Statistical analysis of the swelling process of casein microparticles based on single particle measurements

Khanna

Schulte

et al. 2022

IJMS

Self Cite

Casein microparticles are produced by flocculation of casein micelles due to volume exclusion of pectin and subsequent stabilization by film drying. Transglutaminase post-treatment alters their stability, swelling behavior, and internal structure. Untreated particles sediment due to their size and disintegrate completely after the addition of sodium dodecyl sulfate. The fact that transglutaminase-treated microparticles only sediment at comparable rates under these conditions shows that their structural integrity is not lost due to the detergent. Transglutaminase-treated particles reach an equilibrium final size after swelling instead of decomposing completely. By choosing long treatment times, swelling can also be completely suppressed as experiments at pH 11 show. In addition, deswelling effects also occur within the swelling curves, which enhance with increasing transglutaminase treatment time and are ascribed to the elastic network of cross-linked caseins. We propose a structural model for transglutaminase-treated microparticles consisting of a core of uncross-linked and a shell of cross-linked caseins. A dynamic model describes all swelling curves by considering both casein fractions in parallel. The characteristic correlation length of the internal structure of swollen casein microparticles is pH-independent and decreases with increasing transglutaminase treatment time, as observed also for the equilibrium swelling value of uncross-linked caseins.

Section: Resultsmentioning

confidence: 77%

Effect of Transglutaminase Post-Treatment on the Stability and Swelling Behavior of Casein Micro-Particles

Khanna

Schulte

et al. 2022

IJMS

Self Cite

“…The influence of citrate on the typical two-stage swelling behavior of the CMPs can be simulated with a dynamic model whose basic structure has already been described 25 . Volumes are first calculated from the determined cross-sectional areas for the simulation, assuming the spherical approximation that is satisfied for the swelling process 38 . Within the model, the volume changes by two inflows and two outflows respectively, which are controlled by valves.…”

Section: Methodsmentioning

confidence: 99%

“…For stability analysis, the turbidity of CMPs solution was monitored using a Lambda 365 UV/VIS spectrometer (PerkinElmer, USA) according to the method described by Schulte 38 with slight modification. Briefly, 1.5 mL CMPs dispersion was added to a semi-micro cuvette (Eppendorf AG, Germany) and BisTris buffer was used as reference.…”

Section: Methodsmentioning

confidence: 99%

“…It is important to know the characteristic properties and stability of the produced microparticles before functionalization to protect and use the encapsulated material effectively. The microparticle produced under depletion flocculation has a highly porous inner structure that expands during swelling 38 . The concentration of CaCl 2 in the running solution also has a significant effect on the swelling behavior of the microparticles.…”

Section: Introductionmentioning

confidence: 99%

“…The resulting neutralization of the charges allows stronger hydrophobic contacts between the caseins, which strengthens the internal particle structure 39 . The results of stability experiments with sodium dodecyl sulfate (SDS) indicate that hydrophobic interactions are essential for maintaining the overall structure, because CMPs decompose completely upon addition of the detergent 38 .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Citrate effect on the swelling behaviour and stability of casein microparticles

Asaduzzaman

Pütz

2022

Sci Rep

Self Cite

Casein microparticles obtained from casein micelles by volume exclusion of added pectin and subsequent film drying remain stable in the acidic and neutral pH range, but swell strongly in the basic range. Calcium significantly impacts on the stability and water-binding behavior of phosphorylated caseins and the aggregates and gels formed from them. For a future effective and controlled use as a carrier for bioactive substances, e.g. via the gastrointestinal tract, we therefore investigated how the addition of the calcium chelating agent citrate affects the swelling and stability of the microparticles. Citrate concentrations of 2 mM and above cause a stronger swelling of the microparticles at pH 8, while above 4 mM the second characteristic swelling step starts earlier and thus can also be investigated within the observation time of 120 min. All swelling kinetics can be simulated using seven parameters of a dynamic model, which reproduces the individual swelling steps via volume inflows and outflows into a reservoir. While the rate coefficient for swelling step 1 increases linearly with citrate concentration, no such dependence could be found for swelling step 2. The more citrate is used, the faster the microparticles decompose in turbidity experiments after the addition of sodium dodecyl sulfate, which can be related to a weakening of the hydrophobic interactions.

Soft Matter Engineering for the Fabrication of Functionalized Casein Microparticles

Asaduzzaman

Schulte

Chemie Ingenieur Technik

2023

Self Cite

Dedicated to Prof. Dr.-Ing. Joachim Werther on the occasion of his 80th birthdayThe structural features of the most abundant milk protein casein can be exploited for the targeted production of microparticles with desired properties. After the addition of pectin, the so-called casein micelles reversibly form aggregates of several mm in size, which change their shape due to shear and elongation forces. The soft properties are crucial for the subsequent solidification into stable casein microparticles during film drying. Based on pH-dependent experiments, we show how we analyze and tailor the swelling and disintegration properties of the microparticles for future controlled and instant release applications.