a power function (R 2 > 0.99). This behavior was reported in previous studies with microfiltered and ultrafiltered milk concentrates (Solanki and Rizvi, 2001;Aaltonen, 2012). According to de Kruif (1998), at low to medium concentrations, casein micelles act as hard spheres and viscosity increases moderately with casein content.…”

High concentration of skim milk proteins by ultrafiltration: Characterisation of a dynamic membrane system with a rotating membrane in comparison with a spiral wound membrane

“…It can be seen that there was a strong rise in viscosity with increasing protein concentration. A similar behaviour has already been reported in literature for casein suspensions (Aaltonen, 2012;Bouchoux et al, 2009;Dahbi, Alexander, Trappe, Dhont, & Schurtenberger, 2010;Jin et al, 2014;Solanki & Rizvi, 2001). At low to moderate concentrations the casein micelles behave as hard spheres and the viscosity increases with increasing micelle concentration (De Kruif, 1998).…”

“…However, SWM are not capable of processing highly viscous fluids owing to the generation of high pressure drops within the module at high retentate viscosities (Akoum, Jaffrin, & Ding, 2005;Lipnizki, Casani, & Jonsson, 2005). As the enrichment of total milk protein is accompanied by a strong rise in viscosity (Aaltonen, 2012;Solanki & Rizvi, 2001) the employment of SWMs for this purpose is limited. An alternative to conventional systems is the application of dynamic filtration devices.…”

Characterisation of fractionated skim milk with small-angle X-ray scattering

“…Solanki and Rizvi (2001) also found that the main contributor to viscosity was casein, and that retentate viscosity was reduced by treatments that decreased the stability of the casein (addition of NaCl or citrate, reduction of pH) and consequently altered the structural conformation of the casein micelles. Aaltonen (2012) showed that the viscosity of MF retentate increased with concentration and that acidification before microfiltration decreased the viscosity of the retentate, with this decrease being more pronounced with increased concentration. Protein preparations at casein concentrations above 7.5% display shear-thinning behaviour, and this was more pronounced as concentration increases (Sauer, Doehner, and Moraru, 2012).…”