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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 31: Biomaterials and Biopolymers (joint session BP/CPP)
CPP 31.2: Vortrag
Montag, 16. März 2020, 15:15–15:30, ZEU 250
Dynamics during thermal gelation of egg-white studied using X-ray photon correlation spectroscopy — •Nafisa Begam1, Anita Girelli1, Anastasia Ragulskaya1, Hendrik Rahmann2, Fabian Westermeier3, Christian Gutt2, Fajun Zhang1, and Frank Schreiber1 — 1Universität Tübingen, Germany — 2Universität Siegen, Germany — 3DESY, Germany
Gelation of proteins is a fundamental topic in food industry as well as in condensed matter physics [1]. We report a systematic time dependent study of the dynamics of hen egg-white during its gelation at 80∘C using X-ray photon correlation spectroscopy in the ultra-small angle X-ray scattering mode. Two distinct regimes of dynamics are identified. The initial growth of the aggregates, as expected for heat-induced coagulation of egg-proteins, results in an early stage non-equilibrium dynamics. Interestingly, at the later stage (after ∼ 30 min of heating), the system reaches an equilibrium dynamical state with an average characteristic time scale of few tens of seconds. The intermediate scattering function changes from an exponential to a compressed exponential decay, indicating gel formation. The aggregates eventually show correlated temporally heterogenous dynamics. Such dynamical fluctuations are further quantified in terms of a fourth order intensity correlation function. The monotonic increase in heterogeneity as a function of wave vector transfer observed here is similar to the behavior of strongly attractive colloidal gels [2].
[1] Croguennec et al., J. Food. Sci., 67, 2, (2002)
[2] Fluerasu et al., Phys. Rev. E, 76, 010401(R), (2007)