On the kinetics of acid sodium caseinate gelation using particle tracking to probe the microrheology

Properties of emulsions stabilised by sodium caseinate–chitosan complexes

“…7C). Such behaviour has been probed previously by bulk rheological testing, particle tracking microrheology, diffusing wave spectroscopy and ultrasonic spectroscopy (Chen, Dickinson, & Edwards, 1999;Liu et al, 2007;Liu, Verespej, Corredig, & Alexander, 2008;Moschakis, Murray, & Dickinson, 2010b;Ruis, Venema, & Van der Linden, 2006). The fact that there was a continuous increase in the G 0 over time suggests that structural rearrangements in the gel network structure continuously occur.…”

Evaluation and Correction for Optical Scattering Variations in Laser Speckle Rheology of Biological Fluids

“…Block 3: PSCT-MCRT for simulating g 2 (t)-MSD expression: Experimentally evaluated optical properties, LSR configuration, and sample geometry are used in the PSCT-MCRT simulation to derive an expression for g 2 (t) as a function of MSD. Block 4: Evaluating MSD and | G*(ω) |: Following the measurement of MSD using the modified expression, logarithmic slope of MSD, α(t) = ∂ log <Δr 2 (t)>/∂ log t , is calculated and replaced in the simplified GSER to evaluate the viscoelastic modulus [18]–[20], [22], [23], [25], [26], [36]–[41]. Here K B is the Boltzman constant (1.38×10 −23 ), T is temperature (degrees kelvin), a is the scattering particle size, <Δr 2 (1/ω)> corresponds to <Δr 2 (t)> , evaluated at t = 1/ω, ω = 1/t is the frequency, and Γ represents the gamma function.…”

“…By applying this generalized Stokes'-Einstein relation (GSER), in the final step of our algorithm, MSD was used to extract G*(ω) (Fig. 2, Box 4) [18]–[20], [22], [23], [25], [26], [36]–[41]. To this end logarithmic slope of MSD was calculated and replaced in the simplified GSER to evaluate the viscoelastic modulus [18]–[20], [22], [23], [25], [26], [36]–[41]:Here K B is the Boltzman constant (1.38×10 −23 ), T is temperature (degrees Kelvin), a is the scattering particle radius, <Δr 2 (1/ω)> corresponds to <Δr 2 (t)> , evaluated at t = 1/ω , ω = 1/t is the frequency, Γ represents the gamma function, and α(t) = ∂ log <Δr 2 (t)>/∂ log t| t = 1/ω is the logarithmic slope of MSD.…”

“…In LSR, the sample is illuminated with coherent laser light and the time-varying speckle intensity fluctuations are recorded using a high speed camera. Temporal speckle intensity fluctuations are exquisitely sensitive to the mean square displacement (MSD) of light scattering centers undergoing Brownian motion, and the extent of this thermal motion reflects the viscoelastic properties of the surrounding medium [17]–[26]. To quantify the rate of speckle fluctuations, the correlation coefficient between successive speckle frames is measured over time to obtain the speckle intensity temporal autocorrelation curve, g 2 (t) [27]–[30].…”

“…To quantify the rate of speckle fluctuations, the correlation coefficient between successive speckle frames is measured over time to obtain the speckle intensity temporal autocorrelation curve, g 2 (t) [27]–[30]. The MSD of light scattering centers (also denoted as <Δr 2 (t)> in equations and figures throughout this paper) can be estimated from g 2 (t) [31]–[35], and the Generalized Stokes'-Einstein Relation (GSER) is used to deduce the viscoelastic modulus, G*(ω) from the measured MSD [18]–[20], [22], [23], [25], [26], [36]–[41].…”